another bug?

[cd]

this code doesn't draw anithing:

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  bmp:=createImageFunction(); // 640x480
  bmp.AlphaFill(0);
  bmp2 := bmp.Resample(240,180,rmSimpleStretch);
  bmp.AlphaFill(255);
  image.PutImage(0,0,bmp2,dmSet);while this code draws:

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  bmp:=createImageFunction(); // 640x480
//  bmp.AlphaFill(0);
  bmp2 := bmp.Resample(240,180,rmSimpleStretch);
//  bmp.AlphaFill(255);
  image.PutImage(0,0,bmp2,dmSet);

[circular]

This is normal.

In your the first code, you get bmp2 filled with alpha = 0, so when you draw it, nothing happens.

When you do Resample, there is no link between the two bitmaps after the resampled bitmap is built.

[cd]

ok, i see.
I should have guessed that myself.

another thing:

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image.Draw(Canvas,R,True);seems to not work correctly - garbage output - with rect R twice smaller than the original image.

while

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image.Draw(Canvas,R,False);works fine.

i don't need transparency here, i'd prefer the faster way: the first one with opaque=true should be faster i think, shouldn't it?

[circular]

Yes, opaque is supposed to be slightly faster, when an appropriate system function is available.

On which operating system (windows, linux, qt) are you trying to stretchdraw ?

[cd]

linux gtk

[circular]

Try to replace the following line (line 242 in TBGRAGtkBitmap.DataDrawOpaque in bgragtkbitmap.pas) :

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DataDrawOpaque(ACanvas,Rect,AData,stretched.LineOrder,stretched.Width,stretched.Height);By :

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DataDrawOpaque(ACanvas,Rect,stretched.Data,stretched.LineOrder,stretched.Width,stretched.Height);

[cd]

i have not yet tried the fix you proposed.

for now i have another strange (as i believe) behavior:

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// preparation
  tex:=TBGRABitmap.Create('image.png');
  tex_mask:=TBGRABitmap.Create('image.png');
  tex_mask.AlphaToGrayscale;

// fade in or out (called by timer with increasing/decreasing value of c)
  tex.AlphaFill(255);
  tex.ApplyMask(tex_mask);
  tex.ApplyGlobalOpacity(c);

this code is used to fade out the image (c=255..0) and then to fade in (c=0..255). fade out is just fine, but after c=0 is applied as global opacity the images fades in with no color - just black instead of all ither colors. if i don't fade out down to c=0 opacity (say c=255..1), then the color is not affected.

[circular]

It's normal, because when opacity is zero, it is considered as a transparent pixel, which has BGRAPixelTransparent value, i.e. r=g=b=a=0