curses_display.py

Urwid is a Python library for making text console applications. It has many features including fluid

#!/usr/bin/python
#
# Urwid curses output wrapper.. the horror..
#    Copyright (C) 2004-2007  Ian Ward
#
#    This library is free software; you can redistribute it and/or
#    modify it under the terms of the GNU Lesser General Public
#    License as published by the Free Software Foundation; either
#    version 2.1 of the License, or (at your option) any later version.
#
#    This library is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
#    Lesser General Public License for more details.
#
#    You should have received a copy of the GNU Lesser General Public
#    License along with this library; if not, write to the Free Software
#    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
# Urwid web site: http://excess.org/urwid/

"""
Curses-based UI implementation
"""

from __future__ import nested_scopes

import curses
import _curses
import sys

import util
import escape

KEY_RESIZE = 410 # curses.KEY_RESIZE (sometimes not defined)
KEY_MOUSE = 409 # curses.KEY_MOUSE

_curses_colours = {
	'default':		(-1,			0),
	'black':		(curses.COLOR_BLACK,	0),
	'dark red':		(curses.COLOR_RED,	0),
	'dark green':		(curses.COLOR_GREEN,	0),
	'brown':		(curses.COLOR_YELLOW,	0),
	'dark blue':		(curses.COLOR_BLUE,	0),
	'dark magenta':		(curses.COLOR_MAGENTA,	0),
	'dark cyan':		(curses.COLOR_CYAN,	0),
	'light gray':		(curses.COLOR_WHITE,	0),
	'dark gray':		(curses.COLOR_BLACK,    1),
	'light red':		(curses.COLOR_RED,      1),
	'light green':		(curses.COLOR_GREEN,    1),
	'yellow':		(curses.COLOR_YELLOW,   1),
	'light blue':		(curses.COLOR_BLUE,     1),
	'light magenta':	(curses.COLOR_MAGENTA,  1),
	'light cyan':		(curses.COLOR_CYAN,     1),
	'white':		(curses.COLOR_WHITE,	1),
}


# replace control characters with ?'s
_trans_table = "?"*32+"".join([chr(x) for x in range(32,256)])


class Screen(object):
	def __init__(self):
		self.curses_pairs = [
			(None,None), # Can't be sure what pair 0 will default to
		]
		self.palette = {}
		self.has_color = False
		self.s = None
		self.cursor_state = None
		self._keyqueue = []
		self.prev_input_resize = 0
		self.set_input_timeouts()
		self.last_bstate = 0
		self._started = False

	def register_palette( self, l ):
		"""Register a list of palette entries.

		l -- list of (name, foreground, background, mono),
		     (name, foreground, background) or
		     (name, same_as_other_name) palette entries.

		calls self.register_palette_entry for each item in l
		"""
		
		for item in l:
			if len(item) in (3,4):
				self.register_palette_entry( *item )
				continue
			assert len(item) == 2, "Invalid register_palette usage"
			name, like_name = item
			if not self.palette.has_key(like_name):
				raise Exception("palette entry '%s' doesn't exist"%like_name)
			self.palette[name] = self.palette[like_name]

	def register_palette_entry( self, name, foreground, background,
		mono=None):
		"""Register a single palette entry.

		name -- new entry/attribute name
		foreground -- foreground colour, one of: 'black', 'dark red',
			'dark green', 'brown', 'dark blue', 'dark magenta',
			'dark cyan', 'light gray', 'dark gray', 'light red',
			'light green', 'yellow', 'light blue', 'light magenta',
			'light cyan', 'white', 'default' (black if unable to
			use terminal's default)
		background -- background colour, one of: 'black', 'dark red',
			'dark green', 'brown', 'dark blue', 'dark magenta',
			'dark cyan', 'light gray', 'default' (light gray if
			unable to use terminal's default)
		mono -- monochrome terminal attribute, one of: None (default),
			'bold',	'underline', 'standout', or a tuple containing
			a combination eg. ('bold','underline')
			
		"""
		assert not self._started

		fg_a, fg_b = _curses_colours[foreground]
		bg_a, bg_b = _curses_colours[background]
		if bg_b: # can't do bold backgrounds
			raise Exception("%s is not a supported background colour"%background )
		assert (mono is None or 
			mono in (None, 'bold', 'underline', 'standout') or
			type(mono)==type(()))
	
		for i in range(len(self.curses_pairs)):
			pair = self.curses_pairs[i]
			if pair == (fg_a, bg_a): break
		else:
			i = len(self.curses_pairs)
			self.curses_pairs.append( (fg_a, bg_a) )
		
		self.palette[name] = (i, fg_b, mono)
		
	
	def set_mouse_tracking(self):
		"""
		Enable mouse tracking.  
		
