465 lines
17 KiB
Python
465 lines
17 KiB
Python
# Portions Copyright 2017 Canonical, Ltd.
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Affero General Public License as
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# published by the Free Software Foundation, either version 3 of the
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# License, or (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Affero General Public License for more details.
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#
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# You should have received a copy of the GNU Affero General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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# This is adapted from
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# https://github.com/pimutils/khal/commit/bd7c5f928a7670de9afae5657e66c6dc846688ac, which has this license:
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#
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# Copyright (c) 2013-2015 Christian Geier et al.
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#
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# Permission is hereby granted, free of charge, to any person obtaining a copy of
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# this software and associated documentation files (the "Software"), to deal in
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# the Software without restriction, including without limitation the rights to
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# use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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# the Software, and to permit persons to whom the Software is furnished to do so,
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# subject to the following conditions:
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#
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# The above copyright notice and this permission notice shall be included in all
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# copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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# FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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# COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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# IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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"""Extended versions of urwid containers.
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This module provides versions of urwid's Columns, Pile and ListBox
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containers. It adds support for tab-cycling, callbacks on
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gaining/losing focus and scrollbars on listboxes.
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1. Tab-cycling
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Tab advances to the next selectable item and wraps when it gets to the
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end of the screen. Shift tab goes the other way. In addition, an
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unhandled "enter" key also advances to the next selectable item.
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2. Callbacks when a widget gains/loses focus
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Define lost_focus or gained_focus callbacks on widgets and they'll be
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called when the widget gains or loses focus.
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3. Scrollbars on ListBoxes.
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All ListBoxes in subiquity gain a scrollbar when their contents don't
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entirely fit on screen. The implementation assumes that there are not
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too many elements in the ListBox.
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"""
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import logging
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import urwid
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log = logging.getLogger('subiquitycore.ui.container')
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# The theory of tab-cycling:
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#
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# Tab should advance to the next selectable item and wrap when it gets
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# to the end of the screen. Sounds simple, right? Well...
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#
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# Moving to the next selectable item within a container is pretty
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# simple (it's what up and down do, after all). When a container is
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# tabbed into, the first selectable within that container is selected
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# and vv when it's shift tabbed into, the last selectable is
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# selected. Urwid doesn't provide a native way to do that but it's
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# pretty simple to implement (see the _select_first_selectable /
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# _select_last_selectable methods). The tricky part is wrapping
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# around: only the "outermost" container should wrap around. Urwid
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# doesn't provide much of a way for a container to know about what it
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# is contained in, so what this code does is, when interpreting a key
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# that maps to either of the next selectable / prev selectable
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# commands, passes a different key (the same key with " no wrap"
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# appended) down to its contained widget. Then any containers within
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# the outer one know not to wrap around in response to such a key.
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#
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# There is no support for a tab cycling Columns. It wouldn't be any
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# harder than Pile but as subiquity is intended to be navigable with
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# only up, down and enter, it doesn't actually contain any Columns
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# with more than one selectable (this constraint is enforced by the
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# Columns in this module).
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def _maybe_call(w, methname):
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if w is None:
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return
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m = getattr(w.base_widget, methname, None)
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if m is not None:
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m()
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def _has_other_selectable(widgets, cur_focus):
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for i, w in enumerate(widgets):
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if i != cur_focus and w.selectable():
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return True
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return False
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for key, command in list(urwid.command_map._command.items()):
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if command in ('next selectable', 'prev selectable', urwid.ACTIVATE):
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urwid.command_map[key + ' no wrap'] = command
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enter_advancing_command_map = urwid.command_map.copy()
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enter_advancing_command_map['enter'] = 'next selectable'
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enter_advancing_command_map['enter no wrap'] = 'next selectable'
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class TabCyclingPile(urwid.Pile):
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_command_map = enter_advancing_command_map
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def selectable(self):
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for w, _ in self.contents:
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if w.selectable():
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return True
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return False
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def _select_first_selectable(self):
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"""Select first selectable child (possibily recursively)."""
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for i, (w, o) in enumerate(self.contents):
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if w.selectable():
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self.set_focus(i)
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_maybe_call(w, "_select_first_selectable")
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return
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def _select_last_selectable(self):
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"""Select last selectable child (possibily recursively)."""
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for i, (w, o) in reversed(list(enumerate(self.contents))):
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if w.selectable():
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self.set_focus(i)
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_maybe_call(w, "_select_last_selectable")
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return
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def _widgets(self):
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return [w for (w, o) in self._contents]
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# This is a copy/paste/hack of urwid's implementation. The main
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# reason we can't do this via simple subclassing is the need to
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# call _select_{first,last}_selectable on the newly focused
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# element when the focus changes.
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def keypress(self, size, key ):
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"""Pass the keypress to the widget in focus.
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Unhandled 'up' and 'down' keys may cause a focus change."""
