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Docs: LCL/graphics. Updates the TCanvas.Draw topic to clarify content.

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* Based on suggestions by @jamie in the forum discussion
* https://forum.lazarus.freepascal.org/index.php/topic,67389.0.html.
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dsiders 2024-05-28 18:07:11 +01:00
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docs/xml/lcl/graphics.xml
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@ -8998,21 +8998,39 @@ Draws the image content in SrcGraphic on the canvas at the specified position.
<p>
<var>Draw</var> is reintroduced method in TCanvas; it reimplements the
inherited method to use the TGraphic instance in SrcGraphic as the container
for the image content drawn in the method.
with the image content drawn in the method.
</p>
<p>
No actions are performed in the method if SrcGraphic has not been assigned.
</p>
<p>
Draw calls the StretchDraw method to draw the content in SrcGraphic on the
canvas at the position specified in X and Y. The Width and Height in
SrcGraphic are used to size the destination rectangle on the canvas.
Draw calls the StretchDraw method to render the content in SrcGraphic on the
canvas at the position specified in X and Y. The Width and Height in SrcGraphic
set the bounds for the image rectangle applied to the canvas using StretchDraw.
Since a stretch mode is not enabled when StretchDraw is called, the source
graphic is not enlarged or shrunk to the canvas size. The source graphic is
clipped if its bounds exceeds the canvas bounds. The Draw method in SrcGraphic
performs the actions needed to position and rendering the content to the Pixels
in the canvas.
</p>
<p>
CopyMode determines the raster operation performed for the Pixels affected on
the canvas.
</p>
<p>
Calling Draw causes the OnChanging and OnChange events to be signalled (when
assigned). OnChanging occurs prior to calling Draw in the TGraphic instance.
OnChange occurs after calling Draw in the TGraphic instance.
</p>
</descr>
<seealso>
<link id="TCanvas.StretchDraw"/>
<link id="TCanvas.CopyMode"/>
<link id="TCanvas.OnChange"/>
<link id="TCanvas.OnChanging"/>
<link id="TGraphic.Width"/>
<link id="TGraphic.Height"/>
<link id="TGraphic.Draw"/>
<link id="#rtl.classes.TRect">TRect</link>
</seealso>
</element>