path: root/doc/chalk/tutorial-select-layer.docbook

<sect1 id="tutorial-select-layer">
<title>A Small selections and layers tutorial</title>

<!-- Does someone know a better way to do this? -->
<screenshot>
<screeninfo>The starting image</screeninfo>
<mediaobject>
<imageobject>
<imagedata fileref="tutorial-select-layer-sample.png" format="PNG" />
</imageobject>
<textobject>
<phrase>The starting image</phrase>
</textobject>
<caption><para>The starting image</para></caption>
</mediaobject>
</screenshot>

<para>
The image above is the image we will work with. Start chalk with this 
image (in the documentation folder
<filename>$<envar>TDEDIR</envar>/share/doc/tde/HTML/en/chalk/tutorial-select-layer-sample.png</filename>) 
and save it to your Home folder (by choosing <guilabel>Save Image As...</guilabel>).

Then open it in &chalk; &mdash; your screen will look a bit like this (we have
zoomed in):
</para>

<screenshot>
<screeninfo>Chalk with the starting image</screeninfo>
<mediaobject>
<imageobject>
<imagedata fileref="tutorial-select-layer-1.png" format="PNG" />
</imageobject>
<textobject>
<phrase>The starting image</phrase>
</textobject>
<caption><para>The starting image</para></caption>
</mediaobject>
</screenshot>

<para>
Now try to select the outline of the head with the <guilabel>Select Outline</guilabel> tool: 
</para>

<screenshot>
<screeninfo>The <guilabel>Select Outline</guilabel> tool</screeninfo>
<mediaobject>
<imageobject>
<imagedata fileref="tutorial-select-layer-2.png" format="PNG" />
</imageobject>
<textobject>
<phrase>The <guilabel>Select Outline</guilabel> tool</phrase>
</textobject>
<caption><para>The <guilabel>Select Outline</guilabel> tool</para></caption>
</mediaobject>
</screenshot>

<para>
After you select it, it should look a bit like this picture:
</para>

<screenshot>
<screeninfo>The picture after selecting the head</screeninfo>
<mediaobject>
<imageobject>
<imagedata fileref="tutorial-select-layer-3.png" format="PNG" />
</imageobject>
<textobject>
<phrase>The picture after selecting the head</phrase>
</textobject>
<caption><para>The picture after selecting the head</para></caption>
</mediaobject>
</screenshot>

<para>
If you accidently select too much, you can cut that part easily off by switching the tool to <guilabel>Subtract</guilabel> mode: 
</para>

<screenshot>
<screeninfo>The <guilabel>Subtract</guilabel> mode</screeninfo>
<mediaobject>
<imageobject>
<imagedata fileref="tutorial-select-layer-4.png" format="PNG" />
</imageobject>
<textobject>
<phrase>The <guilabel>Subtract</guilabel> mode</phrase>
</textobject>
<caption><para>The <guilabel>Subtract</guilabel> mode</para></caption>
</mediaobject>
</screenshot>

<para>
Now it's time to make the edges of the selection a bit fuzzy. This can be done by applying <guilabel>Feather</guilabel> to the selection. 
</para>

<screenshot>
<screeninfo><guilabel>Feather</guilabel> selection</screeninfo>
<mediaobject>
<imageobject>
<imagedata fileref="tutorial-select-layer-5.png" format="PNG" />
</imageobject>
<textobject>
<phrase><guilabel>Feather</guilabel> selection</phrase>
</textobject>
<caption><para><guilabel>Feather</guilabel> selection</para></caption>
</mediaobject>
</screenshot>

<para>
Now cut the selection, using
<menuchoice><guimenu>Edit</guimenu><guimenuitem>Cut</guimenuitem></menuchoice>.
Delete the current layer with
<menuchoice><guimenu>Layer</guimenu><guimenuitem>Remove
Layer</guimenuitem></menuchoice>. Paste your selection, with
<menuchoice><guimenu>Edit</guimenu><guimenuitem>Paste</guimenuitem></menuchoice>.
Now we give ourselves a bit more room to work in by resizing the image a bit.
Use the <menuchoice><guimenu>Image</guimenu><guimenuitem>Change Image
Size...</guimenuitem></menuchoice> dialog for this.
</para>

<screenshot>
<screeninfo>The <guilabel>Image Size</guilabel> dialog</screeninfo>
<mediaobject>
<imageobject>
<imagedata fileref="tutorial-select-layer-6.png" format="PNG" />
</imageobject>
<textobject>
<phrase>The <guilabel>Image Size</guilabel> dialog</phrase>
</textobject>
<caption><para>The <guilabel>Image Size</guilabel> dialog</para></caption>
</mediaobject>
</screenshot>

