/usr/lib/python3/dist-packages/urwid/listbox.py is in python3-urwid 2.0.1-2.
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#
# Urwid listbox class
# Copyright (C) 2004-2012 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/
from __future__ import division, print_function
from urwid.compat import xrange, with_metaclass
from urwid.util import is_mouse_press
from urwid.canvas import SolidCanvas, CanvasCombine
from urwid.widget import Widget, nocache_widget_render_instance, BOX, GIVEN
from urwid.decoration import calculate_top_bottom_filler, normalize_valign
from urwid import signals
from urwid.signals import connect_signal
from urwid.monitored_list import MonitoredList, MonitoredFocusList
from urwid.container import WidgetContainerMixin
from urwid.command_map import (CURSOR_UP, CURSOR_DOWN,
CURSOR_PAGE_UP, CURSOR_PAGE_DOWN, CURSOR_MAX_LEFT, CURSOR_MAX_RIGHT)
class ListWalkerError(Exception):
pass
class ListWalker(with_metaclass(signals.MetaSignals, object)):
signals = ["modified"]
def _modified(self):
signals.emit_signal(self, "modified")
def get_focus(self):
"""
This default implementation relies on a focus attribute and a
__getitem__() method defined in a subclass.
Override and don't call this method if these are not defined.
"""
try:
focus = self.focus
return self[focus], focus
except (IndexError, KeyError, TypeError):
return None, None
def get_next(self, position):
"""
This default implementation relies on a next_position() method and a
__getitem__() method defined in a subclass.
Override and don't call this method if these are not defined.
"""
try:
position = self.next_position(position)
return self[position], position
except (IndexError, KeyError):
return None, None
def get_prev(self, position):
"""
This default implementation relies on a prev_position() method and a
__getitem__() method defined in a subclass.
Override and don't call this method if these are not defined.
"""
try:
position = self.prev_position(position)
return self[position], position
except (IndexError, KeyError):
return None, None
class PollingListWalker(object): # NOT ListWalker subclass
def __init__(self, contents):
"""
contents -- list to poll for changes
This class is deprecated. Use SimpleFocusListWalker instead.
"""
import warnings
warnings.warn("PollingListWalker is deprecated, "
"use SimpleFocusListWalker instead.", DeprecationWarning)
self.contents = contents
if not getattr(contents, '__getitem__', None):
raise ListWalkerError("PollingListWalker expecting list like "
"object, got: %r" % (contents,))
self.focus = 0
def _clamp_focus(self):
if self.focus >= len(self.contents):
self.focus = len(self.contents)-1
def get_focus(self):
"""Return (focus widget, focus position)."""
if len(self.contents) == 0: return None, None
self._clamp_focus()
return self.contents[self.focus], self.focus
def set_focus(self, position):
"""Set focus position."""
# this class is deprecated, otherwise I might have fixed this:
assert type(position) == int
self.focus = position
def get_next(self, start_from):
"""
Return (widget after start_from, position after start_from).
"""
pos = start_from + 1
if len(self.contents) <= pos: return None, None
return self.contents[pos],pos
def get_prev(self, start_from):
"""
Return (widget before start_from, position before start_from).
"""
pos = start_from - 1
if pos < 0: return None, None
return self.contents[pos],pos
class SimpleListWalker(MonitoredList, ListWalker):
def __init__(self, contents):
"""
contents -- list to copy into this object
Changes made to this object (when it is treated as a list) are
detected automatically and will cause ListBox objects using
this list walker to be updated.
"""
if not getattr(contents, '__getitem__', None):
raise ListWalkerError("SimpleListWalker expecting list like object, got: %r"%(contents,))
MonitoredList.__init__(self, contents)
self.focus = 0
def _get_contents(self):
"""
Return self.
Provides compatibility with old SimpleListWalker class.
"""
return self
contents = property(_get_contents)
def _modified(self):
if self.focus >= len(self):
self.focus = max(0, len(self)-1)
ListWalker._modified(self)
def set_modified_callback(self, callback):
"""
This function inherited from MonitoredList is not
implemented in SimpleListWalker.
Use connect_signal(list_walker, "modified", ...) instead.
"""
raise NotImplementedError('Use connect_signal('
'list_walker, "modified", ...) instead.')
def set_focus(self, position):
"""Set focus position."""
try:
if position < 0 or position >= len(self):
raise ValueError
except (TypeError, ValueError):
raise IndexError("No widget at position %s" % (position,))
self.focus = position
self._modified()
def next_position(self, position):
"""
Return position after start_from.
"""
if len(self) - 1 <= position:
raise IndexError
return position + 1
def prev_position(self, position):
"""
Return position before start_from.
"""
if position <= 0:
raise IndexError
return position - 1
def positions(self, reverse=False):
"""
Optional method for returning an iterable of positions.
"""
if reverse:
return xrange(len(self) - 1, -1, -1)
return xrange(len(self))
class SimpleFocusListWalker(ListWalker, MonitoredFocusList):
def __init__(self, contents):
"""
contents -- list to copy into this object
Changes made to this object (when it is treated as a list) are
detected automatically and will cause ListBox objects using
this list walker to be updated.
Also, items added or removed before the widget in focus with
normal list methods will cause the focus to be updated
intelligently.
"""
if not getattr(contents, '__getitem__', None):
raise ListWalkerError("SimpleFocusListWalker expecting list like "
"object, got: %r"%(contents,))
MonitoredFocusList.__init__(self, contents)
def set_modified_callback(self, callback):
"""
This function inherited from MonitoredList is not
implemented in SimpleFocusListWalker.
Use connect_signal(list_walker, "modified", ...) instead.
"""
raise NotImplementedError('Use connect_signal('
'list_walker, "modified", ...) instead.')
def set_focus(self, position):
"""Set focus position."""
self.focus = position
self._modified()
def next_position(self, position):
"""
Return position after start_from.
"""
if len(self) - 1 <= position:
raise IndexError
return position + 1
def prev_position(self, position):
"""
Return position before start_from.
"""
if position <= 0:
raise IndexError
return position - 1
def positions(self, reverse=False):
"""
Optional method for returning an iterable of positions.
