调用AlphaBlend()示例

程序代码:
DECLARE long GetDC IN user32 long
DECLARE long ReleaseDC IN user32 long,long
DECLARE long LoadImage IN user32 long,string,long,long,long,long
DECLARE long CreateCompatibleDC IN gdi32 long
DECLARE long GetBitmapDimensionEx IN gdi32 long,string@
DECLARE long DeleteDC IN gdi32 long
DECLARE long SelectObject IN gdi32 long,long
DECLARE long DeleteObject IN gdi32 long
DECLARE long AlphaBlend IN msimg32 long,long,long,long,long,long,long,long,long,long,long
#define IMAGE_BITMAP 0
#define LR_LOADFROMFILE 0x0010
cFile = "D:\temp\巧克力.bmp"
nWidth = 100
nHeight = 140
hdcDest = GetDC(_screen.hWnd)
hBitmap = LoadImage(0, cFile, IMAGE_BITMAP, nWidth, nHeight, LR_LOADFROMFILE)
IF hBitmap == 0
RETURN
ENDIF
hdcSrc = CreateCompatibleDC(0)
IF hdcSrc == 0
DeleteObject(hBitmap)
RETURN
ENDIF
hObjSrc = SelectObject(hdcSrc, hBitmap)
FOR nAlpha=0 TO 255 STEP 17
AlphaBlend(hdcDest, 10, 10, nWidth, nHeight, hdcSrc, 0, 0, nWidth, nHeight, 0x10000*nAlpha)
INKEY(0.8)
ENDFOR
SelectObject(hdcSrc, hObjSrc)
DeleteDC(hdcSrc)
DeleteObject(hBitmap)
ReleaseDC(_screen.hWnd, hdcDest)