使用GD2将png转换为jpg ..透明度问题
问题描述：
I have an image.png with white background and some trasparceny over it.
I tried this to convert the image into jpg:
$data = file_get_contents('image.png');
$resource = imagecreatefromstring($data);
imagejpeg($resource); //> I TRIED WITH QUALITY = 100 TOO
Problem is where the png got the trasparency now the jpg got a pretty huge black zone. This is how jpg looks:
http://img861.imageshack.us/img861/20/context.jpg
Any way to solve the problem?
Edit1:
As suggested by Abiusx I tried this too:
$data = file_get_contents('image.png');
$resource = imagecreatefromstring($data);
imagealphablending($data, false);
imagesavealpha($data, true);
imagejpeg($resource);
But the result was the same. Please note The source .png image is:
(source: tipradar.com)
Thanks to Patrick comment: here the trick: GD! Converting a png image to jpeg and making the alpha by default white and not black
答
This is the function I use to resize a PNG but preserve transparency, if it doesnt help, tell me to extract the parts necessary for you:
function Resize($ImageFile,$OriginalFile)
{
$ext=basename($OriginalFile);
$ext=explode(".",$ext);
$ext=array_pop($ext);
$ext=strtolower($ext);
if ($ext=="jpg" or $ext=="jpeg" or $ext=="jpe")
$img=imagecreatefromjpeg($ImageFile);
elseif ($ext=="png")
$img=imagecreatefrompng($ImageFile);
elseif ($ext=="gif")
$img=imagecreatefromgif($ImageFile);
else
return false;
list($w,$h)=getimagesize($ImageFile);
$dstimg=imagecreatetruecolor(140,100);
imagealphablending($dstimg, false);
imagecopyresampled($dstimg,$img,0,0,0,0,140,100,$w,$h);
imagesavealpha($dstimg, true);
imagepng($dstimg,$ImageFile);
return true;
}