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Message ID: 1177     Entry time: Fri Dec 5 01:41:33 2008
Author: Yoichi 
Type: Configuration 
Category: Computers 
Subject: MEDM screen snapshot now works on linux machines 
As a part of my "make everything work on linux" project, I modified 'updatesnap' script so that linux machines can update MEDM screen snapshots.
Now, all 'updatesnap' in the subsystem directories (like medm/c1/lsc/cmd/updatesnap) are sym-link to /cvs/cds/caltech/medm/c1/cmd/updatesnap.
This script will take a window snapshot to a PNG file, and move the old snapshot to archive folders with date information added to the filename.
For compatibility, it also saves JPEG snapshot. Right now, most of 'view snapshot' menus in MEDM screens are calling 'sdtimage' command, which cannot display PNG files. I installed Imagemagick to op440m. We should change MEDM files to use 'display' command instead of 'sdtimage' so that it can show PNG files.
I've already changed some MEDM screens, but there are so many remaining to be modified.

PNG is better than JPEG for crisp images like screen shots. JPEG performs a sort of spacial Fourier transformations and low-pass filtering to compress the information. If it is used with sharp edges like boundaries of buttons on an MEDM screen, it naturally produces spacial aliasing (ghost images).

I also created several sym-links on the apps/linux/bin directory to mimic the Solaris-only commands, such as 'sdtimage', 'nedit' and 'dtterm'.
For example, nedit is symbolic linked to gedit. Many MEDM buttons/menus, which used to be incompatible with linux, now work fine on the linux machines.
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