而不是使用手工制作的位图,而不是使用Moveto
和LineTo
进行绘制,我将使用自己创建的数组填充并使用它填充屏幕。
现在,数组只是被红色填充,但是,当我绘制到屏幕上时,我会全黑。
这是代码:
void CCGWorkView::OnDraw(CDC* pDC)
{
CCGWorkDoc* pDoc = GetDocument();
ASSERT_VALID(pDoc);
if (!pDoc)
return;
pDCToUse->FillSolidRect(&r, world.bg_color);
BITMAPINFO bminfo;
CPaintDC hdc(this);
CRect rect;
GetWindowRect(&rect);
int h = rect.bottom - rect.top,
w = rect.right - rect.left;
int *bits = new int[w * h];
HDC hdcMem = CreateCompatibleDC(hdc);
HBITMAP bm = CreateCompatibleBitmap(hdc, w, h);
SelectObject(hdcMem, bm);
bminfo.bmiHeader.biSize = sizeof(bminfo.bmiHeader);
bminfo.bmiHeader.biWidth = w;
bminfo.bmiHeader.biHeight = h;
bminfo.bmiHeader.biPlanes = 1;
bminfo.bmiHeader.biBitCount = 32;
bminfo.bmiHeader.biCompression = BI_RGB;
bminfo.bmiHeader.biSizeImage = 0;
bminfo.bmiHeader.biXPelsPerMeter = 1;
bminfo.bmiHeader.biYPelsPerMeter = 1;
bminfo.bmiHeader.biClrUsed = 0;
bminfo.bmiHeader.biClrImportant = 0;
for (int i = 0; i < w * h; i++) {
bits[i] = RGB(255, 0, 0);
}
SetDIBits(hdcMem, bm, 0, h, bits, &bminfo, 0);
BitBlt(hdc, rect.left, rect.top, w, h, hdcMem, rect.left, rect.top, SRCCOPY);
DeleteDC(hdcMem);
DeleteObject(bm);
delete bits;
}
您的代码中有几个问题。
首先,您不需要CPaintDC
,因为pDC
已传递到OnDraw()
函数中。这实际上可能是导致黑色显示的原因,因为新创建的DC已选择了一个像素的黑白位图,并且当您调用CreateCompatibleBitmap()
时,该位图也是单色的。
第二,SetDIBits()
期望RGBQUAD
颜色(https://docs.microsoft.com/en-us/windows/win32/api/wingdi/ns-wingdi-rgbquad),而不是RGB
。
而且,正如Constantine Georgiou所建议的,即使在MFC为您处理的情况下,也应从DC中取消选择位图,然后再删除它,以避免资源泄漏。
这里是修改后的代码:
void CMFCApplication1View::OnDraw(CDC* pDC)
{
CMFCApplication1Doc* pDoc = GetDocument();
ASSERT_VALID(pDoc);
if (!pDoc)
return;
//pDCToUse->FillSolidRect(&r, world.bg_color);
BITMAPINFO bminfo;
CRect rect;
GetClientRect(&rect);
int h = rect.bottom - rect.top,
w = rect.right - rect.left;
int* bits = new int[w * h];
HDC hdcMem = CreateCompatibleDC(pDC->m_hDC);
HBITMAP bm = CreateCompatibleBitmap(pDC->m_hDC, w, h);
HGDIOBJ hOld = SelectObject(hdcMem, bm);
bminfo.bmiHeader.biSize = sizeof(bminfo.bmiHeader);
bminfo.bmiHeader.biWidth = w;
bminfo.bmiHeader.biHeight = h;
bminfo.bmiHeader.biPlanes = 1;
bminfo.bmiHeader.biBitCount = 32;
bminfo.bmiHeader.biCompression = BI_RGB;
bminfo.bmiHeader.biSizeImage = 0;
bminfo.bmiHeader.biXPelsPerMeter = 1;
bminfo.bmiHeader.biYPelsPerMeter = 1;
bminfo.bmiHeader.biClrUsed = 0;
bminfo.bmiHeader.biClrImportant = 0;
RGBQUAD red = { 0, 0, 255, 0 };
for (int i = 0; i < w * h; i++) {
bits[i] = *((int*)&red);
}
SetDIBits(hdcMem, bm, 0, h, bits, &bminfo, DIB_RGB_COLORS);
BitBlt(pDC->m_hDC, rect.left, rect.top, w, h, hdcMem, rect.left, rect.top, SRCCOPY);
SelectObject(hdcMem, hOld);
DeleteDC(hdcMem);
DeleteObject(bm);
delete[] bits;
}