用Windows GDI 繪圖時設定透明色

1. void DrawTransparent(int x,int y,CDC *pDC,CBitmap *pBitmap,COLORREF Color,CRect* rect)
2. {
3. BITMAP bm;
4. pBitmap->GetObject(sizeof(BITMAP),&bm);
5.   CDC ImageDC;
6. ImageDC.CreateCompatibleDC(pDC);
7. CBitmap *pOldImageBitmap=ImageDC.SelectObject(pBitmap);
8. CDC MaskDC;
9. MaskDC.CreateCompatibleDC(pDC);
10. CBitmap MaskBitmap;
11. MaskBitmap.CreateBitmap(bm.bmWidth,bm.bmHeight,1,1,NULL);
12. CBitmap *pOldMaskBitmap=MaskDC.SelectObject(&MaskBitmap);
13. ImageDC.SetBkColor(Color);
14. MaskDC.BitBlt(0,0,bm.bmWidth,bm.bmHeight,&ImageDC,0,0,SRCCOPY);
15. CDC OrDC;
16. OrDC.CreateCompatibleDC(pDC);
17. CBitmap OrBitmap;
18. OrBitmap.CreateCompatibleBitmap(&ImageDC,bm.bmWidth,bm.bmHeight);
19. CBitmap *pOldOrBitmap=OrDC.SelectObject(&OrBitmap);
20. OrDC.BitBlt(0,0,bm.bmWidth,bm.bmHeight,&ImageDC,0,0,SRCCOPY);
21. OrDC.BitBlt(0,0,bm.bmWidth,bm.bmHeight,&MaskDC,0,0,0x220326);
22. CDC TempDC;
23. TempDC.CreateCompatibleDC(pDC);
24. CBitmap TempBitmap;
25. TempBitmap.CreateCompatibleBitmap(&ImageDC,bm.bmWidth,bm.bmHeight);
26. CBitmap *pOldTmepBitmap=TempDC.SelectObject(&TempBitmap);
27. TempDC.BitBlt(0,0,bm.bmWidth,bm.bmHeight,pDC,x,y,SRCCOPY);
28. TempDC.BitBlt(0,0,bm.bmWidth,bm.bmHeight,&MaskDC,0,0,SRCAND);
29. TempDC.BitBlt(0,0,bm.bmWidth,bm.bmHeight,&OrDC,0,0,SRCPAINT);
30. if (rect!=NULL)
31.   pDC->BitBlt(x,y,rect->Width(),rect->Height(),&TempDC,rect->left,rect->top,SRCCOPY);
32.     else
33. pDC->BitBlt(x,y,bm.bmWidth,bm.bmHeight,&TempDC,0,0,SRCCOPY);
34.     TempDC.SelectObject(pOldTmepBitmap);
35. OrDC.SelectObject(pOldOrBitmap);
36. MaskDC.SelectObject(pOldMaskBitmap);
37. ImageDC.SelectObject(pOldImageBitmap);
38. }