"""
if reverse:
return xrange(len(self) - 1, -1, -1)
return xrange(len(self))
class ListBoxError(Exception):
pass
class ListBox(Widget, WidgetContainerMixin):
"""
a horizontally stacked list of widgets
"""
_selectable = True
_sizing = frozenset([BOX])
def __init__(self, body):
"""
:param body: a ListWalker subclass such as
:class:`SimpleFocusListWalker` that contains
widgets to be displayed inside the list box
:type body: ListWalker
"""
self.body = body
try:
connect_signal(self._body, "modified", self._invalidate)
except NameError:
# our list walker has no modified signal so we must not
# cache our canvases because we don't know when our
# content has changed
self.render = nocache_widget_render_instance(self)
# offset_rows is the number of rows between the top of the view
# and the top of the focused item
self.offset_rows = 0
# inset_fraction is used when the focused widget is off the
# top of the view. it is the fraction of the widget cut off
# at the top. (numerator, denominator)
self.inset_fraction = (0,1)
# pref_col is the preferred column for the cursor when moving
# between widgets that use the cursor (edit boxes etc.)
self.pref_col = 'left'
# variable for delayed focus change used by set_focus
self.set_focus_pending = 'first selectable'
# variable for delayed valign change used by set_focus_valign
self.set_focus_valign_pending = None
def _get_body(self):
return self._body
def _set_body(self, body):
if getattr(body, 'get_focus', None):
self._body = body
else:
self._body = SimpleListWalker(body)
self._invalidate()
body = property(_get_body, _set_body, doc="""
a ListWalker subclass such as :class:`SimpleFocusListWalker` that contains
widgets to be displayed inside the list box
""")
def calculate_visible(self, size, focus=False ):
"""
Returns the widgets that would be displayed in
the ListBox given the current *size* and *focus*.
see :meth:`Widget.render` for parameter details
:returns: (*middle*, *top*, *bottom*) or (``None``, ``None``, ``None``)
*middle*
(*row offset*(when +ve) or *inset*(when -ve),
*focus widget*, *focus position*, *focus rows*,
*cursor coords* or ``None``)
*top*
(*# lines to trim off top*,
list of (*widget*, *position*, *rows*) tuples above focus
in order from bottom to top)
*bottom*
(*# lines to trim off bottom*,
list of (*widget*, *position*, *rows*) tuples below focus
in order from top to bottom)
"""
(maxcol, maxrow) = size
# 0. set the focus if a change is pending
if self.set_focus_pending or self.set_focus_valign_pending:
self._set_focus_complete( (maxcol, maxrow), focus )
# 1. start with the focus widget
focus_widget, focus_pos = self._body.get_focus()
if focus_widget is None: #list box is empty?
return None,None,None
top_pos = focus_pos
offset_rows, inset_rows = self.get_focus_offset_inset(
(maxcol,maxrow))
# force at least one line of focus to be visible
if maxrow and offset_rows >= maxrow:
offset_rows = maxrow -1
# adjust position so cursor remains visible
cursor = None
if maxrow and focus_widget.selectable() and focus:
if hasattr(focus_widget,'get_cursor_coords'):
cursor=focus_widget.get_cursor_coords((maxcol,))
if cursor is not None:
cx, cy = cursor
effective_cy = cy + offset_rows - inset_rows
if effective_cy < 0: # cursor above top?
inset_rows = cy
elif effective_cy >= maxrow: # cursor below bottom?
offset_rows = maxrow - cy -1
if offset_rows < 0: # need to trim the top
inset_rows, offset_rows = -offset_rows, 0
# set trim_top by focus trimmimg
trim_top = inset_rows
focus_rows = focus_widget.rows((maxcol,),True)
# 2. collect the widgets above the focus
pos = focus_pos
fill_lines = offset_rows
fill_above = []
top_pos = pos
while fill_lines > 0:
prev, pos = self._body.get_prev( pos )
if prev is None: # run out of widgets above?
offset_rows -= fill_lines
break
top_pos = pos
p_rows = prev.rows( (maxcol,) )
if p_rows: # filter out 0-height widgets
fill_above.append( (prev, pos, p_rows) )
if p_rows > fill_lines: # crosses top edge?
trim_top = p_rows-fill_lines
break
fill_lines -= p_rows
trim_bottom = focus_rows + offset_rows - inset_rows - maxrow
if trim_bottom < 0: trim_bottom = 0
# 3. collect the widgets below the focus
pos = focus_pos
fill_lines = maxrow - focus_rows - offset_rows + inset_rows
fill_below = []
while fill_lines > 0:
next, pos = self._body.get_next( pos )
if next is None: # run out of widgets below?
break
n_rows = next.rows( (maxcol,) )
if n_rows: # filter out 0-height widgets
fill_below.append( (next, pos, n_rows) )
if n_rows > fill_lines: # crosses bottom edge?
trim_bottom = n_rows-fill_lines
fill_lines -= n_rows
break
fill_lines -= n_rows
# 4. fill from top again if necessary & possible
fill_lines = max(0, fill_lines)
if fill_lines >0 and trim_top >0:
if fill_lines <= trim_top:
trim_top -= fill_lines
offset_rows += fill_lines
fill_lines = 0
else:
fill_lines -= trim_top
offset_rows += trim_top
trim_top = 0
pos = top_pos
while fill_lines > 0:
prev, pos = self._body.get_prev( pos )
if prev is None:
break
p_rows = prev.rows( (maxcol,) )
fill_above.append( (prev, pos, p_rows) )
if p_rows > fill_lines: # more than required
trim_top = p_rows-fill_lines
offset_rows += fill_lines
break
fill_lines -= p_rows
offset_rows += p_rows
# 5. return the interesting bits
return ((offset_rows - inset_rows, focus_widget,
focus_pos, focus_rows, cursor ),
(trim_top, fill_above), (trim_bottom, fill_below))
def render(self, size, focus=False ):
"""
Render ListBox and return canvas.