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if not self.contents:
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return key
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# start subiquity change: new code
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downkey = key
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if not key.endswith(' no wrap') and self._command_map[key] in ('next selectable', 'prev selectable'):
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if _has_other_selectable(self._widgets(), self.focus_position):
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downkey += ' no wrap'
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# end subiquity change
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item_rows = None
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if len(size) == 2:
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item_rows = self.get_item_rows(size, focus=True)
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i = self.focus_position
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if self.selectable():
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tsize = self.get_item_size(size, i, True, item_rows)
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# start subiquity change: pass downkey to focus, not key, do not return if command_map[upkey] is next/prev selectable
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upkey = self.focus.keypress(tsize, downkey)
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if self._command_map[upkey] not in ('cursor up', 'cursor down', 'next selectable', 'prev selectable'):
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return upkey
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# end subiquity change
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# begin subiquity change: new code
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if self._command_map[key] == 'next selectable':
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next_fp = self.focus_position + 1
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for i, (w, o) in enumerate(self._contents[next_fp:], next_fp):
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if w.selectable():
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self.set_focus(i)
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_maybe_call(w, "_select_first_selectable")
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return
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if not key.endswith(' no wrap'):
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self._select_first_selectable()
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return key
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elif self._command_map[key] == 'prev selectable':
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for i, (w, o) in reversed(list(enumerate(self._contents[:self.focus_position]))):
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if w.selectable():
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self.set_focus(i)
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_maybe_call(w, "_select_last_selectable")
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return
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if not key.endswith(' no wrap'):
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self._select_last_selectable()
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return key
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# continued subiquity change: set 'meth' appropriately
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elif self._command_map[key] == 'cursor up':
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candidates = list(range(i-1, -1, -1)) # count backwards to 0
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meth = '_select_last_selectable'
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else: # self._command_map[key] == 'cursor down'
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candidates = list(range(i+1, len(self.contents)))
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meth = '_select_first_selectable'
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# end subiquity change
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if not item_rows:
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item_rows = self.get_item_rows(size, focus=True)
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for j in candidates:
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if not self.contents[j][0].selectable():
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continue
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self._update_pref_col_from_focus(size)
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self.focus_position = j
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# begin subiquity change: new code
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_maybe_call(self.focus, meth)
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# end subiquity change
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if not hasattr(self.focus, 'move_cursor_to_coords'):
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return
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rows = item_rows[j]
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if self._command_map[key] == 'cursor up':
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rowlist = list(range(rows-1, -1, -1))
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else: # self._command_map[key] == 'cursor down'
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rowlist = list(range(rows))
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for row in rowlist:
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tsize = self.get_item_size(size, j, True, item_rows)
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if self.focus_item.move_cursor_to_coords(
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tsize, self.pref_col, row):
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break
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return
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# nothing to select
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return key
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class OneSelectableColumns(urwid.Columns):
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def __init__(self, widget_list, dividechars=0, focus_column=None,
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min_width=1, box_columns=None):
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super().__init__(widget_list, dividechars, focus_column, min_width, box_columns)
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selectables = 0
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for w, o in self._contents:
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if w.selectable():
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selectables +=1
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if selectables > 1:
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raise Exception("subiquity only supports one selectable in a Columns")
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class TabCyclingListBox(urwid.ListBox):
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_command_map = enter_advancing_command_map
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def __init__(self, body):
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# urwid.ListBox converts an arbitrary sequence argument to a
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# PollingListWalker, which doesn't work with the below code.
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if getattr(body, 'get_focus', None) is None:
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body = urwid.SimpleFocusListWalker(body)
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super().__init__(body)
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def _set_focus_no_move(self, i):
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# We call set_focus twice because otherwise the listbox
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# attempts to do the minimal amount of scrolling required to
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# get the new focus widget into view, which is not what we
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# want, as if our first widget is a compound widget it results
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# its last widget being focused -- in fact the opposite of
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# what we want!
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self.set_focus(i)
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self.set_focus(i)
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# I don't really understand why this is required but it seems it is.
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self._invalidate()
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def _select_first_selectable(self):
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"""Select first selectable child (possibily recursively)."""
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for i, w in enumerate(self.body):
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if w.selectable():
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self._set_focus_no_move(i)
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_maybe_call(w, "_select_first_selectable")
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return
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def _select_last_selectable(self):
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"""Select last selectable child (possibily recursively)."""
