Gimp Traffic #31 For 12 Feb 2001

By Cris Flagg

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Table Of Contents

Mailing List Stats For This Week

We looked at 58 posts in 172K.

There were 31 different contributors. 12 posted more than once. 1 posted last week too.

The top posters of the week were:

1. GTK+ Colorselector

2 Feb 2001 - 4 Feb 2001 (7 posts) Archive Link: "problem with gtk+ colorselector"

People: Sven NeumannAustin DonnellyUwe Koloska

Uwe Koloska posted that there were problems with changing both the foreground color and the last color chosen. Sven Neumann pointed out that these were default behaviors. He also mentioned that the colorselector has already undergone a major overhaul in the HEAD tree. The color previews as well as all sliders are now global to all color selector notebooks so all selectors should behave identically. He suggested looking at ( for a screenshot. Austin Donnelly pointed out that the GTK+ color selector was a "demo" piece of code for seeing how to interface, designed for programmers, not artists.

2. Denoise

5 Feb 2001 (1 post) Archive Link: "Denoise"

People: Martin Weber

Martin Weber posted a list of links relating to min/max curvature denoising and asked if anyone was interested in implementing them: ( ( ( ( ( (

3. GDynText 1.5.4

8 Feb 2001 - 9 Feb 2001 (5 posts) Archive Link: "ANNOUNCE: GDynText 1.5.4"

People: Tuomas KuosmanenMarco Lambert

Marco Lamberto announced that GDynText 1.5.4 was available at ( and that it compiled with GTK_DISABLE_COMPAT_H defined. Tuomas Kuosmanen asked if it now remembered the font wieght attribute. Marco said it didn't, due to deficiencies in GTK+ standard font selector.

4. Gimp.Themes.Org Repository

4 Feb 2001 - 5 Feb 2001 (4 posts) Archive Link: " ideas"

People: Jordan EvattSven NeumannMarc LehmannCarl B. Constantine

Jordan Evatt announced the creation of From feedback he'd received, several options were given. "

  1. don't create a separate repository for plugins and scripts
  2. things like patterns / gradients / brushes are good
  3. tutorial section probable, but some want that to stay at
" Carl B. Constantine liked the idea and also though it would be a good place for plug-ins. Sven Neumann thought that an overhaul of the Gimp site was in order, rather than simply creating more Gimp sites. Additionally, the plug-ins were currently being reworked and that leaving them out of a separate repository was a good idea. Marc Lehmann pointed out that there were already two repositories being reworked: - maybe soon to be revamped, web-repository - home for plugins, no web-repository
and another repository would not really help anyone.

No one else posted suggestions for Jordan

5. Gimptool DESTDIR patch

4 Feb 2001 (1 post) Archive Link: "gimptool patch to integrate nicely into"

People: Roger Leigh

Roger Leigh posted a patch relating to the discussion of the DESTDIR environment variable discussed at the end of last year

The following is a patch to allow the use of the DESTDIR environment variable when installing/uninstalling plugins. $DESTDIR is prefixed to the installation path, so that things may be installed into a 'staging directory', for packaging or testing purposes. A patch to the manpage is also included. The necessitates putting 'export DESTDIR' in the Makefile so that it is passed to gimptool in the environment.

6. Median Values in a Histogram

8 Feb 2001 (3 posts) Subject: "Value in histogram"

People: Roel SchroevenSven NeumannSven Neumann

Roel Schroeven asked " The value in the Gimp histogram is calculated as the maximum of the red, green and blue channels now. Wouldn't it be better to use the average of the three color channels?" Sven Neumann though the average of the channels was somewhat useless, but suggested adding the intensity "defined as 0.3 r + 0.59 g + 0.11 b"

7. Passing Masks to Histograms

2 Feb 2001 - 5 Feb 2001 (4 posts) Archive Link: "incorrect mask handling in histogram calculation"

People: Roel SchroevenJay CoxAustin Donnelly

Roel Schroeven noticed that the histogram gave results that were not expected. He posted a fix to the code. Austin Donnelly warned that this change might have a detrimental effect on tools that used the histogram without masks. Roel was confident that if the other tools passed a null pointer as a mask, the histogram is still calculated for the entire layer. Jay Cox committed the fix (As well as the median calculation fix).

8. Porting Plug-Ins from 1.18 to 1.20

5 Feb 2001 (3 posts) Archive Link: "porting a plug-in from 1.18 to 1.20"

People: Sven Neumann

David Rohde asked about the proper procedure for porting plug-ins. Sven Neumann pointed to an aptly named script, ( . This, in addition to changing the RGB to GIMP_RGB and reviewing the Libgimp API reference, should make porting a lot easier.

9. PyGimp Fixes

3 Feb 2001 (1 post) Archive Link: "PyGimp Fixes"

People: Hans Breuer

Hans Breuer posted a list of PyGimp fixes. These relate to things the were recently changed or omitted

The definitions of come symbolic constants got lost or changed some while ago:


import gimp
if gimp.major_version > 1 or gimp.major_version==1 and gimp.minor_version>=1:

del gimp


The return values of pdb calling where formerly named with prefix GIMP_PDB_. The current version does simply call them PDB_. Though this does not cause a namespace problem in Python, it breaks at least two Python scripts, which are juggling with the constant prefixes from #GimpPDBArgType (PDB_) to get a mapping for the data types. The scripts are (in cvs) and (in plug-in registry)

# GimpPDBStatustype
should be again renamed to:

10. Other Ideas for the Space Key

4 Feb 2001 (6 posts) Archive Link: "Space key & border area ideas"

People: Guillermo S. Romero

This thread relates to the discussion on temporary tools this week.

