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Pixalated Image Bug

Posted: 2008-03-17T13:39:23-07:00
by plxkarl
Hey,

I've been using

ImageMagick 6.3.1 01/12/07 Q16

on my php4 server and everything was working properly, I've moved my website to php5 server and installed

ImageMagick 6.3.9 03/03/08 Q16

Now when I use functions such as MagickReadImage and after MagickWriteImage (magickwand extension v0.1.9) just for some images (maybe 5% of jpg image i upload) it changes the way my image looks... example below:

Original image:
Image

Uploaded Image
Image

Did anybody experience that problem? Can it be fixed in any way?

These are some more examples of what it does to those images:
Image
Image

Re: Pixalated Image Bug

Posted: 2008-03-21T06:38:19-07:00
by plxkarl
Anybody had the same problem I did?

Re: Pixalated Image Bug

Posted: 2008-03-28T09:38:07-07:00
by plxkarl
bump...

Re: Pixalated Image Bug

Posted: 2008-03-28T10:34:41-07:00
by magick
We can not reproduce the problem you posted. You will need to post an image and a script that can use to reliably reproduce the pixelation. Once we can reproduce the problem we should have a fix for you within a day or two.

Re: Pixalated Image Bug

Posted: 2008-03-28T14:06:28-07:00
by plxkarl
I found the bug. This happens when resizing images from small to large size (streatching them)...

This is the function that causes it...

MagickResizeImage($r, $w, $h, MW_CubicFilter, $blur)

When uploading the following image:

Image

On my php4 server that function produced the following image (Proper):

Image

Same function on my php5 server produces:

Image

Re: Pixalated Image Bug

Posted: 2008-03-28T15:01:31-07:00
by magick
So far we cannot reproduce the problem. What is the value of your blur parameter? It probably should be 1.0. Also, try the Lanzcos filter and see if that makes a difference.

Re: Pixalated Image Bug

Posted: 2008-03-28T15:16:22-07:00
by plxkarl
Thanks, MW_LanczosFilter has fixed the problem.