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php GD library generates high-quality thumbnails (example)

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Release： 2016-07-25 08:55:15
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  3. $FILENAME="image.thumb";

  4. // 生成图片的宽度
  5. $RESIZEWIDTH=400;
  6. // 生成图片的高度
  7. $RESIZEHEIGHT=400;

  8. function ResizeImage($im,$maxwidth,$maxheight,$name){

  9. $width = imagesx($im);
  10. $height = imagesy($im);
  11. if(($maxwidth && $width > $maxwidth) || ($maxheight && $height > $maxheight)){
  12. if($maxwidth && $width > $maxwidth){
  13. $widthratio = $maxwidth/$width;
  14. $RESIZEWIDTH=true;
  15. }
  16. if($maxheight && $height > $maxheight){
  17. $heightratio = $maxheight/$height;
  18. $RESIZEHEIGHT=true;
  19. }
  20. if($RESIZEWIDTH && $RESIZEHEIGHT){
  21. if($widthratio < $heightratio){
  22. $ratio = $widthratio;
  23. }else{
  24. $ratio = $heightratio;
  25. }
  26. }elseif($RESIZEWIDTH){
  27. $ratio = $widthratio;
  28. }elseif($RESIZEHEIGHT){
  29. $ratio = $heightratio;
  30. }
  31. $newwidth = $width * $ratio;
  32. $newheight = $height * $ratio;
  33. if(function_exists("imagecopyresampled")){
  34. $newim = imagecreatetruecolor($newwidth, $newheight);
  35. imagecopyresampled($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);
  36. }else{
  37. $newim = imagecreate($newwidth, $newheight);
  38. imagecopyresized($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);
  39. }
  40. ImageJpeg ($newim,$name . ".jpg");
  41. ImageDestroy ($newim);
  42. }else{
  43. ImageJpeg ($im,$name . ".jpg");
  44. }
  45. }

  46. if($_FILES['image']['size']){

  47. if($_FILES['image']['type'] == "image/pjpeg"){
  48. $im = imagecreatefromjpeg($_FILES['image']['tmp_name']);
  49. }elseif($_FILES['image']['type'] == "image/x-png"){
  50. $im = imagecreatefrompng($_FILES['image']['tmp_name']);
  51. }elseif($_FILES['image']['type'] == "image/gif"){
  52. $im = imagecreatefromgif($_FILES['image']['tmp_name']);
  53. }
  54. if($im){
  55. if(file_exists("$FILENAME.jpg")){
  56. unlink("$FILENAME.jpg");
  57. }
  58. ResizeImage($im,$RESIZEWIDTH,$RESIZEHEIGHT,$FILENAME);
  59. ImageDestroy ($im);
  60. }
  61. }
  62. ?>

复制代码

2，测试代码(demo.php)

  2. /**
  3. * PHP generates high-quality thumbnails
  4. * by bbs.it-home.org
  5. */
  6. include('ResizeImage.php');
  7. if(!empty($_POST)){
  8. echo($FILENAME.".jpg?cache=".rand(0,999999));
  9. }
  10. ?>

复制代码


Related labels：
php GD库生成高质量缩略图(示例)
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