Shallow Thoughts : : gimp

GIMP: Build-it

Are you a GIMP user or Summer of Code student who's been wanting to get involved, but having trouble building, or a bit intimidated by the build process?

I'll be running a session on IRC to help anyone build GIMP on Linux, as part of the OpenHatch "Build it" project.

The session will take place on #gimp on irc.gimp.org (also known as GimpNet), on Fri, Apr 15, 0300 UTC -- that's Thursday night in the Americas. To convert to your time zone, run this command on your local machine:

$ date -d 'Fri Apr 15 03:00 UTC'
Thu Apr 14 20:00:00 PDT 2011

Or try this link: world time server.

This is a time that's usually fairly quiet on #gimp -- European users don't fret, since it's pretty easy to get help there during more Europe-friendly time zones. I'll hang around for at least two hours; that should be plenty of time to build GIMP and all its prerequisites.

For folks new to IRC, note that irc.gimp.org is its own server -- this is not the #gimp channel on Freenode. You can learn more about IRC on the LinuxChix IRC for Beginners page, or, if you have trouble getting an IRC client configured, try this link for mibbit web chat.

Note: The #gimp IRC channel was recently under attack by trolls, and it's possible that it may not be usable at the time of the session. In that case, I will update this blog page with the name of an alternate channel to use, and any other necessarily details.

Preparation

If you want to get your system set up ahead of time, I've put the instructions needed to build on Ubuntu Lucid and other older Linux distros here: Gimp Building Tips (for Linux). I might be able to offer a little help with building on Macs, but no guarantees.

Mac and Windows users, or people running a very old Linux distro (more than a year old) might want to consider an alternate approach: install Virtualbox or VMware and install Ubuntu "Natty Narwhal" (currently still in beta) in a virtual machine.

Of course, this isn't the only time you can get help with building GIMP. There are folks around on #gimp most of the time who are happy to help with problems. But if you've been meaning to get started and want a good excuse, or you've been holding off on asking for help ... come hang out with us and try it!

Tags: gimp, programming, education
[ 11:50 Apr 13, 2011    More gimp | permalink to this entry | comments ]

GIMP: Don't get confused by the Auto button

A couple of people recently have appeared on GIMP IRC channels wondering why no filters or layer operations seemed to work in GIMP, even though they had an image open.

In at least one case, it was a setting most of us had forgotten about: the Auto button. It's easy to miss, but if you turn it on accidentally, you may be unable to do anything in GIMP until you realize what's happened.

The Auto button is the one at the upper right of your Layers dialog. It's on by default, and what it does is ensure that dialogs like Layers, and GIMP's notion of the currently active layer, follow the active image. Open a new image, or click in a different image window, and your Layers dialog switches images -- so whatever you do next will apply to the image you just chose.

If you turn Auto off, then by default, no image and no layer is active. Notice, in the screenshot at left, how no image is shown in the option menu just left of the Auto button.

Even if you open a new image, you can't do anything with it until you explicitly choose an image from the menu.

I'm sure you can see why this could be confusing. So why have that button at all?

Well, it's useful when you're working with lots of images -- for instance, if you want to drag a layer from one image into another image, you can use the menu to switch quickly among images and layers without needing to bring those image windows to the front. I don't find I need it, but for those who do, I guess it can be a real time-saver.

Just to make it even more confusing, not everyone even has the Auto button or the menu next to it. You can turn it off (and gain a little extra vertical space for your layers dialog) with the tiny menu button right above the mode menu. "Show Image Selection" controls whether the image option menu, and the Auto button next to it, will be displayed. "Auto Follow Active Image" is the same toggle as the Auto button itself.

So if you ever get stuck and the Layers dialog doesn't seem to be showing layers from your image, and you can't figure out why ... remember that pesky Auto button. It might just be the problem.

(If not, try quitting GIMP and moving your profile aside. That works for curing all manner of mysterious ills -- including this one. Come to think of it, that deserves an article of its own. Coming soon!)

