winapi - HBITMAP StretchBlt 导致图像饱和

Question

我使用以下代码来调整 win32 HBITMAP 的大小。

HBITMAP ResizeBitmap(HDC hDC, HBITMAP source)
{
    HDC hMemDC2 = CreateCompatibleDC(hDC);
    HGDIOBJ hOld2 = SelectObject(hMemDC2, source);

    BITMAP bitmap = { 0 };
    GetObject(hBitmap, sizeof(BITMAP), &bitmap);

    float SCALE = IMAGE_SCALE;
    int nWidth = (int)ceil(bitmap.bmWidth / SCALE / 32) * 32;
    int nHeight = (int)ceil(bitmap.bmHeight / SCALE / 32) * 32;
    int dWidth = (int)round(bitmap.bmWidth / SCALE);
    int dHeight = (int)round(bitmap.bmHeight / SCALE);

    HDC hMemDC1 = CreateCompatibleDC(hDC);
    HBITMAP hBitmap1 = CreateCompatibleBitmap(hDC, nWidth, nHeight);
    HGDIOBJ hOld1 = SelectObject(hMemDC1, hBitmap1);

    StretchBlt(hMemDC1, 0, 0, dWidth, dHeight, hMemDC2, 0, 0, bitmap.bmWidth, bitmap.bmHeight, SRCCOPY);

    SelectObject(hMemDC1, hOld1);
    SelectObject(hMemDC2, hOld2);
    DeleteDC(hMemDC1);
    DeleteDC(hMemDC2);

    return hBitmap1;
}

但是，我发现新图像已饱和。如原始图像所示

和新图像（请忽略图像中的绿色矩形）

为什么？