colorscheme.py

# Copyright (C) 2009, 2010, 2011  Roman Zimbelmann <romanz@lavabit.com>
# This software is distributed under the terms of the GNU GPL version 3.

"""
Colorschemes define colors for specific contexts.

Generally, this works by passing a set of keywords (strings) to
the colorscheme.get() method to receive the tuple (fg, bg, attr).
fg, bg are the foreground and background colors and attr is the attribute.
The values are specified in ranger.gui.color.

A colorscheme must...

1. be inside either of these directories:
~/.config/ranger/colorschemes/
path/to/ranger/colorschemes/

2. be a subclass of ranger.gui.colorscheme.ColorScheme

3. implement a use(self, context) method which returns (fg, bg, attr).
context is a struct which contains all entries of CONTEXT_KEYS,
associated with either True or False.

define which colorscheme to use by having this to your options.py:
from ranger import colorschemes
colorscheme = "name"
"""

import os
from curses import color_pair

import ranger
from ranger.gui.color import get_color
from ranger.gui.context import Context
from ranger.core.main import allow_access_to_confdir
from ranger.core.shared import SettingsAware
from ranger.ext.cached_function import cached_function
from ranger.ext.iter_tools import flatten

# ColorScheme is not SettingsAware but it will gain access
# to the settings during the initialization.  We can't import
# SettingsAware here because of circular imports.

class ColorScheme(SettingsAware):
	"""
	This is the class that colorschemes must inherit from.

	it defines get() 
	it defines the get() method, which returns the color tuple
	which fits to the given keys.
	"""

	def get(self, *keys):
		"""
		Returns the (fg, bg, attr) for the given keys.

		Using this function rather than use() will cache all
		colors for faster access.
		"""
		context = Context(keys)

		# add custom error messages for broken colorschemes
		color = self.use(context)
		if self.settings.colorscheme_overlay:
			result = self.settings.colorscheme_overlay(context, *color)
			assert isinstance(result, (tuple, list)), \
					"Your colorscheme overlay doesn't return a tuple!"
			assert all(isinstance(val, int) for val in result), \
					"Your colorscheme overlay doesn't return a tuple"\
					" containing 3 integers!"
			color = result
		return color

	@cached_function
	def get_attr(self, *keys):
		"""
		Returns the curses attribute for the specified keys

		Ready to use for curses.setattr()
		"""
		fg, bg, attr = self.get(*flatten(keys))
		return attr | color_pair(get_color(fg, bg))

	def use(self, context):
		"""Use the colorscheme to determine the (fg, bg, attr) tuple.

		Override this method in your own colorscheme.
		"""
		return (-1, -1, 0)

def _colorscheme_name_to_class(signal):
	# Find the colorscheme.  First look in ~/.config/ranger/colorschemes,
	# then at RANGERDIR/colorschemes.  If the file contains a class
	# named Scheme, it is used.  Otherwise, an arbitrary other class
	# is picked.
	if isinstance(signal.value, ColorScheme): return

	scheme_name = signal.value
	usecustom = not ranger.arg.clean

	def exists(colorscheme):
		return os.path.exists(colorscheme + '.py')

	def is_scheme(x):
		try:
			return issubclass(x, ColorScheme)
		except:
			return False

	# create ~/.config/ranger/colorschemes/__init__.py if it doesn't exist
	if usecustom:
		if os.path.exists(signal.fm.confpath('colorschemes')):
			initpy = signal.fm.confpath('colorschemes', '__init__.py')
			if not os.path.exists(initpy):
				open(initpy, 'a').close()

	if usecustom and \
			exists(signal.fm.confpath('colorschemes', scheme_name)):
		scheme_supermodule = 'colorschemes'
	elif exists(signal.fm.relpath('colorschemes', scheme_name)):
		scheme_supermodule = 'ranger.colorschemes'
		usecustom = False
	else:
		scheme_supermodule = None  # found no matching file.

	if scheme_supermodule is None:
		if signal.previous and isinstance(signal.previous, ColorScheme):
			signal.value = signal.previous
		else:
			signal.value = ColorScheme()
		raise Exception("Cannot locate colorscheme `%s'" % scheme_name)
	else:
		if usecustom: allow_access_to_confdir(ranger.arg.confdir, True)
		scheme_module = getattr(__import__(scheme_supermodule,
				globals(), locals(), [scheme_name], 0), scheme_name)
		if usecustom: allow_access_to_confdir(ranger.arg.confdir, False)
		if hasattr(scheme_module, 'Scheme') \
				and is_scheme(scheme_module.Scheme):
			signal.value = scheme_module.Scheme()
		else:
			for var in scheme_module.__dict__.values():
				if var != ColorScheme and is_scheme(var):
					signal.value = var()
					break
			else:
				raise Exception("The module contains no valid colorscheme!")