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diff --git a/doc/tdearch/index.docbook b/doc/tdearch/index.docbook deleted file mode 100644 index 3bc09158..00000000 --- a/doc/tdearch/index.docbook +++ /dev/null @@ -1,3337 +0,0 @@ -<?xml version="1.0" ?> -<!DOCTYPE book PUBLIC "-//KDE//DTD DocBook XML V4.2-Based Variant V1.1//EN" "dtd/kdex.dtd" [ - <!ENTITY % addindex "INCLUDE"> - <!ENTITY % English "INCLUDE" > <!-- change language only here --> -]> - -<book lang="&language;"> - -<bookinfo> -<title>KDE Architecture Overview</title> - -<date></date> -<releaseinfo></releaseinfo> - -<authorgroup> -<author> -<firstname>Bernd</firstname> -<surname>Gehrmann</surname> -<affiliation><address><email>bernd@kdevelop.org</email></address></affiliation> -</author> -</authorgroup> - -<copyright> -<year>2001</year> -<year>2002</year> -<holder>Bernd Gehrmann</holder> -</copyright> - -<legalnotice>&FDLNotice;</legalnotice> - -<abstract> -<para>This documentation gives an overview of the KDE Development Platform</para> -</abstract> - -<keywordset> -<keyword>KDE</keyword> -<keyword>architecture</keyword> -<keyword>development</keyword> -<keyword>programming</keyword> -</keywordset> - -</bookinfo> - -<chapter id="structure"> -<title>Library structure</title> - -<simplesect id="structure-byname"> -<title>Libraries by name</title> - -<variablelist> - -<varlistentry> -<term><ulink url="kdeapi:tdecore/index.html">tdecore</ulink></term> -<listitem><para> -The tdecore library is the basic application framework for every KDE based -program. It provides access to the configuration system, command line -handling, icon loading and manipulation, some special kinds inter-process -communication, file handling and various other utilities. -</para></listitem> -</varlistentry> - -<varlistentry> -<term><ulink url="kdeapi:tdeui/index.html">tdeui</ulink></term> -<listitem><para> -The <literal>tdeui</literal> library provides many widgets and standard -dialogs which Qt doesn't have or which have more features than their Qt -counterparts. It also includes several widgets which are subclassed -from Qt ones and are better integrated with the KDE desktop by -respecting user preferences. -</para></listitem> -</varlistentry> - -<varlistentry> -<term><ulink url="kdeapi:tdeio/index.html">tdeio</ulink></term> -<listitem><para> -The <literal>tdeio</literal> library contains facilities for asynchronous, -network transparent I/O and access to mimetype handling. It also provides the -KDE file dialog and its helper classes. -</para></listitem> -</varlistentry> - -<varlistentry> -<term><ulink url="kdeapi:kjs/index.html">kjs</ulink></term> -<listitem><para> -The <literal>kjs</literal> library provides an implementation of JavaScript. -</para></listitem> -</varlistentry> - -<varlistentry> -<term><ulink url="kdeapi:tdehtml/index.html">tdehtml</ulink></term> -<listitem><para> -The <literal>tdehtml</literal> library contains the TDEHTML part, a HTML browsing -widget, DOM API and parser, including interfaces to Java and JavaScript. -</para></listitem> -</varlistentry> - -</variablelist> - -</simplesect> - - -<simplesect id="structure-grouped"> -<title>Grouped classes</title> - -<para> -Core application skeleton - classes needed by almost every application. -</para> - -<itemizedlist> - -<listitem><formalpara> -<title><ulink url="kdeapi:tdecore/TDEApplication">TDEApplication</ulink></title> -<para> -Initializes and controls a KDE application. -</para> -</formalpara></listitem> - -<listitem><formalpara> -<title><ulink url="kdeapi:tdecore/KUniqueApplication">KUniqueApplication</ulink></title> -<para> -Makes sure only one instance of an application can run simultaneously. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdecore/TDEAboutData">TDEAboutData</ulink></title> -<para> -Holds information for the about box. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdecore/TDECmdLineArgs">TDECmdLineArgs</ulink></title> -<para> -Command line argument processing. -</para> -</formalpara></listitem> - -</itemizedlist> - -<para> -Configuration settings - access to KDE's hierarchical configuration -database, global settings and application resources. -</para> - -<itemizedlist> - -<listitem><formalpara><title><ulink url="kdeapi:tdecore/TDEConfig">TDEConfig</ulink></title> -<para> -Provides access to KDE's configuration database. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdecore/KSimpleConfig">KSimpleConfig</ulink></title> -<para> -Access to simple, non-hierarchical configuration files. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdecore/KDesktopFile">KDesktopFile</ulink></title> -<para> -Access to <literal>.desktop</literal> files. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdecore/TDEGlobalSettings">TDEGlobalSettings</ulink></title> -<para> -Convenient access to not application-specific settings. -</para> -</formalpara></listitem> - -</itemizedlist> - -<para> -File and URL handling - decoding of URLs, temporary files etc. -</para> - -<itemizedlist> - -<listitem><formalpara><title><ulink url="kdeapi:tdecore/KURL">KURL</ulink></title> -<para> -Represents and parses URLs. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdecore/KTempFile">KTempFile</ulink></title> -<para> -Creates unique files for temporary data. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdecore/KSaveFile">KSaveFile</ulink></title> -<para> -Allows to save files atomically. -</para> -</formalpara></listitem> - -</itemizedlist> - -<para> -Interprocess communication - DCOP helper classes and subprocess invocation. -</para> - -<itemizedlist> - -<listitem><formalpara><title><ulink url="kdeapi:tdecore/TDEProcess">TDEProcess</ulink></title> -<para> -Invokes and controls child processes. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdecore/KShellProcess">KShellProcess</ulink></title> -<para> -Invokes child processes via a shell. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdesu/PtyProcess">PtyProcess</ulink></title> -<para> -Communication with a child processes through a pseudo terminal. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdecore/KIPC">KIPC</ulink></title> -<para> -Simple IPC mechanism using X11 ClientMessages. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:dcop/DCOPClient">DCOPClient</ulink></title> -<para> -DCOP messaging. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdecore/KDCOPPropertyProxy">KDCOPPropertyProxy</ulink></title> -<para> -A proxy class publishing Qt properties through DCOP. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeui/KDCOPActionProxy">KDCOPActionProxy</ulink></title> -<para> -A proxy class publishing a DCOP interface for actions. -</para> -</formalpara></listitem> - -</itemizedlist> - -<para> -Utility classes - memory management, regular expressions, string manipulation, -random numbers -</para> - -<itemizedlist> - -<listitem><formalpara><title><ulink url="kdeapi:tdecore/KRegExp">KRegExp</ulink></title> -<para> -POSIX regular expression matching. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdecore/KStringHandler">KStringHandler</ulink></title> -<para> -An extravagant interface for string manipulation. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdecore/TDEZoneAllocator">TDEZoneAllocator</ulink></title> -<para> -Efficient memory allocator for large groups of small objects. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdecore/KRandomSequence">KRandomSequence</ulink></title> -<para> -Pseudo random number generator. -</para> -</formalpara></listitem> - -</itemizedlist> - -<para> -Keyboard accelerators - classes helping to establish consistent key bindings -throughout the desktop. -</para> - -<itemizedlist> - -<listitem><formalpara><title><ulink url="kdeapi:tdecore/TDEAccel">TDEAccel</ulink></title> -<para> -Collection of keyboard shortcuts. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdecore/TDEStdAccel">TDEStdAccel</ulink></title> -<para> -Easy access to the common keyboard shortcut keys. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdecore/TDEGlobalAccel"></ulink></title> -<para> -Collection of system-wide keyboard shortcuts. -</para> -</formalpara></listitem> - -</itemizedlist> - -<para> -Image processing - icon loading and manipulating. -</para> - -<itemizedlist> - -<listitem><formalpara><title><ulink url="kdeapi:tdecore/TDEIconLoader">TDEIconLoader</ulink></title> -<para> -Loads icons in a theme-conforming way. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdecore/TDEIconTheme">TDEIconTheme</ulink></title> -<para> -Helper classes for TDEIconLoader. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdecore/KPixmap">KPixmap</ulink></title> -<para> -A pixmap class with extended dithering capabilities. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeui/KPixmapEffect">KPixmapEffect</ulink></title> -<para> -Pixmap effects like gradients and patterns. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeui/KPixmapIO">KPixmapIO</ulink></title> -<para> -Fast <classname>QImage</classname> to <classname>QPixmap</classname> conversion. -</para> -</formalpara></listitem> - -</itemizedlist> - -<para> -Drag and Drop - drag objects for colors and URLs. -</para> - -<itemizedlist> - -<listitem><formalpara><title><ulink url="kdeapi:tdecore/KURLDrag">KURLDrag</ulink></title> -<para> -A drag object for URLs. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeui/KColorDrag">KColorDrag</ulink></title> -<para> -A drag object for colors. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdecore/KMultipleDrag">KMultipleDrag</ulink></title> -<para> -Allows to construct drag objects from several others. -</para> -</formalpara></listitem> - -</itemizedlist> - -<para> -Auto-Completion -</para> - -<itemizedlist> - -<listitem><formalpara><title><ulink url="kdeapi:tdecore/TDECompletion">TDECompletion</ulink></title> -<para> -Generic auto-completion of strings. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeio/KURLCompletion">KURLCompletion</ulink></title> -<para> -Auto-completion of URLs. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeio/KShellCompletion">KShellCompletion</ulink></title> -<para> -Auto-completion of executables. -</para> -</formalpara></listitem> - -</itemizedlist> - -<para> -Widgets - widget classes for list views, rules, color selection etc. -</para> - -<itemizedlist> - -<listitem><formalpara><title><ulink url="kdeapi:tdeui/TDEListView">TDEListView</ulink></title> -<para> -A variant of <classname>QListView</classname> that honors KDE's system-wide settings. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeui/TDEListView">TDEListBox</ulink></title> -<para> -A variant of <classname>QListBox</classname> that honors KDE's system-wide settings. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeui/TDEListView">TDEIconView</ulink></title> -<para> -A variant of <classname>QIconView</classname> that honors KDE's system-wide settings. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeui/TDEListView">KLineEdit</ulink></title> -<para> -A variant of <classname>QLineEdit</classname> with completion support. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeui/KComboBox">KComboBox</ulink></title> -<para> -A variant of <classname>QComboBox</classname> with completion support. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeui/TDEFontCombo">TDEFontCombo</ulink></title> -<para> -A combo box for selecting fonts. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeui/KColorCombo">KColorCombo</ulink></title> -<para> -A combo box for selecting colors. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeui/KColorButton">KColorButton</ulink></title> -<para> -A button for selecting colors. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeui/KURLCombo">KURLCombo</ulink></title> -<para> -A combo box for selecting file names and URLs. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdefile/KURLRequester">KURLRequester</ulink></title> -<para> -A line edit for selecting file names and URLs. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeui/KRuler">KRuler</ulink></title> -<para> -A ruler widget. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink -url="kdeapi:tdeui/KAnimWidget">KAnimWidget</ulink></title> -<para> -animations. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeui/KNumInput">KNumInput</ulink></title> -<para> -A widget for inputting numbers. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeui/KPasswordEdit">KPasswordEdit</ulink></title> -<para> -A widget for inputting passwords. -</para> -</formalpara></listitem> - -</itemizedlist> - -<para> -Dialogs - full-featured dialogs for file, color and font selection. -</para> - -<itemizedlist> - -<listitem><formalpara><title><ulink url="kdeapi:tdefile/KFileDialog">KFileDialog</ulink></title> -<para> -A file selection dialog. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeui/KColorDialog">KColorDialog</ulink></title> -<para> -A color selection dialog. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeui/TDEFontDialog">TDEFontDialog</ulink></title> -<para> -A font selection dialog. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdefile/TDEIconDialog">TDEIconDialog</ulink></title> -<para> -An icon selection dialog. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeui/KKeyDialog">KKeyDialog</ulink></title> -<para> -A dialog for editing keyboard bindings. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeui/KEditToolBar">KEditToolBar</ulink></title> -<para> -A dialog for editing toolbars. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeui/KTipDialog">KTipDialog</ulink></title> -<para> -A Tip-of-the-day dialog. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeui/TDEAboutDialog">TDEAboutDialog</ulink></title> -<para> -An about dialog. