function showCutImg(showImg){
   var showImg = $(showImg);
   var changeInput = showImg.parents('.showImgDiv').siblings('.CutImage');
   var size = changeInput.siblings('.imgCoord').attr('ratio').split('*');
   var needWidth = size[0];
   var needHeight = size[1];
   var ratio = parseInt(needWidth)/parseInt(needHeight);
   ratio = parseFloat(ratio.toFixed(2));
   var thisFullDiv = showImg.parent();
   var coordArr = changeInput.siblings('.imgCoord').val().split(',');

   thisCutImgWidth = showImg.width();
   thisCutImgHeight = showImg.height()

   thisFullDiv.css('width',thisCutImgWidth);
   thisFullDiv.css('height',thisCutImgHeight);

   if((thisCutImgWidth/thisCutImgHeight)>=ratio){
    var thisCutDivHeight = thisCutImgHeight;
    var thisCutDivWidth = thisCutDivHeight*ratio;
   }else{
    var thisCutDivWidth = thisCutImgWidth;
    var thisCutDivHeight = thisCutDivWidth/ratio;
   }

   var hideWidth = (thisFullDiv.width()-thisCutDivWidth)/2;

   showImg.siblings('.hideImgLeft').width(hideWidth);
   showImg.siblings('.hideImgRight').width(hideWidth);

   var hideHeight = (thisFullDiv.height()-thisCutDivHeight)/2;

   showImg.siblings('.hideImgTop').width(thisCutDivWidth);
   showImg.siblings('.hideImgBottom').width(thisCutDivWidth);

   showImg.siblings('.hideImgTop').height(hideHeight);
   showImg.siblings('.hideImgBottom').height(hideHeight);

   if(hideWidth>0){
    var cutRatioX = thisCutImgWidth/hideWidth;
   }else{
    var cutRatioX = 0
   }

   if(hideHeight>0){
    var cutRatioY = thisCutImgHeight/hideHeight;
   }else{
    var cutRatioY = 0;
   }

   var coord = needWidth+'#'+needHeight+'#'+(cutRatioX)+'#'+(cutRatioY);

   if(coordArr!=''){
    coordArr.push(coord);
   }else{
    coordArr = [coord];
   }

   changeInput.siblings('.imgCoord').val(coordArr);
   $('.fullDiv').on('mousedown',function(e){
    var me = $(this);

    var changeInput = me.parent().siblings('.CutImage');

    var index = me.attr('index');

    var oldx = e.pageX;
    var oldy = e.pageY;

    var imgleft = me.children('.cutImg').position().left;
    var imgtop = me.children('.cutImg').position().top;

    var maxw = me.children('.hideImgLeft').width();
    var maxh = me.children('.hideImgTop').height();

    var goordArr = changeInput.siblings('.imgCoord').val().split(',');

    var cutDivSize = goordArr[index].split('#');

    $(document).mousemove(function(e){
     var newx = e.pageX;
     var newy = e.pageY;

     var movex = newx - oldx;
     var movey = newy - oldy;

     var x = movex + imgleft;
     var y = movey + imgtop;

     if(Math.abs(x)>maxw){
      if(x>0) x = maxw;
      if(x<0) x = -maxw;
     }

     if(Math.abs(y)>maxh){
      if(y>0) y = maxh;
      if(y<0) y = -maxh;
     }

     me.children('.cutImg').css('left',x+'px');
     me.children('.cutImg').css('top',y+'px');

     if(parseInt(maxw - x)>0){
      var cutRatioX = me.children('.cutImg').width()/parseInt(maxw - x);
     }else{
      var cutRatioX = 0;
     }

     if(parseInt(maxh - y)>0){
      var cutRatioY = me.children('.cutImg').height()/parseInt(maxh - y)
     }else{
      var cutRatioY = 0;
     }

     var cutImgPo = (cutRatioX) +'#'+ (cutRatioY);

     var coordVal = cutDivSize[0]+'#'+cutDivSize[1]+'#'+cutImgPo;

     goordArr[index] = coordVal;

     changeInput.siblings('.imgCoord').val(goordArr);


    });
   });


   $(document).on('mouseup',function(e){
    $(document).unbind('mousemove');
   });
  }



