技术交流.

首先看可能取值:

  cmBlackness = BLACKNESS;
  cmDstInvert = DSTINVERT;
  cmMergeCopy = MERGECOPY;
  cmMergePaint = MERGEPAINT;
  cmNotSrcCopy = NOTSRCCOPY;
  cmNotSrcErase = NOTSRCERASE;
  cmPatCopy = PATCOPY;
  cmPatInvert = PATINVERT;
  cmPatPaint = PATPAINT;
  cmSrcAnd = SRCAND;
  cmSrcCopy = SRCCOPY;
  cmSrcErase = SRCERASE;
  cmSrcInvert = SRCINVERT;
  cmSrcPaint = SRCPAINT;
  cmWhiteness = WHITENESS;

看效果.来点儿代码试一下:

procedure TForm3.Button1Click(Sender: TObject);
var
  RC1,RC2:TRect;
begin
  RC1:=Rect(0,0,img1.Width,img1.Height);
  RC2:=Rect(0,0,img2.Width,img2.Height);
  with img2.Canvas do
  begin
    CopyMode:=cmBlackness;//就改这个
    CopyRect(RC1,img1.Canvas,RC2);
  end;
end;

来弄个表格:
原图

好.Bye