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeui/KLineEditDlg">KLineEditDlg</ulink></title> -<para> -A simple dialog for entering text. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdefile/KURLRequesterDlg">KURLRequesterDlg</ulink></title> -<para> -A simple dialog for entering URLs. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeui/KMessageBox">KMessageBox</ulink></title> -<para> -A dialog for signaling errors and warnings. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeui/KPasswordDialog">KPasswordDialog</ulink></title> -<para> -A dialog for inputting passwords. -</para> -</formalpara></listitem> - -</itemizedlist> - -<para> -Actions and XML GUI -</para> - -<itemizedlist> - -<listitem><formalpara><title><ulink url="kdeapi:tdeui/TDEAction">TDEAction</ulink></title> -<para> -Abstraction for an action that can be plugged into menu bars and tool bars. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeui/TDEActionCollection">TDEActionCollection</ulink></title> -<para> -A set of actions. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeui/KXMLGUIClient">KXMLGUIClient</ulink></title> -<para> -A GUI fragment consisting of an action collection and a DOM tree representing their location in the GUI. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeparts/KPartManager">KPartManager</ulink></title> -<para> -Manages the activation of XMLGUI clients. -</para> -</formalpara></listitem> - -</itemizedlist> - -<para> -Plugins and Components -</para> - -<itemizedlist> - -<listitem><formalpara><title><ulink url="kdeapi:tdecore/KLibrary">KLibrary</ulink></title> -<para> -Represents a dynamically loaded library. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdecore/KLibrary">KLibLoader</ulink></title> -<para> -Shared library loading. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdecore/KLibFactory">KLibFactory</ulink></title> -<para> -Object factory in plugins. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeio/KServiceType">KServiceType</ulink></title> -<para> -Represents a service type. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeio/KService">KService</ulink></title> -<para> -Represents a service. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeio/KMimeType">KMimeType</ulink></title> -<para> -Represents a MIME type. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeio/KServiceTypeProfile">KServiceTypeProfile</ulink></title> -<para> -User preferences for MIME type mappings. -</para> -</formalpara></listitem> - -<listitem><formalpara><title><ulink url="kdeapi:tdeio/KServiceTypeProfile">TDETrader</ulink></title> -<para> -Querying for services. -</para> -</formalpara></listitem> - -</itemizedlist> - -</simplesect> - -</chapter> - - - -<chapter id="graphics"> -<title>Graphics</title> - -<sect1 id="graphics-qpainter"> -<title>Low-level graphics with QPainter</title> - -<simplesect id="qpainter-rendering"> -<title>Rendering with QPainter</title> - -<para> -Qt's low level imaging model is based on the capabilities provided by X11 and -other windowing systems for which Qt ports exist. But it also extends these by -implementing additional features such as arbitrary affine transformations for -text and pixmaps. -</para> - -<para> -The central graphics class for 2D painting with Qt is -<ulink url="kdeapi:qt/QPainter">QPainter</ulink>. It can -draw on a -<ulink url="kdeapi:qt/QPaintDevice">QPaintDevice</ulink>. -There are three possible paint devices implemented: One is -<ulink url="kdeapi:qt/QWidget">QWidget</ulink> -which represents a widget on the screen. The second is -<ulink url="kdeapi:qt/QPrinter">QPrinter</ulink> which -represents a printer and produces Postscript output. The third it -the class -<ulink url="kdeapi:qt/QPicture">QPicture</ulink> which -records paint commands and can save them on disk and play them back -later. A possible storage format for paint commands is the W3C standard -SVG. -</para> - -<para> -So, it is possible to reuse the rendering code you use for displaying a -widget for printing, with the same features supported. Of course, in -practice, the code is used in a slightly different context. Drawing -on a widget is almost exclusively done in the paintEvent() method -of a widget class. -</para> - -<programlisting> -void FooWidget::paintEvent() -{ - QPainter p(this); - // Setup painter - // Use painter -} -</programlisting> - -<para> -When drawing on a printer, you have to make sure to use QPrinter::newPage() -to finish with a page and begin a new one - something that naturally is not -relevant for painting widgets. Also, when printing, you may want to use the -<ulink url="kdeapi:qt/QPaintDeviceMetrics">device metrics</ulink> -in order to compute coordinates. -</para> - -</simplesect> - - -<simplesect id="qpainter-transformations"> -<title>Transformations</title> - -<para> -By default, when using QPainter, it draws in the natural coordinate -system of the device used. This means, if you draw a line along the horizontal -axis with a length of 10 units, it will be painted as a horizontal line -on the screen with a length of 10 pixels. However, QPainter can apply arbitrary -affine transformations before actually rendering shapes and curves. An -affine transformation maps the x and y coordinates linearly into x' and -y' according to -</para> - -<mediaobject> -<imageobject><imagedata fileref="affine-general.png"/></imageobject> -</mediaobject> - -<para> -The 3x3 matrix in this equation can be set with QPainter::setWorldMatrix() and -is of type <ulink url="kdeapi:qt/QWMatrix">QWMatrix</ulink>. -Normally, this is the identity matrix, i.e. m11 and m22 are one, and the -other parameters are zero. There are basically three different groups of -transformations: -</para> - -<itemizedlist> - -<listitem><formalpara> -<title>Translations</title> -<para> -These move all points of an object by a fixed amount in -some direction. A translation matrix can be obtained by calling -method m.translate(dx, dy) for a QWMatrix. This corresponds to the -matrix -</para> -</formalpara> - -<mediaobject> -<imageobject><imagedata fileref="affine-translate.png"/></imageobject> -</mediaobject> - -</listitem> - -<listitem><formalpara> -<title>Scaling</title> -<para> -These stretch or shrink the coordinates of an object, making -it bigger or smaller without distorting it. A scaling transformation -can be applied to a QWMatrix by calling m.scale(sx, sy). This corresponds -to the matrix -</para> -</formalpara> - -<mediaobject> -<imageobject><imagedata fileref="affine-scale.png"/></imageobject> -</mediaobject> - -<para> -By setting one of the parameters to a negative value, one can -achieve a mirroring of the coordinate system. -</para> - -</listitem> - -<listitem><formalpara> -<title>Shearing</title> -<para> -A distortion of the coordinate system with two -parameters. A shearing transformation can be applied by calling -m.shear(sh, sv), corresponding to the matrix -</para> -</formalpara> - -<mediaobject> - <imageobject><imagedata fileref="affine-shear.png"/></imageobject> -</mediaobject> - -</listitem> - -<listitem><formalpara> -<title>Rotating</title> -<para> -This rotates an object. A rotation transformation can be -applied by calling m.rotate(alpha). Note that the angle has to be given -in degrees, not as mathematical angle! The corresponding matrix is -</para> -</formalpara> - -<mediaobject> -<imageobject><imagedata fileref="affine-rotate.png"/></imageobject> -</mediaobject> - -<para> -Note that a rotation is equivalent with a combination of -scaling and shearing. -</para> - -</listitem> - -</itemizedlist> - -<para> -Here are some pictures that show the effect of the elementary -transformation to our masquot: -</para> - -<informaltable frame="none"> -<tgroup cols="3"> -<tbody> -<row> -<entry><mediaobject> - <imageobject><imagedata fileref="konqi-normal.png"/></imageobject> -</mediaobject></entry> -<entry><mediaobject> - <imageobject><imagedata fileref="konqi-rotated.png"/></imageobject> -</mediaobject></entry> -<entry><mediaobject> - <imageobject><imagedata fileref="konqi-sheared.png"/></imageobject> -</mediaobject></entry> -<entry><mediaobject> - <imageobject><imagedata fileref="konqi-mirrored.png"/></imageobject> -</mediaobject></entry> -</row> -<row> -<entry>a) Normal</entry> -<entry>b) Rotated by 30 degrees</entry> -<entry>c) Sheared by 0.4</entry> -<entry>d) Mirrored</entry> -</row> -</tbody> -</tgroup> -</informaltable> - -<para> -Transformations can be combined by multiplying elementary matrices. Note that -matrix operations are not commutative in general, and therefore the combined -effect of of a concatenation depends on the order in which the matrices are -multiplied. -</para> - -</simplesect> - - -<simplesect id="qpainter-strokeattributes"> -<title>Setting stroking attributes</title> - -<para> -The rendering of lines, curves and outlines of polygons can be modified by -setting a special pen with QPainter::setPen(). The argument of this function is a -<ulink url="kdeapi:qt/QPen">QPen</ulink> object. The properties -stored in it are a style, a color, a join style and a cap style. -</para> - -<para> -The pen style is member of the enum -<ulink url="kdeapi:qt/Qt#PenStyle-enum">Qt::PenStyle</ulink>. -and can take one of the following values: -</para> - -<mediaobject> - <imageobject><imagedata fileref="penstyles.png"/></imageobject> -</mediaobject> - -<para> -The join style is a member of the enum -<ulink url="kdeapi:qt/Qt#PenJoinStyle-enum">Qt::PenJoinStyle</ulink>. -It specifies how the junction between multiple lines which are attached to each -other is drawn. It takes one of the following values: -</para> - -<informaltable frame="none"> -<tgroup cols="3"> -<tbody> -<row> -<entry><mediaobject> - <imageobject><imagedata fileref="joinmiter.png"/></imageobject> -</mediaobject></entry> -<entry><mediaobject> - <imageobject><imagedata fileref="joinbevel.png"/></imageobject> -</mediaobject></entry> -<entry><mediaobject> - <imageobject><imagedata fileref="joinround.png"/></imageobject> -</mediaobject></entry> -</row> -<row> -<entry>a) MiterJoin</entry> -<entry>c) BevelJoin</entry> -<entry>b) RoundJoin</entry> -</row> -</tbody> -</tgroup> -</informaltable> - -<para> -The cap style is a member of the enum -<ulink url="kdeapi:qt/Qt#PenCapStyle-enum">Qt::PenCapStyle</ulink>and specifies how the end points of lines are drawn. It takes one of the values -from the following table: -</para> - -<informaltable frame="none"> -<tgroup cols="3"> -<tbody> -<row> -<entry><mediaobject> - <imageobject><imagedata fileref="capflat.png"/></imageobject> -</mediaobject></entry> -<entry><mediaobject> - <imageobject><imagedata fileref="capsquare.png"/></imageobject> -</mediaobject></entry> -<entry><mediaobject> - <imageobject><imagedata fileref="capround.png"/></imageobject> -</mediaobject></entry> -</row> -<row> -<entry>a) FlatCap</entry> -<entry>b) SquareCap</entry> -<entry>c) RoundCap</entry> -</row> -</tbody> -</tgroup> -</informaltable> - -</simplesect> - - -<simplesect id="qpainter-fillattributes"> -<title>Setting fill attributes</title> - -<para> -The fill style of polygons, circles or rectangles can be modified by setting -a special brush with QPainter::setBrush(). This function takes a -<ulink url="kdeapi:qt/QBrush">QBrush</ulink> object as argument. -Brushes can be constructed in four different ways: -</para> - -<itemizedlist> -<listitem> -<para>QBrush::QBrush() - This creates a brush that does not fill shapes.</para> -</listitem> -<listitem> -<para>QBrush::QBrush(BrushStyle) - This creates a black brush with one of the default -patterns shown below.</para> -</listitem> -<listitem> -<para>QBrush::QBrush(const QColor &, BrushStyle) - This creates a colored brush -with one of the patterns shown below.</para> -</listitem> -<listitem> -<para>QBrush::QBrush(const QColor &, const QPixmap) - This creates a colored -brush with the custom pattern you give as second parameter.</para> -</listitem> -</itemizedlist> - -<para> -A default brush style is from the enum -<ulink url="kdeapi:qt/Qt#BrushStyle-enum">Qt::BrushStyle</ulink>. -Here is a picture of all predefined patterns: -</para> - -<mediaobject> - <imageobject><imagedata fileref="brushstyles.png"/></imageobject> -</mediaobject> - -<para> -A further way to customize the brush behavior is to use the function -QPainter::setBrushOrigin(). -</para> - -</simplesect> - - -<simplesect id="qpainter-color"> -<title>Color</title> - -<para> -Colors play a role both when stroking curves and when filling shapes. In Qt, -colors are represented by the class -<ulink url="kdeapi:qt/QColor">QColor</ulink>. Qt does not support -advanced graphics features like ICC color profiles and color correction. Colors -are usually constructed by specifying their red, green and blue components, as -the RGB model is the way pixels are composed of on a monitor. -</para> - -<para> -It is also possible to use hue, saturation and value. This HSV representation is -what you use in the Gtk color dialog, e.g. in GIMP. There, the hue corresponds -to the angle on the color wheel, while the saturation corresponds to the -distance from the center of the circle. The value can be chosen with a separate -slider. -</para> - -</simplesect> - - -<simplesect id="qpainter-paintsettings"> -<title>Other settings</title> - -<para> -Normally, when you paint on a paint device, the pixels you draw replace those -that were there previously. This means, if you paint a certain region with -a red color and paint the same region with a blue color afterwards, only -the blue color will be visible. Qt's imaging model does not support -transparency, i.e. a way to blend the painted foreground with the background. -However, there is a simple way to combine background and foreground with -boolean operators. The method QPainter::setRasterOp() sets the used operator, -which comes from the enum -<ulink url="kdeapi:qt/Qt#RasterOp-enum">RasterOp</ulink>. -</para> - -<para> -The default is CopyROP which ignores the background. Another popular choice is -XorROP. If you paint a black line with this operator on a colored image, then -the covered area will be inverted. This effect is for example used to create -the rubberband selections in image manipulation programs known as -"marching ants". -</para> - -</simplesect> - - -<simplesect id="qpainter-primitives"> -<title>Drawing graphics primitives</title> - -<para> -In the following we list the elementary graphics elements supported by -QPainter. Most of them exist in several overloaded versions which take a -different number of arguments. For example, methods that deal with rectangles -usually either take a -<ulink url="kdeapi:qt/QRect">QRect</ulink> as argument or a set -of four integers. -</para> - -<itemizedlist> -<listitem> -<para>Drawing a single point - drawPoint().