在内存中的BITMAPINFO上写文本 [英] Write text on BITMAPINFO in memory

问题描述

我从.avi视频中以BITMAPINFO的形式检索一帧，我想在其上写一个字符串，并且我不想使用OpenCV.我可以编写一个库来手动更改图像中像素的颜色以形成字母，但这会花费很多时间.图像是32位RGBA

I retrieve a frame from a .avi video as BITMAPINFO and I want to write a string on it, and I dont want to use OpenCV.I could write a library which manually changes the pixel color from the image , to form letters, but it would take a lot of time. The image is 32 bits RGBA

pbmi = (BITMAPINFO*)AVIStreamGetFrame(pgf, i);
BYTE *pPixelSrc = (sizeof(BITMAPINFO) + (BYTE*)pbmi);
long width,height;
width = *((long*)(((BYTE*)pbmi)+4));
height = *((long*)(((BYTE*)pbmi)+8));
//Draw string on data pPixelSrc

推荐答案

使用GDI函数(或Gdiplus)以DrawText或TextOut绘制文本.位图可能会颠倒，可能必须翻转.检查height

Use the GDI function, or Gdiplus, to draw text with DrawText or TextOut. The bitmap could be upside down, it may have to be flipped. Check the sign for height

int width = pbmi->bmiHeader.biWidth;
int height = pbmi->bmiHeader.biHeight;

auto hdc = GetDC(0);
auto memdc = CreateCompatibleDC(hdc);
auto hbitmap = CreateBitmap(width, height, 1, 32, pPixelSrc);
auto oldbmp = SelectObject(memdc, hbitmap);

TextOut(memdc, 0, 0, "123", 3);

SelectObject(memdc, oldbmp);
GetDIBits(memdc, hbitmap, 0, height, pPixelSrc, pbmi, 0);

DeleteObject(hbitmap);
DeleteDC(memdc);
ReleaseDC(0, hdc);

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