当WindowProc收到WM_PAINT消息时如何找到窗口的脏区域...？
我有一个用 C++（非 MFC）编写的内部 API，在 win32 API 之上实现。我的应用程序正在为每个 WM_PAINT 调用绘制整个窗口。有没有一种方法可以让我只找到脏/无效区域，以便我可以优化绘制函数以仅在与脏区域相交的视图中绘制。
我在 BeginPaint - EndPaint 语句之间尝试了以下代码，但失败了。整个窗户都是黑色的。如果我将优化标志设置为 0，窗口绘制得很好，但绘制速度太慢。有什么建议吗？？？
#if Optimize
// get the inval region and pass it down
HRGN invalRegion = CreateRectRgn(0,0,0,0);
int retVal = ::GetClipRgn( myHDC,invalRegion);
Assert (retVal != -1);
if(retVal == 0)
return; // nothing to draw.
else if(retVal == 1)
Draw(invalRegion); // a valid dirty region handle.
else
#endif
Draw(NULL); // this results in drawing calls to all views in the window.
I have an inhouse API written in C++ (no MFC), implemented on top of win32 API. My app is drawing the whole window for each WM_PAINT call. Is there a way i could find only the dirty/inval region so that i can optimize my draw functions to draw only in the views that intersect with the dirty region.
I tried the following code between BeginPaint - EndPaint statements and failed horribly. whole window was black. If i set Optimize flag to 0, the window draws fine but the drawing is too slow. Any suggestions...??.
#if Optimize
// get the inval region and pass it down
HRGN invalRegion = CreateRectRgn(0,0,0,0);
int retVal = ::GetClipRgn( myHDC,invalRegion);
Assert (retVal != -1);
if(retVal == 0)
return; // nothing to draw.
else if(retVal == 1)
Draw(invalRegion); // a valid dirty region handle.
else
#endif
Draw(NULL); // this results in drawing calls to all views in the window.
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您是否尝试过使用
PAINTSTRUCT中的rcPaint RECT？ GetClipRgn 的文档明确指出它不 指的是由 BeginPaint 创建的剪切区域，但仅限于通过SelectClipRgn显式选择的区域。Have you tried using the
rcPaint RECTfrom thePAINTSTRUCT? GetClipRgn's docs specifically say it does not refer to the clipping region created by BeginPaint, but only those explicitly selected in viaSelectClipRgn.