see :meth:`Widget.render` for details
"""
(maxcol, maxrow) = size
middle, top, bottom = self.calculate_visible(
(maxcol, maxrow), focus=focus)
if middle is None:
return SolidCanvas(" ", maxcol, maxrow)
_ignore, focus_widget, focus_pos, focus_rows, cursor = middle
trim_top, fill_above = top
trim_bottom, fill_below = bottom
combinelist = []
rows = 0
fill_above.reverse() # fill_above is in bottom-up order
for widget,w_pos,w_rows in fill_above:
canvas = widget.render((maxcol,))
if w_rows != canvas.rows():
raise ListBoxError("Widget %r at position %r within listbox calculated %d rows but rendered %d!"% (widget,w_pos,w_rows, canvas.rows()))
rows += w_rows
combinelist.append((canvas, w_pos, False))
focus_canvas = focus_widget.render((maxcol,), focus=focus)
if focus_canvas.rows() != focus_rows:
raise ListBoxError("Focus Widget %r at position %r within listbox calculated %d rows but rendered %d!"% (focus_widget,focus_pos,focus_rows, focus_canvas.rows()))
c_cursor = focus_canvas.cursor
if cursor != c_cursor:
raise ListBoxError("Focus Widget %r at position %r within listbox calculated cursor coords %r but rendered cursor coords %r!" %(focus_widget,focus_pos,cursor,c_cursor))
rows += focus_rows
combinelist.append((focus_canvas, focus_pos, True))
for widget,w_pos,w_rows in fill_below:
canvas = widget.render((maxcol,))
if w_rows != canvas.rows():
raise ListBoxError("Widget %r at position %r within listbox calculated %d rows but rendered %d!"% (widget,w_pos,w_rows, canvas.rows()))
rows += w_rows
combinelist.append((canvas, w_pos, False))
final_canvas = CanvasCombine(combinelist)
if trim_top:
final_canvas.trim(trim_top)
rows -= trim_top
if trim_bottom:
final_canvas.trim_end(trim_bottom)
rows -= trim_bottom
if rows > maxrow:
raise ListBoxError("Listbox contents too long! Probably urwid's fault (please report): %r" % ((top,middle,bottom),))
if rows < maxrow:
bottom_pos = focus_pos
if fill_below: bottom_pos = fill_below[-1][1]
if trim_bottom != 0 or self._body.get_next(bottom_pos) != (None,None):
raise ListBoxError("Listbox contents too short! Probably urwid's fault (please report): %r" % ((top,middle,bottom),))
final_canvas.pad_trim_top_bottom(0, maxrow - rows)
return final_canvas
def get_cursor_coords(self, size):
"""
See :meth:`Widget.get_cursor_coords` for details
"""
(maxcol, maxrow) = size
middle, top, bottom = self.calculate_visible(
(maxcol, maxrow), True)
if middle is None:
return None
offset_inset, _ignore1, _ignore2, _ignore3, cursor = middle
if not cursor:
return None
x, y = cursor
y += offset_inset
if y < 0 or y >= maxrow:
return None
return (x, y)
def set_focus_valign(self, valign):
"""Set the focus widget's display offset and inset.
:param valign: one of:
'top', 'middle', 'bottom'
('fixed top', rows)
('fixed bottom', rows)
('relative', percentage 0=top 100=bottom)
"""
vt, va = normalize_valign(valign,ListBoxError)
self.set_focus_valign_pending = vt, va
def set_focus(self, position, coming_from=None):
"""
Set the focus position and try to keep the old focus in view.
:param position: a position compatible with :meth:`self._body.set_focus`
:param coming_from: set to 'above' or 'below' if you know that
old position is above or below the new position.
:type coming_from: str
"""
if coming_from not in ('above', 'below', None):
raise ListBoxError("coming_from value invalid: %r" %
(coming_from,))
focus_widget, focus_pos = self._body.get_focus()
if focus_widget is None:
raise IndexError("Can't set focus, ListBox is empty")
self.set_focus_pending = coming_from, focus_widget, focus_pos
self._body.set_focus(position)
def get_focus(self):
"""
Return a `(focus widget, focus position)` tuple, for backwards
compatibility. You may also use the new standard container
properties :attr:`focus` and :attr:`focus_position` to read these values.
"""
return self._body.get_focus()
def _get_focus(self):
"""
Return the widget in focus according to our :obj:`list walker <ListWalker>`.
"""
return self._body.get_focus()[0]
focus = property(_get_focus,
doc="the child widget in focus or None when ListBox is empty")
def _get_focus_position(self):
"""
Return the list walker position of the widget in focus. The type
of value returned depends on the :obj:`list walker <ListWalker>`.
"""
w, pos = self._body.get_focus()
if w is None:
raise IndexError("No focus_position, ListBox is empty")
return pos
focus_position = property(_get_focus_position, set_focus, doc="""
the position of child widget in focus. The valid values for this
position depend on the list walker in use.
:exc:`IndexError` will be raised by reading this property when the
ListBox is empty or setting this property to an invalid position.
""")
def _contents(self):
class ListBoxContents(object):
__getitem__ = self._contents__getitem__
return ListBoxContents()
def _contents__getitem__(self, key):
# try list walker protocol v2 first
getitem = getattr(self._body, '__getitem__', None)
if getitem:
try:
return (getitem(key), None)
except (IndexError, KeyError):
raise KeyError("ListBox.contents key not found: %r" % (key,))
# fall back to v1
w, old_focus = self._body.get_focus()
try:
try:
self._body.set_focus(key)
return self._body.get_focus()[0]
except (IndexError, KeyError):
raise KeyError("ListBox.contents key not found: %r" % (key,))
finally:
self._body.set_focus(old_focus)
contents = property(lambda self: self._contents, doc="""
An object that allows reading widgets from the ListBox's list
walker as a `(widget, options)` tuple. `None` is currently the only
value for options.
.. warning::
This object may not be used to set or iterate over contents.
You must use the list walker stored as
:attr:`.body` to perform manipulation and iteration, if supported.
""")
def options(self):
"""
There are currently no options for ListBox contents.
Return None as a placeholder for future options.