  $(".CutImage").change(function(){

   $(this).siblings('.imgCoord').val('');

   if($(this).prop('multiple')!=true){  //判断是否多文件上传
    var objUrl = getObjectURL1(this.files[0]) ;

    var showImgWidth = $(this).siblings('.showImgDiv').attr('showImgWidth');

    if(!showImgWidth)
    {
     showImgWidth = '150';
    }

    if (objUrl) {
      html = '';
      html += '<div style="border:1px solid #000;position:relative;z-index:2;overflow:hidden;cursor:move;-webkit-user-select:none;-moz-user-select:none;-ms-user-select:none;user-select:none;" index="0" class="fullDiv">';
      html += '<div style="position:absolute;background:#ccc;top:0;z-index:4;opacity:0.95;left:0;right:0;margin:auto;" class="hideImgTop"></div>';
      html += '<div style="position:absolute;background:#ccc;bottom:0;z-index:4;opacity:0.95;left:0;right:0;margin:auto;" class="hideImgBottom"></div>';
      html += '<div style="position:absolute;height:100%;background:#ccc;left:0;z-index:4;opacity:0.95;" class="hideImgLeft"></div><div style="position:absolute;z-index:3;left:0;right:0;top:0;bottom:0;margin:auto;" class="cutDiv"></div>';
      html += '<div style="position:absolute;height:100%;background:#ccc;right:0;z-index:4;opacity:0.95;" class="hideImgRight"></div>';
      html += '<img style="position:absolute;z-index:1;width:'+showImgWidth+'px" onload="showCutImg(this)" class="cutImg" class="imgshover" src="/UploadFiles/2021-04-02/'+objUrl+'">

html代码（这些代码要放在同一级）


<!-- 文件上传标签，添加class属性CutImage -->
<input class="CutImage" type="file" name="img" />

<!-- 传送图片裁剪比例等参数，要添加class属性imgCoord，ratio为裁剪后要保存的宽高width*height -->
<input ratio="100*100" type="hidden" class="imgCoord" name="imgCoord">

<!-- 图片预览，要添加class属性showImgDiv，showImgWidth表示预览时的宽度 -->
<div showImgWidth="100" class="showImgDiv"></div>


php代码


/*图片上传代码略 下面直接进行图片裁剪*/

/**
 * [cut_img 图片裁剪函数]
 * Author: 程威明
 * @param array $imgs   图片路径数组
 * @param array $info   裁剪信息數組，包括裁剪后要保存的宽高、图片大小与裁剪开始坐标之比
 * @param bool $cover   是否覆盖原图，默认不覆盖
 * @return array    若覆盖原图返回裁剪数量，不覆盖返回图片路径组成的数组
 */
function cut_img($imgs=array(),$infoarr=null,$cover=false)
{
 if($infoarr==null) return $imgs;

 //判断是否为数组（必须是一个以图片路径组成的数组）
 $imgs = is_array($imgs)?$imgs:array($imgs);

 //把多个裁剪信息切成单个信息组成的数组
 $infoarr = explode(',', $infoarr);

 $save_file = array();

 $i=0;
 foreach($imgs as $file){

  //如果不覆盖原图，可重新定义图片保存路径
  if(false==$cover){
   $file = $file;
  }

  //把裁剪信息切割成数组，第一个为要保存的宽第二个为要保存的高，第三和第四个为图片宽高与裁剪起点的比例
  $info = explode('#', $infoarr[$i]);

  //裁剪宽高比
  $ratio = $info[0]/$info[1];

  //判断图片是否存在
  if(!file_exists($file)) continue;

  //获取图片信息
  $imgize = getimagesize($file);

  //图片宽度
  $width = $imgize[0];
  //图片高度
  $height = $imgize[1];

  //图片裁剪起点坐标
  $x = $info[2]==0?0:$imgize[0]/$info[2];
  $y = $info[3]==0?0:$imgize[1]/$info[3];

  //判断图片原宽高比与裁剪宽高比的大小
  if($width/$height>=$ratio){
   $width = $height*$ratio;//如大于即为裁剪宽度
  }else{
   $height = $width/$ratio;//如小于即为裁剪高度
  }

  //裁剪的寬高不能超出圖片大小
  if(($width+$x)>$imgize[0]){
   $width = $width-($width+$x-$imgize[0]);
  }

  if(($height+$y)>$imgize[1]){
   $height = $height-($height+$y-$imgize[1]);
  }

  //创建源图的实例
  $src = imagecreatefromstring(file_get_contents($file));

  //創建一個圖像
  $new_image = imagecreatetruecolor($info[0], $info[1]);

  //分配颜色
  $color = imagecolorallocate($new_image,255,255,255);
  //定义为透明色
  imagecolortransparent($new_image,$color);
  //填充图片
  imagefill($new_image,0,0,$color);

  //拷贝图片并保存成指定大小
  imagecopyresized($new_image, $src, 0, 0, $x, $y, $info[0], $info[1], $width, $height);

  //保存

  if(false==$cover){
   $file = rtrim(dirname($file),'/').'/c_'.basename($file);
   $save_file[] = $file;
  }

  imagejpeg($new_image,$file);

  imagedestroy($new_image);
  imagedestroy($src);

  $i++;
 }

 if(false==$cover){
  return $save_file;
 }else{
  return $i;
 }
}




以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。