Search found 11 matches

by alexcgt
2018-06-22T00:19:38-07:00
Forum: Users
Topic: How to prevent alpha channel association during conversion?
Replies: 9
Views: 3033

Re: How to prevent alpha channel association during conversion?

Thanks, fmw42 -- I'll keep that in mind!
by alexcgt
2018-06-21T08:03:48-07:00
Forum: Users
Topic: How to prevent alpha channel association during conversion?
Replies: 9
Views: 3033

Re: How to prevent alpha channel association during conversion?

truecoloralpha does work in a way but it still generates an empty alpha channel for images with no alpha channels and I prefer it wouldn't do that. It's Ok for now though -- I have a non-IM related solution.
(btw., I don't believe that truecoloralpha is mentioned in command line options reference)
by alexcgt
2018-06-20T04:55:08-07:00
Forum: Users
Topic: TIFF with alpha produces a corrupt output when JPG compressed.
Replies: 9
Views: 2653

Re: TIFF with alpha produces a corrupt output when JPG compressed.

A very interesting suggestion regarding JP2 and Photoshop seems to be opening it correctly.
Unfortunately, I'm constrained by the formats which are supported by Unity3D and it currently doesn't have a support for JP2.
by alexcgt
2018-06-20T02:30:38-07:00
Forum: Users
Topic: TIFF with alpha produces a corrupt output when JPG compressed.
Replies: 9
Views: 2653

Re: TIFF with alpha produces a corrupt output when JPG compressed.

Thanks, snibgo. At first, I thought it might be the libtiff trouble but it turns out to be something entirely different. I spent many hours just to find out that the Photoshop indeed doesn't support JPEG-compressed TIFF containing alpha channels . The problem is that it won't notify you about the in...
by alexcgt
2018-06-19T00:42:51-07:00
Forum: Users
Topic: TIFF with alpha produces a corrupt output when JPG compressed.
Replies: 9
Views: 2653

Re: TIFF with alpha produces a corrupt output when JPG compressed.

It didn't work with Q16 either. Q8, Q16, Dynamic, Static, Win32 -- they all produce corrupt alpha. Oddly XnView doesn't see the image as corrupted but I don't trust XnView anymore. And Photoshop shows the image as corrupted. I was under the impression that IM install has everything that is required....
by alexcgt
2018-06-18T06:58:16-07:00
Forum: Users
Topic: TIFF with alpha produces a corrupt output when JPG compressed.
Replies: 9
Views: 2653

Re: TIFF with alpha produces a corrupt output when JPG compressed.

Version: ImageMagick 7.0.8-0 Q8 x64 2018-06-12 http://www.imagemagick.org Copyright: Copyright (C) 1999-2018 ImageMagick Studio LLC License: http://www.imagemagick.org/script/license.php Visual C++: 180040629 Features: Cipher DPC Modules OpenMP Delegates (built-in): bzlib cairo flif freetype gslib ...
by alexcgt
2018-06-18T06:27:08-07:00
Forum: Users
Topic: TIFF with alpha produces a corrupt output when JPG compressed.
Replies: 9
Views: 2653

TIFF with alpha produces a corrupt output when JPG compressed.

Compressing TIFF images containing alpha channel using JPG compression will randomly produce corrupt images. The very same images without alpha channels will produce the correct output. Source TIF image: https://www.dropbox.com/s/3kehra55qw8308q/rgba.tif?dl=0 Screenshot of the compressed source imag...
by alexcgt
2018-06-18T05:30:11-07:00
Forum: Users
Topic: How to prevent alpha channel association during conversion?
Replies: 9
Views: 3033

Re: How to prevent alpha channel association during conversion?

Thank you very much! It looks like -type truecolor does work. True, it discards alpha channel completely and using -type truecolormatte does just the opposite by forcing an alpha channel in images which don't have one initially but it's good solution for now. I'm still not happy about IM converting ...
by alexcgt
2018-06-15T02:24:49-07:00
Forum: Users
Topic: How to prevent alpha channel association during conversion?
Replies: 9
Views: 3033

Re: How to prevent alpha channel association during conversion?

Thanks, fmw42 , and snigbo . I actually did find the same solutions before posting but they didn't quite work or so I thought. I gave it another try and here's what I found: When converting an RGBA image containing non-grayscale color values everything works as expected (i.e. alpha un/association wo...
by alexcgt
2018-06-14T06:12:37-07:00
Forum: Users
Topic: How to prevent alpha channel association during conversion?
Replies: 9
Views: 3033

How to prevent alpha channel association during conversion?

Hello, everyone. It seems that ImageMagick turns a regular alpha channel into an associated alpha channel if a converted image has only grayscale color values despite being an RGB image. How to force the conversion process not to change the output color space and most importantly keep an alpha chann...