<para>
Add a new layer, and place it below the old layer. You do this by selecting
the new layer in the layerbox, and then pressing the little 'down' arrow at the bottom.
Now we are going to select the area around the head with a contiguous select
(the tool has a selection-with-bucketfill icon at the border).
</para>

<screenshot>
<screeninfo>The <guilabel>Select Contiguous</guilabel> tool</screeninfo>
<mediaobject>
<imageobject>
<imagedata fileref="tutorial-select-layer-7.png" format="PNG" />
</imageobject>
<textobject>
<phrase>The <guilabel>Select Contiguous</guilabel> tool</phrase>
</textobject>
<caption><para>The <guilabel>Select Contiguous</guilabel> tool</para></caption>
</mediaobject>
</screenshot>

<para>
Make sure to select <guilabel>Sample merged</guilabel> in the tool options:
</para>

<screenshot>
<screeninfo>The <guilabel>Sample merged</guilabel> option</screeninfo>
<mediaobject>
<imageobject>
<imagedata fileref="tutorial-select-layer-8.png" format="PNG" />
</imageobject>
<textobject>
<phrase>The <guilabel>Sample merged</guilabel> option</phrase>
</textobject>
<caption><para>The <guilabel>Sample merged</guilabel> option</para></caption>
</mediaobject>
</screenshot>

<para>
Feather the selection again, and invert it.
Select the <guilabel>Contiguous Fill</guilabel> tool (this is a different tool than
the <guilabel>Contiguous Select</guilabel> tool) and use it on the layer. 
</para>

<screenshot>
<screeninfo>The <guilabel>Contiguous Fill</guilabel> tool</screeninfo>
<mediaobject>
<imageobject>
<imagedata fileref="tutorial-select-layer-9.png" format="PNG" />
</imageobject>
<textobject>
<phrase>The <guilabel>Contiguous Fill</guilabel> tool</phrase>
</textobject>
<caption><para>The <guilabel>Contiguous Fill</guilabel> tool</para></caption>
</mediaobject>
</screenshot>

<para>
Deselect with <menuchoice><guimenu>Select</guimenu><guimenuitem>Deselect</guimenuitem></menuchoice>.
You'll notice some artefacts of the feathering at the sides. You can select them easily with a rectangular selection and then cut them.
</para>

<screenshot>
<screeninfo>The <guilabel>Select Rectangular</guilabel> tool</screeninfo>
<mediaobject>
<imageobject>
<imagedata fileref="tutorial-select-layer-10.png" format="PNG" />
</imageobject>
<textobject>
<phrase>The <guilabel>Select Rectangular</guilabel> tool</phrase>
</textobject>
<caption><para>The <guilabel>Select Rectangular</guilabel> tool</para></caption>
</mediaobject>
</screenshot>

<para>
Move the shadow layer a bit down and to the right to make it look nice.
</para>

<screenshot>
<screeninfo>Moving the shadow layer</screeninfo>
<mediaobject>
<imageobject>
<imagedata fileref="tutorial-select-layer-11.png" format="PNG" />
</imageobject>
<textobject>
<phrase>Moving the shadow layer</phrase>
</textobject>
<caption><para>Moving the shadow layer</para></caption>
</mediaobject>
</screenshot>

<para>
Now you can use the <guilabel>Crop</guilabel> tool to make the image better fit around the head.
</para>

<screenshot>
<screeninfo>The <guilabel>Crop</guilabel> tool</screeninfo>
<mediaobject>
<imageobject>
<imagedata fileref="tutorial-select-layer-12.png" format="PNG" />
</imageobject>
<textobject>
<phrase>The <guilabel>Crop</guilabel> tool</phrase>
</textobject>
<caption><para>The <guilabel>Crop</guilabel> tool</para></caption>
</mediaobject>
</screenshot>

<para>
Save the image, and you're done :-)
</para>

<screenshot>
<screeninfo>The resulting image</screeninfo>
<mediaobject>
<imageobject>
<imagedata fileref="tutorial-select-layer-13.png" format="PNG" />
</imageobject>
<textobject>
<phrase>The resulting image</phrase>
</textobject>
<caption><para>The resulting image</para></caption>
</mediaobject>
</screenshot>

<para>
Thanks go to Bart Coppens for providing this tutorial. The original is available at <ulink url="http://www.bartcoppens.be/chalk/hackergotchi.html">http://www.bartcoppens.be/chalk/hackergotchi.html</ulink>.
</para>

</sect1>