"""
return None
def _set_focus_valign_complete(self, size, focus):
"""
Finish setting the offset and inset now that we have have a
maxcol & maxrow.
"""
(maxcol, maxrow) = size
vt,va = self.set_focus_valign_pending
self.set_focus_valign_pending = None
self.set_focus_pending = None
focus_widget, focus_pos = self._body.get_focus()
if focus_widget is None:
return
rows = focus_widget.rows((maxcol,), focus)
rtop, rbot = calculate_top_bottom_filler(maxrow,
vt, va, GIVEN, rows, None, 0, 0)
self.shift_focus((maxcol, maxrow), rtop)
def _set_focus_first_selectable(self, size, focus):
"""
Choose the first visible, selectable widget below the
current focus as the focus widget.
"""
(maxcol, maxrow) = size
self.set_focus_valign_pending = None
self.set_focus_pending = None
middle, top, bottom = self.calculate_visible(
(maxcol, maxrow), focus=focus)
if middle is None:
return
row_offset, focus_widget, focus_pos, focus_rows, cursor = middle
trim_top, fill_above = top
trim_bottom, fill_below = bottom
if focus_widget.selectable():
return
if trim_bottom:
fill_below = fill_below[:-1]
new_row_offset = row_offset + focus_rows
for widget, pos, rows in fill_below:
if widget.selectable():
self._body.set_focus(pos)
self.shift_focus((maxcol, maxrow),
new_row_offset)
return
new_row_offset += rows
def _set_focus_complete(self, size, focus):
"""
Finish setting the position now that we have maxcol & maxrow.
"""
(maxcol, maxrow) = size
self._invalidate()
if self.set_focus_pending == "first selectable":
return self._set_focus_first_selectable(
(maxcol,maxrow), focus)
if self.set_focus_valign_pending is not None:
return self._set_focus_valign_complete(
(maxcol,maxrow), focus)
coming_from, focus_widget, focus_pos = self.set_focus_pending
self.set_focus_pending = None
# new position
new_focus_widget, position = self._body.get_focus()
if focus_pos == position:
# do nothing
return
# restore old focus temporarily
self._body.set_focus(focus_pos)
middle,top,bottom=self.calculate_visible((maxcol,maxrow),focus)
focus_offset, focus_widget, focus_pos, focus_rows, cursor=middle
trim_top, fill_above = top
trim_bottom, fill_below = bottom
offset = focus_offset
for widget, pos, rows in fill_above:
offset -= rows
if pos == position:
self.change_focus((maxcol, maxrow), pos,
offset, 'below' )
return
offset = focus_offset + focus_rows
for widget, pos, rows in fill_below:
if pos == position:
self.change_focus((maxcol, maxrow), pos,
offset, 'above' )
return
offset += rows
# failed to find widget among visible widgets
self._body.set_focus( position )
widget, position = self._body.get_focus()
rows = widget.rows((maxcol,), focus)
if coming_from=='below':
offset = 0
elif coming_from=='above':
offset = maxrow-rows
else:
offset = (maxrow-rows) // 2
self.shift_focus((maxcol, maxrow), offset)
def shift_focus(self, size, offset_inset):
"""
Move the location of the current focus relative to the top.
This is used internally by methods that know the widget's *size*.
See also :meth:`.set_focus_valign`.
:param size: see :meth:`Widget.render` for details
:param offset_inset: either the number of rows between the
top of the listbox and the start of the focus widget (+ve
value) or the number of lines of the focus widget hidden off
the top edge of the listbox (-ve value) or ``0`` if the top edge
of the focus widget is aligned with the top edge of the
listbox.
:type offset_inset: int
"""
(maxcol, maxrow) = size
if offset_inset >= 0:
if offset_inset >= maxrow:
raise ListBoxError("Invalid offset_inset: %r, only %r rows in list box"% (offset_inset, maxrow))
self.offset_rows = offset_inset
self.inset_fraction = (0,1)
else:
target, _ignore = self._body.get_focus()
tgt_rows = target.rows( (maxcol,), True )
if offset_inset + tgt_rows <= 0:
raise ListBoxError("Invalid offset_inset: %r, only %r rows in target!" %(offset_inset, tgt_rows))
self.offset_rows = 0
self.inset_fraction = (-offset_inset,tgt_rows)
self._invalidate()
def update_pref_col_from_focus(self, size):
"""Update self.pref_col from the focus widget."""
# TODO: should this not be private?
(maxcol, maxrow) = size
widget, old_pos = self._body.get_focus()
if widget is None: return
pref_col = None
if hasattr(widget,'get_pref_col'):
pref_col = widget.get_pref_col((maxcol,))
if pref_col is None and hasattr(widget,'get_cursor_coords'):
coords = widget.get_cursor_coords((maxcol,))
if type(coords) == tuple:
pref_col,y = coords
if pref_col is not None:
self.pref_col = pref_col
def change_focus(self, size, position,
offset_inset = 0, coming_from = None,
cursor_coords = None, snap_rows = None):
"""
Change the current focus widget.
This is used internally by methods that know the widget's *size*.
See also :meth:`.set_focus`.
