UI (colour) themes play a role in two parts: when writing to the
console and for the xpce-based development tools such as
PceEmacs or the graphical debugger. Coloured console output is based on
ansi_format/3.
The central message infra structure based on
print_message/2
labels message (components) with a Prolog term that specifies the role.
This is mapped to concrete colours by means of the hook prolog:console_color/2.
Theming the IDE uses xpce class variables that are initialised
from Prolog when xpce is loaded.
Themes are implemented as a Prolog file in the file search path
library/theme. A theme can be loaded using (for example) the directive
below in the user's initialization file (see section
2.2).
:- use_module(library(theme/dark)).
The theme file library(theme/auto) is provided to
automatically choose a reasonable theme based on the environment. The
current version detects the background color on xterm compatible
terminal emulators (found on most Unix systems) and loads the dark
theme if the background is‘darkish’.
The following notes apply to the different platforms on which
SWI-Prolog is supported:
- Unix/Linux
- If an xterm compatible terminal emulator is used to run Prolog you may
wish to load either an explicit theme or
library(theme/auto).
- Windows
- The swipl-win.exe graphical application can be themed by loading
a theme file. The theme file also sets the foreground and background
colours for the console.
Theme support was added in SWI-Prolog 8.1.11. Only part of the IDE
tools are covered and the only additional theme (dark) is
not net well balanced. The interfaces between the theme file and notably
the IDE components is not very well established. Please contribute by
improving the dark theme. Once that is complete and
properly functioning we can start adding new themes.
