删除HBITMAP会在运行时导致访问冲突

Question

我有以下代码来截取窗口的截图,并获取其中特定像素的颜色:

void ProcessScreenshot(HWND hwnd){

HDC WinDC;
HDC CopyDC;
HBITMAP hBitmap;
RECT rt;

GetClientRect (hwnd, &rt);
WinDC = GetDC (hwnd);
CopyDC = CreateCompatibleDC (WinDC);

//Create a bitmap compatible with the DC
hBitmap = CreateCompatibleBitmap (WinDC,
    rt.right - rt.left, //width
    rt.bottom - rt.top);//height

SelectObject (CopyDC, hBitmap);

BitBlt (CopyDC,   //destination
    0,0,
    rt.right - rt.left, //width
    rt.bottom - rt.top, //height
    WinDC,    //source
    0, 0,
    SRCCOPY);       

COLORREF col = ::GetPixel(CopyDC,145,293);

// Do some stuff with the pixel colour.... 

delete hBitmap;

ReleaseDC(hwnd, WinDC);
ReleaseDC(hwnd, CopyDC);

}

行'删除hBitmap;' 导致运行时错误:访问冲突.我想我不能像那样删除它？

因为位图占用了大量空间,如果我没有摆脱它,我将最终导致巨大的内存泄漏.我的问题是:释放DC的HBITMAP是否处理这个问题,或者即使在我发布DC之后它仍然存在？如果是后一种情况,我该如何正确摆脱HBITMAP？

Answer 1

你必须用DeleteObject,而不是销毁GDI对象delete.后者仅用于释放使用分配的对象new.