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-based 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;
}