Resize graphic proportionally
lazarus / 39-Graphics

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vonskie · 2018-02-09 21:04

What am I doing wrong here?

If bmp.width =< then it works okay

If bmp.width > does not scale correctly

What am I doing wrong?

if (checkboxresize.Checked) then
        begin
           if bmp.Width > bmp.Height then
          begin
            bmp.ResampleFilter := rfBestQuality;
            BGRAReplace(bmp,
            // bmp.resample(width,height)
            bmp.Resample(screen.width,(screen.Width * bmp.Height) div
bmp.Width) as TBGRABitmap);
           end
          else
          begin
          
            bmp.ResampleFilter := rfBestQuality;
            BGRAReplace(BMP,
            bmp.resample((screen.Height * bmp.Width) div
bmp.Height,screen.height) as TBGRABitmap);
          end;

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vonskie · 2018-02-10 01:05

Here is a way that works

if (resizechecked) then
                begin

                  ratioX := screen.width / bmp.Width;
                  ratioY := screen.Height / bmp.Height;
                  ratio := Min(ratioX, ratioY);

                  newWidth := trunc(bmp.Width * ratio);
                  newHeight := trunc(bmp.Height * ratio);

                  bmp.ResampleFilter := rfBestQuality;
                   BGRAReplace(BMP, bmp.resample(newwidth,newheight) 
as
                      TBGRABitmap);

                end;