</para> -</listitem> -<listitem> -<para>Drawing lines - drawLine(), drawLineSegments() and drawPolyLine().</para> -</listitem> -<listitem> -<para>Drawing and filling rectangles - drawRect(), drawRoundRect(), -fillRect() and eraseRect().</para> -</listitem> -<listitem> -<para>Drawing and filling circles, ellipses and parts or them - -drawEllipse(), drawArc(), drawPie and drawChord().</para> -</listitem> -<listitem> -<para>Drawing and filling general polygons - drawPolygon().</para> -</listitem> -<listitem> -<para>Drawing bezier curves - drawQuadBezier() [drawCubicBezier in Qt 3.0].</para> -</listitem> -</itemizedlist> - -</simplesect> - - -<simplesect id="qpainter-pixmaps"> -<title>Drawing pixmaps and images</title> - -<para> -Qt provides two very different classes to represent images. -</para> - -<para> -<ulink url="kdeapi:qt/QPixmap">QPixmap</ulink> directly corresponds -to the pixmap objects in X11. Pixmaps are server-side objects and may - on a -modern graphics card - even be stored directly in the card's memory. This makes -it <emphasis>very</emphasis> efficient to transfer pixmaps to the screen. Pixmaps also act as -an off-screen equivalent of widgets - the QPixmap class is a subclass of -QPaintDevice, so you can draw on it with a QPainter. Elementary drawing -operations are usually accelerated by modern graphics. Therefore, a common usage -pattern is to use pixmaps for double buffering. This means, instead of painting -directly on a widget, you paint on a temporary pixmap object and use the -<ulink url="kdeapi:qt/QPaintDevice#bitBlt-1">bitBlt</ulink> -function to transfer the pixmap to the widget. For complex repaints, this helps -to avoid flicker. -</para> - -<para> -In contrast, <ulink url="kdeapi:qt/QImage">QImage</ulink> objects -live on the client side. Their emphasis in on providing direct access to the -pixels of the image. This makes them of use for image manipulation, and things -like loading and saving to disk (QPixmap's load() method takes QImage as -intermediate step). On the other hand, painting an image on a widget is a -relatively expensive operation, as it implies a transfer to the X server, -which can take some time, especially for large images and for remote servers. -Depending on the color depth, the conversion from QImage to QPixmap may also -require dithering. -</para> - -</simplesect> - - -<simplesect id="qpainter-drawingtext"> -<title>Drawing text</title> - -<para> -Text can be drawn with one of the overloaded variants of the method -QPainter::drawText(). These draw a QString either at a given point or in a given -rectangle, using the font set by QPainter::setFont(). There is also a parameter -which takes an ORed combination of some flags from the enums -<ulink url="kdeapi:qt/Qt#AlignmentFlags-enum">Qt::AlignmentFlags</ulink> -and -<ulink url="kdeapi:qt/Qt#TextFlags-enum">Qt::TextFlags</ulink> -</para> - -<para> -Beginning with version 3.0, Qt takes care of the complete text layout even for -languages written from right to left. -</para> - -<para> -A more advanced way to display marked up text is the -<ulink url="kdeapi:qt/QSimpleRichText">QSimpleRichText</ulink> -class. Objects of this class can be constructed with a piece of text using -a subset of the HTML tags, which is quite rich and provides even tables. -The text style can be customized by using a -<ulink url="kdeapi/qt/QStyleSheet">QStyleSheet</ulink> (the -documentation of the tags can also be found here). Once the rich text object has -been constructed, it can be rendered on a widget or another paint device with -the QSimpleRichText::draw() method. -</para> - -</simplesect> - -</sect1> - - -<sect1 id="graphics-qcanvas"> -<title>Structured graphics with QCanvas</title> - -<para> -QPainter offers a powerful imaging model for painting on widgets and pixmaps. -However, it can also be cumbersome to use. Each time your widget receives -a paint event, it has to analyze the QPaintEvent::region() or -QPaintEvent::rect() which has to be redrawn. Then it has to setup a -QPainter and paint all objects which overlap with that region. For example, -image a vector graphics program which allows to drag objects like polygons, -circles and groups of them around. Each time those objects move a bit, the -widget's mouse event handler triggers a paint event for the whole area covered -by the objects in their old position and in their new position. Figuring -out the necessary redraws and doing them in an efficient way can be difficult, -and it may also conflict with the object-oriented structure of the program's -source code. -</para> - -<para> -As an alternative, Qt contains the class -<ulink url="kdeapi:qt/QCanvas">QCanvas</ulink> in which -you put graphical objects like polygons, text, pixmaps. You may also provide -additional items by subclassing -<ulink url="kdeapi:qt/QCanvasItem">QCanvasItem</ulink> or -one of its more specialized subclasses. A canvas can be shown on the screen by -one or more widgets of the class -<ulink url="kdeapi:qt/QCanvas">QCanvasView</ulink> which -you have to subclass in order to handle user interactions. Qt takes care of -all repaints of objects in the view, whether they are caused by the widget -being exposed, new objects being created or modified or other things. By using -double buffering, this can be done in an efficient and flicker-free way. -</para> - -<para> -Canvas items can overlap each other. In this case, the visible one depends on -the z order which can be assigned by QCanvasItem::setZ(). Items can also be -made visible or invisible. You can also provide a background to be drawn -"behind" all items and a foreground. For associating mouse events with objects, -in the canvas, there is the method QCanvas::collisions() which returns a list -of items overlapping with a given point. Here we show a screenshot of a canvas -view in action: -</para> - -<mediaobject> -<imageobject><imagedata fileref="canvas.png"/></imageobject> -</mediaobject> - -<para> -Here, the mesh is drawn in the background. Furthermore, there is a -QCanvasText item and a violet QCanvasPolygon. The butterfly is a -QCanvasPixmap. It has transparent areas, so you can see the underlying -items through it. -</para> - -<para> -A tutorial on using QCanvas for writing sprite-based games can be -found <ulink url="http://zez.org/article/articleview/2/1/">here</ulink>. -</para> - -</sect1> - - -<sect1 id="graphics-qglwidget"> -<title>3D graphics with OpenGL</title> - -<simplesect id="qglwidget-lowlevel"> -<title>Low-level interface</title> - -<para> -The de facto standard for rendering 3D graphics today is -<ulink url="http://www.opengl.org">OpenGL</ulink>. Implementations of this -specification come with Microsoft Windows, Mac OS X and XFree86 and often -support the hardware acceleration features offered by modern graphics cards. -OpenGL itself only deals with rendering on a specified area of the framebuffer -through a <emphasis>GL context</emphasis> and does not have any interactions -with the toolkit of the environment -</para> - -<para> -Qt offers the widget <ulink url="kdeapi:qt/QGLWidget">QGLWidget</ulink> -which encapsulates a window with an associated GL context. Basically, you use it -by subclassing it and reimplementing some methods. -</para> - -<itemizedlist> - -<listitem><para> -Instead of reimplementing paintEvent() and using QPainter to draw the widget's -contents, you override paintGL() and use GL commands to render a scene. QLWidget -will take care of making its GL context the current one before paintGL() is -called, and it will flush afterwards. -</para></listitem> - -<listitem><para> -The virtual method initializeGL() is called once before the first time resizeGL() -or paintGL() are called. This can be used to construct display lists for objects, -and make any initializations. -</para></listitem> - -<listitem><para> -Instead of reimplementing resizeEvent(), you override resizeGL(). This can -be used to set the viewport appropriately. -</para></listitem> - -<listitem><para> -Instead of calling update() when the state of the scene has changed - for example -when you animate it with a timer -, you should call updateGL(). This will trigger -a repaint. -</para></listitem> - -</itemizedlist> - -<para> -In general, QGLWidget behaves just like any other widget, i.e. for example -you can process mouse events as usual, resize the widget and combine it with -others in a layout. -</para> - -<mediaobject> -<imageobject><imagedata fileref="opengl.png"/></imageobject> -</mediaobject> - -<para> -Qt contains some examples of QGLWidget usage in its <literal>demo</literal> -example. A collection of tutorials can be found -<ulink url="http://www.libsdl.org/opengl/intro.html">here</ulink>, -and more information and a reference of OpenGL is available on the -<ulink url="http://www.opengl.org">OpenGL homepage</ulink>. -</para> - -</simplesect> - - -<simplesect id="qglwidget-highlevel"> -<title>High-level interfaces</title> - -<para> -OpenGL is a relatively low-level interface for drawing 3D graphics. In the same -way QCanvas gives the programmer a higher-level interface which details with -objects and their properties, there are also high-level interfaces for 3D graphics. -One of the most popular is Open Inventor. Originally a technology developed by SGI, -there is today also the open source implementation -<ulink url="http://www.coin3d.org">Coin</ulink>, complemented by a toolkit binding to Qt -called SoQt. -</para> - -<para> -The basic concept of Open Inventor is that of a <emphasis>scene</emphasis>. -A scene can be loaded from disk and saved in a special format closely related -to <ulink url="http://www.vrml.org">VRML</ulink>. A scene consists of a -collection of objects called <emphasis>nodes</emphasis>. Inventor already -provides a rich collection of reusable nodes, such as cubes, cylinders and -meshes, furthermore light sources, materials, cameras etc. Nodes are -represented by C++ classes and can be combined and subclassed. -</para> - -<para> -An introduction to Inventor can be found -<ulink url="http://www.motifzone.com/tmd/articles/OpenInventor/OpenInventor.html">here</ulink> -(in general, you can substitute all mentions of SoXt by SoQt in this article). -</para> - -</simplesect> - -</sect1> - -</chapter> - - - -<chapter id="userinterface"> -<title>User interface</title> - -<sect1 id="userinterface-actionpattern"> -<title>The action pattern</title> - -<para></para> - -</sect1> - - -<sect1 id="userinterface-xmlgui"> -<title>Defining menus and toolbars in XML</title> - -<simplesect id="xmlgui-intro"> -<title>Introduction</title> - -<para> -While the <link linkend="userinterface-actionpattern">action pattern</link> -allows to encapsulate actions triggered by the user in an object which can be -"plugged" somewhere in the menu bars or toolbars, it does not by itself solve -the problem of constructing the menus themselves. In particular, you have to -build all popup menus in C++ code and explicitly insert the actions in a -certain order, under consideration of the style guide for standard actions. -This makes it pretty difficult to allow the user to customize the menus or -change shortcuts to fit his needs, without changing the source code. -</para> - -<para> -This problem is solved by a set of classes called <literal>XMLGUI</literal>. -Basically, this separates actions (coded in C++) from their appearance in menu -bars and tool bars (coded in XML). Without modifying any source code, menus -can be simply customized by adjusting an XML file. Furthermore, it helps -to make sure that standard actions (such as -<menuchoice><guimenu>File</guimenu><guimenuitem>Open</guimenuitem></menuchoice> -or <menuchoice><guimenu>Help</guimenu><guimenuitem>About</guimenuitem></menuchoice>) -appear in the locations suggested by the style guide. XMLGUI is especially -important for modular programs, where the items appearing in the menu bar may -come from many different plugins or parts. -</para> - -<para> -KDE's class for toplevel windows, -<ulink url="kdeapi:tdeui/TDEMainWindow.html">TDEMainWindow</ulink>, -inherits -<ulink url="kdeapi:tdeui/KXMLGUIClient.html">KXMLGUIClient</ulink> -and therefore supports XMLGUI out of the box. All actions created within it must -have the client's <literal>actionCollection()</literal> as parent. A call to -<literal>createGUI()</literal> will then build the whole set of menu and tool -bars defined the applications XML file (conventionally with the suffix -<literal>ui.rc</literal>). -</para> - -</simplesect> - - -<simplesect id="xmlgui-kviewexample"> -<title>An example: Menu in KView</title> - -<para> -In the following, we take KDE's image view <application>KView</application> as -example. It has a <literal>ui.rc</literal> file named -<filename>kviewui.rc</filename> which is installed with the -<filename>Makefile.am</filename> snippet -</para> - -<programlisting> -rcdir = $(kde_datadir)/kview -rc_DATA = kviewui.rc -</programlisting> - -<para> -Here is an excerpt from the <filename>kviewui.rc</filename> file. For -simplicity, we show only the definition of the <guimenu>View</guimenu> menu. -</para> - -<programlisting> -<!DOCTYPE kpartgui> -<kpartgui name="kview"> - <MenuBar> - <Menu name="view" > - <Action name="zoom50" /> - <Action name="zoom100" /> - <Action name="zoom200" /> - <Action name="zoomMaxpect" /> - <Separator/> - <Action name="fullscreen" /> - </Menu> - </MenuBar> -</kpartgui> -</programlisting> - -<para> -The corresponding part of the setup in C++ is: -</para> - -<programlisting> - KStdAction::zoomIn ( this, SLOT(slotZoomIn()), actionCollection() ); - KStdAction::zoomOut ( this, SLOT(slotZoomOut()), actionCollection() ); - KStdAction::zoom ( this, SLOT(slotZoom()), actionCollection() ); - new TDEAction ( i18n("&Half size"), ALT+Key_0, - this, SLOT(slotHalfSize()), - actionCollection(), "zoom50" ); - new TDEAction ( i18n("&Normal size"), ALT+Key_1, - this, SLOT(slotDoubleSize()), - actionCollection(), "zoom100" ); - new TDEAction ( i18n("&Double size"), ALT+Key_2, - this, SLOT(slotDoubleSize()), - actionCollection(), "zoom200" ); - new TDEAction ( i18n("&Fill Screen"), ALT+Key_3, - this, SLOT(slotFillScreen()), - actionCollection(), "zoomMaxpect" ); - new TDEAction ( i18n("Fullscreen &Mode"), CTRL+SHIFT+Key_F, - this, SLOT(slotFullScreen()), - actionCollection(), "fullscreen" ); -</programlisting> - -<para> -The <guimenu>View</guimenu> menu resulting from this GUI definition looks like -in this screenshot: -</para> - -<mediaobject> -<imageobject><imagedata fileref="kview-menu.png"/></imageobject> -</mediaobject> - -<para> -The XML file begins with a document type declaration. The DTD for kpartgui can -be found in the tdelibs sources in <filename>tdeui/kpartgui.dtd</filename>. The -outermost element of the file contains the instance name of the application as -attribute. It can also contain a version number in the form "version=2". This -is useful when you release new versions of an application with a changed menu -structure, e.g. with more features. If you bump up the version number of the -<literal>ui.rc</literal> file, KDE makes sure that any customized version of -the file is discarded and the new file is used instead. -</para> - -<para> -The next line, <literal><MenuBar></literal>, contains a declaration of a -menu bar. You can also insert any number of <literal><ToolBar></literal> -declarations in order to create some tool bars. The menu contains a submenu -with the name "view". This name is already predefined, and thus you see a -translated version of the word "View" in the screenshot. If you declare your -own submenus, you have to add the title explicitly. For example, -<application>KView</application> has a submenu with the title "Image" which is -declared as follows: -</para> - -<programlisting> -<Menu name="image" > - <text>&amp;Image</text> - ... -</Menu> -</programlisting> - -<para> -In KDE's automake framework, such titles are automatically extracted and put -into the application's <ulink url="tde-i18n-howto.html"><literal>.po</literal></ulink> -file , so it is considered by translators. Note that you have to write the -accelerator marker "&" in the form XML compliant form "&amp;". -</para> - -<para> -Let us come back to the example. <application>KView</application>'s -<guimenu>View</guimenu> menu contains a couple of custom actions: -<literal>zoom50</literal>, <literal>zoom100</literal>, -<literal>zoom200</literal>, <literal>zoomMaxpect</literal> and -<literal>fullscreen</literal>, declared with a -<literal><Action></literal> element. The separator in the -screenshots corresponds to the <literal><Separator></literal> element. -</para> - -<para> -You will note that some menu items do not not have a corresponding element in -the XML file. These are <emphasis>standard actions</emphasis>. Standard -actions are created by the class -<ulink url="kdeapi:tdeui/KStdAction.html">KStdAction</ulink>. -When you create such actions in your application (such as in the C++ example -above), they will automatically be inserted in a prescribed position, and -possibly with an icon and a shortcut key. You can look up these locations in -the file <filename>tdeui/ui_standards.rc</filename> in the tdelibs sources. -</para> - -</simplesect> - - -<simplesect id="xmlgui-konqexample"> -<title>An example: Toolbars in Konqueror</title> - -<para> -For the discussion of toolbars, we switch to -<application>Konqueror</application>'s GUI definition. This excerpt defines -the location bar, which contains the input field for URLs. -</para> - -<programlisting> -<ToolBar name="locationToolBar" fullWidth="true" newline="true" > - <text>Location Toolbar</text> - <Action name="clear_location" /> - <Action name="location_label" /> - <Action name="toolbar_url_combo" /> - <Action name="go_url" /> -</ToolBar> -</programlisting> - -<para> -The first thing we notice is that there are a lot more attributes than for -menu bars. These include: -</para> - -<itemizedlist> - -<listitem><para> -<literal>fullWidth</literal>: Tells XMLGUI that the toolbar has the same width as the - toplevel window. Af this is "false", the toolbar only takes as much space as - necessary, and further toolbars are put in the same row. -</para></listitem> - -<listitem><para> -<literal>newline</literal>: This is related to the option above. If newline is "true", -the toolbar starts a new row. Otherwise it may be put in the row together -with the previous toolbar. -</para></listitem> - -<listitem><para> -<literal>noEdit</literal>: Normally toolbars can be customized by the user, -e.g. in <menuchoice><guimenu>Settings</guimenu><guimenuitem>Configure -Toolbars</guimenuitem></menuchoice> in -<application>Konqueror</application>. Setting this option to "true" marks this -toolbar as not editable. This is important for toolbars which are filled with -items at runtime, e.g. <application>Konqueror</application>'s bookmark toolbar. -</para></listitem> - -<listitem><para> -<literal>iconText</literal>: Tells XMLGUI to show the text of the action next to the -icon. Normally, the text is only shown as a tooltip when the mouse cursor -remains over the icon for a while. Possible values for this attribute are -"icononly" (shows only the icon), "textonly" (shows only the text), -"icontextright" (shows the text on the right side of the icon) and -"icontextbottom" (shows the text beneath the icon). -</para></listitem> - - -<listitem><para> -<literal>hidden</literal>: If this is "true", the toolbar is not visible initially -and must be activated by some menu item. -</para></listitem> - - -<listitem><para> -<literal>position</literal>: The default for this attribute is "top", meaning that the -toolbar is positioned under the menu bar. For programs with many tools, -such as graphics programs, it may be interesting to replace this with -"left", "right" or "bottom". -</para></listitem> - -</itemizedlist> - -</simplesect> - - -<simplesect id="xmlgui-dynamical"> -<title>Dynamical menus</title> - -<para> -Obviously, an XML can only contain a static description of a user interface. -Often, there are menus which change at runtime. For example, -<application>Konqueror</application>'s <guimenu>Location</guimenu> menu -contains a set of items <guimenuitem>Open with Foo</guimenuitem> with the -applications able to load a file with a given MIME type. Each time the -document shown changes, the list of menu items is updated. XMLGUI is prepared -to handle such cases with the notion of <emphasis>action lists</emphasis>. -An action list is declared as one item in the XML file, but consists of -several actions which are plugged into the menu at runtime. The above example -is implemented with the following declaration in -<application>Konqueror</application>'s XML file: -</para> - -<programlisting> -<Menu name="file"> - <text>&amp;Location</text> - ... - <ActionList name="openwith"> - ... -</Menu> -</programlisting> - -<para> -The function <function>KXMLGUIClient::plugActionList()</function> is then used -to add actions to be displayed, whereas the function -<function>KXMLGuiClient::unplugActionList()</function> removes all -plugged actions. The routine responsible for updating looks as follows: -</para> - -<programlisting> -void MainWindow::updateOpenWithActions() -{ - unplugActionList("openwith"); - openWithActions.clear(); - for ( /* iterate over the relevant services */ ) { - TDEAction *action = new TDEAction( ...); - openWithActions.append(action); - } - plugActionList("openwith", openWithActions); -} -</programlisting> - -<para> -Note that in contrast to the static actions, the ones created here are -<emphasis>not</emphasis> constructed with the action collection as parent, and -you are responsible for deleting them for yourself. The simplest way to achievethis -is by using <literal>openWithActions.setAutoDelete(true)</literal> in the above -example. -</para> - -</simplesect> - - -<simplesect id="xmlgui-contextmenus"> -<title>Context menus</title> - -<para> -The examples above only contained cases where a main window's menubar and -toolbars were created. In the cases, the processes of constructing these -containers is completely hidden from you behind the -<function>createGUI()</function> call (except if you have custom containers). -However, there are cases, where you want to construct other containers and -populate them with GUI definitions from the XML file. One such example are -context menus. In order to get a pointer to a context menu, you have to -ask the client's factory for it: -</para> - -<programlisting> -void MainWindow::popupRequested() -{ - QWidget *w = factory()->container("context_popup", this); - QPopupMenu *popup = static_cast<QPopupMenu *>(w); - popup->exec(QCursor::pos()); -} -</programlisting> - -<para> -The method <function>KXMLGUIFactory::container()</function> used above looks -whether it finds a container in the XML file with the given name. Thus, a -possible definition could look as follows: -</para> - -<programlisting> -... -<Menu name="context_popup"> - <Action name="file_add"/> - <Action name="file_remove"/> -</Menu> -... -</programlisting> - -</simplesect> - -</sect1> - - -<sect1 id="help"> -<title>Providing online help</title> - -<para> -Making a program easy and intuitive to use involves a wide range of -facilities which are usually called online help. Online help has several, -partially conflicting goals: on the one, it should give the user answers -to the question "How can I do a certain task?", on the other hand it -should help the user exploring the application and finding features he -doesn't yet know about. It is important to recognize that this can only -be achieved by offering several levels of help: -</para> - -<itemizedlist> - -<listitem><para> -Tooltips are tiny labels that pop up over user interface elements when -the mouse remains there longer. They are especially important for tool- -bars, where icons are not always sufficient to explain the purpose of -a button. -</para></listitem> - -<listitem><para> -"What's this?" help is usually a longer and richer explanation of a widget -or a menu item. It is also more clunky to use: In dialogs, it can be invoked -in two ways: either by pressing -<keycombo><keycap>Shift</keycap><keycap>F1</keycap></keycombo> or by clicking -on the question mark in the title bar (where the support of the latter depends -on the window manager). The mouse pointer then turns into an arrow with a -question mark, and the help window appears when a user interfact element has -been clicked. "What's this?" help for menu items is usually activated by a -button in the toolbar which contains an arrow and a question mark. -</para></listitem> - -<listitem><para> -The problem with this approach is that the user can't see whether a widget -provides help or not. When the user activates the question mark button and -doesn't get any help window when clicking on a user interface element, he -will get frustrated very quickly. -</para> - -<para> -The advantage of "What's this?" help windows as provided by Qt and KDE is that -they can contain <ulink url="kdeapi:qt/QStyleSheet">rich text</ulink>, -i.e. the may contain different fonts, bold and italic text and even images and tables. -</para> - -<para> -An example of "What's this?" help: -</para> - -<mediaobject> -<imageobject><imagedata fileref="whatsthis.png"/></imageobject> -</mediaobject> - -</listitem> - -<listitem><para> -Finally, every program should have a manual. A manual is normally viewed in -<application>KHelpCenter</application> by activating the -<guimenu>Help</guimenu> menu. That means, a complete additional application -pops up and diverts the user from his work. Consequently, consulting the -manual should only be necessary if other facilities like tooltips and what's -this help are not sufficient. Of course, a manual has the advantage that it -does not explain single, isolated aspects of the user interface. Instead, it -can explain aspects of the application in a greater context. Manuals for KDE -are written using the <ulink url="http://i18n.kde.org">DocBook</ulink> markup -language. -</para></listitem> - -</itemizedlist> - -<para> -From the programmer's point of view, Qt provides an easy to use API for online -help. To assign a tooltip to widget, use the -<ulink url="kdeapi:qt/QToolTip">QToolTip</ulink> class. -</para> - -<programlisting> -QToolTip::add(w, i18n("This widget does something.")) -</programlisting> - -<para> -If the menu bars and tool bars are created using the <ulink url="actionpattern.html"> -action pattern</ulink>, the string used as tooltip is derived from the first argument -of the <ulink url="kdeapi:tdeui/TDEAction.html">TDEAction</ulink> constructor: -</para> - -<programlisting> -action = new TDEAction(i18n("&Delete"), "editdelete", - SHIFT+Key_Delete, actionCollection(), "del") -</programlisting> - -<para> -Here it is also possible to assign a text which is shown in the status bar when the -respective menu item is highlighted: -</para> - -<programlisting> -action->setStatusText(i18n("Deletes the marked file")) -</programlisting> - -<para> -The API for "What's this?' help is very similar. In dialogs, use the following -code: -</para> - -<programlisting> -QWhatsThis::add(w, i18n("<qt>This demonstrates <b>Qt</b>'s" - " rich text engine.