Tags: gimp, ui
[ 10:04 Feb 19, 2011    More gimp | permalink to this entry | comments ]

New GIMP Arrow Designer

While writing a blog post on GIMP's confusing Auto button (to be posted soon), I needed some arrows, and discovered a bug in my Arrow Designer script when making arrows that are mostly vertical.

So I fixed it. You can get the new Arrow Designer 0.5 on my GIMP Arrow Designer page.

It's purely a coincidence that I discovered this a week before SCALE, where I'll be speaking on Writing GIMP Scripts and Plug-Ins. Arrow Designer is one of my showpieces for making interactive plug-ins with GIMP-Python, so I'm glad I noticed the bug when I did.

Tags: gimp, programming, python
[ 20:28 Feb 18, 2011    More gimp | permalink to this entry | comments ]

Editing Batches of Photos with GIMP and David's Batch Processor

Have a lot of images to edit, but confused by command-line tools like ImageMagick? Try David's Batch Processor, a GIMP plug-in that lets you apply multiple operations like resize, rotate, or brightness/contrast to groups of photos.

The article is on Linux Planet: Editing Batches of Photos Easily on Linux.

Tags: writing, gimp
[ 10:07 Dec 23, 2010    More gimp | permalink to this entry | comments ]

More advanced GIMP tricks for cutting parts out of photos

My previous Linux Planet article covered beginner tips for cutting foreground objects out of photographs. Part 2, from last week, covers some more flexible advanced techniques you'll want to use as your GIMP skills increase.

Find out how to put a butterfly in space!

Read it here: More GIMP tricks for cutting objects of photos

Tags: writing, gimp
[ 14:14 Nov 15, 2010    More gimp | permalink to this entry | comments ]

GIMP tricks for isolating parts of photos

Today's Linux Planet article covers some basic tips for how to cut a foreground object out of a photograph, so you can grab that penguin or flower or motorcycle and paste it somewhere else.

Read it here: GIMP tricks for isolating parts of photos

This is mostly beginner stuff, for people who haven't done this at all. Part II, in two weeks, will cover more advanced techniques.

Tags: writing, gimp
[ 14:37 Oct 28, 2010    More gimp | permalink to this entry | comments ]

GIMP Wallpaper script improvements

Dave was using some old vacation photos to test filesystem performance, and that made me realize that I had beautiful photos from the same trip that I hadn't yet turned into desktop backgrounds.

Sometimes I think that my GIMP Wallpaper script is the most useful of the GIMP plug-ins I've written. It's such a simple thing ... but I bet I use it more than any of my other plug-ins, and since I normally make backgrounds for at least two resolutions (my 1680x1050 desktop and my 1366x768 laptop), it certainly saves me a lot of time and hassle.

But an hour into my background-making, I started to have nagging doubts. I wasn't renaming these images, just keeping the original filenames from the camera, like pict0828.jpg. What if if some of these were overwriting images of the same name? The one thing my script doesn't do is check for that, and gimp_file_save doesn't pop up any warnings. I've always meant to add a check for it.

Of course, once the doubts started, I had to stop generating backgrounds and start generating code. And I'm happy with the result: wallpaper-0.4.py warns and won't let you save over an old background image, but keeps all the logic in one dialog rather than popping up extra warnings.

Now I can generate backgrounds without worrying that I'm stomping on earlier ones.

Tags: gimp, programming, gtk
[ 21:25 Sep 26, 2010    More gimp | permalink to this entry | comments ]

How to save on modeling fees

At the Terrible's Sands Regency in Reno, Dave noticed this ad on the table in the room. "Wait -- isn't that the same guy, twice?"

Sure enough -- not just the same person, but the same photo, with different hair and neck pixeled in.

I guess Photoshop/GIMP artists are cheaper than photo models these days.

We spotted the same model in other ads around the hotel, sometimes masquerading as other races as well.

Tags: gimp, photoshop, humor
[ 16:28 Jul 29, 2010    More gimp | permalink to this entry | comments ]