大家好,我遇到了双缓冲问题。
我不知道为什么,但我的文本没有绘制(没有双缓冲文本正在绘制)。
代码如下:
m_hDC = BeginPaint(m_hWnd, &m_ps);
m_graphics = new Graphics(m_hDC);
memDC = CreateCompatibleDC(m_hDC);
pMemGraphics = new Graphics(memDC);
pMemGraphics->DrawString(L"Hello world!", -1, font, PointF(100, 100), &brush);
BitBlt(m_hDC, 0, 0, 500, 200, memDC, 0, 0, SRCCOPY);
EndPaint(m_hWnd, &m_ps);
delete(pMemGraphics);
delete(m_graphics);
怎么了?
CreateCompatibleDC 不会创建您可以在其上绘图的 Canvas 。您必须创建位图并将其分配给上下文。
试试这个:
m_hDC = BeginPaint(m_hWnd, &m_ps);
memDC = CreateCompatibleDC(m_hDC);
HBITMAP hBM = CreateCompatibleBitmap(m_hDC, 500, 200);
SelectObject(memDC, hBM);
// Now you can draw on memDC
// Fill with white color
RECT r;
SetRect(&r, 0, 0, 500, 200);
FillRect(memDC, &r, GetStockObject(WHITE_BRUSH));
// Draw text
::TextOut(memDC, 100, 100, "Hello world!", 12);
// Paint on window
BitBlt(m_hDC, 0, 0, 500, 200, memDC, 0, 0, SRCCOPY);
DeleteObject(hBM);
DeleteDC(memDC);
EndPaint(m_hWnd, &m_ps);