php动态处理图片后输出显示

php动态改变图片尺寸后输出，输出图片时使用下面的地址：
image_resize.php?img=image.jpg&w=150&h=150&constrain=1
w和h为要显示的尺寸

1. header ("Content-type: image/jpeg");
2. /*
3. JPEG / PNG Image Resizer
4. Parameters (passed via URL):
6. img = path / url of jpeg or png image file
8. percent = if this is defined, image is resized by it's
9. value in percent (i.e. 50 to divide by 50 percent)
11. w = image width
13. h = image height
15. constrain = if this is parameter is passed and w and h are set
16. to a size value then the size of the resulting image
17. is constrained by whichever dimension is smaller
19. Requires the PHP GD Extension
21. Outputs the resulting image in JPEG Format
23. By: Michael John G. Lopez - www.sydel.net
24. Filename : imgsize.php
25. */
27. $img = $_GET['img'];
28. $percent = $_GET['percent'];
29. $constrain = $_GET['constrain'];
30. $w = $_GET['w'];
31. $h = $_GET['h'];
33. // get image size of img
34. $x = @getimagesize($img);
35. // image width
36. $sw = $x[0];
37. // image height
38. $sh = $x[1];
40. if ($percent > 0) {
41. // calculate resized height and width if percent is defined
42. $percent = $percent * 0.01;
43. $w = $sw * $percent;
44. $h = $sh * $percent;
45. } else {
46. if (isset ($w) AND !isset ($h)) {
47. // autocompute height if only width is set
48. $h = (100 / ($sw / $w)) * .01;
49. $h = @round ($sh * $h);
50. } elseif (isset ($h) AND !isset ($w)) {
51. // autocompute width if only height is set
52. $w = (100 / ($sh / $h)) * .01;
53. $w = @round ($sw * $w);
54. } elseif (isset ($h) AND isset ($w) AND isset ($constrain)) {
55. // get the smaller resulting image dimension if both height
56. // and width are set and $constrain is also set
57. $hx = (100 / ($sw / $w)) * .01;
58. $hx = @round ($sh * $hx);
60. $wx = (100 / ($sh / $h)) * .01;
61. $wx = @round ($sw * $wx);
63. if ($hx $h = (100 / ($sw / $w)) * .01;
64. $h = @round ($sh * $h);
65. } else {
66. $w = (100 / ($sh / $h)) * .01;
67. $w = @round ($sw * $w);
68. }
69. }
70. }
72. $im = @ImageCreateFromJPEG ($img) or // Read JPEG Image
73. $im = @ImageCreateFromPNG ($img) or // or PNG Image
74. $im = @ImageCreateFromGIF ($img) or // or GIF Image
75. $im = false; // If image is not JPEG, PNG, or GIF
77. if (!$im) {
78. // We get errors from PHP's ImageCreate functions...
79. // So let's echo back the contents of the actual image.
80. readfile ($img);
81. } else {
82. // Create the resized image destination
83. $thumb = @ImageCreateTrueColor ($w, $h);
84. // Copy from image source, resize it, and paste to image destination
85. @ImageCopyResampled ($thumb, $im, 0, 0, 0, 0, $w, $h, $sw, $sh);
86. // Output resized image
87. @ImageJPEG ($thumb);
88. }
89. ?>

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