printer.py

import numpy as np
from PIL import ImageFont, ImageDraw, Image


class Printer:

    def __init__(self, font_file: str, font_size: int):
        self.font_size = font_size
        self.font = ImageFont.truetype(font_file, font_size)

    def print(self, width, height, text_gen: iter):
        """
        Print text on a `width` x `height` canvas
        :param width: the width of the canvas
        :param height: the height of the canvas
        :param text_gen: a generator which yield text to draw upon the canvas
        :return: A generator, yielding `image` and `text`(label)
        """
        for text, seq_len in text_gen:
            # 生成空白图像, (宽度，高度 )
            img = Image.new("1", (width, height), color="white")

            # 绘图句柄
            draw = ImageDraw.Draw(img)

            # 获取字体的宽度，高度
            font_width, font_height = self.font.getsize(text)

            # 获取文字的offset位置,获取字体的大小
            # offsetx, offsety = self.font.getoffset(text)

            # 实现居中，确定begin_x, begin_y位置，就能实现字居中
            begin_x, begin_y = (width - font_width) // 2, (height - font_height) // 2

            # 绘图
            draw.text((begin_x, begin_y), text, font=self.font, fill="black")
            im = (np.array(img.getdata()).astype(np.uint8)).reshape(height, width)
            yield im, text

    def print_one(self, width, height, text):
        im = Image.new("1", (width, height), color='black')
        draw = ImageDraw.Draw(im)
        text_width, text_height = self.font.getsize(text)
        begin_x, begin_y = (width - text_width) // 2, (height - text_height) // 2
        draw.text((begin_x, begin_y), text, font=self.font, fill="white")
        img = (np.array(im.getdata()).astype(np.uint8)).reshape(height, width)
        return img