Resizing png transparent with JImage, final file not copied

Question

I'm using JImage to resize uploaded images but when I try to resize transparent png, the resulting image isn't copied to the directory. I'm not able to understand what the issue is. The toFile() method doesn't copy the transparent png in directory, it works well with jpg and png with no transparency.

The code that i'am using is the following :

$image = new JImage($originalFile);
$properties = JImage::getImageFileProperties($originalFile);
$resizedImage = $image->resize('200', '200', true);

$mime = $properties->mime;

if ($mime == 'image/jpeg')
{
    $type = IMAGETYPE_JPEG;
}
elseif ($mime = 'image/png')
{
    $type = IMAGETYPE_PNG;
}
elseif ($mime = 'image/gif')
{
    $type = IMAGETYPE_GIF;
}

$resizedImage->toFile($finalFile, $type);

Any ideas on how to make it work with transparent png?

Answer 1

If you look at the JImage implementation, it exposes no calls to imagealphablending and other routines typically used to handle transparent images; but looking into the implementation of resize() and crop() it seems to be handling the transparency itself. So (if you're using Joomla 3.x) the code should work with transparent images already.

If you have a use case where it doesn't work, and you're not trying to convert from or to jpg (which of course doesn't support transparency in the first place), just add more info here.

I could point out that the issue may lie with the apparent errors in your code:

elseif ($mime = 'image/png')

you seem to be using one "=" instead of two "=="