【图像处理】opencv 动态在右上角写自定义的字

cv2.putText(img, text, org, fontFace, fontScale, color[, thickness[, lineType[, bottomLeftOrigin]])
简单的使用：
主要参数：图片数据，写入字符，基准坐标，字体，字体比例，颜色，粗细等

cv2.putText()
putText(img, text, org, fontFace, fontScale, color[, thickness[, lineType[, bottomLeftOrigin]]]) -> img
.   @brief Draws a text string.
.
.   The function cv::putText renders the specified text string in the image. Symbols that cannot be rendered
.   using the specified font are replaced by question marks. See #getTextSize for a text rendering code
.   example.
.
.   @param img Image.
.   @param text Text string to be drawn.
.   @param org Bottom-left corner of the text string in the image.
.   @param fontFace Font type, see #HersheyFonts.
.   @param fontScale Font scale factor that is multiplied by the font-specific base size.
.   @param color Text color.
.   @param thickness Thickness of the lines used to draw a text.
.   @param lineType Line type. See #LineTypes
.   @param bottomLeftOrigin When true, the image data origin is at the bottom-left corner. Otherwise,
.   it is at the top-left corner.

cv2.getTextSize得到文本尺寸参数:text,
fontFace, fontScale, thickness
官方文档：
参考：https://blog.csdn.net/Dontla/article/details/103139195
对cv2.getTextSize的返回值的详细介绍，返回格式如下(width,height),bottom

def getTextSize(text, fontFace, fontScale, thickness): # real signature unknown; restored from __doc__
    getTextSize(text, fontFace, fontScale, thickness) -> retval, baseLine
    .   @brief Calculates the width and height of a text string.
    	计算文本字符串的宽度和高度。
    .   
    .   The function cv::getTextSize calculates and returns the size of a box that contains the specified text.
    .   That is, the following code renders some text, the tight box surrounding it, and the baseline: :
    	计算并返回包含指定文本的框的大小。
     。 也就是说，以下代码呈现了一些文本，其周围的紧框和基线：
    .   @code
    .   String text = "Funny text inside the box";
    .   int fontFace = FONT_HERSHEY_SCRIPT_SIMPLEX;
    .   double fontScale = 2;
    .   int thickness = 3;
    .   
    .   Mat img(600, 800, CV_8UC3, Scalar::all(0));
    .   
    .   int baseline=0;
    .   Size textSize = getTextSize(text, fontFace,
    .   fontScale, thickness, &baseline);
    .   baseline += thickness;
    .   
    .   // center the text 文字居中
    .   Point textOrg((img.cols - textSize.width)/2,
    .   (img.rows + textSize.height)/2);
    .   
    .   // draw the box 画盒子
    .   rectangle(img, textOrg + Point(0, baseline),
    .   textOrg + Point(textSize.width, -textSize.height),
    .   Scalar(0,0,255));
    .   // ... and the baseline first 首先是基线
    .   line(img, textOrg + Point(0, thickness),
    .   textOrg + Point(textSize.width, thickness),
    .   Scalar(0, 0, 255));
    .   
    .   // then put the text itself 然后把文字本身
    .   putText(img, text, textOrg, fontFace, fontScale,
    .   Scalar::all(255), thickness, 8);
    .   @endcode
    .   
    .   @param text Input text string. 输入文字字符串。
    .   @param fontFace Font to use, see #HersheyFonts. 要使用的字体，请参见#HersheyFonts。
    .   @param fontScale Font scale factor that is multiplied by the font-specific base size.
    					 字体比例因子，用来被特定字体的基本大小相乘。
    .   @param thickness Thickness of lines used to render the text. See #putText for details.
    					 用于渲染文本的线的粗细。 有关详细信息，请参见#putText。
    .   @param[out] baseLine y-coordinate of the baseline relative to the bottom-most text
    .   point. 基线相对于最底下的文本点的y坐标。
    .   @return The size of a box that contains the specified text. 包含指定文本的框的大小。
    .   
    .   @see putText
    pass

简单使用：
主要使用参数：字符，字体，字符比例，粗细

cv2.getTextSize('Fmg_b',cv2.FONT_HERSHEY_SIMPLEX, 1, 2)

对cv2.getTextSize的返回值的详细介绍
返回的格式如下,(是以putText的坐标做为基准点)

(width, height),bottom

在这里插入图片描述

# ref:https://blog.csdn.net/weixin_40293999/article/details/137425447
import cv2
import numpy as np

text = "Hello World!!!"
# 要使用的字体
fontFace = cv2.FONT_HERSHEY_SIMPLEX
fontScale = 1
thickness = 2
(width, height), bottom = cv2.getTextSize(text, fontFace, fontScale=fontScale, thickness=thickness)
image = np.zeros((512, 512, 3), np.uint8)
H, W, C = image.shape
cv2.putText(image, text, (W - width, height), fontFace, fontScale, color=(0, 0, 255), thickness=thickness,
            lineType=cv2.LINE_AA)

cv2.imshow("image", image)
cv2.waitKey(0)
cv2.destroyAllWindows()