python3.6环境下安装freetype库和基本使用方法(推荐)
FreeType库是一个完全免费(开源)的、高质量的且可移植的字体引擎,它提供统一的接口来访问多种字体格式文件,包括TrueType, OpenType, Type1, CID, CFF, Windows FON/FNT, X11 PCF等。在做图像展示的时候,可以写入中文文字,效果还是很好。
在之前安装库时基本都是直接切换到python3.6环境下直接pip install XXX,在安装freetype直接pip install freetype
不可以了,查了半天又是编译又是官网下载的,太麻烦,不推荐。
(1)正确的安装方法:
注意:一定要加上 -py
pip install freetype-py
(2)常用调用方法
已经封装好了一个文件,可直接保存后调用。
import freetype import copy class put_chinese_text(object): def __init__(self, ttf): self._face = freetype.Face(ttf) def draw_text(self, image, pos, text, text_size, 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 ''' 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 ypos = int(ascender) text = text img = self.draw_string(image, pos[0], pos[1] + 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 pen = freetype.Vector() pen.x = x_pos << 6 # div 64 pen.y = y_pos << 6 hscale = 1.0 matrix = freetype.Matrix(int(hscale) * 0x10000, int(0.2 * 0x10000), \ int(0.0 * 0x10000), int(1.1 * 0x10000)) cur_pen = freetype.Vector() pen_translate = freetype.Vector() image = copy.deepcopy(img) for cur_char in text: self._face.set_transform(matrix, pen_translate) self._face.load_char(cur_char) kerning = self._face.get_kerning(prev_char, cur_char) pen.x += kerning.x slot = self._face.glyph bitmap = slot.bitmap cur_pen.x = pen.x cur_pen.y = pen.y - slot.bitmap_top * 64 self.draw_ft_bitmap(image, bitmap, cur_pen, color) pen.x += slot.advance.x prev_char = cur_char return image def draw_ft_bitmap(self, img, bitmap, pen, color): ''' draw each char :param bitmap: bitmap :param pen: pen :param color: pen color e.g.(0,0,255) - red :return: image ''' x_pos = pen.x >> 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: try: 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] except: continue if __name__ == '__main__': # just for test import cv2 line = '毛不易' img = cv2.imread('./aa.jpg') color_ = (0, 255, 0) # Green pos = (3, 3) text_size = 24 ft = put_chinese_text('yahei.ttf') image = ft.draw_text(img, pos, line, text_size, color_) cv2.imshow('ss', image) cv2.waitKey(0)
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