我正在尝试在窗口内显示用户监视器，这些监视器都缩小到最大可能的大小。目前它没有使用缓冲区，我不确定如何创建一个我需要的。
由于它动态绘制显示器，不再需要使用WM_ERASEBKGND重绘整个窗口白色，当调整大小时我想，经过大量阅读后，绘制整个虚拟桌面的缩放表示＆ ＃39;作为内存DIB是最好的方法：因此我可以填充显示器之间的空白区域，从而使它不必重绘它们。
多部分问题。是否正在建议一个可以BitBlt显示的内存规模虚拟桌面？要做到这一点，我会使用CreateDIBSection吗？
目前我的WM_PAINT看起来像这样：
hdc = BeginPaint(hwnd, &ps);
innerBorder = 2;
additional = 350;
ratio = (static_cast<double>(sA.getDesktop()->right - sA.getDesktop()->left) / (sA.getDesktop()->bottom - sA.getDesktop()->top));
cxMax = max((innerBorder * 2), min((cA.right - border), (((cA.bottom - border - additional) * ratio))));
cyMax = max((innerBorder * 2) , min((cA.bottom - border - additional), (((cA.right - border) / ratio))));
cxBorder = (cA.right - cxMax) / 2;
SelectObject(hdc, GetStockObject(DC_PEN));
SelectObject(hdc, GetStockObject(DC_BRUSH));
SetDCPenColor(hdc, RGB(255, 255, 255));
//Draw Borders around virtual desktop
Rectangle(hdc, cA.left, cA.top, cxBorder, cA.bottom);
Rectangle(hdc, cA.right - cxBorder, cA.top, cA.right, cA.bottom);
//Draw Borders around virtual desktop
Rectangle(hdc, cxBorder, cA.top, cA.right - cxBorder, (border / 2));
Rectangle(hdc, cxBorder, cyMax + (border / 2), cA.right - cxBorder, cA.bottom);
for (i = 0; i < sA.getNumberOfMonitors(); i++)
{
rT = {
((static_cast<float>(sA.getMonitor(i)->rcMonitor.left - sA.getDesktop()->left) / (sA.getDesktop()->right - sA.getDesktop()->left)) * cxMax) + cxBorder + innerBorder,
((static_cast<float>(sA.getMonitor(i)->rcMonitor.top - sA.getDesktop()->top) / (sA.getDesktop()->bottom - sA.getDesktop()->top)) * cyMax) + (border / 2) + innerBorder,
((static_cast<float>(sA.getMonitor(i)->rcMonitor.right - sA.getDesktop()->left) / (sA.getDesktop()->right - sA.getDesktop()->left)) * cxMax) + cxBorder - innerBorder,
((static_cast<float>(sA.getMonitor(i)->rcMonitor.bottom - sA.getDesktop()->top) / (sA.getDesktop()->bottom - sA.getDesktop()->top)) * cyMax) + (border / 2) - innerBorder,
};
SetDCPenColor(hdc, RGB(255, 255, 255));
//Draw Borders around Monitor RECT
Rectangle(hdc, rT.left - innerBorder, rT.top, rT.left, rT.bottom);
Rectangle(hdc, rT.right, rT.top, rT.right + innerBorder, rT.bottom);
Rectangle(hdc, rT.left - innerBorder, rT.bottom, rT.right + innerBorder, rT.bottom + innerBorder);
Rectangle(hdc, rT.left - innerBorder, rT.top - innerBorder, rT.right + innerBorder, rT.top);
//Draw Monitor RECT
SetDCPenColor(hdc, RGB(0, 0, 0));
Rectangle(hdc, rT.left, rT.top, rT.right, rT.bottom);
DrawText(hdc, sA.getMonitor(i)->szDevice, strlen(sA.getMonitor(i)->szDevice), &rT, DT_CENTER | DT_BOTTOM | DT_NOPREFIX | DT_SINGLELINE);
}
EndPaint(hwnd, &ps);
其中大部分只是计算显示器与窗口的相对大小，而且绘图很少。我确实希望它从图像加载填充和边框。我想我几乎撞到了一堵砖墙。我不知道如何继续创建内存缓冲区。
编辑：我创建内存缓冲区的许多尝试之一，这会导致单色位图。
hdcDisplay = BeginPaint(hwnd, &ps);
hdcBuffer = CreateCompatibleDC(hdcDisplay);
innerBorder = 2;
additional = 350;
ratio = (static_cast<double>(sA.getDesktop()->right - sA.getDesktop()->left) / (sA.getDesktop()->bottom - sA.getDesktop()->top));
