php+js实现裁剪任意形状图片

html2canvas($(\".head1pic\"), {
     onrendered: function(canvas) { 
     url = canvas.toDataURL(\"image/png\", 1.0);
       sourcePic = \"assets/images/demo.png\";
       maskPic = \"assets/images/jinmao.png\";
          cropPicName = \"cropDog1\";
          // ajax php截图
          $.ajax({
          type: \'post\',
           url: \'getpicture\',
          data: {
            \"sourcePic\": sourcePic,
            \"maskPic\": maskPic,
            \"cropPicName\": cropPicName
            },
         success: function(data) {
             $(\".page2Bg\")[0].setAttribute(\"src\", \"assets/images/crop/cropDog1.png\"); 
            },
         error: function(data) {
              console.log(data)
              }
            });
       }
 });

 public function actionGetpicture()
  {  
     $request = Yii::$app->request;
    $sourcePic=$request->post(\'sourcePic\');
    $maskPic=$request->post(\'maskPic\'); 
    $cropPicName=$request->post(\'cropPicName\'); 
 
    // $sourcePic=\"http://bings.local.com/bi_ngs2_2/assets/images/yinpian1/page2Bg4.png\";
    // $maskPic=\"http://bings.local.com/bi_ngs2_2/assets/images/jinmao.png\";
    $source = imagecreatefrompng( $sourcePic );
    $mask = imagecreatefrompng( $maskPic); 
    // Apply mask to source
    // imagealphamask( $source, $mask );
    $this->imagealphamask ($source, $mask );
    // Output
    header( \"Content-type: image/png\"); 
    // 生成截取后的图片并保存在本地
    imagepng( $source,\"assets/images/crop/\".$cropPicName.\".png\" );
    //销毁图片内存
    imagedestroy($source);
      
  }
 
  public function imagealphamask( &$picture, $mask ) {
    // Get sizes and set up new picture
    $xSize = imagesx( $picture );
    $ySize = imagesy( $picture );
    $newPicture = imagecreatetruecolor( $xSize, $ySize );
    imagesavealpha( $newPicture, true );
    imagefill( $newPicture, 0, 0, imagecolorallocatealpha( $newPicture, 100, 100, 0, 127 ) );
 
    // Resize mask if necessary
    // if( $xSize != imagesx( $mask ) || $ySize != imagesy( $mask ) ) {
    //   $tempPic = imagecreatetruecolor( $xSize, $ySize );
    //   imagecopyresampled( $tempPic, $mask, 0, 0, 0, 0, $xSize, $ySize, imagesx( $mask ), imagesy( $mask ) );
    //   imagedestroy( $mask );
    //   $mask = $tempPic;
    // }
 
    // Perform pixel- d alpha map application
    for( $x = 0; $x < $xSize; $x++ ) {
      for( $y = 0; $y < $ySize; $y++ ) {
        $alpha = imagecolorsforindex( $mask, imagecolorat( $mask, $x, $y ) );
        //small mod to extract alpha, if using a black(transparent) and white
        //mask file instead change the following line back to Jules\'s original:
        // $alpha = 127 - floor($alpha[\'black\'] / 2);
        //or a white(transparent) and black mask file:
        // $alpha = floor($alpha[\'black\'] / 2);
        $alpha = $alpha[\'alpha\'];
        $color = imagecolorsforindex( $picture, imagecolorat( $picture, $x, $y ) );
        //preserve alpha by comparing the two values
        if ($color[\'alpha\'] > $alpha)
          $alpha = $color[\'alpha\'];
        //kill data for fully transparent pixels
        if ($alpha == 127) {
          $color[\'red\'] = 0;
          $color[\'blue\'] = 0;
          $color[\'green\'] = 0;
        }
        imagesetpixel( $newPicture, $x, $y, imagecolorallocatealpha( $newPicture, $color[ \'red\' ], $color[ \'green\' ], $color[ \'blue\' ], $alpha ) );
      }
    }
 
    // Copy back to original picture
    imagedestroy( $picture );
    $picture = $newPicture;
  }