Bug 162934

Summary: Non-square pixels (e.g. for FAX) are not handled properly.
Product: [Applications] okular Reporter: Steve Underwood <steveu>
Component: TIFF backendAssignee: Okular developers <okular-devel>
Status: RESOLVED FIXED    
Severity: normal    
Priority: NOR    
Version: 0.6.3   
Target Milestone: ---   
Platform: Fedora RPMs   
OS: Linux   
Latest Commit: Version Fixed In:
Attachments: Simple FAX Tiff file

Description Steve Underwood 2008-05-31 06:38:53 UTC 
Version:           0.6.3 (using KDE 4.0.4)
Installed from:    Fedora RPMs
OS:                Linux

The distros are dropping kfax for okular as their FAX reader. Its a good FAX viewer tool, except for one killer....

Okular seems to ignore the pixel resolution information in a TIFF file, and assumes pixels are square. This means a fine resolution FAX (pixels are almost 1:1) looks OK, but a standard or super-fine resolution FAX (pixels are about 2:1 or 1:2 geometry) appears badly squashed in the y or x direction. This is a problem with quite a few image viewers, but it makes them unacceptable as FAX viewers.
Comment 1 Pino Toscano 2008-05-31 10:56:34 UTC 
Do you have a sample document which shows the issue?
Comment 2 Steve Underwood 2008-05-31 11:17:55 UTC 
Created attachment 25026 [details]
Simple FAX Tiff file

Attached is the simplest possible test TIFF file - a plain white standard
resolution A4 FAX page. When displayed in okular it looks much wider than it is
high. However, using tiffdump on the file you will see that it is as follows:

ImageWidth (256) SHORT (3) 1<1728>
ImageLength (257) SHORT (3) 1<1100>
ResolutionUnit (296) SHORT (3) 1<2>
XResolution (282) RATIONAL (5) 1<204>
YResolution (283) RATIONAL (5) 1<98>

Now, 1728 pixels wide at 204 per inch is 8.47 inches wide, and 1100 lines at 98
per inch is 11.22 inches long. The image should actually be the shape of a
normal A4 page.
Comment 3 Pino Toscano 2008-05-31 12:38:19 UTC 
Thanks for the test case, useful indeed; would you mind adding some graphics to it, so I can test the rendering as well?
Comment 4 Pino Toscano 2008-05-31 13:39:13 UTC 
Oh, found one in an old email :)
Comment 5 Pino Toscano 2008-05-31 13:41:18 UTC 
SVN commit 814835 by pino:

If a directory in a TIFF carries information about the resolution, use them to calculate its real size.
And, when generating a pixmap, request the RGBA image of the original size.
BUG: 162934


 M  +30 -2     generator_tiff.cpp  


WebSVN link: http://websvn.kde.org/?view=rev&revision=814835
Comment 6 Pino Toscano 2008-05-31 13:41:44 UTC 
SVN commit 814836 by pino:

Backport:
If a directory in a TIFF carries information about the resolution, use them to calculate its real size.
And, when generating a pixmap, request the RGBA image of the original size.
CCBUG: 162934


 M  +30 -2     generator_tiff.cpp  


WebSVN link: http://websvn.kde.org/?view=rev&revision=814836