<ul>" - "<li>Foo</li>" - "<li>Bar</li>" - "</ul></qt>")) -</programlisting> - -<para> -For menu items, use -</para> - -<programlisting> -action->setWhatsThis(i18n("Deletes the marked file")) -</programlisting> - -<para> -The invocation of <application>KHelpCenter</application> is encapsulated in the -<ulink url="kdeapi:tdecore/TDEApplication">TDEApplication</ulink> -class. In order to show the manual of your application, just use -</para> - -<programlisting> -kapp->invokeHelp() -</programlisting> - -<para> -This displays the first page with the table of contents. When you want to -display only a certain section of the manual, you can give an additional -argument to <function>invokeHelp()</function> determining the anchor which -the browser jumps to. -</para> - -</sect1> - -</chapter> - - - -<chapter id="components"> -<title>Components and services</title> - -<sect1 id="components-services"> -<title>KDE services</title> - -<simplesect id="services-whatarekdeservices"> -<title>What are KDE services?</title> - -<para> -The notion of a <emphasis>service</emphasis> is a central concept in KDE's -modular architecture. There is no strict technical implementation connected -with this term - services can be plugins in the form of shared libraries, -or they can be programs controlled via <ulink url="dcop.html">DCOP</ulink>. -By claiming to be of a certain <emphasis>service type</emphasis>, a service -promises to implement certain APIs or features. In C++ terms, one can think -of a service type as an abstract class, and a service as an implementation -of that interface. -</para> - -<para> -The advantage of this separation is clear: An application utilizing a service -type does not have to know about possible implementations of it. It just uses -the APIs associated with the service type. In this way, the used service can be -changed without affecting the application. Also, the user can configure which -services he prefers for certain features. -</para> - -<para> -Some examples: -</para> - -<itemizedlist> - -<listitem><para> -The HTML rendering engine used in <application>Konqueror</application> is an -embedable component that implements the service types -<literal>KParts/ReadOnlyPart</literal> and <literal>Browser/View</literal>. -</para></listitem> -<listitem><para> -In <application>TDevelop</application> HEAD, most functionality is packaged in -plugins with the service type <literal>TDevelop/Part</literal>. At startup, -all services with this type are loaded, such that you can extend the IDE in a -very flexible way. -</para></listitem> -<listitem><para> -In the icon view, <application>Konqueror</application> displays - if enabled - -thumbnail pictures of images, HTML pages, PDF and text files. This ability can -be extended. If you want it to display preview pictures of your own data files -with some MIME type, you can implement a service with service type -<classname>ThumbCreator</classname>. -</para></listitem> - -</itemizedlist> - -<para> -Obviously, a service is not only characterized by the service types it -implements, but also by some <emphasis>properties</emphasis>. For example, a -ThumbCreator does not only claim to implement the C++ class with the type -<classname>ThumbCreator</classname>, it also has a list of MIME types it is -responsible for. Similarly, TDevelop parts have the programming language they -support as a property. When an application requests a service type, it can -also list constraints on the properties of the service. In the above example, -when TDevelop loads the plugins for a Java project, it asks only for the -plugins which have Java as the programming language property. For this -purpose, KDE contains a full-blown CORBA-like <emphasis>trader</emphasis> with -a complex query language. -</para> - -</simplesect> - - -<simplesect id="services-definingservicetypes"> -<title>Defining service types</title> - -<para> -New service types are added by installing a description of them into the -directory <filename>TDEDIR/share/servicetypes</filename>. In an automake -framework, this can be done with this <filename>Makefile.am</filename> -snippet: -</para> - -<programlisting> -kde_servicetypesdir_DATA = tdeveloppart.desktop -EXTRA_DIST = $(kde_servicetypesdir_DATA) -</programlisting> - -<para> -The definition <filename>tdeveloppart.desktop</filename> of a -<application>TDevelop</application> part looks as follows: -</para> - -<programlisting> -[Desktop Entry] -Type=ServiceType -X-TDE-ServiceType=TDevelop/Part -Name=TDevelop Part - -[PropertyDef::X-TDevelop-Scope] -Type=QString - -[PropertyDef::X-TDevelop-ProgrammingLanguages] -Type=QStringList - -[PropertyDef::X-TDevelop-Args] -Type=QString -</programlisting> - -<para> -In addition to the usual entries, this example demonstrates how you declare -that a service has some properties. Each property definition corresponds -to a group <literal>[PropertyDef::name]</literal> in the configuration file. In -this group, the <literal>Type</literal> entry declares the type of the property. -Possible types are everything that can be stored in a -<ulink url="kdeapi:qt/QVariant">QVariant</ulink>. -</para> - -</simplesect> - - -<simplesect id="services-defininglibraryservices"> -<title>Defining shared library services</title> - -<para> -Service definitions are stored in the directory -<filename>TDEDIR/share/services</filename>: -</para> - -<programlisting> -kde_servicesdir_DATA = kdevdoxygen.desktop -EXTRA_DIST = $(kde_servicesdir_DATA) -</programlisting> - -<para> -The content of the following example file -<filename>tdevdoxygen.desktop</filename> defines the -<literal>KDevDoxygen</literal> plugin with the service type -<literal>TDevelop/Part</literal>: -</para> - -<programlisting> -[Desktop Entry] -Type=Service -Comment=Doxygen -Name=KDevDoxygen -ServiceTypes=TDevelop/Part -X-TDE-Library=libtdevdoxygen -X-TDevelop-ProgrammingLanguages=C,C++,Java -X-TDevelop-Scope=Project -</programlisting> - -<para> -In addition to the usual declarations, an important entry is -<literal>X-TDE-Library</literal>. This contains the name of the libtool -library (without the <literal>.la</literal> extension). It also fixes -(with the prefix <literal>init_</literal> prepended) the name of the exported -symbol in the library which returns an object factory. For the above example, -the library must contain the following function: -</para> - -<programlisting> -extern "C" { - void *init_libtdevdoxygen() - { - return new DoxygenFactory; - } -}; -</programlisting> - -<para> -The type of the factory class <classname>DoxygenFactory</classname> depends on -the specific service type the service implements. In our example of a TDevelop -plugin, the factory must be a <classname>KDevFactory</classname> (which -inherits <classname>KLibFactory</classname>). More common examples are -<ulink url="kdeapi:tdeparts/KParts::Factory">KParts::Factory</ulink> -which is supposed to produce -<ulink url="kdeapi:tdeparts/KParts::ReadOnlyPart">KParts::ReadOnlyPart</ulink> -objects or in most cases the generic -<ulink url="kdeapi:tdecore/KLibFactory">KLibFactory</ulink>. -</para> - -</simplesect> - - -<simplesect id="services-usinglibraryservices"> -<title>Using shared library services</title> - -<para> -In order to use a shared library service in an application, you need to obtain a -<ulink url="kdeapi:tdeio/KService.html">KService</ulink> object -representing it. This is discussed in the -<ulink url="mime.html">section about MIME types</ulink> (and in a section about the -trader to be written :-) -</para> - -<para> -With the <classname>KService</classname> object at hand, you can very simply -load the library and get a pointer to its factory object: -</para> - -<programlisting> -KService *service = ... -QString libName = QFile::encodeName(service->library()); -KLibFactory *factory = KLibLoader::self()->factory(libName); -if (!factory) { - QString name = service->name(); - QString errorMessage = KLibLoader::self()->lastErrorMessage(); - KMessageBox::error(0, i18n("There was an error loading service %1.\n" - "The diagnostics from libtool is:\n%2") - .arg(name).arg(errorMessage); -} -</programlisting> - -<para> -From this point, the further proceeding depends again on the service type. For -generic plugins, you create objects with the method -<ulink url="kdeapi:tdecore/KLibFactory.html#ref3">KLibFactory::create()</ulink>. -For KParts, you must cast the factory pointer to the more specific KParts::Factory and use -its create() method: -</para> - -<programlisting> -if (factory->inherits("KParts::Factory")) { - KParts::Factory *partFactory = static_cast<KParts::Factory*>(factory); - QObject *obj = partFactory->createPart(parentWidget, widgetName, - parent, name, "KParts::ReadOnlyPart"); - ... -} else { - cout << "Service does not implement the right factory" << endl; -} -</programlisting> - -</simplesect> - - -<simplesect id="services-definingdcopservices"> -<title>Defining DCOP services</title> - -<para> -A DCOP service is usually implemented as a program that is started up when it is -needed. It then goes into a loop and listens for DCOP connections. The program -may be an interactive one, but it may also run completely or for a part of its -lifetime as a daemon in the background without the user noticing it. An example -for such a daemon is <literal>tdeio_uiserver</literal>, which implements user interaction -such as progress dialog for the TDEIO library. The advantage of such a centralized -daemon in this context is that e.g. the download progress for several different -files can be shown in one window, even if those downloads were initiated from -different applications. -</para> - -<para> -A DCOP service is defined differently from a shared library service. Of course, -it doesn't specify a library, but instead an executable. Also, DCOP services -do not specify a ServiceType line, because usually they are started by their -name. As additional properties, it contains two lines: -</para> - -<para> -<literal>X-DCOP-ServiceType</literal> specifies the way the service is -started. The value <literal>Unique</literal> says that the service must not be -started more than once. This means, if you try to start this service (e.g. via -<ulink url="kdeapi:tdecore/TDEApplication.html#startServiceByName"> -TDEApplication::startServiceByName()</ulink>, KDE looks whether it is already -registered with DCOP and uses the running service. If it is not registered yet, -KDE will start it up and wait until is registered. Thus, you can immediately -send DCOP calls to the service. In such a case, the service should be implemented -as a -<ulink url="kdeapi:tdecore/KUniqueApplication.html">KUniqueApplication</ulink>. -</para> - -<para> -The value <literal>Multi</literal> for <literal>X-DCOP-ServiceType</literal> says that multiple -instances of the service can coexist, so every attempt to start the service -will create another process. As a last possibility the value <literal>None</literal> -can be used. In this case, a start of the service will not wait until it -is registered with DCOP. -</para> - -<para> -<literal>X-TDE-StartupNotify</literal> should normally be set to false. Otherwise, when -the program is started, the task bar will show a startup notification, or, depending -on the user's settings, the cursor will be changed. -</para> - -<para> -Here is the definition of <literal>tdeio_uiserver</literal>: -</para> - -<programlisting> -[Desktop Entry] -Type=Service -Name=tdeio_uiserver -Exec=tdeio_uiserver -X-DCOP-ServiceType=Unique -X-TDE-StartupNotify=false -</programlisting> - -</simplesect> - - -<simplesect id="services-usingdcopservices"> -<title>Using DCOP services</title> - -<para> -A DCOP service is started with one of several methods in the TDEApplication -class: -</para> - -<programlisting> -DCOPClient *client = kapp->dcopClient(); -client->attach(); -if (!client->isApplicationRegistered("tdeio_uiserver")) { - QString error; - if (TDEApplication::startServiceByName("tdeio_uiserver", QStringList(), &error)) - cout << "Starting kioserver failed with message " << error << endl; -} -... -QByteArray data, replyData; -QCString replyType; -QDataStream arg(data, IO_WriteOnly); -arg << true; -if (!client->call("tdeio_uiserver", "UIServer", "setListMode(bool)", - data, replyType, replyData)) - cout << "Call to tdeio_uiserver failed" << endl; -... -</programlisting> - -<para> -Note that the example of a DCOP call given here uses explicit marshalling -of arguments. Often you will want to use a stub generated by dcopidl2cpp -instead, because it is much simpler and less error prone. -</para> - -<para> -In the example given here, the service was started "by name", i.e. the -first argument to <function>TDEApplication::startServiceByName()</function> is -the name is appearing in the <literal>Name</literal> line of the desktop -file. An alternative is to use -<function>TDEApplication::startServiceByDesktopName()</function>, which takes -the file name of its desktop file as argument, i.e. in this case -<literal>"tdeio_uiserver.desktop"</literal>. -</para> - -<para> -All these calls take a list of URLs as a second argument, which is given -to the service on the command line. The third argument is a pointer to a -<classname>QString</classname>. If starting the service fails, this argument -is set to a translated error message. -</para> - -</simplesect> - -</sect1> - - -<sect1 id="components-mime"> -<title>MIME types</title> - -<simplesect id="mime-whataremimetypes"> -<title>What are MIME types?