php+js实现裁剪任意形状图片


						最近做到相关的项目，由于项目使用html2canvas，但是不支持css mask属性，故，利用php后台来裁剪。

准备两张图片，一张是镂空PNG图案，一张是任意纯色图片。

便能够在纯色图片上裁剪出镂空的图案为PNG文件。

见下图。

首先两张PNG图片：



生成图片



 JS片段：





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)

              }

            });

       }

 });





PHP的片段：





 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;

  } 





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中文源码网。