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author | Timothy Pearson <kb9vqf@pearsoncomputing.net> | 2011-11-08 12:31:36 -0600 |
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committer | Timothy Pearson <kb9vqf@pearsoncomputing.net> | 2011-11-08 12:31:36 -0600 |
commit | d796c9dd933ab96ec83b9a634feedd5d32e1ba3f (patch) | |
tree | 6e3dcca4f77e20ec8966c666aac7c35bd4704053 /doc/customstyles.doc | |
download | tqt3-d796c9dd933ab96ec83b9a634feedd5d32e1ba3f.tar.gz tqt3-d796c9dd933ab96ec83b9a634feedd5d32e1ba3f.zip |
Test conversion to TQt3 from Qt3 8c6fc1f8e35fd264dd01c582ca5e7549b32ab731
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diff --git a/doc/customstyles.doc b/doc/customstyles.doc new file mode 100644 index 000000000..e3ce114b9 --- /dev/null +++ b/doc/customstyles.doc @@ -0,0 +1,228 @@ +/**************************************************************************** +** +** Documentation for creating custom styles with QStyle +** +** Copyright (C) 1992-2008 Trolltech ASA. All rights reserved. +** +** This file is part of the Qt GUI Toolkit. +** +** This file may be used under the terms of the GNU General +** Public License versions 2.0 or 3.0 as published by the Free +** Software Foundation and appearing in the files LICENSE.GPL2 +** and LICENSE.GPL3 included in the packaging of this file. +** Alternatively you may (at your option) use any later version +** of the GNU General Public License if such license has been +** publicly approved by Trolltech ASA (or its successors, if any) +** and the KDE Free Qt Foundation. +** +** Please review the following information to ensure GNU General +** Public Licensing retquirements will be met: +** http://trolltech.com/products/qt/licenses/licensing/opensource/. +** If you are unsure which license is appropriate for your use, please +** review the following information: +** http://trolltech.com/products/qt/licenses/licensing/licensingoverview +** or contact the sales department at sales@trolltech.com. +** +** This file may be used under the terms of the Q Public License as +** defined by Trolltech ASA and appearing in the file LICENSE.QPL +** included in the packaging of this file. Licensees holding valid Qt +** Commercial licenses may use this file in accordance with the Qt +** Commercial License Agreement provided with the Software. +** +** This file is provided "AS IS" with NO WARRANTY OF ANY KIND, +** INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR +** A PARTICULAR PURPOSE. Trolltech reserves all rights not granted +** herein. +** +**********************************************************************/ + +/*! +\page customstyles.html + +\title Style overview + +A style in Qt implements the look and feel found in a GUI for a +particular platform. For example, Windows platforms may use the +Windows or Windows-XP style, Unix platforms may use the Motif style, +and so on. + +This is a short guide that describes the steps that are necessary to +get started creating and using custom styles with the Qt 3.x style +API. First, we go through the steps necessary to create a style: +\list 1 +\i Pick a base style to inherit from. +\i Re-implement the necessary functions in the derived class. +\endlist +Then we explain how to use the new style from within your own +applications, or as a plugin that can be used by existing Qt +applications. + +\section1 Creating a custom style + +\section2 1. Pick a base style to inherit from. + +The first step is to pick one of the base styles provided with Qt to +build your custom style from. The choice will depend on what look and +feel you are trying to achieve. We recommend that you choose from the +QWindowsStyle derived classes or the QMotifStyle derived classes. +These are the two base look and feel classes in the Qt style engine. +Inheriting directly from QCommonStyle is also an option if you want to +start almost from scratch when implementing your style. In this simple +example we will inherit from QWindowsStyle. + +\section2 2. Re-implement the necessary functions in your derived class. + +Depending on which parts of the base style you want to change, you +must re-implement the functions that are used to draw those parts +of the interface. If you take a look at the \l{QStyle} documentation, +you