:param size: see :meth:`Widget.render` for details
:param position: a position compatible with :meth:`self._body.set_focus`
:param offset_inset: either the number of rows between the
top of the listbox and the start of the focus widget (+ve
value) or the number of lines of the focus widget hidden off
the top edge of the listbox (-ve value) or 0 if the top edge
of the focus widget is aligned with the top edge of the
listbox (default if unspecified)
:type offset_inset: int
:param coming_from: either 'above', 'below' or unspecified `None`
:type coming_from: str
:param cursor_coords: (x, y) tuple indicating the desired
column and row for the cursor, a (x,) tuple indicating only
the column for the cursor, or unspecified
:type cursor_coords: (int, int)
:param snap_rows: the maximum number of extra rows to scroll
when trying to "snap" a selectable focus into the view
:type snap_rows: int
"""
(maxcol, maxrow) = size
# update pref_col before change
if cursor_coords:
self.pref_col = cursor_coords[0]
else:
self.update_pref_col_from_focus((maxcol,maxrow))
self._invalidate()
self._body.set_focus(position)
target, _ignore = self._body.get_focus()
tgt_rows = target.rows( (maxcol,), True)
if snap_rows is None:
snap_rows = maxrow - 1
# "snap" to selectable widgets
align_top = 0
align_bottom = maxrow - tgt_rows
if ( coming_from == 'above'
and target.selectable()
and offset_inset > align_bottom ):
if snap_rows >= offset_inset - align_bottom:
offset_inset = align_bottom
elif snap_rows >= offset_inset - align_top:
offset_inset = align_top
else:
offset_inset -= snap_rows
if ( coming_from == 'below'
and target.selectable()
and offset_inset < align_top ):
if snap_rows >= align_top - offset_inset:
offset_inset = align_top
elif snap_rows >= align_bottom - offset_inset:
offset_inset = align_bottom
else:
offset_inset += snap_rows
# convert offset_inset to offset_rows or inset_fraction
if offset_inset >= 0:
self.offset_rows = offset_inset
self.inset_fraction = (0,1)
else:
if offset_inset + tgt_rows <= 0:
raise ListBoxError("Invalid offset_inset: %s, only %s rows in target!" %(offset_inset, tgt_rows))
self.offset_rows = 0
self.inset_fraction = (-offset_inset,tgt_rows)
if cursor_coords is None:
if coming_from is None:
return # must either know row or coming_from
cursor_coords = (self.pref_col,)
if not hasattr(target,'move_cursor_to_coords'):
return
attempt_rows = []
if len(cursor_coords) == 1:
# only column (not row) specified
# start from closest edge and move inwards
(pref_col,) = cursor_coords
if coming_from=='above':
attempt_rows = range( 0, tgt_rows )
else:
assert coming_from == 'below', "must specify coming_from ('above' or 'below') if cursor row is not specified"
attempt_rows = range( tgt_rows, -1, -1)
else:
# both column and row specified
# start from preferred row and move back to closest edge
(pref_col, pref_row) = cursor_coords
if pref_row < 0 or pref_row >= tgt_rows:
raise ListBoxError("cursor_coords row outside valid range for target. pref_row:%r target_rows:%r"%(pref_row,tgt_rows))
if coming_from=='above':
attempt_rows = range( pref_row, -1, -1 )
elif coming_from=='below':
attempt_rows = range( pref_row, tgt_rows )
else:
attempt_rows = [pref_row]
for row in attempt_rows:
if target.move_cursor_to_coords((maxcol,),pref_col,row):
break
def get_focus_offset_inset(self, size):
"""Return (offset rows, inset rows) for focus widget."""
(maxcol, maxrow) = size
focus_widget, pos = self._body.get_focus()
focus_rows = focus_widget.rows((maxcol,), True)
offset_rows = self.offset_rows
inset_rows = 0
if offset_rows == 0:
inum, iden = self.inset_fraction
if inum < 0 or iden < 0 or inum >= iden:
raise ListBoxError("Invalid inset_fraction: %r"%(self.inset_fraction,))
inset_rows = focus_rows * inum // iden
if inset_rows and inset_rows >= focus_rows:
raise ListBoxError("urwid inset_fraction error (please report)")
return offset_rows, inset_rows
def make_cursor_visible(self, size):
"""Shift the focus widget so that its cursor is visible."""
(maxcol, maxrow) = size
focus_widget, pos = self._body.get_focus()
if focus_widget is None:
return
if not focus_widget.selectable():
return
if not hasattr(focus_widget,'get_cursor_coords'):
return
cursor = focus_widget.get_cursor_coords((maxcol,))
if cursor is None:
return
cx, cy = cursor
offset_rows, inset_rows = self.get_focus_offset_inset(
(maxcol, maxrow))
if cy < inset_rows:
self.shift_focus( (maxcol,maxrow), - (cy) )
return
if offset_rows - inset_rows + cy >= maxrow:
self.shift_focus( (maxcol,maxrow), maxrow-cy-1 )
return
def keypress(self, size, key):
"""Move selection through the list elements scrolling when
necessary. Keystrokes are first passed to widget in focus
in case that widget can handle them.
Keystrokes handled by this widget are:
'up' up one line (or widget)
'down' down one line (or widget)
'page up' move cursor up one listbox length (or widget)
'page down' move cursor down one listbox length (or widget)
"""
(maxcol, maxrow) = size
if self.set_focus_pending or self.set_focus_valign_pending:
self._set_focus_complete( (maxcol,maxrow), focus=True )
focus_widget, pos = self._body.get_focus()
if focus_widget is None: # empty listbox, can't do anything
return key
if focus_widget.selectable():
key = focus_widget.keypress((maxcol,),key)
if key is None:
self.make_cursor_visible((maxcol,maxrow))
return None
def actual_key(unhandled):
if unhandled:
return key
# pass off the heavy lifting
if self._command_map[key] == CURSOR_UP:
return actual_key(self._keypress_up((maxcol, maxrow)))
if self._command_map[key] == CURSOR_DOWN:
return actual_key(self._keypress_down((maxcol, maxrow)))
if self._command_map[key] == CURSOR_PAGE_UP:
return actual_key(self._keypress_page_up((maxcol, maxrow)))
if self._command_map[key] == CURSOR_PAGE_DOWN:
return actual_key(self._keypress_page_down((maxcol, maxrow)))
if self._command_map[key] == CURSOR_MAX_LEFT:
return actual_key(self._keypress_max_left())
if self._command_map[key] == CURSOR_MAX_RIGHT:
return actual_key(self._keypress_max_right())
return key
def _keypress_max_left(self):
self.focus_position = next(iter(self.body.positions()))
self.set_focus_valign('top')
return True
def _keypress_max_right(self):
self.focus_position = next(iter(self.body.positions(reverse=True)))
self.set_focus_valign('bottom')
return True
def _keypress_up(self, size):
(maxcol, maxrow) = size
middle, top, bottom = self.calculate_visible(
(maxcol,maxrow), True)
if middle is None: return True
focus_row_offset,focus_widget,focus_pos,_ignore,cursor = middle
trim_top, fill_above = top
row_offset = focus_row_offset
# look for selectable widget above
pos = focus_pos
widget = None
for widget, pos, rows in fill_above:
row_offset -= rows
if rows and widget.selectable():
# this one will do
self.change_focus((maxcol,maxrow), pos,
row_offset, 'below')
return
# at this point we must scroll
row_offset += 1
self._invalidate()
while row_offset > 0:
# need to scroll in another candidate widget
widget, pos = self._body.get_prev(pos)
if widget is None:
# cannot scroll any further
return True # keypress not handled
rows = widget.rows((maxcol,), True)
row_offset -= rows
if rows and widget.selectable():
# this one will do
self.change_focus((maxcol,maxrow), pos,
row_offset, 'below')
return
if not focus_widget.selectable() or focus_row_offset+1>=maxrow:
# just take top one if focus is not selectable
# or if focus has moved out of view
if widget is None:
self.shift_focus((maxcol,maxrow), row_offset)
return
self.change_focus((maxcol,maxrow), pos,
row_offset, 'below')
return
# check if cursor will stop scroll from taking effect
if cursor is not None:
x,y = cursor
if y+focus_row_offset+1 >= maxrow:
# cursor position is a problem,
# choose another focus
if widget is None:
# try harder to get prev widget
widget, pos = self._body.get_prev(pos)
if widget is None:
return # can't do anything
rows = widget.rows((maxcol,), True)
row_offset -= rows
if -row_offset >= rows:
# must scroll further than 1 line
row_offset = - (rows-1)
self.change_focus((maxcol,maxrow),pos,
row_offset, 'below')