</title> - -<para> -MIME types are used to describe the content type of files or data -chunks. Originally they were introduced in order to allow sending around image -or sound files etc. by e-mail (MIME stands for "Multipurpose Internet Mail -Extensions"). Later this system was also used by web browsers to determine how -to present data sent by a web server to the user. For example, an HTML page -has a MIME type "text/html", a postscript file "application/postscript". In -KDE, this concept is used at a variety of places: -</para> - -<itemizedlist> - -<listitem><para> -In <application>Konqueror</application>'s icon view, files are represented by -icons. Each MIME type has a certain associated icon shown here. -</para></listitem> - -<listitem><para> -When you click onto a file icon or a file name in -<application>Konqueror</application>, either the file is shown in an embedded -view, or an application associated with the file type is opened. -</para></listitem> - -<listitem><para> -When you drag and drop some data from one application to another (or -within the same application), the drop target may choose to accept only -certain data types. Furthermore, it will handle image data different -from textual data. -</para></listitem> - -<listitem><para> -Clipboard data has a MIME type. Traditionally, X programs only handle -pixmaps or texts, but with Qt, there are no restrictions on the data type. -</para></listitem> - -</itemizedlist> - -<para> -From the above examples, it is clear that MIME handling is a complex issue. -First, it is necessary to establish a mapping from file names to MIME types. -KDE goes one step further in allowing even file contents to be mapped to -MIME types, for cases in which the file name is not available. Second, it -is necessary to map MIME types to applications or libraries which can view -or edit a file with a certain type, or create a thumbnail picture for it. -</para> - -<para> -There is a variety of APIs to figure out the MIME type of data or files. In -general, there is a certain speed/reliability trade-off you have to make. You -can find out the type of a file by examining only its file name (i.e. in most -cases the file name extension). For example, a file -<filename>foo.jpg</filename> is normally "image/jpeg". In cases where the -extension is stripped off this is not safe, and you actually have to look at -the contents of the file. This is of course slower, in particular for files -that have to be downloaded via HTTP first. The content-based method is based -on the file <filename>TDEDIR/share/mimelnk/magic</filename> and therefore -difficult to extend. But in general, MIME type information can easily be made -available to the system by installing a <literal>.desktop</literal> file, and -it is efficiently and conveniently available through the KDE libraries. -</para> - -</simplesect> - - -<simplesect id="mime-definingmimetypes"> -<title>Defining MIME types</title> - -<para> -Let us define a type <literal>"application/x-foo"</literal> for our new -<application>foobar</application> program. To this end, you have to write a -file <filename>foo.desktop</filename> and install it into -<filename>TDEDIR/share/mimelnk/application</filename>. (This is the usual -location, which may differ between distributions). This can be done by adding -this to the <filename>Makefile.am</filename>: -</para> - -<programlisting> -mimedir = $(kde_mimedir)/application -mime_DATA = foo.desktop -EXTRA_DIST = $(mime_DATA) -</programlisting> - -<para> -The file <filename>foo.desktop</filename> should look as follows: -</para> - -<programlisting> -[Desktop Entry] -Type=MimeType -MimeType=application/x-foo -Icon=fooicon -Patterns=*.foo; -DefaultApp=foobar -Comment=Foo Data File -Comment[de]=Foo Datei -</programlisting> - -<para> -The <literal>"Comment"</literal> entry is supposed to be translated. Since the -<filename>.desktop</filename> file specifies an icon, you should also install -an icon <filename>fooicon.png</filename>, which represents the file e.g. in -<application>Konqueror</application>. -</para> - -<para> -In the KDE libraries, such a type definition is mapped to an instance of the -class <ulink url="kdeapi:tdeio/KMimeType.html">KMimeType</ulink>. -Use this like in the following example: -</para> - -<programlisting> -KMimeType::Ptr type = KMimeType::mimeType("application/x-foo"); -cout << "Type: " << type->name() < endl; -cout << "Icon: " << type->icon() < endl; -cout << "Comment: " << type->icon() < endl; -QStringList patterns = type->patterns(); -QStringList::ConstIterator it; -for (it = patterns.begin(); it != patterns.end(); ++it) - cout << "Pattern: " << (*it) << endl; -</programlisting> - -</simplesect> - - -<simplesect id="mime-determiningmimetypes"> -<title>Determining the MIME type of data</title> - -<para> -The fast method for determining the type of a file is -<function>KMimeType::findByURL()</function>. This looks for the URL string and -in most cases determines the type from the extension. For certain protocols -(e.g. http, man, info), this mechanism is not used. For example, CGI scripts -on web servers written in Perl often have the extension -<literal>.pl</literal>, which would indicate a -<literal>"text/x-perl"</literal> type. However, we file delivered by the -server is the output of this script, which is normally HTML. For such a case, -<function>KMimeType::findByURL()</function> returns the MIME type -<literal>"application/octet-stream"</literal> (available through -<function>KMimeType::defaultMimeType()</function>), which indicates a failure -to find out the type. -</para> - -<programlisting> -KMimeType::Ptr type = KMimeType::findByURL("/home/bernd/foobar.jpg"); -if (type->name() == KMimeType::defaultMimeType()) - cout << "Could not find out type" << endl; -else - cout << "Type: " << type->name() << endl; -</programlisting> - -<para> -(this method has some more arguments, but these are undocumented, so simply -forget about them.) -</para> - -<para> -You may want to find out a MIME from the contents of file instead of -the file name. This is more reliable, but also slower, as it requires -reading a part of the file. This is done with the -<ulink url="kdeapi:tdeio/KMimeMagic.html">KMimeMagic</ulink> -class, which has different error handling: -</para> - -<programlisting> -KMimeMagicResult *result = KMimeMagic::self()->findFileType("/home/bernd/foobar.jpg"); -if (!result || !result->isValid()) - cout << "Could not find out type" << endl; -else - cout << "Type: " << result->mimeType() << endl; -</programlisting> - -<para> -As a variant of this function, you can also determine the type of a memory -chunk. This is e.g. used in <application>Kate</application> in order to find -out the highlighting mode: -</para> - -<programlisting> -QByteArray array; -... -KMimeMagicResult *result = KMimeMagic::self()->findBufferType(array); -if (!result || !result->isValid()) - cout << "Could not find out type" << endl; -else - cout << "Type: " << result->mimeType() << endl; -</programlisting> - -<para> -Of course, even KMimeMagic is only able to determine a file type from the -contents of a local file. For remote files, there is a further possibility: -</para> - -<programlisting> -KURL url("http://developer.kde.org/favicon.ico"); -QString type = TDEIO::NetAccess::mimetype(url); -if (type == KMimeType::defaultMimeType()) - cout << "Could not find out type" << endl; -else - cout << "Type: " << type << endl; -</programlisting> - -<para> -This starts a TDEIO job to download a part of the file and check this. -Note that this function is perhaps quite slow and blocks the program. Normally -you will only want to use this if <function>KMimeType::findByURL()</function> -has returned <literal>"application/octet-stream"</literal>. -</para> - -<para> -On the other hand, if you do not want to block your application, you can also -explicitly start the TDEIO job and connect to some of its signals: -</para> - -<programlisting> -void FooClass::findType() -{ - KURL url("http://developer.kde.org/favicon.ico"); - TDEIO::MimetypeJob *job = TDEIO::mimetype(url); - connect( job, SIGNAL(result(TDEIO::Job*)), - this, SLOT(mimeResult(TDEIO::Job*)) ); -} - -void FooClass::mimeResult(TDEIO::Job *job) -{ - if (job->error()) - job->showErrorDialog(); - else - cout << "MIME type: " << ((TDEIO::MimetypeJob *)job)->mimetype() << endl; -} -</programlisting> - -</simplesect> - - -<simplesect id="mime-mappingmimetypes"> -<title>Mapping a MIME type to an application or service</title> - -<para> -When an application is installed, it installs a <literal>.desktop</literal> -file which contains a list of MIME types this application can load. Similarly, -components like KParts make this information available by their service -<literal>.desktop</literal> files. So in general, there are several programs -and components which can process a given MIME type. You can obtain such a list -from the class <classname>KServiceTypeProfile</classname>: -</para> - -<programlisting> -KService::OfferList offers = KServiceTypeProfile::offers("text/html", "Application"); -KService::OfferList::ConstIterator it; -for (it = offers.begin(); it != offers.end(); ++it) { - KService::Ptr service = (*it); - cout << "Name: " << service->name() << endl; -} -</programlisting> - -<para> -The return value of this function is a list of service offers. A -<classname>KServiceOffer</classname> object packages a KService::Ptr together -with a preference number. The list returned by -<function>KServiceTypeProfile::offers()</function> is ordered by the user's -preference. The user can change this by calling <command>"keditfiletype -text/html"</command> or choosing <guimenuitem>Edit File Type</guimenuitem> on -<application>Konqueror</application>'s context menu on a HTML file. -</para> - -<para> -In the above example, an offer list of the applications supporting -<literal>text/html</literal> was requested. This will - among others - contain -HTML editors like <application>Quanta Plus</application>. You can also replace -the second argument <literal>"Application"</literal> by -<literal>"KParts::ReadOnlyPart"</literal>. In that case, you get a list of -embedable components for presenting HTML content, for example TDEHTML. -</para> - -<para> -In most cases, you are not interested in the list of all service offers -for a combination of MIME type and service type. There is a convenience -function which gives you only the service offer with the highest preference: -</para> - -<programlisting> -KService::Ptr offer = KServiceTypeProfile::preferredService("text/html", "Application"); -if (offer) - cout << "Name: " << service->name() << endl; -else - cout << "No appropriate service found" << endl; -</programlisting> - -<para> -For even more complex queries, there is a full-blown CORBA-like -<ulink url="kdeapi:tdeio/TDETrader.html">trader</ulink>. -</para> - -<para> -In order to run an application service with some URLs, use -<ulink url="kdeapi:tdeio/KRun.html">KRun</ulink>: -</para> - -<programlisting> -KURL::List urlList; -urlList << "http://www.ietf.org/rfc/rfc1341.txt?number=1341"; -urlList << "http://www.ietf.org/rfc/rfc2046.txt?number=2046"; -KRun::run(offer.service(), urlList); -</programlisting> - -</simplesect> - - -<simplesect id="mime-misc"> -<title>Miscellaneous</title> - -<para> -In this section, we want to list some APIs which are loosely related -to the previous discussion. -</para> - -<para> -Getting an icon for a URL. This looks for the type of the URL -and returns the associated icon. -</para> - -<programlisting> -KURL url("ftp://ftp.kde.org/pub/incoming/wibble.c"); -QString icon = KMimeType::iconForURL(url); -</programlisting> - -<para> -Running a URL. This looks for the type of the URL and starts the -user's preferred program associated with this type. -</para> - -<programlisting> -KURL url("http://dot.kde.org"); -new KRun(url); -</programlisting> - -</simplesect> - -</sect1> - - -<sect1 id="nettransparency"> -<title>Network transparency</title> - -<simplesect id="nettransparency-intro"> -<title>Introduction</title> - -<para> -In the age of the world wide web, it is of essential importance that desktop -applications can access resources over the internet: they should be able to -download files from a web server, write files to an ftp server or read mails -from a web server. Often, the ability to access files regardless of their -location is called <emphasis>network transparency</emphasis>. -</para> - -<para> -In the past, different approaches to this goals were implemented. The old NFS -file system is an attempt to implement network transparency on the level of -the POSIX API. While this approach works quite well in local, closely coupled -networks, it does not scale for resources to which access is unreliable and -possibly slow. Here, <emphasis>asynchronicity</emphasis> is important. While -you are waiting for your web browser to download a page, the user interface -should not block. Also, the page rendering should not begin when the page is -completely available, but should updated regularly as data comes in. -</para> - -<para> -In the KDE libraries, network transparency is implemented in the TDEIO API. The -central concept of this architecture is an IO <emphasis>job</emphasis>. A job -may copy, or delete files or similar things. Once a job is started, it works -in the background