		After calling this function get_input will include mouse
		click events along with keystrokes.
		"""
		rval = curses.mousemask( 0 
			| curses.BUTTON1_PRESSED | curses.BUTTON1_RELEASED
			| curses.BUTTON2_PRESSED | curses.BUTTON2_RELEASED
			| curses.BUTTON3_PRESSED | curses.BUTTON3_RELEASED
			| curses.BUTTON4_PRESSED | curses.BUTTON4_RELEASED
			| curses.BUTTON_SHIFT | curses.BUTTON_ALT
			| curses.BUTTON_CTRL )

	def start(self):
		"""
		Initialize the screen and input mode.
		"""
		assert self._started == False

		self.s = curses.initscr()
		self._started = True
		self.has_color = curses.has_colors()
		if self.has_color:
			curses.start_color()
			if curses.COLORS < 8:
				# not colourful enough
				self.has_color = False
		if self.has_color:
			try:
				curses.use_default_colors()
				self.has_default_colors=True
			except _curses.error:
				self.has_default_colors=False
		self._setup_colour_pairs()
		curses.noecho()
		curses.meta(1)
		curses.halfdelay(10) # use set_input_timeouts to adjust
		self.s.keypad(0)
		
	
	def stop(self):
		"""
		Restore the screen.
		"""
		if self._started == False:
			return
		curses.echo()
		self._curs_set(1)
		try:
			curses.endwin()
		except _curses.error:
			pass # don't block original error with curses error

		self._started = False
	
	def run_wrapper(self,fn):
		"""Call fn in fullscreen mode.  Return to normal on exit.
		
		This function should be called to wrap your main program loop.
		Exception tracebacks will be displayed in normal mode.
		"""
	
		try:
			self.start()
			return fn()
		finally:
			self.stop()

	def _setup_colour_pairs(self):
	
		k = 1
		if self.has_color:
			if len(self.curses_pairs) > curses.COLOR_PAIRS:
				raise Exception("Too many colour pairs!  Use fewer combinations.")
		
			for fg,bg in self.curses_pairs[1:]:
				if not self.has_default_colors and fg == -1:
					fg = _curses_colours["black"][0]
				if not self.has_default_colors and bg == -1:
					bg = _curses_colours["light gray"][0]
				curses.init_pair(k,fg,bg)
				k+=1
		else:
			wh, bl = curses.COLOR_WHITE, curses.COLOR_BLACK
		
		self.attrconv = {}
		for name, (cp, a, mono) in self.palette.items():
			if self.has_color:
				self.attrconv[name] = curses.color_pair(cp)
				if a: self.attrconv[name] |= curses.A_BOLD
			elif type(mono)==type(()):
				attr = 0
				for m in mono:
					attr |= self._curses_attr(m)
				self.attrconv[name] = attr
			else:
				attr = self._curses_attr(mono)
				self.attrconv[name] = attr
	
	def _curses_attr(self, a):
		if a == 'bold':
			return curses.A_BOLD
		elif a == 'standout':
			return curses.A_STANDOUT
		elif a == 'underline':
			return curses.A_UNDERLINE
		else:
			return 0
				
				


	def _curs_set(self,x):
		if self.cursor_state== "fixed" or x == self.cursor_state: 
			return
		try:
			curses.curs_set(x)
			self.cursor_state = x
		except _curses.error:
			self.cursor_state = "fixed"

	
	def _clear(self):
		self.s.clear()
		self.s.refresh()
	
	
	def _getch(self, wait_tenths):
		if wait_tenths==0:
			return self._getch_nodelay()
		curses.halfdelay(wait_tenths)
		self.s.nodelay(0)
		return self.s.getch()
	
	def _getch_nodelay(self):
		self.s.nodelay(1)
		while 1:
			# this call fails sometimes, but seems to work when I try again
			try:
				curses.cbreak()
				break
			except _curses.error:
				pass
			
		return self.s.getch()

	def set_input_timeouts(self, max_wait=0.5, complete_wait=0.1, 
		resize_wait=0.1):
		"""
		Set the get_input timeout values.  All values have a granularity
		of 0.1s, ie. any value between 0.15 and 0.05 will be treated as
		0.1 and any value less than 0.05 will be treated as 0. 
	
		max_wait -- amount of time in seconds to wait for input when
			there is no input pending
		complete_wait -- amount of time in seconds to wait when
			get_input detects an incomplete escape sequence at the
			end of the available input
		resize_wait -- amount of time in seconds to wait for more input
			after receiving two screen resize requests in a row to
			stop urwid from consuming 100% cpu during a gradual
			window resize operation
		"""

		def convert_to_tenths( s ):
			return int( (s+0.05)*10 )

		self.max_tenths = convert_to_tenths(max_wait)
		self.complete_tenths = convert_to_tenths(complete_wait)
		self.resize_tenths = convert_to_tenths(resize_wait)
	
	def get_input(self, raw_keys=False):
		"""Return pending input as a list.

		raw_keys -- return raw keycodes as well as translated versions

		This function will immediately return all the input since the
		last time it was called.  If there is no input pending it will
		wait before returning an empty list.  The wait time may be
		configured with the set_input_timeouts function.

		If raw_keys is False (default) this function will return a list