StretchBlt 的翻转功能是在 源hdc 的宽和高上变个符号吧,怎么不好使呢?
北漂17载 2004-05-07 03:07:09 代码:
GetObject (hstScope, sizeof(BITMAP), &bm);
GetClientRect (hwnd, &rect);
aMemDC = CreateCompatibleDC (hdc);
SelectObject (aMemDC, hstScope);
SetStretchBltMode (hdc, STRETCH_DELETESCANS);
StretchBlt(hdc, 0, 0,rect.right , rect.bottom,
aMemDC, 0, 0,bm.bmWidth,bm.bmHeight,SRCCOPY);
DeleteDC (aMemDC);
能缩放,正常显示,但是在bm.bmWidth变为:-1*bm.bmWidth 时不但不翻转而且没有显示,why??