and does not block the application. Any communication from -the job back to the application - like delivering data or progress information -- is done integrated with the Qt event loop. -</para> - -<para> -Background operation is achieved by starting <emphasis>ioslaves</emphasis> to -perform certain tasks. ioslaves are started as separate processes and are -communicated with through UNIX domain sockets. In this way, no multi-threading -is necessary and unstable slaves can not crash the application that uses them. -</para> - -<para> -File locations are expressed by the widely used URLs. But in KDE, URLs do not -only expand the range of addressable files beyond the local file system. It -also goes in the opposite direction - e.g. you can browse into tar archives. -This is achieved by nesting URLs. For example, a file in a tar archive on -a http server could have the URL -</para> - -<programlisting> -http://www-com.physik.hu-berlin.de/~bernd/article.tgz#tar:/paper.tex -</programlisting> - -</simplesect> - - -<simplesect id="nettransparency-usingkio"> -<title>Using TDEIO</title> - -<para> -In most cases, jobs are created by calling functions in the TDEIO namespace. -These functions take one or two URLs as arguments, and possible other -necessary parameters. When the job is finished, it emits the signal -<literal>result(TDEIO::Job*)</literal>. After this signal has been emitted, the job -deletes itself. Thus, a typical use case will look like this: -</para> - -<programlisting> -void FooClass::makeDirectory() -{ - SimpleJob *job = TDEIO::mkdir(KURL("file:/home/bernd/tdeiodir")); - connect( job, SIGNAL(result(TDEIO::Job*)), - this, SLOT(mkdirResult(TDEIO::Job*)) ); -} - -void FooClass::mkdirResult(TDEIO::Job *job) -{ - if (job->error()) - job->showErrorDialog(); - else - cout << "mkdir went fine" << endl; -} -</programlisting> - -<para> -Depending on the type of the job, you may connect also to other -signals. -</para> - -<para> -Here is an overview over the possible functions: -</para> - -<variablelist> - -<varlistentry><term>TDEIO::mkdir(const KURL &url, int permission)</term> -<listitem><para> -Creates a directory, optionally with certain permissions. -</para></listitem> -</varlistentry> - -<varlistentry><term>TDEIO::rmdir(const KURL &url)</term> -<listitem><para> -Removes a directory. -</para></listitem> -</varlistentry> - -<varlistentry><term>TDEIO::chmod(const KURL &url, int permissions)</term> -<listitem><para> -Changes the permissions of a file. -</para></listitem> -</varlistentry> - -<varlistentry><term>TDEIO::rename(const KURL &src, const KURL &dest, - bool overwrite)</term> -<listitem><para> -Renames a file. -</para></listitem> -</varlistentry> - -<varlistentry><term>TDEIO::symlink(const QString &target, const KURL &dest, - bool overwrite, bool showProgressInfo)</term> -<listitem><para> -Creates a symbolic link. -</para></listitem> -</varlistentry> - -<varlistentry><term>TDEIO::stat(const KURL &url, bool showProgressInfo)</term> -<listitem><para> -Finds out certain information about the file, such as size, modification -time and permissions. The information can be obtained from -TDEIO::StatJob::statResult() after the job has finished. -</para></listitem> -</varlistentry> - -<varlistentry><term>TDEIO::get(const KURL &url, bool reload, bool showProgressInfo)</term> -<listitem><para> -Transfers data from a URL. -</para></listitem> -</varlistentry> - -<varlistentry><term>TDEIO::put(const KURL &url, int permissions, bool overwrite, - bool resume, bool showProgressInfo)</term> -<listitem><para> -Transfers data to a URL. -</para></listitem> -</varlistentry> - -<varlistentry><term>TDEIO::http_post(const KURL &url, const QByteArray &data, - bool showProgressInfo)</term> -<listitem><para>Posts data. Special for HTTP. -</para></listitem> -</varlistentry> - -<varlistentry><term>TDEIO::mimetype(const KURL &url, bool showProgressInfo)</term> -<listitem><para> -Tries to find the MIME type of the URL. The type can be obtained from -TDEIO::MimetypeJob::mimetype() after the job has finished. -</para></listitem> -</varlistentry> - -<varlistentry><term>TDEIO::file_copy(const KURL &src, const KURL &dest, int permissions, - bool overwrite, bool resume, bool showProgressInfo)</term> -<listitem><para> -Copies a single file. -</para></listitem> -</varlistentry> - -<varlistentry><term>TDEIO::file_move(const KURL &src, const KURL &dest, int permissions, - bool overwrite, bool resume, bool showProgressInfo)</term> -<listitem><para> -Renames or moves a single file. -</para></listitem> -</varlistentry> - -<varlistentry><term>TDEIO::file_delete(const KURL &url, bool showProgressInfo)</term> -<listitem><para> -Deletes a single file. -</para></listitem> -</varlistentry> - -<varlistentry><term>TDEIO::listDir(const KURL &url, bool showProgressInfo)</term> -<listitem><para> -Lists the contents of a directory. Each time some new entries are known, the -signal TDEIO::ListJob::entries() is emitted. -</para></listitem> -</varlistentry> - -<varlistentry><term>TDEIO::listRecursive(const KURL &url, bool showProgressInfo)</term> -<listitem><para> -Similar to the listDir() function, but this one is recursive. -</para></listitem> -</varlistentry> - -<varlistentry><term>TDEIO::copy(const KURL &src, const KURL &dest, bool showProgressInfo)</term> -<listitem><para> -Copies a file or directory. Directories are copied recursively. -</para></listitem> -</varlistentry> - -<varlistentry><term>TDEIO::move(const KURL &src, const KURL &dest, bool showProgressInfo)</term> -<listitem><para> -Moves or renames a file or directory. -</para></listitem> -</varlistentry> - -<varlistentry><term>TDEIO::del(const KURL &src, bool shred, bool showProgressInfo)</term> -<listitem><para> -Deletes a file or directory. -</para></listitem> -</varlistentry> - -</variablelist> - -</simplesect> - - -<simplesect id="nettransparency-direntries"> -<title>Directory entries</title> - -<para> -Both the TDEIO::stat() and TDEIO::listDir() jobs return their results as a type -UDSEntry, UDSEntryList resp. The latter is defined as QValueList<UDSEntry>. -The acronym UDS stands for "Universal directory service". The principle behind -it is that the a directory entry only carries the information which an ioslave -can provide, not more. For example, the http slave does not provide any -information about access permissions or file owners. -Instead, a UDSEntry is a list of UDSAtoms. Each atom provides a specific piece -of information. It consists of a type stored in m_uds and either an integer -value in m_long or a string value in m_str, depending on the type. -</para> - -<para> -The following types are currently defined: -</para> - -<itemizedlist> - -<listitem><para> -UDS_SIZE (integer) - Size of the file. -</para></listitem> - -<listitem><para> -UDS_USER (string) - User owning the file. -</para></listitem> - -<listitem><para> -UDS_GROUP (string) - Group owning the file. -</para></listitem> - -<listitem><para> -UDS_NAME (string) - File name. -</para></listitem> - -<listitem><para> -UDS_ACCESS (integer) - Permission rights of the file, as e.g. stored -by the libc function stat() in the st_mode field. -</para></listitem> - -<listitem><para> -UDS_FILE_TYPE (integer) - The file type, as e.g. stored by stat() in the -st_mode field. Therefore you can use the usual libc macros like S_ISDIR to -test this value. Note that the data provided by ioslaves corresponds to -stat(), not lstat(), i.e. in case of symbolic links, the file type here is -the type of the file pointed to by the link, not the link itself. -</para></listitem> - -<listitem><para> -UDS_LINK_DEST (string) - In case of a symbolic link, the name of the file -pointed to. -</para></listitem> - -<listitem><para> -UDS_MODIFICATION_TIME (integer) - The time (as in the type time_t) when the -file was last modified, as e.g. stored by stat() in the st_mtime field. -</para></listitem> - -<listitem><para> -UDS_ACCESS_TIME (integer) - The time when the file was last accessed, as -e.g. stored by stat() in the st_atime field. -</para></listitem> - -<listitem><para> -UDS_CREATION_TIME (integer) - The time when the file was created, as e.g. -stored by stat() in the st_ctime field. -</para></listitem> - -<listitem><para> -UDS_URL (string) - Provides a URL of a file, if it is not simply the -the concatenation of directory URL and file name. -</para></listitem> - -<listitem><para> -UDS_MIME_TYPE (string) - MIME type of the file -</para></listitem> - -<listitem><para> -UDS_GUESSED_MIME_TYPE (string) - MIME type of the file as guessed by the -slave. The difference to the previous type is that the one provided here -should not be taken as reliable (because determining it in a reliable way -would be too expensive). For example, the KRun class explicitly checks the -MIME type if it does not have reliable information. -</para></listitem> - -</itemizedlist> - -<para> -Although the way of storing information about files in a -<classname>UDSEntry</classname> is flexible and practical from the ioslave -point of view, it is a mess to use for the application programmer. For -example, in order to find out the MIME type of the file, you have to iterate -over all atoms and test whether <literal>m_uds</literal> is -<literal>UDS_MIME_TYPE</literal>. Fortunately, there is an API which is a lot -easier to use: the class <classname>KFileItem</classname>. -</para> - -</simplesect> - - -<simplesect id="nettransparency-syncuse"> -<title>Synchronous usage</title> - -<para> -Often, the asynchronous API of TDEIO is too complex to use and therefore -implementing full asynchronicity is not a priority. For example, in a program -that can only handle one document file at a time, there is little that can be -done while the program is downloading a file anyway. For these simple cases, -there is a mucher simpler API in the form of a set of static functions in -TDEIO::NetAccess. For example, in order to copy a file, use -</para> - -<programlisting> -KURL source, target; -source = ...; -target = ... -TDEIO::NetAccess::copy(source, target); -</programlisting> - -<para> -The function will return after the complete copying process has finished. Still, -this method provides a progress dialog, and it makes sure that the application -processes repaint events. -</para> - -<para> -A particularly interesting combination of functions is -<function>download()</function> in combination with -<function>removeTempFile()</function>. The former downloads a file from given -URL and stores it in a temporary file with a unique name. The name is stored -in the second argument. <emphasis>If</emphasis> the URL is local, the file is -not downloaded, and instead the second argument is set to the local file -name. The function <function>removeTempFile()</function> deletes the file -given by its argument if the file is the result of a former download. If that -is not the case, it does nothing. Thus, a very easy to use way of loading -files regardless of their location is the following code snippet: -</para> - -<programlisting> -KURL url; -url = ...; -QString tempFile; -if (TDEIO::NetAccess::download(url, tempFile) { - // load the file with the name tempFile - TDEIO::NetAccess::removeTempFile(tempFile); -} -</programlisting> - -</simplesect> - - -<simplesect id="nettransparency-metadata"> -<title>Meta data</title> - -<para> -As can be seen above, the interface to IO jobs is quite abstract and does not -consider any exchange of information between application and IO slave that -is protocol specific. This is not always appropriate. For example, you may give -certain parameters to the HTTP slave to control its caching behavior or -send a bunch of cookies with the request. For this need, the concept of meta -data has been introduced. When a job is created, you can configure it by adding -meta data to it. Each item of meta data consists of a key/value pair. For -example, in order to prevent the HTTP slave from loading a web page from its -cache, you can use: -</para> - -<programlisting> -void FooClass::reloadPage() -{ - KURL url("http://www.kdevelop.org/index.html"); - TDEIO::TransferJob *job = TDEIO::get(url, true, false); - job->addMetaData("cache", "reload"); - ... -} -</programlisting> - -<para> -The same technique is used in the other direction, i.e. for communication from -the slave to the application. The method -<function>Job::queryMetaData()</function> asks for the value of the certain -key delivered by the slave. For the HTTP slave, one such example is the key -<literal>"modified"</literal>, which contains a (stringified representation of) -the date when the web page was last modified. An example how you can use this -is the following: -</para> - -<programlisting> -void FooClass::printModifiedDate() -{ - KURL url("http://developer.kde.org/documentation/kde2arch/index.html"); - TDEIO::TransferJob *job = TDEIO::get(url, true, false); - connect( job, SIGNAL(result(TDEIO::Job*)), - this, SLOT(transferResult(TDEIO::Job*)) ); -} - -void FooClass::transferResult(TDEIO::Job *job) -{ - QString mimetype; - if (job->error()) - job->showErrorDialog(); - else { - TDEIO::TransferJob *transferJob = (TDEIO::TransferJob*) job; - QString modified = transferJob->queryMetaData("modified"); - cout << "Last modified: " << modified << endl; -} -</programlisting> - -</simplesect> - - -<simplesect id="nettransparency-scheduling"> -<title>Scheduling</title> - -<para> -When using the TDEIO API, you usually do not have to cope with the details of -starting IO slaves and communicating with them. The normal use case is to -start a job and with some parameters and handle the signals the jobs emits. -</para> - -<para> -Behind the curtains, the scenario is a lot more complicated. When you create a -job, it is put in a queue. When the application goes