美丽Python：将图片转换成ASCII图案的艺术

很多年前，我还在大学上学，参加了一个由FOSSEE组织的学习小组，在那里，我第一次知道了“Python”，并深深的喜欢上了它。它的简单、对复杂问题的优雅解决方案让我吃惊。下面的这个图片转ASCII码工具就是我在这个学习小组里学到的。

工作原理

我首先将给定的图片缩放到一个适合用ASCII表现的分辨率尺寸。让后再将图片转换成灰度级图片(黑白图片)。在黑白图片模式下，灰度有256个等 级，换句话说，每个像素的明暗度是用一个8 bit的值表示。0 表示颜色是黑色，256表示颜色是白色。我们把0-256分成11个小区间，每一个小区间用一个ASCII字符表示。并且字符表现出的颜色深浅要和这个区 间的灰度相匹配。我使用PIL库处理图片。下面的代码写的很明白，你一定能看懂。对于不同的图片，输出的效果可能有些不同，效果有好有差，但你可以通过调 整这11个ASCII来测试生成的效果。

依赖的库

PIL(Python Imaging Library)

在Ubuntu环境下

$ sudo pip install Pillow

代码:

from PIL import Image

ASCII_CHARS = [ '#', '?', '%', '.', 'S', '+', '.', '*', ':', ',', '@']    def scale_image(image, new_width=100):      """Resizes an image preserving the aspect ratio.      """      (original_width, original_height) = image.size      aspect_ratio = original_height/float(original_width)      new_height = int(aspect_ratio * new_width)        new_image = image.resize((new_width, new_height))      return new_image    def convert_to_grayscale(image):      return image.convert('L')    def map_pixels_to_ascii_chars(image, range_width=25):      """Maps each pixel to an ascii char based on the range      in which it lies.        0-255 is divided into 11 ranges of 25 pixels each.      """        pixels_in_image = list(image.getdata())      pixels_to_chars = [ASCII_CHARS[pixel_value/range_width] for pixel_value in              pixels_in_image]        return "".join(pixels_to_chars)    def convert_image_to_ascii(image, new_width=100):      image = scale_image(image)      image = convert_to_grayscale(image)        pixels_to_chars = map_pixels_to_ascii_chars(image)      len_pixels_to_chars = len(pixels_to_chars)        image_ascii = [pixels_to_chars[index: index + new_width] for index in              xrange(0, len_pixels_to_chars, new_width)]        return "\n".join(image_ascii)    def handle_image_conversion(image_filepath):      image = None      try:          image = Image.open(image_filepath)      except Exception, e:          print "Unable to open image file {image_filepath}.".format(image_filepath=image_filepath)          print e          return        image_ascii = convert_image_to_ascii(image)      print image_ascii    if __name__=='__main__':      import sys        image_file_path = sys.argv[1]      handle_image_conversion(image_file_path)

欢迎报告bug和提出改进意见！

(英文，CC Licensed)
来自：http://netsmell.com/beautiful-python-a-simple-ascii-art-generator-from-images.html