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Bug 479807 - 150% Zoom shows checkerbox (transparency) pattern
150% Zoom shows checkerbox (transparency) pattern
Status: RESOLVED FIXED
Product: GIMP
Classification: Other
Component: User Interface
2.4.x
Other All
: Normal normal
: 2.4
Assigned To: GIMP Bugs
GIMP Bugs
: 480598 484671 485346 (view as bug list)
Depends on:
Blocks:
 
 
Reported: 2007-09-24 13:32 UTC by JRd1st
Modified: 2008-10-30 19:59 UTC
See Also:
GNOME target: ---
GNOME version: ---


Attachments
Patch to fix the numerical overflow in box_filter() (7.17 KB, patch)
2007-09-24 18:55 UTC, Simon Budig
none Details | Review

Description JRd1st 2007-09-24 13:32:30 UTC
Please describe the problem:
When I use 150% zoom, the image I'm viewing disappears and shows only a checkerbox (transparency) pattern.  Going to 200% brings the image back.  

I tried with several images with the same result.  I went back to RC2 and the problem was gone.

Steps to reproduce:
1. Open a large JPG
2. Use Zoom + or map mouse wheel to zoom in/out
3. Zoom to 150%


Actual results:
As described above

Expected results:
The image should zoom to 150%

Does this happen every time?
Yes, at least with the jpg's I opened

Other information:
Comment 1 Sven Neumann 2007-09-24 13:46:41 UTC
I cannot reproduce this behavior. How large exactly are the images that you tried?
Comment 2 Simon Budig 2007-09-24 13:49:57 UTC
I can reproduce this with a 3200x2400 image. Eeek.

A 3165x2374 image is not affected, a 3166x2375 image is affected. 3166x2374 shows horizontal artefacts.

This almost certainly is caused by one of my fixes to bug #474509.
Comment 3 JRd1st 2007-09-24 13:56:52 UTC
(In reply to comment #1)
> I cannot reproduce this behavior. How large exactly are the images that you
> tried?
> 
3264x2448 or thereabout.  It's the size I usually use for my pics. 
Comment 4 Simon Budig 2007-09-24 14:09:00 UTC
This is caused by my change to box_filter in gimpdisplayshell-render.c. The footprint in x- and y direction depend on the image size now and get too big for this function. Some creative shifting around is needed when determining the footprint.
Comment 5 Simon Budig 2007-09-24 18:55:37 UTC
Created attachment 96129 [details] [review]
Patch to fix the numerical overflow in box_filter()

This is a patch that shifts the footprint of a pixel into an acceptable working range. It seems to fix the problem for me.
Comment 6 Simon Budig 2007-09-26 14:46:19 UTC
*** Bug 480598 has been marked as a duplicate of this bug. ***
Comment 7 Simon Budig 2007-09-26 14:50:33 UTC
Fixed in SVN:

2007-09-26  Simon Budig  <simon@gimp.org>

        * app/display/gimpdisplayshell-render.c: fix the numerical overflow
        for the new box-filtering stuff.

        Fixes bug #479807.
Comment 8 Sven Neumann 2007-10-08 12:44:38 UTC
*** Bug 484671 has been marked as a duplicate of this bug. ***
Comment 9 Michael Schumacher 2007-10-10 11:17:09 UTC
*** Bug 485346 has been marked as a duplicate of this bug. ***