以下程式碼是本人從網上找的，和大家分享一下^

(note:)這是去掉背景色繪製BMP圖片的程式碼

void TransparentBitmap(HDC hdc, HBITMAP hBitmap, int xStart, int yStart, int xadd , int yadd , COLORREF cTransparentColor) {    

BITMAP   m_bm;   COLORREF   cColor;  

 // 建立臨時DC  

 HDC   hMem, hBack, hObject, hTemp, hSave;  

hBack   = CreateCompatibleDC(hdc);  

 hObject = CreateCompatibleDC(hdc);  

hMem   = CreateCompatibleDC(hdc);  

 hSave   = CreateCompatibleDC(hdc);    

 hTemp   = CreateCompatibleDC(hdc);  

// 選入點陣圖

  SelectObject(hTemp, hBitmap);    

GetObject(hBitmap, sizeof(BITMAP), (LPSTR)&m_bm);  

 //顯示點陣圖寬高

  POINT     ptSize;   /

/ 取得點陣圖的寬度

  ptSize.x = m_bm.bmWidth;  

  // 取得點陣圖的該度  

ptSize.y = m_bm.bmHeight;    

  // 轉換為邏輯點值  

 DPtoLP(hTemp, &ptSize, 1);  

 // 建立臨時點陣圖  

 HBITMAP   bmBack, bmObject, bmMem, bmSave;  

// 單色點陣圖

  bmBack   = CreateBitmap(ptSize.x, ptSize.y, 1, 1, NULL);  

  bmObject = CreateBitmap(ptSize.x, ptSize.y, 1, 1, NULL);  

 // 與裝置相容點陣圖   bmMem   = CreateCompatibleBitmap(hdc, ptSize.x, ptSize.y);  

 bmSave     = CreateCompatibleBitmap(hdc, ptSize.x, ptSize.y);  

// 將建立的臨時點陣圖選入臨時DC中  

HBITMAP   OldbmBack, OldbmObject, OldbmMem, OldbmSave;   OldbmBack   = (HBITMAP)SelectObject(hBack, bmBack);  

OldbmObject = (HBITMAP)SelectObject(hObject, bmObject);  

 OldbmMem   = (HBITMAP)SelectObject(hMem, bmMem);  

OldbmSave   = (HBITMAP)SelectObject(hSave, bmSave);  

// 設定對映模式  

 SetMapMode(hTemp, GetMapMode(hdc));  

// 先保留原始點陣圖  

 BitBlt(hSave, 0, 0, ptSize.x, ptSize.y, hTemp, 0, 0, SRCCOPY);  

// 將背景顏色設定為需透明的顏色  

 cColor = SetBkColor(hTemp, cTransparentColor);  

 // 建立目標遮蔽碼

  BitBlt(hObject, 0, 0, ptSize.x, ptSize.y, hTemp, 0, 0, SRCCOPY);  

// 恢復源DC的原始背景色  

SetBkColor(hTemp, cColor);  

// 建立反轉的目標遮蔽碼  

BitBlt(hBack, 0, 0, ptSize.x, ptSize.y, hObject, 0, 0, NOTSRCCOPY);  

 // 拷貝主DC的背景到目標DC  

 BitBlt(hMem, 0, 0, ptSize.x, ptSize.y, hdc, xStart, yStart, SRCCOPY);  

 // 遮蔽點陣圖的顯示區  

BitBlt(hMem, 0, 0, ptSize.x, ptSize.y, hObject, 0, 0, SRCAND);  

 // 遮蔽點陣圖中的透明色  

BitBlt(hTemp, 0, 0, ptSize.x, ptSize.y, hBack, 0, 0, SRCAND);  

// 將點陣圖與目標DC的背景左異或操作  

 BitBlt(hMem, 0, 0, ptSize.x, ptSize.y, hTemp, 0, 0, SRCPAINT);  

// 拷貝目標到螢幕上  

StretchBlt(hdc, xStart, yStart, ptSize.x+xadd, ptSize.y+yadd, hMem, 0, 0, ptSize.x, ptSize.y,SRCCOPY);  

// 恢復原始點陣圖  

BitBlt(hTemp, 0, 0, ptSize.x, ptSize.y, hSave, 0, 0, SRCCOPY);  

 // 刪除臨時記憶體點陣圖  

DeleteObject(SelectObject(hBack, OldbmBack));  

 DeleteObject(SelectObject(hObject, OldbmObject));  

DeleteObject(SelectObject(hMem, OldbmMem));  

 DeleteObject(SelectObject(hSave, OldbmSave));

// 刪除臨時記憶體DC  

DeleteDC(hMem);  

eleteDC(hBack);  

eleteDC(hObject);  

DeleteDC(hSave);  

 DeleteDC(hTemp); }