David Alm: Automated Syncronization with Documentation

2012-10-18T17:18:32Z

Automated Syncronization with Documentation

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'''Class:''' [[Class IGDIPlus.TGPGraphics|TGPGraphics]]

== Syntax ==
=== Delphi: ===
<code>
'''function''' GetHalftonePalette() : HPALETTE;
</code>

=== C++ Builder: ===
<code>
HPALETTE '''__fastcall''' GetHalftonePalette();
</code>

=== Visual C++ (MFC): ===
<code>
HPALETTE GetHalftonePalette();
</code>

== Summary ==
Returns a Windows halftone palette.

== Description ==
Call this method to get a Windows halftone palette.

Example:

The following example draws the same image twice. Before the
image is drawn the second time, the code gets a halftone
palette, selects the palette into a device context, and
realizes the palette.

<code>
var
AGraphics1 : [[Interface IGDIPlus.IGPGraphics|IGPGraphics]];
AGraphics2 : [[Interface IGDIPlus.IGPGraphics|IGPGraphics]];
AImage : [[Interface IGDIPlus.IGPImage|IGPImage]];
APalette : HPALETTE;

begin

AImage := [[Class IGDIPlus.TGPImage|TGPImage]].Create( 'Mosaic.png' );
</code>
<code lang="delphi">

</code>

<code>
AGraphics1 := [[Class IGDIPlus.TGPGraphics|TGPGraphics]].Create( ACanvas );
AGraphics1.[[Method function IGDIPlus.TGPGraphics.DrawImage(IGPImage;TGPPoint) : TGPGraphics|DrawImage]](AImage, 10, 10);
</code>
<code lang="delphi">
Araphics1 := NIL;

APalette := [[Class IGDIPlus.TGPGraphics|TGPGraphics]].GetHalftonePalette();
SelectPalette( ACanvas.Handle, APalette, FALSE);
RealizePalette( ACanvas.Handle );

</code>

<code>
AGraphics2 := [[Class IGDIPlus.TGPGraphics|TGPGraphics]].Create( ACanvas );
graphics2.[[Method function IGDIPlus.TGPGraphics.DrawImage(IGPImage;TGPPoint) : TGPGraphics|DrawImage]](AImage, 300, 10);
</code>
<code lang="delphi">
Araphics2 := NIL;
DeleteObject( APalette);
end;
</code>
Remarks
The purpose of the GetHalftonePalette method is to enable
GDI+ to produce a better quality halftone when the display
uses 8 bits per pixel. To display an image using the halftone
palette, use the following procedure:

1. Call GetHalftonePalette to get a GDI+ halftone palette.
2. Select the halftone palette into a device context.
3. Realize the palette by calling the RealizePalette
function.
4. Construct a Graphics object from a handle to the device
context.
5. Call the [[Method function IGDIPlus.TGPGraphics.DrawImage(IGPImage;TGPPoint) : TGPGraphics|DrawImage]] method of the Graphics object.

Be sure to delete the palette when you have finished using
it. If you do not follow the preceding procedure, then on an
8-bits-per-pixel-display device, the default, 16-color
process is used, which results in a lesser quality halftone.

Method function IGDIPlus.TGPGraphics.GetHalftonePalette() : HPALETTE - Revision history

David Alm: Automated Syncronization with Documentation