Python 图片尺寸缩放的4种方式

最近由于网站对图片尺寸的需要，用python写了个小脚本，方便进行图片尺寸的一些调整，特记录如下：

1. 
   
2. # coding=utf-8
3. import Image
4. import shutil
5. import os
8. class Graphics:
9. infile = 'D:\\myimg.jpg'
10. outfile = 'D:\\adjust_img.jpg'
12. @classmethod
13. def fixed_size(cls, width, height):
14. """按照固定尺寸处理图片"""
15. im = Image.open(cls.infile)
16. out = im.resize((width, height),Image.ANTIALIAS)
17. out.save(cls.outfile)
19. @classmethod
20. def resize_by_width(cls, w_divide_h):
21. """按照宽度进行所需比例缩放"""
22. im = Image.open(cls.infile)
23. (x, y) = im.size
24. x_s = x
25. y_s = x/w_divide_h
26. out = im.resize((x_s, y_s), Image.ANTIALIAS)
27. out.save(cls.outfile)
29. @classmethod
30. def resize_by_height(cls, w_divide_h):
31. """按照高度进行所需比例缩放"""
32. im = Image.open(cls.infile)
33. (x, y) = im.size
34. x_s = y*w_divide_h
35. y_s = y
36. out = im.resize((x_s, y_s), Image.ANTIALIAS)
37. out.save(cls.outfile)
39. @classmethod
40. def resize_by_size(cls, size):
41. """按照生成图片文件大小进行处理(单位KB)"""
42. size *= 1024
43. im = Image.open(cls.infile)
44. size_tmp = os.path.getsize(cls.infile)
45. q = 100
46. while size_tmp > size and q > 0:
47. print q
48. out = im.resize(im.size, Image.ANTIALIAS)
49. out.save(cls.outfile, quality=q)
50. size_tmp = os.path.getsize(cls.outfile)
51. q -= 5
52. if q == 100:
53. shutil.copy(cls.infile, cls.outfile)
55. @classmethod
56. def cut_by_ratio(cls, width, height):
57. """按照图片长宽比进行分割"""
58. im = Image.open(cls.infile)
59. width = float(width)
60. height = float(height)
61. (x, y) = im.size
62. if width > height:
63. region = (0, int((y-(y * (height / width)))/2), x, int((y+(y * (height / width)))/2))
64. elif width < height:
65. region = (int((x-(x * (width / height)))/2), 0, int((x+(x * (width / height)))/2), y)
66. else:
67. region = (0, 0, x, y)
69. #裁切图片
70. crop_img = im.crop(region)
71. #保存裁切后的图片
72. crop_img.save(cls.outfile)