这是我目前正在做的:
- 通过
GetWindowDC
获取窗口DC - 使用
CreateCompatibleDC
创建一个兼容的 DC - 在我的兼容 DC 上调用
GetPixel
不幸的是,我所有的 GetPixel 调用都返回 CLR_INVALID
。这是我的代码。
bool Gameboard::Refresh()
{
bool ret = false;
HDC context, localContext;
context = GetWindowDC(m_window);
if (context != NULL)
{
localContext = CreateCompatibleDC(context);
if (localContext != NULL)
{
if (BitBlt(localContext, 0, 0, GameboardInfo::BoardWidth, GameboardInfo::BoardHeight,
context, GameboardInfo::TopLeft.x, GameboardInfo::TopLeft.y, SRCCOPY))
{
ret = true;
// several calls to GetPixel which all return CLR_INVALID
}
DeleteDC(localContext);
}
ReleaseDC(m_window, context);
}
return ret;
}
有什么想法吗?
最佳答案
我相信您需要在您的设备环境中选择一个位图。
“必须在设备上下文中选择位图,否则,将在所有像素上返回 CLR_INVALID。” - GetPixel()
bool Gameboard::Refresh()
{
bool ret = false;
HDC context, localContext;
HGDIOBJ origHandle;
context = GetWindowDC(m_window);
if (context != NULL)
{
localContext = CreateCompatibleDC(context);
origHandle = SelectObject(localcontext,CreateCompatibleBitmap(context, GameboardInfo::BoardWidth, GameboardInfo::BoardHeight));
if (localContext != NULL)
{
if (BitBlt(localContext, 0, 0, GameboardInfo::BoardWidth, GameboardInfo::BoardHeight,
context, GameboardInfo::TopLeft.x, GameboardInfo::TopLeft.y, SRCCOPY))
{
ret = true;
// several calls to GetPixel which all return CLR_INVALID
}
SelectObject(localcontext, origHandle);
DeleteDC(localContext);
}
ReleaseDC(m_window, context);
}
return ret;
}
关于c++ - 使用 BitBlt 获取另一个窗口的单个像素,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/8698049/