Why does this Seg fault? bgrareplace
lazarus / 39-Graphics

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vonskie · 2017-09-13 14:55

Why does this Seg fault here


>>>>bgrareplace(bmp,newimage);
      
Here is the code

Am I using bgrareplace correctly?


bmp := TBGRABitmap.Create;
        bmp.LoadFromfile(imageselected.Text);

        try
        newimage := TBGRABitmap.Create(screen.Width, screen.Height,
BGRABlack);
        newimage.PutImage(0, 0, bmp, dmDrawWithTransparency);
        bgrareplace(bmp,newimage);
        finally
        newimage.free;
        end;

        bmp.SaveToFile(filepath + 'wallpaper.bmp');
        bmp.free;

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lainz · 2017-09-15 17:37

You can upload a small program that reproduces the error?

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vonskie · 2017-09-15 21:50

i think bgrareplace automatically frees newimage so the finally
newimage.free was an issue.

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lainz · 2017-09-15 22:38

Quote from: vonskie on September 15, 2017, 11:50:43 pmi think
bgrareplace automatically frees newimage so the finally newimage.free
was an issue.

BGRAReplace is designed to replace the same image, like

BGRAReplace(bmp, bmp.Resample(...) as TBGRABitmap);

Because some methods creates a new bitmap, usually you want to be the
same bitmap as output, like when you do, for example, resample, blur
and other filters.

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circular · 2017-09-17 17:10

Indeed. BGRAReplace frees the destination image.