opencv添加汉字

起因

opencv的mat图片上 如果添加非中午字符 或者英文的话 使用opencv自带的putText就可以满足需求

但是添加汉字的话 putText就会出现问题

可以使用如下函数 在mat上添加汉字

函数

void putTextZH(Mat &dst, const char *str, Point org, Scalar color, int fontsize,
               const char *fn, bool italic, bool underline) {
  CV_Assert(dst.data != 0 && (dst.channels() == 1 || dst.channels() == 3));

  int x, y, r, b;
  //坐标点大于图像宽和高直接返回
  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;        //字体高度
  lf.lfWidth = 0;                 //平均宽度
  lf.lfEscapement = 0;            //字符排列角度
  lf.lfOrientation = 0;           //字符本身旋转的角度
  lf.lfWeight = 2;                //设置字体线条的宽度
  lf.lfItalic = italic;           //斜体
  lf.lfUnderline = underline;     //下划线
  lf.lfStrikeOut = 0;             //是否字符中央加横线
  lf.lfCharSet = DEFAULT_CHARSET; //字符集
  lf.lfOutPrecision = 0;          //字体的精确度
  lf.lfQuality = PROOF_QUALITY;   //字体质量
  lf.lfPitchAndFamily = 0;        //选择字体的间距和字体家族
  strcpy_s(lf.lfFaceName, fn);    //字体的名称

  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_s(buf, str);
  char *bufT[1 << 12]; //这个用于分隔字符串后剩余的字符，可能会超出。

  //处理多行
  {
    int nnh = 0;
    int cw, ch;

    const char *ln = strtok_s(buf, "\n", bufT);
    while (ln != 0) {
      GetStringSize(hdc, ln, &cw, &ch);
      strBaseW = max(strBaseW, cw);
      strBaseH = max(strBaseH, ch);

      ln = strtok_s(0, "\n", bufT);
      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_s(buf, str);
  const char *ln = strtok_s(buf, "\n", bufT);
  int outTextY = 0;
  while (ln != 0) {
    TextOutA(hdc, 0, outTextY, ln, strlen(ln));
    outTextY += singleRow;
    ln = strtok_s(0, "\n", bufT);
  }
  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

Mat imText;
if (m_colorMap) {
  imText = Mat(text_size, CV_8UC3, Scalar(255, 255, 255));
} else if (m_colorMap == 0) {
  imText = Mat(text_size, CV_8UC1, Scalar(255));
}

origin.x = 0;
origin.y = text_size.height - 6;

char *p = (char *)text.data();
putTextZH(imText, p, Point(origin.x + 20, 4), Scalar(120, 120, 120), 22,
          "微软雅黑", 0, 0);