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php上传图片等比缩放图片的代码

时间：2021-07-01 10:21:17 帮助过：15人阅读

  3. /**

  4. *
  5. * @author zhao jinhan
  6. * @date 2014年1月13日11:54:30
  7. * @email xb_zjh@126.com
  8. *
  9. */
  10. header('Content-type:text/html; charset=utf-8');
  11. //定义缩略图的宽高
  12. define('THUMB_WIDTH',300);
  13. define('THUMB_HEIGHT',300);
  14. /**
  15. * 重新生成上传的文件名
  16. * @return string
  17. * @author zhao jinhan
  18. *
  19. */
  20. function _file_type($filetype = null){
  21. switch($filetype)
  22. {
  23. case "image/jpeg":
  24. $fileextname = "jpg";
  25. break;
  26. case "image/gif":
  27. $fileextname = "gif";
  28. break;
  29. case "image/png":
  30. $fileextname = "png";
  31. break;
  32. default:
  33. $fileextname = false;
  34. break;
  35. }
  36. return $fileextname?date('YmdHis',time()).'.'.$fileextname:false;
  37. }
  38. /**
  39. *
  40. * @param string $filename
  41. * @param string $width
  42. * @param string $height
  43. * @param string $quality
  44. * @param string $savepath
  45. * @return boolean
  46. */
  47. function _make_thumb($filename='', $width=THUMB_WIDTH, $height=THUMB_HEIGHT, $savepath='./upload'){
  48. if(file_exists($filename)){
  49. //上传图片的尺寸
  50. $imagesize=getimagesize($filename);
  51. $imagewidth=$imagesize[0];
  52. $imageheight=$imagesize[1];
  53. $mime = $imagesize['mime'];
  54. //宽高比例
  55. $ratio = $imagewidth/$imageheight;
  56. //新建一个背景图片
  57. $bgimg = imagecreatetruecolor($width, $height);
  58. $white = imagecolorallocate($bgimg, 255, 255, 255);
  59. //填充背景色为白色
  60. imagefill($bgimg,0,0,$white);
  61. if($mime == 'image/gif'){
  62. $im = @imagecreatefromgif($filename); /* Attempt to open */
  63. $outfun = 'imagegif';
  64. }elseif($mime == 'image/png'){
  65. $im = @imagecreatefrompng($filename); /* Attempt to open */
  66. $outfun = 'imagepng';
  67. }else{
  68. $im = @imagecreatefromjpeg($filename); /* Attempt to open */
  69. $outfun = 'imagejpeg';
  70. }
  71. if($ratio > 1){
  72. //宽度较大
  73. if($imagewidth > $width){
  74. //缩放图片到背景图片上
  75. $new_width = $width;
  76. $new_height = ($width*$imageheight)/$imagewidth;
  77. $bg_y = ceil(abs(($height-$new_height)/2));
  78. imagecopyresampled($bgimg, $im, 0, $bg_y, 0, 0, $new_width, $new_height, $imagewidth, $imageheight);
  79. }else{
  80. //复制图片到背景图片上
  81. $copy = true;
  82. }
  83. }else{
  84. //高度较大
  85. if($imageheight > $height){
  86. //缩放图片
  87. $new_height = $height;
  88. $new_width = ($height*$imagewidth)/$imageheight;
  89. $bg_x = ceil(($width-$new_width)/2);
  90. imagecopyresampled($bgimg, $im, $bg_x, 0, 0, 0, $new_width, $new_height, $imagewidth, $imageheight);
  91. }else{
  92. //复制图片到背景图片上
  93. $copy = true;
  94. }
  95. }
  96. if($copy){
  97. //复制图片到背景图片上
  98. $bg_x = ceil(($width-$imagewidth)/2);
  99. $bg_y = ceil(($height-$imageheight)/2);
  100. imagecopy($bgimg, $im, $bg_x, $bg_y, 0, 0, $imagewidth, $imageheight);
  101. }
  102. $ext = _file_type($mime);
  103. $outfun($bgimg, $savepath.'/'.$ext);
  104. imagedestroy($bgimg);
  105. return $savepath.'/'.$ext;
  106. }else{
  107. return false;
  108. }
  109. }
  110. if($_POST){
  111. $size = $_POST['size']?strtoupper(trim($_POST['size'])):'2M';
  112. $imgsize = $_FILES['img']['size']?$_FILES['img']['size']/(1024*1024):0;
  113. $imgwidth = $imgheight = $_POST['width-height']?intval($_POST['width-height']):300;
  114. //自定定义文件上传大小
  115. ini_set('upload_max_filesize',$size);
  116. $mathsize = str_replace('M','',$size);
  117. if($imgsize>$mathsize){
  118. echo "图片大小不得超过{$size}!";
  119. return;
  120. }
  121. if($file_name = _file_type($_FILES['img']['type'])){
  122. if($_FILES['img']['error'] == UPLOAD_ERR_OK){
  123. $savepath = 'upload/';
  124. if(!is_dir($savepath)){
  125. mkdir($savepath,0644);
  126. }
  127. //生成缩略图
  128. $thumb_file = _make_thumb($_FILES['img']['tmp_name'], $imgwidth, $imgheight, $savepath);
  129. //move_uploaded_file($_FILES['img']['tmp_name'],$savepath.$file_name);
  130. echo "生成后的图片为:";
  131. }else{
  132. echo $_FILES['img']['error'];
  133. return;
  134. }
  135. }else{
  136. echo "图片格式不正确,请上传jpg,gif,png的格式!";
  137. return;
  138. }

  139. }else{

  140. echo <<
  144. 缩放图片保存成正方形
  150. EOT;
  151. }

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