给一张透明的png图片添加阴影效果

[php]代码库

<?php
  /* Read the image into the object */
  $im = new Imagick( 'a.jpg' );
  $im->setImageFormat("png");
  $im->thumbnailImage( 200, null );
  $shadow = $im->clone();
  $shadow->setImageBackgroundColor( new ImagickPixel( 'black' ) );
  $shadow->shadowImage( 80, 3, 5, 5 );
  $shadow->compositeImage( $im, Imagick::COMPOSITE_OVER, 0, 0 );
 header( "Content-Type: image/jpeg" );
 echo $shadow;
?>