PHP的PNG透明度

Question

嘿，当我从png创建缩略图时，尝试保持png的透明度时遇到麻烦，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：

$fileName= "../js/ajaxupload/tees/".$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);

Answer 1

过去，我已经成功地做到了：

$thumb = imagecreatetruecolor($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);

我发现输出图像使用质量更好的imagecopyresampled()比imagecopyresized()