OpenCV Basics Tutorial - draw text cv :: putText [1]

Text drawing functions

Function name	description
cv :: putText ()	Draws the specified text in the picture
cv::getTextSize()	Gets a character width and height

Draw text [cv :: putText]

Detailed API follows

void cv::putText(
    cv::Mat& img, // 待绘制的图像
    const string& text, // 待绘制的文字
    cv::Point origin, // 文本框的左下角
    int fontFace, // 字体 (如cv::FONT_HERSHEY_PLAIN)
    double fontScale, // 尺寸因子，值越大文字越大
    cv::Scalar color, // 线条的颜色（RGB）
    int thickness = 1, // 线条宽度
    int lineType = 8, // 线型（4邻域或8邻域，默认8邻域）
    bool bottomLeftOrigin = false // true='origin at lower left'
);

FontFace parameters which fonts are supported as follows

Identifier	description
FONT_HERSHEY_SIMPLEX                   = 0	! <Normal size sans-serif font size Normal sans serif
FONT_HERSHEY_PLAIN                         = 1	! <Small size sans-serif font small sans serif
FONT_HERSHEY_DUPLEX                     = 2	! <Normal size sans-serif font (more complex than FONT_HERSHEY_SIMPLEX) normal size sans serif
FONT_HERSHEY_COMPLEX                 = 3	! <Normal size serif font sans serif normal size is more complex than FONT_HERSHEY_DUPLEX
FONT_HERSHEY_TRIPLEX                    = 4	!< normal size serif font (more complex than FONT_HERSHEY_COMPLEX   Normal size sans-serif font, more complex than FONT_HERSHEY_COMPLEX
FONT_HERSHEY_COMPLEX_SMALL = 5	!< smaller version of FONT_HERSHEY_COMPLEX Trumpet version of FONT_HERSHEY_COMPLEX
FONT_HERSHEY_SCRIPT_SIMPLEX   = 6	! <Hand-writing style font handwriting font
FONT_HERSHEY_SCRIPT_COMPLEX = 7	!< more complex variant of FONT_HERSHEY_SCRIPT_SIMPLEX More complex than FONT_HERSHEY_SCRIPT_SIMPLEX variants
FONT_ITALIC                                          = 16	!< flag for italic font

Any listed in the table to a font can be used in combination and CV :: FONT_ITALIC (or operated by) obtained in italics

Each font has a "natural" size, when fontScale than 1.0, before drawing the text font size by scaling the number

Validation code, and the following results

#include<iostream>
#include<opencv2\opencv.hpp>

using namespace cv;

int main()
{
    Mat img = imread("E:/myFile/picture/kobe.jpg");
    const std::string str1 = "Hello Kobe!";

    putText(img, str1, Point2i(40, 150), FONT_HERSHEY_SIMPLEX, 1, Scalar(0, 255, 0), 1, 8, false);
    putText(img, str1, Point2i(40, 180), FONT_HERSHEY_PLAIN, 1, Scalar(0, 255, 0), 1, 8, false);
    putText(img, str1, Point2i(40, 210), FONT_HERSHEY_DUPLEX, 1, Scalar(0, 255, 0), 1, 8, false);
    putText(img, str1, Point2i(40, 240), FONT_HERSHEY_COMPLEX, 1, Scalar(0, 255, 0), 1, 8, false);
    putText(img, str1, Point2i(40, 270), FONT_HERSHEY_TRIPLEX, 1, Scalar(0, 255, 0), 1, 8, false);
    putText(img, str1, Point2i(40, 300), FONT_HERSHEY_COMPLEX_SMALL, 1, Scalar(0, 255, 0), 1, 8, false);
    putText(img, str1, Point2i(40, 330), FONT_HERSHEY_SCRIPT_SIMPLEX, 1, Scalar(0, 255, 0), 1, 8, false);
    putText(img, str1, Point2i(40, 360), FONT_HERSHEY_SCRIPT_COMPLEX, 1, Scalar(0, 255, 0), 1, 8, false);
    putText(img, str1, Point2i(40, 390), FONT_ITALIC | FONT_HERSHEY_PLAIN, 1, Scalar(0, 255, 0), 1, 8, false);

    imshow("kobe", img);
    waitKey(0);
    return 0;
}

OpenCV Basics Tutorial - draw text cv :: getTextSize [2] See the following URL

https://blog.csdn.net/Gary_ghw/article/details/103746709