python自带的PIL库扩展图片大小给图片加上文字描述

　　利用python自带的PIL库扩展图片大小给图片加上文字描述。大多都是库函数调用，只是给定图片宽度后计算文字所需行数的代码需要写。 代码比较丑，but it works.

#!/usr/bin/env python3from PIL import Image, ImageDraw, ImageFontimport mathtext="尽管曾作为皇家猎场而存在，意大利大帕拉迪索国家公园一直保留着其野性的一面。画面里的赤狐静静地匍匐在秋草丛中等待时机，它的身躯与自然融为一体。所有狐狸都是机会主义者，生活在大帕拉迪索的赤狐也不例外；如果有可能，无论是鱼类还是野兔，即便是人类野餐留下的残羹冷炙，它们也不介意吃个一干二净。"def make_text_image(width, white, text, save_path, mode = "rgb"):    """    生成一个文字图形, white=1，表示白底黑字，否则为黑底白字    """    # 字体可能要改    # linux查看支持的汉字字体 # fc-list :lang=zh    ft = ImageFont.truetype("DroidSansFallbackFull.ttf", 15)    w, h = ft.getsize(text)    # 计算要几行    lines = math.ceil(w / width) + 1    height = h * lines    # 一个汉字的宽度    one_zh_width, h = ft.getsize("中")    if len(mode) == 1:  # L, 1        background = (255)        color = (0)    if len(mode) == 3:  # RGB        background = (255, 255, 255)        color = (0,0,0)    if len(mode) == 4:  # RGBA, CMYK        background = (255, 255, 255, 255)        color = (0,0,0,0)    newImage = Image.new(mode, (width, height), background if white else color)    draw = ImageDraw.Draw(newImage)    # 分割行    text = text + " " #处理最后少一个字问题    text_list = []    start = 0    end = len(text) - 1    while start < end:        for n in range(end):            try_text = text[start:start+n]            w,h = ft.getsize(try_text)            if w + 2*one_zh_width > width:                break        text_list.append(try_text[0:-1])        start = start + n - 1;    # print(text_list)    i = 0    for t in text_list:         draw.text((one_zh_width, i * h), t, color if white else background, font=ft)        i = i + 1    newImage.save(save_path);def resize_canvas(org_image="aa.jpg", add_image="222.jpg", new_image_path="save2.jpg"):    org_im = Image.open(org_image)    org_width, org_height = org_im.size    mode = org_im.mode    make_text_image(org_width, 0, text, "222.jpg", mode)    add_im = Image.open(add_image)    add_width, add_height = add_im.size    mode = org_im.mode    newImage = Image.new(mode, (org_width, org_height + add_height))    newImage.paste(org_im, (0, 0, org_width, org_height))    newImage.paste(add_im, (0, org_height, add_width, add_height + org_height))    newImage.save(new_image_path)resize_canvas()

原图

改之后的图

参考资料：
PIL库帮助文档http://pillow.readthedocs.io/en/latest/reference/ImageFont.html?highlight=getsize
加水印的学习 https://wanglu.info/1273.html
扩展图片大小的学习 https://ask.helplib.com/1334235
计算字符串像素的学习 http://blog.csdn.net/icamera0/article/details/50762050