PHP的PNG透明度
问题描述：
当我从png创建缩略图时，尝试在png上保持透明会遇到麻烦，有人对此有任何经验吗?任何帮助都会很棒，这是我目前正在做的事情:
Hey having some trouble trying to maintain transparency on a png when i create a thumbnail from it, anyone any experience with this? any help would be great, here's what i am currently doing:
$fileName= "../js/ajaxupload/tees/".$fileName;
list($width, $height) = getimagesize($fileName);
$newwidth = 257;
$newheight = 197;
$thumb = imagecreatetruecolor($newwidth, $newheight);
imagealphablending($thumb, true);
$source = imagecreatefrompng($fileName);
imagealphablending($source, true);
imagecopyresized($thumb, $source, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);
imagesavealpha($thumb, true);
imagepng($thumb,$newFilename);
答
过去，我已经成功地做到了这一点:
I have had success doing it like this in the past:
$thumb = imagecreatetruecolor($newwidth, $newheight);
imagealphablending($thumb, false);
imagesavealpha($thumb, true);
$source = imagecreatefrompng($fileName);
imagealphablending($source, true);
imagecopyresampled($thumb, $source, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);
imagepng($thumb,$newFilename);
我发现使用imagecopyresampled()的输出图像质量比imagecopyresized()
I found the output image quality much better using imagecopyresampled() than imagecopyresized()