调用SetDIBits修改位图内容

通过调用SetDIBits直接修改位图数据。下面的示例在黑色背景上画了一个十字。

void CTest5Dlg::OnOK() { // TODO: Add extra validation here CClientDC dc(this); CDC memDC; memDC.CreateCompatibleDC(&dc); CBitmap bmp; bmp.CreateCompatibleBitmap(&dc, 300, 200); memDC.SelectObject(&bmp); BITMAPINFO bmpInfo; bmpInfo.bmiHeader.biSize = sizeof(BITMAPINFOHEADER); bmpInfo.bmiHeader.biWidth = 300; bmpInfo.bmiHeader.biHeight = -200; bmpInfo.bmiHeader.biPlanes = 1; bmpInfo.bmiHeader.biBitCount = 24; bmpInfo.bmiHeader.biCompression = BI_RGB; bmpInfo.bmiHeader.biSizeImage = 0; bmpInfo.bmiHeader.biXPelsPerMeter = 3000; bmpInfo.bmiHeader.biYPelsPerMeter = 3000; bmpInfo.bmiHeader.biClrUsed = 0; bmpInfo.bmiHeader.biClrImportant = 0; long nLnBytes = (bmpInfo.bmiHeader.biWidth*3+3)/4*4; BYTE *pData = new BYTE[nLnBytes*abs(bmpInfo.bmiHeader.biHeight)]; //清成黑色 memset(pData,0,nLnBytes*abs(bmpInfo.bmiHeader.biHeight)); //画一个十字 for(int i=10; i<90; i++) { //横线, 黄色 pData[50*nLnBytes+i*3+1] = 255; //g pData[50*nLnBytes+i*3+2] = 255; //r //竖线, 蓝色 pData[i*nLnBytes+50*3] = 255; //b } SetDIBits(dc.m_hDC, bmp, 0, abs(bmpInfo.bmiHeader.biHeight), pData, &bmpInfo, DIB_RGB_COLORS); delete []pData; dc.BitBlt(0, 0, bmpInfo.bmiHeader.biWidth, abs(bmpInfo.bmiHeader.biHeight), &memDC, 0, 0, SRCCOPY); }

 效果图：