Guillermo S. Romero posted a list of things that could be tied to space bar activities. "

" He also suggested that the border around an image be put to good use. It could serve as a scratch area, and should exist even if zoomed in. Paint could be applied to the area, and disappear after a certain amount of time. It also eliminates the need to start with a bigger canvas and crop the final image because of image edge issues.

Alan liked the alt + space bar idea, since it eliminated the need for developers to anticipate users needs. Using the border as a scratch area sounded like a temporary layer, which allows the artist to see what a color looks like when applied to the image. Guillermo S. Romero said he uses Ctrl + Z a lot, and would rather use some sort of scratch area. He also thought there was a benefit to being able to start a painting operation outside of the defined border. An example of why this is needed can be seen when using the bird brush at the edge of the canvas. Matthew Peters mentioned problems using height maps that extended past the edge of the image. Airbrushing just outside the canvas is also impossible.

There were no more posts in this thread

11. How to Run Scripts Synchronously

6 Feb 2001 - 7 Feb 2001 (2 posts) Archive Link: "How do you run scripts synchronously?"

People: Jay Cox

Tim Lambert wanted to know how to run scripts synchronously, since the Gimp didn't seam thread safe. The goal was to allow Scheme code, called from C, to wait until the Scheme thread had completed before more processing is done. Jay Cox didn't think there was a good way to do this, but posted one anyway. It used a parasite as a mutex lock.

C code should look something like this:
gimp_image_parasite_detach(imageID, "myplugin-mutexlock"); /* in case it is left over from a previous call */
while (!(p = gimp_image_parasite_find(imageID, "myplugin-mutexlock")) usleep(500);
gimp_image_parasite_detach(imageID, "myplugin-mutexlock"); /* clean up parasite */
-rest of plugin goes here-

In your scheme function you will want to add a parasite to the image with the name "myplugin-mutexlock" as the last statement in the script.

Jay pointed out that if the script-fu failed, the plugin would never return and the program would hang.

12. Temporary Tool Assignments

2 Feb 2001 (2 posts) Archive Link: "Idea: Temporary tool assignment"

People: Guillermo S. Romero

Alan suggested that the Gimp add more temporary tools, like photoshop. Guillermo S. Romero suggested Alan make a list of tools " Please try all the tools and make a list of the ones that do nothing with Ctrl and / or Shift and / or Alt (before clicking / after clicking, like with Circle selection). Advice: set pointer to cross and icon, that way it gives hints about what is happening (or will if you click). Also keep open the Tool Options dialog, and watch the buttons change. Tab also does magic when over an image (hit again to get the volunteer back from backstag... err... nimbo). " He said that most of the basic operations are there.

13. Proposal for a Texture Selector

3 Feb 2001 - 4 Feb 2001 (4 posts) Archive Link: "Proposal for a texture selector"

People: David A. BartoldSven Neumann

David A. Bartold a texture selector be added to the Gimp. "I propose to create a new dialog box similar to the pattern selector. Instead of containing tilable RGB pixmaps, it will contain tileable greyscale heightfield pixmaps. These textures will be used by some tools to simulate, for example, paper grain. The user can see the current texture in the main window and in the Device status window. It will be near the current brush selection, pattern, and gradient. " David had an algorithm that creates a new mask from the texture information " new_mask[x][y] = MAX (mask[x][y] - texture[x + offset_x][y + offset_y], 0) " This is similar to setting wax = 0% and opacity = 100% in DigiPencil

Sven Neumann thought it sounded like a reasonable idea, but cautioned any development to wait a few weeks until the currently-in-development GimpData object was complete. This object would create a standard interface to this sort of thing and eliminate the cut and paste tpye create that necessitated the Gimp 1.2 rewrite.

14. Wideangle Distortion Plugin

1 Feb 2001 (1 post) Subject: "Wideangle distortion plugin"

People: David Hodson

David Hodson posted a plugin "which corrects (or creates) the barrel (or pincushion) distortion common to wideangle lenses. It's designed to let you store and reuse corrections for specific lenses (as well as just play)." The plugin is locatd at (

15. Wishlist for Gimp 1.4/2.0

3 Feb 2001 - 5 Feb 2001 (3 posts) Archive Link: "New wishlist for next GIMP available??"

People: Sven NeumannDaniel Egger

Avi Bercovich asked about how to contribute to the Gimp wishlist. Sven Neumann responded that there would be very few new features in Gimp-2.0 since the goal of the current development cycle was to clean up the codebase. The TODO file (which should probably be called IDEAS) had a list of ideas, as well as the TODO.xml document in the HEAD brand of the CVS Tree. Daniel Egger pointed to the bugtracker at as a good place to keep ideas from getting lost







Sharon And Joy

Kernel Traffic is grateful to be developed on a computer donated by Professor Greg Benson and Professor Allan Cruse in the Department of Computer Science at the University of San Francisco. This is the same department that invented FlashMob Computing. Kernel Traffic is hosted by the generous folks at All pages on this site are copyright their original authors, and distributed under the terms of the GNU General Public License version 2.0.