复制带阴影和透明背景的图像

Question

我试图复制一个具有阴影（即alpha通道）和透明背景的PNG图像。但是，生成的图像以黑色绘制阴影和透明背景。我尝试了imagecopy和imagecopymerge;没有得到有效的结果，这与原始图像不一样。

Preview of the images.

$src = imagecreatefrompng('img_box3-bg.png'); 

/* Using imagecopy. */ 
$dest = imagecreatetruecolor(116, 100); 
imagecopy($dest, $src, 0, 0, 0, 0, 116, 100); 
imagepng($dest, 'img_box3-bg.imagecopy.png'); 
imagedestroy($dest); 

/* Using imagecopymerge. */ 
$dest2 = imagecreatetruecolor(116, 100); 
imagecopymerge($dest2, $src, 0, 0, 0, 0, 116, 100, 100); 
imagepng($dest2, 'img_box3-bg.imagecopymerge.png'); 
imagedestroy($dest2); 

imagedestroy($src); 

帮助？事先感谢。

Answer 1

事情是这样的：

$src = imagecreatefrompng('img_box3-bg.png'); 

/* Using imagecopy. */ 
$dest = imagecreatetruecolor(116, 100); 

// this is new 
imagesavealpha($dest, true); 
$transparent = imagecolorallocatealpha($dest, 0, 0, 0, 127); 
imagefill($dest, 0, 0, $transparent); 

imagecopy($dest, $src, 0, 0, 0, 0, 116, 100); 

header('Content-Type: image/png'); 
imagepng($dest); 
imagedestroy($dest);