bug#705: Viewing pgm (raw) does not work when multiple bytes per sample in Windows XP

[Eric Moyer]

From:  <eric_moyer@yahoo.com>
To: bug-gnu-emacs@gnu.org
Subject: Viewing pgm (raw) does not work when multiple bytes per sample
--text follows this line--

Please write in English if possible, because the Emacs maintainers
usually do not have translators to read other languages for them.

Your bug report will be posted to the bug-gnu-emacs@gnu.org mailing list,
and to the gnu.emacs.bug news group.

Please describe exactly what actions triggered the bug
and the precise symptoms of the bug:

When I load a raw mode pgm file (format P5) in image mode, it does not
display correctly if its maxval is 65535 (I haven't tried maxval >
255 but less that 65535, but I suspect they would have the same
problem).  The image displayed is the right dimensions but only the
top quarter of the actual image is shown and it is stretched to the
same dimensions by the insertion of rows and columns of black pixels
every othe row and column.  The image displays correctly when I
convert the pgm file to the plain text format (format P3) using the
same bit depth.

I have attached a gzipped copy of file which causes the problem in raw mode 
(resultSegMul.pgm.gz).  I have also attached the same file in plain mode 
(resultSegMul.plain.pgm.gz), which displays correctly.  I have also attached 
two files showing screen-shots of the incorrect behavior and the expected 
behavior.

If Emacs crashed, and you have the Emacs process in the gdb debugger,
please include the output from the following gdb commands:
    `bt full' and `xbacktrace'.
If you would like to further debug the crash, please read the file
c:/emacs-22.1/etc/DEBUG for instructions.


In GNU Emacs 22.1.1 (i386-mingw-nt5.1.2600)
 of 2007-06-02 on RELEASE
Windowing system distributor `Microsoft Corp.', version 5.1.2600
configured using `configure --with-gcc (3.4) --cflags -Ic:/gnuwin32/include'

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: ENU
  locale-coding-system: cp1252
  default-enable-multibyte-characters: t

Major mode: Fundamental

Minor modes in effect:
  encoded-kbd-mode: t
  tooltip-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  blink-cursor-mode: t
  unify-8859-on-encoding-mode: t
  utf-translate-cjk-mode: t
  auto-compression-mode: t
  column-number-mode: t
  line-number-mode: t

Recent input:
[ 0 ] ; C-x C-s <left> <left> <backspace> 2 <end> C-x 
C-s <left> <left> <backspace> 0 <end> C-x C-s <down-mouse-1> 
<mouse-1> <down-mouse-1> <mouse-1> <help-echo> 2 5 
6 * <end> C-x C-s <down-mouse-1> <mouse-1> <down-mouse-1> 
<mouse-1> <left> <backspace> <backspace> <backspace> 
1 C-x C-s <up> <up> <down> <down> <right> <down> <left> 
<left> <left> <left> <left> <left> <left> <left> <left> 
<left> <left> <left> <left> <left> <left> <left> <left> 
<left> <left> <left> <left> <left> <left> <left> <backspace> 
2 5 6 C-x C-s <end> <left> + <left> <left> <left> <left> 
<left> <left> <left> <left> <left> <left> <left> <left> 
<left> <left> <left> <left> <left> <left> <end> <left> 
1 6 * i n I m a g e [ y ] [ x ] [ 1 <backspace> <backspace> 
<backspace> <backspace> <backspace> <backspace> <backspace> 
<backspace> <backspace> <backspace> <backspace> <backspace> 
<backspace> <backspace> <backspace> <backspace> <backspace> 
<backspace> <backspace> C-x C-s <left> <left> <left> 
<left> <left> <left> <left> <left> <left> <left> <left> 
<left> <left> <left> <left> <left> <backspace> <backspace> 
<backspace> <backspace> C-x C-s <down-mouse-1> <mouse-1> 
<down> <down> <down> <down> <down> <down> <down> <down> 
<down> <down> <down> <down> <down> <down> <down> <down> 
<down> <down> <down> <down> <down> <down> <down> <down> 
<up> <left> <left> <left> <left> <left> <left> <left> 
<left> <left> <left> <left> <tab> <up> <up> <up> <up> 
<up> <up> <up> <up> <up> <up> <up> <up> <up> <up> <up> 
<up> <up> <up> <up> <up> <up> <up> <up> <up> <up> <up> 
<up> <up> <up> <up> <up> <up> <up> <up> <up> <up> <down> 
<down> <down> <down> <down> <down> <down> <down> <down> 
<down> <down> <down> <down> <down> <down> <down> <down> 
<down> <down> <down> <down> <down> <down> <down> <help-echo> 
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo> 
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo> 
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo> 
<help-echo> <help-echo> <menu-bar> <help-menu> <about> 
<help-echo> <wheel-down> <wheel-up> <help-echo> <help-echo> 
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo> 
<help-echo> <help-echo> <help-echo> <help-echo> <menu-bar> 
<help-menu> <report-emacs-bug>

Recent messages:
Wrote c:/cygwin/home/Eric/Berk-Segmentation/SegmentationApp/Rutgers 
Segmentation/Code/ppmToSegPPM.cc
(No files need saving)
Auto-saving...done
Wrote c:/cygwin/home/Eric/Berk-Segmentation/SegmentationApp/Rutgers 
Segmentation/Code/ppmToSegPPM.cc
(No files need saving)
Mark set [2 times]
Wrote c:/cygwin/home/Eric/Berk-Segmentation/SegmentationApp/Rutgers 
Segmentation/Code/ppmToSegPPM.cc
(No files need saving)
Wrote c:/cygwin/home/Eric/Berk-Segmentation/SegmentationApp/Rutgers 
Segmentation/Code/ppmToSegPPM.cc [10 times]
Loading emacsbug...done

resultSegMul.pgm.gz
Description: application/gzip

resultSegMul.plain.pgm.gz
Description: application/gzip

screen-shot_correct-display.png
Description: PNG image

screen-shot_incorrect-display.png
Description: PNG image