Question

win32 用多个画刷画FillRect矩形，多次拖拉窗口，会被白色覆盖，为什么？

for (int i = 0; i<200; i++)
{
FillRect(gdc, &rect[i], CreateSolidBrush(colorRef[i])); //矩形无边框
DeleteObject(CreateSolidBrush(colorRef[i]));
}
我试过用双缓冲也一样
这样可以啊，多次拖拉窗口重绘都没有问题，fillrect不用SelectObject不是可以吗，怎么样吖？
HBRUSH hBrush, hBrush0;
for (int i = 0; i<200; i++)
{
hBrush = CreateSolidBrush(colorRef[i]);
hBrush0 = SelectObject(gdc, hBrush);
FillRect(gdc, &rect[i], hBrush);
SelectObject(gdc, hBrush0);
//DeleteObject(SelectObject(gdc, GetStockObject(BLACK_BRUSH)));
//SelectObject(gdc, CreateSolidBrush(colorRef[0]));
//DeleteObject(SelectObject(hdc, GetStockObject(WHITE_BRUSH)));
//FillRect(gdc, &rect[i], CreateSolidBrush(colorRef[i]));
//DeleteObject(CreateSolidBrush(colorRef[i]));
DeleteObject(hBrush);
}

Answer 1

因为系统会帮你用窗口画刷清除原来的