How to process images in equal proportions in php

This article mainly analyzes how to process images in equal proportions in PHP. Friends who need it can refer to it. I hope it can help everyone. Let’s take a look with the editor below.

<?
   // 获得任意大小图像，不足地方拉伸，不产生变形，不留下空白
   function my_image_resize($src_file, $dst_file , $new_width , $new_height) {
  $new_width= intval($new_width);
          $new_height=intval($new_width);
          if($new_width <1 || $new_height <1) {
                  echo "params width or height error !";
                  exit();
           }
           if(!file_exists($src_file)) {
                   echo $src_file . " is not exists !";
                   exit();
           }
           // 图像类型
           $type=exif_imagetype($src_file);
           $support_type=array(IMAGETYPE_JPEG , IMAGETYPE_PNG , IMAGETYPE_GIF);
           if(!in_array($type, $support_type,true)) {
                   echo "this type of image does not support! only support jpg , gif or png";
                   exit();
           }
           //Load image
           switch($type) {
                   case IMAGETYPE_JPEG :
                           $src_img=imagecreatefromjpeg($src_file);
                   break;
                   case IMAGETYPE_PNG :
                           $src_img=imagecreatefrompng($src_file);
                   break;
                   case IMAGETYPE_GIF :
                           $src_img=imagecreatefromgif($src_file);
                   break;
                   default:
                           echo "Load image error!";
                           exit();
                   }
                   $w=imagesx($src_img);
                   $h=imagesy($src_img);
                   $ratio_w=1.0 * $new_width / $w;//源图像与目标图像宽的比
                   $ratio_h=1.0 * $new_height / $h;
                   $ratio=1.0;
                   // 生成的图像的高宽比原来的都小，或都大 ，原则是 取大比例放大，取大比例缩小（缩小的比例就比较小了）
                   if( ($ratio_w < 1 && $ratio_h < 1) || ($ratio_w > 1 && $ratio_h > 1)) {
                   if($ratio_w < $ratio_h) {
                           $ratio = $ratio_h ; // 情况一，宽度的比例比高度方向的小，按照高度的比例标准来裁剪或放大
                   }else {
                           $ratio = $ratio_w ;
                   }
                   // 定义一个中间的临时图像，该图像的宽高比 正好满足目标要求
                   $inter_w=(int)($new_width / $ratio);
                   $inter_h=(int) ($new_height / $ratio);
                   $inter_img=imagecreatetruecolor($inter_w , $inter_h);
                   //var_dump($inter_img);
                   imagecopy($inter_img, $src_img, 0,0,0,0,$inter_w,$inter_h);
                   // 生成一个以最大边长度为大小的是目标图像$ratio比例的临时图像
                   // 定义一个新的图像
                   $new_img=imagecreatetruecolor($new_width,$new_height);
                   //var_dump($new_img);exit();
                   imagecopyresampled($new_img,$inter_img,0,0,0,0,$new_width,$new_height,$inter_w,$inter_h);
                   switch($type) {
                           case IMAGETYPE_JPEG :
                                   imagejpeg($new_img, $dst_file,100); // 存储图像
                           break;
                           case IMAGETYPE_PNG :
                                   imagepng($new_img,$dst_file,100);
                           break;
                           case IMAGETYPE_GIF :
                                   imagegif($new_img,$dst_file,100);
                           break;
                           default:
                           break;
                   }
           } else {                     // end if 1  目标图像 的一个边大于原图，一个边小于原图 ，先放大平普图像，然后裁剪
                   // =if( ($ratio_w < 1 && $ratio_h > 1) || ($ratio_w >1 && $ratio_h <1) )
                   $ratio=$ratio_h>$ratio_w? $ratio_h : $ratio_w; //取比例大的那个值
                   // 定义一个中间的大图像，该图像的高或宽和目标图像相等，然后对原图放大
                   $inter_w=(int)($w * $ratio);
                   $inter_h=(int) ($h * $ratio);
                   $inter_img=imagecreatetruecolor($inter_w , $inter_h);
                   //将原图缩放比例后裁剪
                   imagecopyresampled($inter_img,$src_img,0,0,0,0,$inter_w,$inter_h,$w,$h);
                   // 定义一个新的图像
                   $new_img=imagecreatetruecolor($new_width,$new_height);
                    imagecopy($new_img, $inter_img, 0,0,0,0,$new_width,$new_height);
                   switch($type) {
                           case IMAGETYPE_JPEG :
                                   imagejpeg($new_img, $dst_file,100); // 存储图像
                           break;
                           case IMAGETYPE_PNG :
                                   imagepng($new_img,$dst_file,100);
                           break;
                           case IMAGETYPE_GIF :
                                   imagegif($new_img,$dst_file,100);
                           break;
                           default:
                           break;
                   }
           }// if3}// end function
 my_image_resize(&#39;1.jpg&#39;,&#39;111.jpg&#39;,&#39;100px&#39;,&#39;100px&#39;);
?>

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