cxMax = max((innerBorder * 2), min((cA.right - border), (((cA.bottom - border - additional) * ratio))));
cyMax = max((innerBorder * 2) , min((cA.bottom - border - additional), (((cA.right - border) / ratio))));
cxBorder = (cA.right - cxMax) / 2;
hBitmapDraw = CreateCompatibleBitmap(hdcDisplay, cxMax, cyMax);
hBitmapPrevious = static_cast<HBITMAP>(SelectObject(hdcBuffer, hBitmapDraw));
GetObject(hBitmapDraw, sizeof(BITMAP), &bmpDraw);
BITMAPINFOHEADER bmpInfo;
bmpInfo.biSize = sizeof(BITMAPINFOHEADER);
bmpInfo.biWidth = cxMax;
bmpInfo.biHeight = cyMax;
bmpInfo.biPlanes = 1;
bmpInfo.biBitCount = 32;
bmpInfo.biCompression = BI_RGB;
bmpInfo.biSizeImage = 0;
bmpInfo.biXPelsPerMeter = 0;
bmpInfo.biYPelsPerMeter = 0;
bmpInfo.biClrUsed = 0;
bmpInfo.biClrImportant = 0;
//pBitmapBits = (BYTE*)malloc(sizeof(BYTE)* cxMax * 3 * cyMax);
//hBitmapDraw = CreateDIBSection(hdcDisplay, (BITMAPINFO *)&bmpInfo, DIB_RGB_COLORS, NULL, NULL, 0);
SelectObject(hdcBuffer, hBitmapDraw);
SelectObject(hdcBuffer, GetStockObject(DC_PEN));
SelectObject(hdcBuffer, GetStockObject(DC_BRUSH));
SetDCPenColor(hdcBuffer, RGB(255, 255, 255));
for (i = 0; i < sA.getNumberOfMonitors(); i++)
{
rT = {
((static_cast<float>(sA.getMonitor(i)->rcMonitor.left - sA.getDesktop()->left) / (sA.getDesktop()->right - sA.getDesktop()->left)) * cxMax) + cxBorder + innerBorder,
((static_cast<float>(sA.getMonitor(i)->rcMonitor.top - sA.getDesktop()->top) / (sA.getDesktop()->bottom - sA.getDesktop()->top)) * cyMax) + (border / 2) + innerBorder,
((static_cast<float>(sA.getMonitor(i)->rcMonitor.right - sA.getDesktop()->left) / (sA.getDesktop()->right - sA.getDesktop()->left)) * cxMax) + cxBorder - innerBorder,
((static_cast<float>(sA.getMonitor(i)->rcMonitor.bottom - sA.getDesktop()->top) / (sA.getDesktop()->bottom - sA.getDesktop()->top)) * cyMax) + (border / 2) - innerBorder,
};
SetDCPenColor(hdcBuffer, RGB(255, 255, 255));
//Draw Borders
Rectangle(hdcBuffer, rT.left - innerBorder, rT.top, rT.left, rT.bottom);
Rectangle(hdcBuffer, rT.right, rT.top, rT.right + innerBorder, rT.bottom);
Rectangle(hdcBuffer, rT.left - innerBorder, rT.bottom, rT.right + innerBorder, rT.bottom + innerBorder);
Rectangle(hdcBuffer, rT.left - innerBorder, rT.top - innerBorder, rT.right + innerBorder, rT.top);
SetDCPenColor(hdcBuffer, RGB(0, 0, 0));
Rectangle(hdcBuffer, rT.left, rT.top, rT.right, rT.bottom);
DrawText(hdcBuffer, sA.getMonitor(i)->szDevice, strlen(sA.getMonitor(i)->szDevice), &rT, DT_CENTER | DT_BOTTOM | DT_NOPREFIX | DT_SINGLELINE);
}
BitBlt(hdcDisplay, cxBorder, (border / 2), cxMax - cxBorder, cyMax, hdcBuffer, cxBorder, border/2, SRCCOPY);
SelectObject(hdcBuffer, hBitmapPrevious);
DeleteDC(hdcBuffer);
EndPaint(hwnd, &ps);
答案 0 :(得分：1)
您可以通过执行以下操作绘制位图：
HDC memDC = CreateCompatibleDC(hdc);
HBITMAP memBM = CreateCompatibleBitmap(hdc, nWidth, nHeight);
SelectObject(memDC, memBM);
只需使用hdc替换代码中的memDC来电。然后，您可以使用memDC作为源DC来呼叫StretchBlt。
完成内存DC后，使用DeleteDC进行清理。
MSDN有一个Scaling an image使用此技术的示例。您可以使用绘图逻辑替换DrawBitmap代码。