return
# if all else fails, just shift the current focus.
self.shift_focus((maxcol,maxrow), focus_row_offset+1)
def _keypress_down(self, size):
(maxcol, maxrow) = size
middle, top, bottom = self.calculate_visible(
(maxcol,maxrow), True)
if middle is None: return True
focus_row_offset,focus_widget,focus_pos,focus_rows,cursor=middle
trim_bottom, fill_below = bottom
row_offset = focus_row_offset + focus_rows
rows = focus_rows
# look for selectable widget below
pos = focus_pos
widget = None
for widget, pos, rows in fill_below:
if rows and widget.selectable():
# this one will do
self.change_focus((maxcol,maxrow), pos,
row_offset, 'above')
return
row_offset += rows
# at this point we must scroll
row_offset -= 1
self._invalidate()
while row_offset < maxrow:
# need to scroll in another candidate widget
widget, pos = self._body.get_next(pos)
if widget is None:
# cannot scroll any further
return True # keypress not handled
rows = widget.rows((maxcol,))
if rows and widget.selectable():
# this one will do
self.change_focus((maxcol,maxrow), pos,
row_offset, 'above')
return
row_offset += rows
if not focus_widget.selectable() or focus_row_offset+focus_rows-1 <= 0:
# just take bottom one if current is not selectable
# or if focus has moved out of view
if widget is None:
self.shift_focus((maxcol,maxrow),
row_offset-rows)
return
# FIXME: catch this bug in testcase
#self.change_focus((maxcol,maxrow), pos,
# row_offset+rows, 'above')
self.change_focus((maxcol,maxrow), pos,
row_offset-rows, 'above')
return
# check if cursor will stop scroll from taking effect
if cursor is not None:
x,y = cursor
if y+focus_row_offset-1 < 0:
# cursor position is a problem,
# choose another focus
if widget is None:
# try harder to get next widget
widget, pos = self._body.get_next(pos)
if widget is None:
return # can't do anything
else:
row_offset -= rows
if row_offset >= maxrow:
# must scroll further than 1 line
row_offset = maxrow-1
self.change_focus((maxcol,maxrow),pos,
row_offset, 'above', )
return
# if all else fails, keep the current focus.
self.shift_focus((maxcol,maxrow), focus_row_offset-1)
def _keypress_page_up(self, size):
(maxcol, maxrow) = size
middle, top, bottom = self.calculate_visible(
(maxcol,maxrow), True)
if middle is None: return True
row_offset, focus_widget, focus_pos, focus_rows, cursor = middle
trim_top, fill_above = top
# topmost_visible is row_offset rows above top row of
# focus (+ve) or -row_offset rows below top row of focus (-ve)
topmost_visible = row_offset
# scroll_from_row is (first match)
# 1. topmost visible row if focus is not selectable
# 2. row containing cursor if focus has a cursor
# 3. top row of focus widget if it is visible
# 4. topmost visible row otherwise
if not focus_widget.selectable():
scroll_from_row = topmost_visible
elif cursor is not None:
x,y = cursor
scroll_from_row = -y
elif row_offset >= 0:
scroll_from_row = 0
else:
scroll_from_row = topmost_visible
# snap_rows is maximum extra rows to scroll when
# snapping to new a focus
snap_rows = topmost_visible - scroll_from_row
# move row_offset to the new desired value (1 "page" up)
row_offset = scroll_from_row + maxrow
# not used below:
scroll_from_row = topmost_visible = None
# gather potential target widgets
t = []
# add current focus
t.append((row_offset,focus_widget,focus_pos,focus_rows))
