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cssmask属性，故，利用php后台来裁

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脚本之家。