Python圖像處理之gif動態圖的解析與合成操作詳解

2020-01-04 13:39:28

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本文實例講述了Python圖像處理之gif動態圖的解析與合成操作。分享給大家供大家參考，具體如下：

gif動態圖是在現在已經司空見慣，朋友圈里也經常是一言不合就斗圖。這里，就介紹下如何使用python來解析和生成gif圖像。

一、gif動態圖的合成

如下圖，是一個gif動態圖。

Python,圖像處理之,gif,動態圖

gif動態圖的解析可以使用PIL圖像模塊即可，具體代碼如下：

#-*- coding: UTF-8 -*-import osfrom PIL import Imagedef analyseImage(path):  '''  Pre-process pass over the image to determine the mode (full or additive).  Necessary as assessing single frames isn't reliable. Need to know the mode  before processing all frames.  '''  im = Image.open(path)  results = {    'size': im.size,    'mode': 'full',  }  try:    while True:      if im.tile:        tile = im.tile[0]        update_region = tile[1]        update_region_dimensions = update_region[2:]        if update_region_dimensions != im.size:          results['mode'] = 'partial'          break      im.seek(im.tell() + 1)  except EOFError:    pass  return resultsdef processImage(path):  '''  Iterate the GIF, extracting each frame.  '''  mode = analyseImage(path)['mode']  im = Image.open(path)  i = 0  p = im.getpalette()  last_frame = im.convert('RGBA')  try:    while True:      print "saving %s (%s) frame %d, %s %s" % (path, mode, i, im.size, im.tile)      '''      If the GIF uses local colour tables, each frame will have its own palette.      If not, we need to apply the global palette to the new frame.      '''      if not im.getpalette():        im.putpalette(p)      new_frame = Image.new('RGBA', im.size)      '''      Is this file a "partial"-mode GIF where frames update a region of a different size to the entire image?      If so, we need to construct the new frame by pasting it on top of the preceding frames.      '''      if mode == 'partial':        new_frame.paste(last_frame)      new_frame.paste(im, (0,0), im.convert('RGBA'))      new_frame.save('%s-%d.png' % (''.join(os.path.basename(path).split('.')[:-1]), i), 'PNG')      i += 1      last_frame = new_frame      im.seek(im.tell() + 1)  except EOFError:    passdef main():  processImage('test_gif.gif')if __name__ == "__main__":  main()

解析結果如下，由此可見改動態圖實際上是由14張相同分辨率的靜態圖組合而成

Python,圖像處理之,gif,動態圖

二、gif動態圖的合成

gif圖像的合成，使用imageio庫（https://pypi.python.org/pypi/imageio）

代碼如下：

#-*- coding: UTF-8 -*-import imageiodef create_gif(image_list, gif_name):  frames = []  for image_name in image_list:    frames.append(imageio.imread(image_name))  # Save them as frames into a gif  imageio.mimsave(gif_name, frames, 'GIF', duration = 0.1)  returndef main():  image_list = ['test_gif-0.png', 'test_gif-2.png', 'test_gif-4.png',         'test_gif-6.png', 'test_gif-8.png', 'test_gif-10.png']  gif_name = 'created_gif.gif'  create_gif(image_list, gif_name)if __name__ == "__main__":  main()

這里，使用第一步解析出來的圖像中的8幅圖，間副的間隔時間為0.1s，合成新的gif動態圖如下：

Python,圖像處理之,gif,動態圖