pos = focus_pos
# include widgets from calculate_visible(..)
for widget, pos, rows in fill_above:
row_offset -= rows
t.append( (row_offset, widget, pos, rows) )
# add newly visible ones, including within snap_rows
snap_region_start = len(t)
while row_offset > -snap_rows:
widget, pos = self._body.get_prev(pos)
if widget is None: break
rows = widget.rows((maxcol,))
row_offset -= rows
# determine if one below puts current one into snap rgn
if row_offset > 0:
snap_region_start += 1
t.append( (row_offset, widget, pos, rows) )
# if we can't fill the top we need to adjust the row offsets
row_offset, w, p, r = t[-1]
if row_offset > 0:
adjust = - row_offset
t = [(ro+adjust, w, p, r) for (ro,w,p,r) in t]
# if focus_widget (first in t) is off edge, remove it
row_offset, w, p, r = t[0]
if row_offset >= maxrow:
del t[0]
snap_region_start -= 1
# we'll need this soon
self.update_pref_col_from_focus((maxcol,maxrow))
# choose the topmost selectable and (newly) visible widget
# search within snap_rows then visible region
search_order = (list(xrange(snap_region_start, len(t)))
+ list(xrange(snap_region_start-1, -1, -1)))
#assert 0, repr((t, search_order))
bad_choices = []
cut_off_selectable_chosen = 0
for i in search_order:
row_offset, widget, pos, rows = t[i]
if not widget.selectable():
continue
if not rows:
continue
# try selecting this widget
pref_row = max(0, -row_offset)
# if completely within snap region, adjust row_offset
if rows + row_offset <= 0:
self.change_focus( (maxcol,maxrow), pos,
-(rows-1), 'below',
(self.pref_col, rows-1),
snap_rows-((-row_offset)-(rows-1)))
else:
self.change_focus( (maxcol,maxrow), pos,
row_offset, 'below',
(self.pref_col, pref_row), snap_rows )
# if we're as far up as we can scroll, take this one
if (fill_above and self._body.get_prev(fill_above[-1][1])
== (None,None) ):
pass #return
# find out where that actually puts us
middle, top, bottom = self.calculate_visible(
(maxcol,maxrow), True)
act_row_offset, _ign1, _ign2, _ign3, _ign4 = middle
# discard chosen widget if it will reduce scroll amount
# because of a fixed cursor (absolute last resort)
if act_row_offset > row_offset+snap_rows:
bad_choices.append(i)
continue
if act_row_offset < row_offset:
bad_choices.append(i)
continue
# also discard if off top edge (second last resort)
if act_row_offset < 0:
bad_choices.append(i)
cut_off_selectable_chosen = 1
continue
return
# anything selectable is better than what follows:
if cut_off_selectable_chosen:
return
if fill_above and focus_widget.selectable():
# if we're at the top and have a selectable, return
if self._body.get_prev(fill_above[-1][1]) == (None,None):
pass #return
# if still none found choose the topmost widget
good_choices = [j for j in search_order if j not in bad_choices]
for i in good_choices + search_order:
row_offset, widget, pos, rows = t[i]
if pos == focus_pos: continue
if not rows: # never focus a 0-height widget
continue
# if completely within snap region, adjust row_offset
if rows + row_offset <= 0:
snap_rows -= (-row_offset) - (rows-1)
row_offset = -(rows-1)
self.change_focus( (maxcol,maxrow), pos,
row_offset, 'below', None,
snap_rows )
return
# no choices available, just shift current one
self.shift_focus((maxcol, maxrow), min(maxrow-1,row_offset))
# final check for pathological case where we may fall short
middle, top, bottom = self.calculate_visible(
(maxcol,maxrow), True)
act_row_offset, _ign1, pos, _ign2, _ign3 = middle
if act_row_offset >= row_offset:
# no problem
return
# fell short, try to select anything else above
if not t:
return
_ign1, _ign2, pos, _ign3 = t[-1]
widget, pos = self._body.get_prev(pos)
if widget is None:
# no dice, we're stuck here
return
# bring in only one row if possible
rows = widget.rows((maxcol,), True)
self.change_focus((maxcol,maxrow), pos, -(rows-1),
'below', (self.pref_col, rows-1), 0 )
def _keypress_page_down(self, size):
(maxcol, maxrow) = size
middle, top, bottom = self.calculate_visible(
(maxcol,maxrow), True)
if middle is None: return True
row_offset, focus_widget, focus_pos, focus_rows, cursor = middle
trim_bottom, fill_below = bottom
# bottom_edge is maxrow-focus_pos rows below top row of focus
bottom_edge = maxrow - row_offset
# scroll_from_row is (first match)
# 1. bottom edge if focus is not selectable
# 2. row containing cursor + 1 if focus has a cursor
# 3. bottom edge of focus widget if it is visible
# 4. bottom edge otherwise
if not focus_widget.selectable():
scroll_from_row = bottom_edge
elif cursor is not None:
x,y = cursor
scroll_from_row = y + 1
elif bottom_edge >= focus_rows:
scroll_from_row = focus_rows
else:
scroll_from_row = bottom_edge
# snap_rows is maximum extra rows to scroll when
# snapping to new a focus
snap_rows = bottom_edge - scroll_from_row
# move row_offset to the new desired value (1 "page" down)
row_offset = -scroll_from_row
# not used below:
scroll_from_row = bottom_edge = None
# gather potential target widgets
t = []
# add current focus
t.append((row_offset,focus_widget,focus_pos,focus_rows))
