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Bug 154621 - "pnmtopgm" handles transparency incorrectly when working with colormapped PNG
Summary: "pnmtopgm" handles transparency incorrectly when working with colormapped PNG
Alias: None
Product: Fedora
Classification: Fedora
Component: netpbm
Version: 3
Hardware: i386
OS: Linux
Target Milestone: ---
Assignee: Jindrich Novy
QA Contact: Ben Levenson
Depends On:
TreeView+ depends on / blocked
Reported: 2005-04-13 03:40 UTC by Robert Wilhite
Modified: 2013-07-02 23:07 UTC (History)
1 user (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Last Closed: 2005-04-14 15:11:48 UTC

Attachments (Terms of Use)

Description Robert Wilhite 2005-04-13 03:40:04 UTC
Description of problem:
"pnmtopgm" handles transparency incorrectly when working with colormapped PNG

Version-Release number of selected component (if applicable):

How reproducible:
fails predictably

Steps to Reproduce:
1. grab a PNG from the pixmaps directory
2. convert it to PNM
3. reduce the colors below 256 to enable colormap handling
4. use pnmtopng with -transparent option, so for example...

pngtopnm /usr/share/pixmaps/gnomemeeting-splash.png | pnmdepth 10 | pnmtopng
-trans white > /tmp/test4.png
Actual results:
white region of picture is not transparent

Expected results:
white region of picture should be transparent

Additional info:
1. Worked fine in FC2.
2. Run that pipeline above about 20 times; it will occasionally seg-fault.
3. If you leave the "pnmdepth 10" step out, then pnmtopng doesn't try to create
a colormapped image, and the transparency works correctly.
4. This is my first time reporting a bug, so I hope I don't totally suck.

Comment 1 Jindrich Novy 2005-04-14 15:11:48 UTC
I tried that with netpbm-10.26.4 and netpbm-10.27 and I see it works now. So
upgrading to the latest devel netpbm should solve your problem.
(the white colour is transparent in the /tmp/test4.png image)


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