back to the event loop, -TDEIO allocates slave processes for the jobs in the queue. For the first jobs -started, this is trivial: an IO slave for the appropriate protocol is started. -However, after the job (like a download from an http server) has finished, it -is not immediately killed. Instead, it is put in a pool of idle slaves and -killed after a certain time of inactivity (current 3 minutes). If a new request -for the same protocol and host arrives, the slave is reused. The obvious -advantage is that for a series of jobs for the same host, the cost for creating -new processes and possibly going through an authentication handshake is saved. -</para> - -<para> -Of course, reusing is only possible when the existing slave has already finished -its previous job. when a new request arrives while an existing slave process is -still running, a new process must be started and used. In the API usage in the -examples above, there are no limitation for creating new slave processes: if you -start a consecutive series of downloads for 20 different files, then TDEIO will -start 20 slave processes. This scheme of assigning slaves to jobs is called -<emphasis>direct</emphasis>. It not always the most appropriate scheme, as it -may need much memory and put a high load on both the client and server machines. -</para> - -<para> -So there is a different way. You can <emphasis>schedule</emphasis> jobs. If -you do this, only a limited number (currently 3) of slave processes for a -protocol will be created. If you create more jobs than that, they are put in a -queue and are processed when a slave process becomes idle. This is done as -follows: -</para> - -<programlisting> -KURL url("http://developer.kde.org/documentation/kde2arch/index.html"); -TDEIO::TransferJob *job = TDEIO::get(url, true, false); -TDEIO::Scheduler::scheduleJob(job); -</programlisting> - -<para> -A third possibility is <emphasis>connection oriented</emphasis>. For example, -for the IMAP slave, it does not make any sense to start multiple processes for -the same server. Only one IMAP connection at a time should be enforced. In -this case, the application must explicitly deal with the notion of a slave. It -has to deallocate a slave for a certain connection and then assign all jobs -which should go through the same connection to the same slave. This can again -be easily achieved by using the TDEIO::Scheduler: -</para> - -<programlisting> -KURL baseUrl("imap://bernd@albert.physik.hu-berlin.de"); -TDEIO::Slave *slave = TDEIO::Scheduler::getConnectedSlave(baseUrl); - -TDEIO::TransferJob *job1 = TDEIO::get(KURL(baseUrl, "/INBOX;UID=79374")); -TDEIO::Scheduler::assignJobToSlave(slave, job1); - -TDEIO::TransferJob *job2 = TDEIO::get(KURL(baseUrl, "/INBOX;UID=86793")); -TDEIO::Scheduler::assignJobToSlave(slave, job2); - -... - -TDEIO::Scheduler::disconnectSlave(slave); -</programlisting> - -<para> -You may only disconnect the slave after all jobs assigned to it are guaranteed -to be finished. -</para> - -</simplesect> - - -<simplesect id="nettransparency-definingslaves"> -<title>Defining an ioslave</title> - -<para> -In the following we discuss how you can add a new ioslave to the system. -In analogy to services, new ioslaves are advertised to the system by -installing a little configuration file. The following Makefile.am -snippet installs the ftp protocol: -</para> - -<programlisting> -protocoldir = $(kde_servicesdir) -protocol_DATA = ftp.protocol -EXTRA_DIST = $(mime_DATA) -</programlisting> - -<para> -The contents of the file ftp.protocol is as follows: -</para> - -<programlisting> -[Protocol] -exec=tdeio_ftp -protocol=ftp -input=none -output=filesystem -listing=Name,Type,Size,Date,Access,Owner,Group,Link, -reading=true -writing=true -makedir=true -deleting=true -Icon=ftp -</programlisting> - -<para> -The <literal>"protocol"</literal> entry defines for which protocol this slave -is responsible. <literal>"exec"</literal> is (in contrast what you would -expect naively) the name of the library that implements the slave. When the -slave is supposed to start, the <command>"tdeinit"</command> executable is -started which in turn loads this library into its address space. So in -practice, you can think of the running slave as a separate process although it -is implemented as library. The advantage of this mechanism is that it saves a -lot of memory and reduces the time needed by the runtime linker. -</para> - -<para> -The "input" and "output" lines are not used currently. -</para> - -<para> -The remaining lines in the <literal>.protocol</literal> file define which -abilities the slave has. In general, the features a slave must implement are -much simpler than the features the TDEIO API provides for the application. The -reason for this is that complex jobs are scheduled to a couple of subjobs. For -example, in order to list a directory recursively, one job will be started for -the toplevel directory. Then for each subdirectory reported back, new subjobs -are started. A scheduler in TDEIO makes sure that not too many jobs are active -at the same time. Similarly, in order to copy a file within a protocol that -does not support copying directly (like the <literal>ftp:</literal> protocol), -TDEIO can read the source file and then write the data to the destination -file. For this to work, the <literal>.protocol</literal> must advertise the -actions its slave supports. -</para> - -<para> -Since slaves are loaded as shared libraries, but constitute standalone programs, -their code framework looks a bit different from normal shared library plugins. -The function which is called to start the slave is called -<function>kdemain()</function>. This function does some initializations and -then goes into an event loop and waits for requests by the application using -it. This looks as follows: -</para> - -<programlisting> -extern "C" { int kdemain(int argc, char **argv); } - -int kdemain(int argc, char **argv) -{ - TDELocale::setMainCatalogue("tdelibs"); - TDEInstance instance("tdeio_ftp"); - (void) TDEGlobal::locale(); - - if (argc != 4) { - fprintf(stderr, "Usage: tdeio_ftp protocol " - "domain-socket1 domain-socket2\n"); - exit(-1); - } - - FtpSlave slave(argv[2], argv[3]); - slave.dispatchLoop(); - return 0; -} -</programlisting> - -</simplesect> - - -<simplesect id="nettransparency-implementingslaves"> -<title>Implementing an ioslave</title> - -<para> -Slaves are implemented as subclasses of <classname>TDEIO::SlaveBase</classname> -(FtpSlave in the above example). Thus, the actions listed in the -<literal>.protocol</literal> correspond to certain virtual functions in -<classname>TDEIO::SlaveBase</classname> the slave implementation must -reimplement. Here is a list of possible actions and the corresponding virtual -functions: -</para> - -<variablelist> - -<varlistentry><term>reading - Reads data from a URL</term> -<listitem><para>void get(const KURL &url)</para></listitem></varlistentry> - -<varlistentry><term>writing - Writes data to a URL and create the file if it does not exist yet.</term> -<listitem><para>void put(const KURL &url, int permissions, bool overwrite, bool resume)</para></listitem></varlistentry> - -<varlistentry><term>moving - Renames a file.</term> -<listitem><para>void rename(const KURL &src, const KURL &dest, bool overwrite)</para></listitem></varlistentry> - -<varlistentry><term>deleting - Deletes a file or directory.</term> -<listitem><para>void del(const KURL &url, bool isFile)</para></listitem></varlistentry> - -<varlistentry><term>listing - Lists the contents of a directory.</term> -<listitem><para>void listDir(const KURL &url)</para></listitem></varlistentry> - -<varlistentry><term>makedir - Creates a directory.</term> -<listitem><para>void mkdir(const KURL &url, int permissions)</para></listitem></varlistentry> - -</variablelist> - -<para> -Additionally, there are reimplementable functions not listed in the <literal>.protocol</literal> -file. For these operations, TDEIO automatically determines whether they are supported -or not (i.e. the default implementation returns an error). -</para> - -<variablelist> - -<varlistentry><term>Delivers information about a file, similar to the C function stat().</term> -<listitem><para>void stat(const KURL &url)</para></listitem></varlistentry> - -<varlistentry><term>Changes the access permissions of a file.</term> -<listitem><para>void chmod(const KURL &url, int permissions)</para></listitem></varlistentry> - -<varlistentry><term>Determines the MIME type of a file.</term> -<listitem><para>void mimetype(const KURL &url)</para></listitem></varlistentry> - -<varlistentry><term>Copies a file.</term> -<listitem><para>copy(const KURL &url, const KURL &dest, int permissions, bool overwrite)</para></listitem></varlistentry> - -<varlistentry><term>Creates a symbolic link.</term> -<listitem><para>void symlink(const QString &target, const KURL &dest, bool overwrite)</para></listitem></varlistentry> - -</variablelist> - -<para> -All these implementation should end with one of two calls: If the operation -was successful, they should call <literal>finished()</literal>. If an error has occurred, -<literal>error()</literal> should be called with an error code as first argument and a -string in the second. Possible error codes are listed as enum -<type>TDEIO::Error</type>. The second argument is usually the URL in -question. It is used e.g. in <function>TDEIO::Job::showErrorDialog()</function> -in order to parameterize the human-readable error message. -</para> - -<para> -For slaves that correspond to network protocols, it might be interesting to -reimplement the method <function>SlaveBase::setHost()</function>. This is -called to tell the slave process about the host and port, and the user name -and password to log in. In general, meta data set by the application can be -queried by <function>SlaveBase::metaData()</function>. You can check for the -existence of meta data of a certain key with -<function>SlaveBase::hasMetaData()</function>. -</para> - -</simplesect> - - -<simplesect id="nettransparency-communication"> -<title>Communicating back to the application</title> - -<para> -Various actions implemented in a slave need some way to communicate data back -to the application using the slave process: -</para> - -<itemizedlist> - -<listitem><para> -<function>get()</function> sends blocks of data. This is done with -<function>data()</function>, which takes a <classname>QByteArray</classname> -as argument. Of course, you do not need to send all data at once. If you send -a large file, call <function>data()</function> with smaller data blocks, so -the application can process them. Call <function>finished()</function> when -the transfer is finished. -</para></listitem> - -<listitem><para> -<function>listDir()</function> reports information about the entries of a -directory. For this purpose, call <function>listEntries()</function> with a -<classname>TDEIO::UDSEntryList</classname> as argument. Analogously to -<function>data()</function>, you can call this several times. When you are -finished, call <function>listEntry()</function> with the second argument set -to true. You may also call <function>totalSize()</function> to report the -total number of directory entries, if known. -</para></listitem> - -<listitem><para> -<function>stat()</function> reports information about a file like size, MIME -type, etc. Such information is packaged in a -<classname>TDEIO::UDSEntry</classname>, which will be discussed below. Use -<function>statEntry()</function> to send such an item to the application. -</para></listitem> - -<listitem><para> -<function>mimetype()</function> calls <function>mimeType()</function> with a -string argument. -</para></listitem> - -<listitem><para> -<function>get()</function> and <function>copy()</function> may want to provide -progress information. This is done with the methods -<function>totalSize()</function>, <function>processedSize()</function>, -<function>speed()</function>. The total size and processed size are reported -as bytes, the speed as bytes per second. -</para></listitem> - -<listitem><para> -You can send arbitrary key/value pairs of meta data with -<function>setMetaData()</function>. -</para></listitem> - -</itemizedlist> - -</simplesect> - - -<simplesect id="nettransparency-interacting"> -<title>Interacting with the user</title> - -<para> -Sometimes a slave has to interact with the user. Examples include informational -messages, authentication dialogs and confirmation dialogs when a file is about -to be overwritten. -</para> - -<itemizedlist> - -<listitem><para> -<function>infoMessage()</function> - This is for informational feedback, such -as the message "Retrieving data from <host>" from the http slave, which -is often displayed in the status bar of the program. On the application side, -this method corresponds to the signal -<function>TDEIO::Job::infoMessage()</function>. -</para></listitem> - -<listitem><para> -<function>warning()</function> - Displays a warning in a message box with -<function>KMessageBox::information()</function>. If a message box is still -open from a former call of warning() from the same slave process, nothing -happens. -</para></listitem> - -<listitem><para> -<function>messageBox()</function> - This is richer than the previous -method. It allows to open a message box with text and caption and some -buttons. See the enum <type>SlaveBase::MessageBoxType</type> for reference. -</para></listitem> - -<listitem><para> -<function>openPassDlg()</function> - Opens a dialog for the input of user name -and password. -</para></listitem> - -</itemizedlist> - -</simplesect> - -</sect1> - -</chapter> - - - -<appendix id="misc"> -<title>Licensing</title> - -&underFDL; -&underGPL; - -</appendix> - -</book> |