pos = focus_pos
row_offset += focus_rows
# include widgets from calculate_visible(..)
for widget, pos, rows in fill_below:
t.append( (row_offset, widget, pos, rows) )
row_offset += rows
# add newly visible ones, including within snap_rows
snap_region_start = len(t)
while row_offset < maxrow+snap_rows:
widget, pos = self._body.get_next(pos)
if widget is None: break
rows = widget.rows((maxcol,))
t.append( (row_offset, widget, pos, rows) )
row_offset += rows
# determine if one above puts current one into snap rgn
if row_offset < maxrow:
snap_region_start += 1
# if we can't fill the bottom we need to adjust the row offsets
row_offset, w, p, rows = t[-1]
if row_offset + rows < maxrow:
adjust = maxrow - (row_offset + rows)
t = [(ro+adjust, w, p, r) for (ro,w,p,r) in t]
# if focus_widget (first in t) is off edge, remove it
row_offset, w, p, rows = t[0]
if row_offset+rows <= 0:
del t[0]
snap_region_start -= 1
# we'll need this soon
self.update_pref_col_from_focus((maxcol,maxrow))
# choose the bottommost selectable and (newly) visible widget
# search within snap_rows then visible region
search_order = (list(xrange(snap_region_start, len(t)))
+ list(xrange(snap_region_start-1, -1, -1)))
#assert 0, repr((t, search_order))
bad_choices = []
cut_off_selectable_chosen = 0
for i in search_order:
row_offset, widget, pos, rows = t[i]
if not widget.selectable():
continue
if not rows:
continue
# try selecting this widget
pref_row = min(maxrow-row_offset-1, rows-1)
# if completely within snap region, adjust row_offset
if row_offset >= maxrow:
self.change_focus( (maxcol,maxrow), pos,
maxrow-1, 'above',
(self.pref_col, 0),
snap_rows+maxrow-row_offset-1 )
else:
self.change_focus( (maxcol,maxrow), pos,
row_offset, 'above',
(self.pref_col, pref_row), snap_rows )
# find out where that actually puts us
middle, top, bottom = self.calculate_visible(
(maxcol,maxrow), True)
act_row_offset, _ign1, _ign2, _ign3, _ign4 = middle
# discard chosen widget if it will reduce scroll amount
# because of a fixed cursor (absolute last resort)
if act_row_offset < row_offset-snap_rows:
bad_choices.append(i)
continue
if act_row_offset > row_offset:
bad_choices.append(i)
continue
# also discard if off top edge (second last resort)
if act_row_offset+rows > maxrow:
bad_choices.append(i)
cut_off_selectable_chosen = 1
continue
return
# anything selectable is better than what follows:
if cut_off_selectable_chosen:
return
# if still none found choose the bottommost widget
good_choices = [j for j in search_order if j not in bad_choices]
for i in good_choices + search_order:
row_offset, widget, pos, rows = t[i]
if pos == focus_pos: continue
if not rows: # never focus a 0-height widget
continue
# if completely within snap region, adjust row_offset
if row_offset >= maxrow:
snap_rows -= snap_rows+maxrow-row_offset-1
row_offset = maxrow-1
self.change_focus( (maxcol,maxrow), pos,
row_offset, 'above', None,
snap_rows )
return
# no choices available, just shift current one
self.shift_focus((maxcol, maxrow), max(1-focus_rows,row_offset))
# final check for pathological case where we may fall short
middle, top, bottom = self.calculate_visible(
(maxcol,maxrow), True)
act_row_offset, _ign1, pos, _ign2, _ign3 = middle
if act_row_offset <= row_offset:
# no problem
return
# fell short, try to select anything else below
if not t:
return
_ign1, _ign2, pos, _ign3 = t[-1]
widget, pos = self._body.get_next(pos)
if widget is None:
# no dice, we're stuck here
return
# bring in only one row if possible
rows = widget.rows((maxcol,), True)
self.change_focus((maxcol,maxrow), pos, maxrow-1,
'above', (self.pref_col, 0), 0 )
def mouse_event(self, size, event, button, col, row, focus):
"""
Pass the event to the contained widgets.
May change focus on button 1 press.
"""
(maxcol, maxrow) = size
middle, top, bottom = self.calculate_visible((maxcol, maxrow),
focus=True)
if middle is None:
return False
_ignore, focus_widget, focus_pos, focus_rows, cursor = middle
trim_top, fill_above = top
_ignore, fill_below = bottom
fill_above.reverse() # fill_above is in bottom-up order
w_list = ( fill_above +
[ (focus_widget, focus_pos, focus_rows) ] +
fill_below )
wrow = -trim_top
for w, w_pos, w_rows in w_list:
if wrow + w_rows > row:
break
wrow += w_rows
else:
return False
focus = focus and w == focus_widget
if is_mouse_press(event) and button==1:
if w.selectable():
self.change_focus((maxcol,maxrow), w_pos, wrow)
if not hasattr(w,'mouse_event'):
return False
return w.mouse_event((maxcol,), event, button, col, row-wrow,
focus)
def ends_visible(self, size, focus=False):
"""
Return a list that may contain ``'top'`` and/or ``'bottom'``.
i.e. this function will return one of: [], [``'top'``],
[``'bottom'``] or [``'top'``, ``'bottom'``].
convenience function for checking whether the top and bottom
of the list are visible
"""
(maxcol, maxrow) = size
l = []
middle,top,bottom = self.calculate_visible( (maxcol,maxrow),
focus=focus )
if middle is None: # empty listbox
return ['top','bottom']
trim_top, above = top
trim_bottom, below = bottom
if trim_bottom == 0:
row_offset, w, pos, rows, c = middle
row_offset += rows
for w, pos, rows in below:
row_offset += rows
if row_offset < maxrow:
l.append('bottom')
elif self._body.get_next(pos) == (None,None):
l.append('bottom')
if trim_top == 0:
row_offset, w, pos, rows, c = middle
for w, pos, rows in above:
row_offset -= rows
if self._body.get_prev(pos) == (None,None):
l.insert(0, 'top')
return l
def __iter__(self):
"""
Return an iterator over the positions in this ListBox.
If self._body does not implement positions() then iterate
from the focus widget down to the bottom, then from above
the focus up to the top. This is the best we can do with
a minimal list walker implementation.
"""
positions_fn = getattr(self._body, 'positions', None)
if positions_fn:
for pos in positions_fn():
yield pos
return
focus_widget, focus_pos = self._body.get_focus()
if focus_widget is None:
return
pos = focus_pos
while True:
yield pos
w, pos = self._body.get_next(pos)
if not w: break
pos = focus_pos
while True:
w, pos = self._body.get_prev(pos)
if not w: break
yield pos
def __reversed__(self):
"""
Return a reversed iterator over the positions in this ListBox.
If :attr:`body` does not implement :meth:`positions` then iterate
from above the focus widget up to the top, then from the focus
widget down to the bottom. Note that this is not actually the
reverse of what `__iter__()` produces, but this is the best we can
do with a minimal list walker implementation.
"""
positions_fn = getattr(self._body, 'positions', None)
if positions_fn:
for pos in positions_fn(reverse=True):
yield pos
return
focus_widget, focus_pos = self._body.get_focus()
if focus_widget is None:
return
pos = focus_pos
while True:
w, pos = self._body.get_prev(pos)
if not w: break
yield pos
pos = focus_pos
while True:
yield pos
w, pos = self._body.get_next(pos)
if not w: break
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