Created Sunday 2/1/2005
This document discusses the Gimp 2 image manipulation and paint program. Examples, scripts and directories may be specific to Gimp 2.2
Gimp plug-ins are a little different to scripts and are typically delivered as source code e.g., writtin in C. Gimp plug-ins can be installed at either the system level, which make the plug-in available to all users or they can be installed a the user level in the user's local gimp configuration. These two locations are, respectively:
Often, the gimp-2.2 user plug-ins are delivered as .c source. Use gimptool-2.0 to compile and install these plug-ins. With Gimp 2.2, there's a symlink called gimptool that points to gimptool-2.0). E.g.,
bash $ gimptool someplugin.c
In the above example, the plugin someplugin is compiled and linked to binary and installed to the user-level plug-in directory ~/.gimp-2.2/plug-ins.
There are many 3rd party add-ons and scriptlets which can significantly extend the base gimp fuctionality. Gimp has a built-in Lisp interpretor (using the Scheme dialect) and also supports add-ons written in perl and php. Scripts written in either scheme, perl or php provide features ranging from bump mapping, logo generation, red-eye reduction and a bunch of other interesting features. These add-ons can be installed to either the system environment (accessible to all users) or to the user's local gimp configuration. These two locations are:
The gimptool-2.0 can be used in Makefiles and build configuration tools to determine where the Gimp libraries and headers are located. This is done using the gimptool, which is a symlink to gimptool-2.0. The following illustrate this:
bash $ gimptool --gimpplugindir /usr/lib/gimp/2.0
bash $ gimptool --libdir /usr/lib
bash $ gimptool --gimpdatadir /usr/share/gimp/2.0
An image with a solid colour background can be made transparent by combining a Color to Alpha Filter with the wand tool. The following steps illustrate the this process:
Some parts of the background may not be accessible to the transparency filter in the first pass, which is why the select and repeat steps are required. This will be true for any image that includes an enclosed area, such as that made by a circle or square and etc.
This tutorial has a step by step guide to adding a fade out to a region of an existing non-transparent (png) image.
The gimp as an action for Aquiring a screen image. This can be either the entire root window (with child window contents) or a particular frame. The sub-menu item "Aquire" from the "File" menu has a menu item called "Screenshot...". This menu item opens a dialog from which properties for capturing a single window or the entire screen can be specified. Options such as "delay" allow the user to specify a period in seconds to wait before the snap takes place. This provides the user with the opportunity to raise the window to snap, or to open menus on the winow being snapped and so on.
The "Area" section of the dialog has three options:
The import program of the ImageMagick suite is a command line tool that provides similar image capture and manipulation. The import tool is far more sophisticated in the level of control the user has over selecting the image capture properties. For example, the image depth and format and geometry can be specified, along with the X-Server support (permissions permitting of course) so that the tool can capture image content from a remote X-Server.
Stuart Moorfoot © 1 Jan 2005 foo@bund.com.au