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;
- }
来源: https://www.jb51.net/article/149849.htm