Is it possible to use GIMP's image capabilities from an Android application?

Question

I was using opencv for some time for programming in Android, and I now see that the Gimp library is much stronger. Where can I find a starting point to learn Gimp? I also want to know the basic concepts behind of Gimp plugins. In the past, I used C APIs in opencv. How could I write the code for android? Also, what packages do I need to install in windows to start using Gimp?

Answer 1

ALthough GIMP dows have some standalone libraries that perform some image manipulation, most image manipulation is done either by GIMP's core program or through GIMP's plug-ins. Both approaches need to have the entire program installed and running (though not necessarily usin a display).

I know nothing on Andorid progrmaing, and don't knwo how can one install ordinary native code in C and call it from Android apps - if you are very familiar with it, you might have a chance in your attempt.

However GIMP itself relies on a extensive ecosystem of libraries, including, but not limited to, glib, gtk+, cairo, pango, gegl - and each of these in turn might have other pre-requisites. Since Windows does not have a working package manager to authomatically install libraries and header files of these various libraries, working with these natively on Windows, though the code of each of them is multiplatform and can run on Windows and other OSses,is very hard. So hard that hthe people who build GIMP for Windows themselves do so in a Linux environment, from where they cros-compile GIMP for Windows.

Making all of these libraries work on an Android is probably not hard if you are using the GNU ecosystem around the Android's Linux kernel , and not just the bare Android environment (I don't know enough about android to even know if that is possible).

All in all: it will be though for you, and demand a whole lot of research.

One of GIMP's libraries, the GEGL (Generic Graphics Library) has a lot less prerequistes, and can be used as an ordinary library. I think you can probably build it with just glib and Babl as prerequisites. This is the library that will replace current's GIMP core, and reimplement the operations of most existing plug-ins -- so it might be enough for you.
If you can get GEGL running and usable from an Android system share that with the World --it would be , in itelsef, a project worth of a Google Summer of Code project. (And still would be about an order of magnitude easier than getting GIMP code in there to be used as a library from other applications).

Finally -- if you want just a couple of GIMP's effects, if the effect is implemented as a Plug-in in GIMP, the plug-ins' code is quite straightforward. So, while it would be hard to get the whole GIMP environment inside Android, copying the functions that actually perform the pixel manipulation from GIMP's source tree and converting them to work in a java method inside your app would not be hard. Just remember to comply with the license in this case: GIMP's plugins code is under GPLv3. (the GEGL library is only LGPL)

In short: no, you can't use GIMP's "libraries" as native code from an Android app -if you can use OpenCV, you have a good chance of being able to use GEGL instead. Only orting the algorithms of certain plugins to manipulate pixels in your app would be easier.

However -- if your application would allow delegating Image Processing to an internet based server, setting up an HTTP application to receive a image, use GIMP to process it, and stream it back would be a simple thing to do.

(So, you could not apply effects in real time, but would allow one to, for example, take a photo, select a series of effects from menus, and send it to the server for processing)

Answer 2

GIMP uses quite a bit of memory when loading brushes. If you drop all of the useless plug-ins, and build it from source. You may be able to get it working but you will have to build ALL of the linked libraries directly into the executable.

In other words; build linked libraries directly into the code as a static build. In this manner things may function properly unless one of those linked libraries call another linked library.

Getting the libraries themselves to work on the OS may provide additional programs opportunities to use them. Additionally, GTK+ (GIMP Tool Kit), GIMP's interface is also rather bloated and ugly.

If all else fails, you'll simply have to settle for a smaller program with the features you're looking for on the fly ( Levels, Curves, the clone tool, dodge and burn, etc. ) Layers are also nice, but editing a a large megapixel image begins to eat up memory rather quickly and most android device don't have a swap partition.