python 解决OpenCV显示中文字符

因工作需要，要在图片中显示中文字符，并且要求速度足够快，在网上搜罗一番后，总结下几个解决方法。

1.方法一：转PIL后使用PIL相关函数添加中文字符

from PIL import Image, ImageDraw, ImageFontimport cv2import numpy as np# cv2读取图片，名称不能有汉字img = cv2.imread('pic1.jpeg') # cv2和PIL中颜色的hex码的储存顺序不同cv2img = cv2.cvtColor(img, cv2.COLOR_BGR2RGB) pilimg = Image.fromarray(cv2img)# PIL图片上打印汉字draw = ImageDraw.Draw(pilimg) # 图片上打印#simsun 宋体font = ImageFont.truetype("simsun.ttf", 40, encoding="utf-8") #位置，文字，颜色==红色，字体引入draw.text((20, 20), "你好", (255, 0, 0), font=font) # PIL图片转cv2 图片cv2charimg = cv2.cvtColor(np.array(pilimg), cv2.COLOR_RGB2BGR)cv2.imshow("img", cv2charimg)cv2.waitKey (0)cv2.destroyAllWindows()

存在的缺点：cv2->pil 中 Image.fromarray(img)存在耗时4~5ms

2.方法二：opencv重新编译带freetype

编译过程略。

import cv2import numpy as np# 创建一个黑色的图像img = np.zeros((300, 500, 3), dtype=np.uint8)# 中文文本text = '你好，OpenCV！'# 设置字体相关参数font_path = 'path/to/your/chinese/font.ttf'  # 替换为你的中文字体文件路径font_size = 24font_color = (255, 255, 255)thickness = 2# 使用 truetype 字体加载中文字体font = cv2.freetype.createFreeType2()font.loadFontData(font_path)# 在图像上放置中文文本position = (50, 150)font.putText(img, text, position, font_size, font_color, thickness=thickness)# 显示图像cv2.imshow('Image with Chinese Text', img)cv2.waitKey(0)cv2.destroyAllWindows()

缺点：编译过程复杂繁琐，容易报一些列的错误，编译时确保已index.php/tags-98.html" >安装第三方库freetype和harfbuzz，并且配置编译参数时需打开freetype。

3.方法三：使用freetype-py

pip install freetype-py

ft.py

               import numpy as npimport freetypeimport copyimport pdbimport time class PutChineseText(object):    def __init__(self, ttf, text_size):        self._face = freetype.Face(ttf)        hscale = 1.0        self.matrix = freetype.Matrix(int(hscale)*0x10000, int(0.2*0x10000),int(0.0*0x10000), int(1.1*0x10000))        self.cur_pen = freetype.Vector()        self.pen_translate = freetype.Vector()        self._face.set_transform(self.matrix, self.pen_translate)        self._face.set_char_size(text_size * 64)        metrics = self._face.size        ascender = metrics.ascender/64.0         #descender = metrics.descender/64.0        #height = metrics.height/64.0        #linegap = height - ascender + descender        self.ypos = int(ascender)        self.pen = freetype.Vector()     def draw_text(self, image, pos, text, text_color):        '''        draw chinese(or not) text with ttf        :param image:     image(numpy.ndarray) to draw text        :param pos:       where to draw text        :param text:      the context, for chinese should be unicode type        :param text_size: text size        :param text_color:text color        :return:          image        '''                 # if not isinstance(text, unicode):        #     text = text.decode('utf-8')        img = self.draw_string(image, pos[0], pos[1]+self.ypos, text, text_color)        return img     def draw_string(self, img, x_pos, y_pos, text, color):        '''        draw string        :param x_pos: text x-postion on img        :param y_pos: text y-postion on img        :param text:  text (unicode)        :param color: text color        :return:      image        '''        prev_char = 0                self.pen.x = x_pos  6        y_pos = pen.y >> 6        cols = bitmap.width        rows = bitmap.rows         glyph_pixels = bitmap.buffer         for row in range(rows):            for col in range(cols):                if glyph_pixels[row*cols + col] != 0:                    img[y_pos + row][x_pos + col][0] = color[0]                    img[y_pos + row][x_pos + col][1] = color[1]                    img[y_pos + row][x_pos + col][2] = color[2]  if __name__ == '__main__':    # just for test    import cv2     line = '你好'    img = np.zeros([300,300,3])     color_ = (0,255,0) # Green    pos = (40, 40)    text_size = 24     ft = PutChineseText('font/simsun.ttc',text_size=20)    t1 = time.time()    image = ft.draw_text(img, pos, line, color_)    print(f'draw load . ({time.time() - t1:.3f}s)')     cv2.imshow('ss', image)    cv2.waitKey(0)

缺点：每个字符耗时在0.3~1ms左右，耗时略大。

4.方法四：使用OpenCV5.0

4.1 编译opencv5.x版本

编译过程较复杂，不推荐。

4.2 使用rolling版本

卸载原先安装的opencv

pip uninstall opencv-pythonpip uninstall opencv-contrib-python

安装rolling版本

pip install opencv-python-rollingpip install opencv-contrib-python-rolling

安装完毕后，cv2.putText即可支持中文字符。

缺点：5.0版本暂未正式发布，可能存在不稳定情况

优点：耗时几乎没有