[SOLVED] - StretchDraw Problums
lazarus / 39-Graphics

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BenJones · 2013-05-31 23:14

hi , I am trying to make an editor for small 16x16 bitmaps.
ok so I load a 16x16 icon in the a TImage control, now I have other
TImage that has the width and height of 288, I use StretchDraw to copy
the 16x16 bitmap into the bigger image. but I am seeing problems such
as colors as been changed, e.g. some colours look like they been
lightened or darkened. any ideas what wrong.

anyway here is the code I use though I can't see anything wrong. and
don't understand why it would start changing colors.

Code: [Select]var
  bmp: TBitmap;
  r: TRect;
begin

  bmp := TBitmap.Create;

  r.Left := 0;
  r.Top := 0;
  r.Right := 288;
  r.Bottom := 288;

  //Using this shows incorrect colors.
  bmp.LoadFromFile('c:\out\demo.bmp');
  imgcanvas.Canvas.StretchDraw(r,bmp);

  //This works fine.
  {StretchBlt(imgcanvas.Canvas.Handle, 0, 0,
    288, 288, bmp.Canvas.Handle, 0, 0, 16, 16, SRCCOPY);
   }

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User137 · 2013-06-01 02:54

You are using the functions differently. Right and Bottom are not the
same as Width, Height. The rectangle should be (0, 0) - (287, 287).
Pixel width from 0 to 288 is 289.

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BenJones · 2013-06-01 08:10

No sure what you mean I or I done something wrong, I tryed what you
said the icon draws on the bigger image, but a few colors are like
they been lightened StretchBlt works with no problums. any chnace you
can have a look at my project
I added my project so you can see the problum.
Thanks.

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Jurassic Pork · 2013-06-01 09:01

hello BenJones,

i have tried your project. No problem, the colors in the big image are
the same that in the small. Then the question : what is your version
of Lazarus, your OS ?
tried on Lazarus 1.1 svn 41453  Windows 7 .

Friendly, J.P

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BenJones · 2013-06-01 16:20

hi using lazarus 1.0.8 on Windows 7

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BenJones · 2013-06-01 16:31

I just downloaded
Lazarus-1.1-40379-fpc-2.6.0-20130224-win32.exe and it working fine
now.