TCanvas.CopyRect方法中参数CopyMode的意义

首先看可能取值:

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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:

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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

CopyMode	效果
Blackness	用黑色填充目标矩形区域.
Whiteness	用白色填充目标矩形区域
DstInvert	将目标矩形图象进行反相
MERGECOPY	将源矩形图象与指定的图案刷(Pattern)进行布尔"与"运算
MERGEPAINT	将源矩形图形经过反相后，与目标矩形图象进行布尔"或"运算
NOTSRCCOPY	将源矩形图象经过反相后，复制到目标矩形上
NOTSRCERASE	先将源矩形图象与目标矩形图象进行布尔"或"运算，然后再将得图象进行反相
PATCOPY	将指定的图案刷复制到目标矩形上
PATINVERT	将指定的图案刷与目标矩形图象进行布尔"异或"运算
PATPAINT	先将源矩形图象进行反相，与指定的图案刷进行布尔"或"运算，再与目标矩形图象进行布尔"或"运算SRCAND 将源矩形图象与目标矩形图象进行布尔"与"运算
SRCCOPY	将源矩形图象直接复制到目标矩形上
SRCERASE	将目标矩形图象进行反相，再与源矩形图象进行布尔"与"运算
SRCINVERT	将源矩形图象与目标矩形图象进行布尔"异或"运算
SRCPAINT	将源矩形图象与目标矩形图象进行布尔"或"运算

好.Bye

http://www.cnblogs.com/huangjacky/archive/2010/02/27/1674653.html