使用 BitBlt 捕捉桌面像素颜色 [英] Using BitBlt to capture desktop pixel colors

问题描述

现在我正在使用 GetPixel() 从桌面检索大约 64 个像素以获得它们的颜色.我读到 GetPixel() 很慢，但不认为它对几个像素有影响，但每次运行例程需要 1.5 秒.在做了一些研究之后，我得出结论，bitblt 似乎是我正在寻找的.我想要做的是抓取桌面的定义区域(包括所有窗口)，然后抓取给定偏移量的像素颜色.这是我现在正在做的:

Right now I'm using GetPixel() to retrieve about 64 pixels from the desktop in order to obtain their color. I read about GetPixel() being slow but didn't think it would matter for a few pixels but it's taking like 1.5 seconds each time I run the routine. After doing some research I've concluded that bitblt seems like what I'm looking for. What I want to do is grab a defined area of the desktop (including all windows) and then grab pixel colors at given offsets. Here's what I'm doing now:

     for (y=0;y<=7;y++) {
     for (x=0;x<=7;x++) {
     //gameScreen is a struct containing the offset from the top left of the monitor
     //to the area of the screen I need
         grid[y][x]=getColor(gameScreen.x+((x*40)+20),gameScreen.y+((y*40)+20));
         }
     }

int getColor(int x, int y) {
//create new point at given coordinates
POINT point;
point.x=x;
point.y=y;
//convert to logical points
DPtoLP(desktopDC,&point,2);
//get pixel color
//desktopDC is an HDC from GetWindowDC(GetDesktopWindow())
int pixel=GetPixel(desktopDC,point.x,point.y);
return pixel;

}

我找到了大量的教程和文档，但对 Windows API 来说太新了，他们对我来说并没有做太多.谢谢！

I've found a decent amount of tutorial and documentation, but being so new to the windows API they aren't doing to much for me. Thanks!

推荐答案

您可能想要:

• 创建CompatibleDC
• 创建CompatibleBitmap
• SelectObject，保存原始位图
• BitBlt
• 获取DIBits
• SelectObject，放回原始位图
• 删除位图
• 删除DC

如果您定期执行此操作，那么您应该只执行前三个步骤一次，重复 BitBlt 和 GetDIBits，并在程序完成时重复最后三个步骤.

If you're doing this periodically, then you should do the first three steps only once, repeat BitBlt and GetDIBits, and the last three when your program finishes.

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