TBGRABitmap image palette converting
lazarus / 39-Graphics

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SteenJorgensen · 2019-07-27 07:22

I need help for converting a TBGRABitmap to a customize palette.

In my code i end up with a image in correct size but i also need to
converted all the color to 20 different TColor i have pre-defined.

This give me trouble, any idea?


I use BGRABitmap v10.4.

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circular · 2019-07-27 20:58

Ok. So you can supply your palette using a TBGRAPalette object (unit
BGRAPalette). You can add your color using AddColor.

Then you can use a TBGRAColorQuantizer object (unit
BGRAColorQuantization). Create it using your palette as a parameter.

With ApplyDitheringInplace, it replaces the colors directly. Otherwise
GetDitheredBitmap will return a new bitmap.

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SteenJorgensen · 2019-07-29 05:51

Thanks, great!

I have made a little test procedure and this works with 20 color. BUT
not with my colorpallet. I can't find where to put the pallette
parameter in, in the TBGRAColorQuantizer.create.
 
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TForm1.bTestConvClick(Sender: TObject);var  ImageP: TBGRABitmap; 
Quant: TBGRAColorQuantizer;  WorkPalette: TBGRAPalette;begin  Try   
WorkPalette := TBGRAPalette.Create;    If FileExists('WorkPallet.pal')
then      WorkPalette.LoadFromFile('WorkPallet.pal');     ImageP  :=
TBGRABitmap.Create(200, 200, ColorToBGRA(ColorToRGB(clBtnFace)));   
BGRAReplace(ImageP, ImageCrop.Resample(200, 200, rmFineResample));   
Quant := TBGRAColorQuantizer.Create(ImageP, acFullChannelInPalette,
20);    Quant.ApplyDitheringInplace(daNearestNeighbor, ImageP);    
ImageP.Draw(Panel10.Canvas, 0, 0, True);   finally    ImageP.Free;   
WorkPalette.Free;  end;end;

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circular · 2019-07-29 10:43

When creating TBGRAColorQuantizer, change the parameter of Create to
your palette WorkPalette instead of ImageP.

Note that you can also replace
Code: Delphi  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i     ImageP
 := TBGRABitmap.Create(200, 200, ColorToBGRA(ColorToRGB(clBtnFace))); 
  BGRAReplace(ImageP, ImageCrop.Resample(200, 200, rmFineResample));by
Code: Delphi  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i     ImageP
 := ImageCrop.Resample(200, 200, rmFineResample) as TBGRABitmap;