OpenCV 显示中文汉字，未使用CvxText和FreeType库
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原文链接：https://blog.csdn.net/wanggao_1990/article/details/52955056
OpenCV显示中文汉字，未使用CvxText和FreeType库
采用windows的GDI显示系统的TrueType字体，没有封装，就两个函数，分成了h和cpp文件，可以自己编辑文件名和函数名，亦可以直接将cpp的代码复制到你需要的程序中。
putText.h
putText.cpp
演示
文件putText.h
后面的cpp文件有一些简要说明。
#ifndef PUTTEXT_H_#define PUTTEXT_H_#include <windows.h>#include <string>#include <opencv2/opencv.hpp>using namespace cv;void GetStringSize(HDC hDC, const char* str, int* w, int* h);void putTextZH(Mat &dst, const char* str, Point org, Scalar color, int fontSize, const char *fn = "Arial", bool italic = false, bool underline = false);#endif // PUTTEXT_H_
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putText.cpp
第二个函数putTextZH()，默认使用Arial字体，也可以设置成操作系统中已经安装的字体，如“宋体”、“微软雅黑”、“Times New Roman”等；默认显示非斜体、非下划线。
#include "putText.h"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 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; 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_s(lf.lfFaceName, fn);
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);
}
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演示
读取一个图片加入字体，显示。
#include "opencv2/opencv.hpp"#include "putText.h"using namespace std;using namespace cv;int main()
{
Mat img = imread("src.jpg");
putTextZH(img, "Arial字体换...\n行显示!", Point(50, 50), Scalar(0, 0, 255), 30, "Arial");
putTextZH(img, "微软雅黑字体换...\n行，斜体，下划线，显示!", Point(50, 100), Scalar(0, 255, 0), 30, "微软雅黑", true, true);
putTextZH(img, "楷体字体换...\n行，斜体，下划线，显示!", Point(50, 200), Scalar(128, 255, 0), 30, "楷体", true, true);
imshow("test", img);
waitKey(); return 0;
}
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加上字体显示效果如下：
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