will find a list of the different primitives, controls and complex +controls. In this example we will first change the look of the +standard arrows that are used in the QWindowsStyle. The arrows are +PrimitiveElements that are drawn by the drawPrimitive() function, +so we need to re-implement that function. We need the following class +declaration: + +\code +#include <qwindowsstyle.h> + +class CustomStyle : public QWindowsStyle { + Q_OBJECT +public: + CustomStyle(); + ~CustomStyle(); + + void drawPrimitive( PrimitiveElement pe, + QPainter *p, + const QRect & r, + const QColorGroup & cg, + SFlags flags = Style_Default, + const QStyleOption & = QStyleOption::Default ) const; + +private: + // Disabled copy constructor and operator= + CustomStyle( const CustomStyle & ); + CustomStyle& operator=( const CustomStyle & ); +}; +\endcode + +Note that we disable the copy constructor and the '=' operator for our +style. QObject is the base class for all style classes in Qt, and a +QObject inherently cannot be copied since there are some aspects of it +that are not copyable. + +From the QStyle docs we see that \c PE_ArrowUp, \c PE_ArrowDown, \c +PE_ArrowLeft and \c PE_ArrowRight are the primitives we need to do +something with. We get the following in our drawPrimitive() function: + +\code +CustomStyle::CustomStyle() +{ +} + +CustomStyle::~CustomStyle() +{ +} + +void CustomStyle::drawPrimitive( PrimitiveElement pe, + QPainter * p, + const QRect & r, + const QColorGroup & cg, + SFlags flags, + const QStyleOption & opt ) const +{ + // we are only interested in the arrows + if (pe >= PE_ArrowUp && pe <= PE_ArrowLeft) { + QPointArray pa( 3 ); + // make the arrow cover half the area it is supposed to be + // painted on + int x = r.x(); + int y = r.y(); + int w = r.width() / 2; + int h = r.height() / 2; + x += (r.width() - w) / 2; + y += (r.height() - h) /2; + + switch( pe ) { + case PE_ArrowDown: + pa.setPoint( 0, x, y ); + pa.setPoint( 1, x + w, y ); + pa.setPoint( 2, x + w / 2, y + h ); + break; + case PE_ArrowUp: + pa.setPoint( 0, x, y + h ); + pa.setPoint( 1, x + w, y + h ); + pa.setPoint( 2, x + w / 2, y ); + break; + case PE_ArrowLeft: + pa.setPoint( 0, x + w, y ); + pa.setPoint( 1, x + w, y + h ); + pa.setPoint( 2, x, y + h / 2 ); + break; + case PE_ArrowRight: + pa.setPoint( 0, x, y ); + pa.setPoint( 1, x, y + h ); + pa.setPoint( 2, x + w, y + h / 2 ); + break; + default: break; + + } + + // use different colors to indicate that the arrow is + // enabled/disabled + if ( flags & Style_Enabled ) { + p->setPen( cg.mid() ); + p->setBrush( cg.brush( QColorGroup::ButtonText ) ); + } else { + p->setPen( cg.buttonText() ); + p->setBrush( cg.brush( QColorGroup::Mid ) ); + } + p->drawPolygon( pa ); + } else { + // let the base style handle the other primitives + QWindowsStyle::drawPrimitive( pe, p, r, cg, flags, data ); + } +} +\endcode + +\section2 Using a custom style + +There are several ways of using a custom style in a Qt application. +The simplest way is to include the following lines of code in the +application's main() function: + +\code +#include "customstyle.h" + +int main( int argc, char ** argv ) +{ + QApplication::setStyle( new CustomStyle() ); + // do the usual routine on creating your QApplication object etc. +} +\endcode + +Note that you must also include the \c customstyle.h and \c +customstyle.cpp files in your project. + +2. Creating and using a pluggable style + +You may want to make your style available for use in other +applications, some of which may not be yours and are not available for +you to recompile. The Qt Plugin system makes it possible to create +styles as plugins. Styles created as plugins are loaded as shared +objects at runtime by Qt itself. Please refer to the \link +plugins-howto.html Qt Plugin\endlink documentation for more +information on how to go about creating a style plugin. + +Compile your plugin and put it into $QTDIR/plugins/styles. We now have +a pluggable style that Qt can load automatically. To use your new +style with existing applications, simply start the application with +the following argument: + +\code +./application -style custom +\endcode + +The application will use the look and feel from the custom style you +implemented. + +*/ |