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for i, w in reversed(list(enumerate(self.body))):
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if w.selectable():
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self._set_focus_no_move(i)
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_maybe_call(w, "_select_last_selectable")
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return
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def keypress(self, size, key):
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downkey = key
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if not key.endswith(' no wrap') and self._command_map[key] in ('next selectable', 'prev selectable'):
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if _has_other_selectable(self.body, self.focus_position):
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downkey += ' no wrap'
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upkey = super().keypress(size, downkey)
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if upkey != downkey:
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key = upkey
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if len(self.body) == 0:
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return key
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if self._command_map[key] == 'next selectable':
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next_fp = self.focus_position + 1
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for i, w in enumerate(self.body[next_fp:], next_fp):
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if w.selectable():
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self.set_focus(i)
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_maybe_call(w, "_select_first_selectable")
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return None
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if not key.endswith(' no wrap'):
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self._select_first_selectable()
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return key
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elif self._command_map[key] == 'prev selectable':
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for i, w in reversed(list(enumerate(self.body[:self.focus_position]))):
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if w.selectable():
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self.set_focus(i)
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_maybe_call(w, "_select_last_selectable")
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return None
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if not key.endswith(' no wrap'):
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self._select_last_selectable()
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return key
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else:
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return key
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class FocusTrackingMixin:
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def __init__(self, *args, **kw):
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super().__init__(*args, **kw)
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self._contents.set_focus_changed_callback(self._focus_changed)
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def lost_focus(self):
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try:
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cur_focus = self.focus
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except IndexError:
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pass
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else:
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_maybe_call(cur_focus, 'lost_focus')
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def gained_focus(self):
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_maybe_call(self.focus, 'gained_focus')
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def _focus_changed(self, new_focus):
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try:
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cur_focus = self.focus
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except IndexError:
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pass
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else:
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_maybe_call(cur_focus, 'lost_focus')
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_maybe_call(self[new_focus], 'gained_focus')
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self._invalidate()
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class FocusTrackingPile(FocusTrackingMixin, TabCyclingPile):
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pass
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class FocusTrackingColumns(FocusTrackingMixin, OneSelectableColumns):
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pass
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class FocusTrackingListBox(TabCyclingListBox):
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def __init__(self, *args, **kw):
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super().__init__(*args, **kw)
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self.body.set_focus_changed_callback(self._focus_changed)
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self._in_set_focus_complete = False
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def _focus_changed(self, new_focus):
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if not self._in_set_focus_complete:
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_maybe_call(self.focus, 'lost_focus')
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_maybe_call(self.body[new_focus], 'gained_focus')
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self._invalidate()
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def lost_focus(self):
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_maybe_call(self.focus, 'lost_focus')
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def gained_focus(self):
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_maybe_call(self.focus, 'gained_focus')
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def _set_focus_complete(self, size, focus):
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self._in_set_focus_complete = True
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try:
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super()._set_focus_complete(size, focus)
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finally:
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self._in_set_focus_complete = False
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Columns = FocusTrackingColumns
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Pile = FocusTrackingPile
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class ScrollBarListBox(FocusTrackingListBox):
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def __init__(self, walker=None):
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def f(char, attr):
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return urwid.AttrMap(urwid.SolidFill(char), attr)
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self.bar = Pile([
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('weight', 1, f("\N{BOX DRAWINGS LIGHT VERTICAL}", 'scrollbar_bg')),
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('weight', 1, f("\N{FULL BLOCK}", 'scrollbar_fg')),
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('weight', 1, f("\N{BOX DRAWINGS LIGHT VERTICAL}", 'scrollbar_bg')),
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])
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super().__init__(walker)
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def render(self, size, focus=False):
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visible = self.ends_visible(size, focus)
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if len(visible) == 2:
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return super().render(size, focus)
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else:
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# This implementation assumes that the number of rows is
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# not too large (and in particular is finite). That's the
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# case for all the listboxes we have in subiquity today.
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maxcol, maxrow = size
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offset, inset = self.get_focus_offset_inset((maxcol - 1, maxrow))
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seen_focus = False
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height = height_before_focus = 0
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focus_widget, focus_pos = self.body.get_focus()
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# Scan through the rows calculating total height and the
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# height of the rows before the focus widget.
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for widget in self.body:
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rows = widget.rows((maxcol - 1,))
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if widget is focus_widget:
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seen_focus = True
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elif not seen_focus:
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height_before_focus += rows
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height += rows
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# Calculate the number of rows off the top and bottom of
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# the listbox.
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if 'top' in visible:
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top = 0
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else:
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top = height_before_focus + inset - offset
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if 'bottom' in visible:
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bottom = 0
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else:
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bottom = height - top - maxrow
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# Prevent the box from being squished to 0 rows. Input of
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#
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# ('weight', maxrow)
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#
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# gets
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#
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# round(maxrow / (top + maxrow + bottom))
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#
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# rows and that being < 1 simplifies to the below).
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if maxrow*maxrow < height:
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boxopt = self.bar.options('given', 1)
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else:
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boxopt = self.bar.options('weight', maxrow)
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self.bar.contents[:] = [
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(self.bar.contents[0][0], self.bar.options('weight', top)),
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(self.bar.contents[1][0], boxopt),
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(self.bar.contents[2][0], self.bar.options('weight', bottom)),
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]
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canvases = [
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(super().render((maxcol - 1, maxrow), focus), self.focus_position, True, maxcol - 1),
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(self.bar.render((1, maxrow)), None, False, 1)
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]
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return urwid.CanvasJoin(canvases)
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ListBox = ScrollBarListBox
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