OpenCV实现图像上添加汉字

OpenCV已经更新至3.0了，但自带函数putText依然不支持图像上添加汉字，所以下面实现了图像中添加汉字功能，话不多说，代码奉上。

void GetStringSize(HDC hDC, const char* str, int* w, int* h)
{
	SIZE size;
	GetTextExtentPoint32A(hDC, str, strlen(str), &size);
	if(w != 0) *w = size.cx;
	if(h != 0) *h = size.cy;
}
 
void paDrawString(Mat& dst, const char* str, Point org, Scalar color, int fontSize, bool italic, bool underline)
{
	CV_Assert(dst.data != 0 && (dst.channels() == 1 || dst.channels() == 3));
 
	int x, y, r, b;
	if(org.x > dst.cols || org.y > dst.rows) return;
	x = org.x < 0 ? -org.x : 0;
	y = org.y < 0 ? -org.y : 0;
 
	LOGFONTA lf;
	lf.lfHeight         = - fontSize ;
	lf.lfWidth          = 0 ;
	lf.lfEscapement     = 0 ;
	lf.lfOrientation    = 0 ;
	lf.lfWeight         = 5;
	lf.lfItalic         = italic ;	//斜体
	lf.lfUnderline      = underline ;	//下划线
	lf.lfStrikeOut       = 0 ;
	lf.lfCharSet        = DEFAULT_CHARSET ;
	lf.lfOutPrecision    = 0 ;
	lf.lfClipPrecision    = 0 ;
	lf.lfQuality         = PROOF_QUALITY ;
	lf.lfPitchAndFamily  = 0 ;
	strcpy (lf.lfFaceName, "华文行楷" );
 
	HFONT hf = CreateFontIndirectA(&lf);
	HDC hDC = CreateCompatibleDC(0);
	HFONT hOldFont = (HFONT)SelectObject(hDC, hf);
 
	int strBaseW = 0, strBaseH = 0;
	int singleRow = 0;
	char buf[1 << 12];
	strcpy(buf, str);
 
	//处理多行
	{
		int nnh = 0;
		int cw, ch;
		const char* ln = strtok(buf, "\n");
		while(ln != 0)
		{
			GetStringSize(hDC, ln, &cw, &ch);
			strBaseW = max(strBaseW, cw);
			strBaseH = max(strBaseH, ch);
 
			ln = strtok(0, "\n");
			nnh++;
		}
		singleRow = strBaseH;
		strBaseH *= nnh;
	}
 
	if(org.x + strBaseW < 0 || org.y + strBaseH < 0)
	{
		SelectObject(hDC, hOldFont);
		DeleteObject(hf);
		DeleteObject(hDC);
		return;
	}
 
	r = org.x + strBaseW > dst.cols? dst.cols - org.x - 1 : strBaseW - 1;	
	b = org.y + strBaseH > dst.rows ? dst.rows - org.y - 1 : strBaseH - 1;
	org.x = org.x < 0 ? 0 : org.x;
	org.y = org.y < 0 ? 0 : org.y;
 
	BITMAPINFO bmp = {0};
	BITMAPINFOHEADER& bih = bmp.bmiHeader;
	int strDrawLineStep = strBaseW * 3 % 4 == 0 ? strBaseW * 3 : (strBaseW * 3 + 4 - ((strBaseW * 3) % 4));
 
	bih.biSize=sizeof(BITMAPINFOHEADER);
	bih.biWidth=strBaseW;
	bih.biHeight=strBaseH;
	bih.biPlanes=1;
	bih.biBitCount=24;
	bih.biCompression=BI_RGB;
	bih.biSizeImage=strBaseH * strDrawLineStep;
	bih.biClrUsed=0;
	bih.biClrImportant=0;
 
	void* pDibData = 0;
	HBITMAP hBmp = CreateDIBSection(hDC, &bmp, DIB_RGB_COLORS, &pDibData, 0, 0);
 
	CV_Assert(pDibData != 0);
	HBITMAP hOldBmp = (HBITMAP)SelectObject(hDC, hBmp);
 
	//color.val[2], color.val[1], color.val[0]
	SetTextColor(hDC, RGB(255, 255, 255));
	SetBkColor(hDC, 0);
	//SetStretchBltMode(hDC, COLORONCOLOR);
 
	strcpy(buf, str);
	const char* ln = strtok(buf, "\n");
	int outTextY = 0;
	while(ln != 0)
	{
		TextOutA(hDC, 0, outTextY, ln, strlen(ln));
		outTextY += singleRow;
		ln = strtok(0, "\n");
	}
	uchar* dstData = (uchar*)dst.data;
	int dstStep = dst.step/sizeof(dstData[0]);
	unsigned char* pImg = (unsigned char*)dst.data + org.x * dst.channels() + org.y * dstStep;
	unsigned char* pStr = (unsigned char*)pDibData + x * 3;
	for(int tty = y; tty <= b; ++tty)
	{
		unsigned char* subImg = pImg + (tty - y) * dstStep;
		unsigned char* subStr = pStr + (strBaseH - tty - 1) * strDrawLineStep;
		for (int ttx = x; ttx <= r; ++ttx)
		{
			for (int n = 0; n < dst.channels(); ++n){
				double vtxt = subStr[n] / 255.0;
				int cvv =  vtxt * color.val[n] + (1 - vtxt) * subImg[n];
				subImg[n] = cvv > 255 ? 255 : (cvv < 0 ? 0 : cvv);
			}
 
			subStr += 3;
			subImg += dst.channels();
		}
	}
 
	SelectObject(hDC, hOldBmp);
	SelectObject(hDC, hOldFont);
	DeleteObject(hf);
	DeleteObject(hBmp);
	DeleteDC(hDC);
}

调用demo如下：

void main()
{
	Mat img = imread("cat.jpg");
	if(!img.data)
	{
		cout<<"load image error"<<endl;
		return;
	}
	paDrawString(img, "测试汉字哈...\n换行了哟\n真的可以啊！！！~",Point(10, 10), Scalar(255,0,0), 50, true, true);
	imshow("img", img);
	waitKey();
}