helpwidget.py

#!/usr/bin/python3
#
# Copyright (C) 2009, Joseph C. Lee
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA


from gettext import gettext as _

import cairo

from gi.repository import Gtk
from gi.repository import Gdk
from gi.repository import Rsvg

import math
import os
import time

import powerd
import board
from anim import Anim
from gridwidget import BoardDrawer, RemovalDrawer, WinDrawer

if 'SUGAR_BUNDLE_PATH' in os.environ:
    from sugar3.graphics import style
    _DEFAULT_SPACING = style.DEFAULT_SPACING
    _DEFAULT_PADDING = style.DEFAULT_PADDING
    _BG_COLOR = tuple(style.COLOR_SELECTION_GREY.get_rgba()[:3])
    _TOOLBAR_COLOR = tuple(style.COLOR_TOOLBAR_GREY.get_rgba()[:3])
    _PREVIEW_TRIM_WIDTH = style.GRID_CELL_SIZE * 4

    aspect_ratio = Gdk.Screen.width() * 100 // Gdk.Screen.height()
    if aspect_ratio > 159:
        _PREVIEW_TRIM_WIDTH = style.GRID_CELL_SIZE * 11
else:
    # Fallbacks for non-Sugar testing.
    _DEFAULT_SPACING = 15
    _DEFAULT_PADDING = 6
    _BG_COLOR = (0.75, 0.75, 0.75)
    _TOOLBAR_COLOR = (0.16, 0.16, 0.16)
    _PREVIEW_TRIM_WIDTH = 0

_CURSOR_COLOR = (.8, .8, .8)
_CURSOR_OUTLINE_COLOR = (.4, .4, .4)

# Proportion of the _PreviewWidget's height occupied by emulated button bar.
_ICON_HEIGHT = 0.1

# Proportion of the _PreviewWidget's height to scale the mouse cursor.
_CURSOR_SCALE = 0.12

# Proportion of the _PreviewWidget's cursor width to make the thickness of its
# lines.
_CURSOR_WEIGHT_SCALE = 0.15
_CURSOR_OUTLINE_WEIGHT_SCALE = 0.3

# Proportion of the _PreviewWidget's cursor width to make the mouse click
# animation.
_CLICK_INNER_RADIUS = 0.1
_CLICK_OUTER_RADIUS = 0.7

# Proportion of the _PreviewWidget's cursor width to make the thickness of the
# click animation's lines.
_CLICK_WEIGHT_SCALE = 0.1
_CLICK_OUTLINE_WEIGHT_SCALE = 0.2

# Speed of the click animation, in seconds.
_CLICK_SPEED = 0.2

# Speed of the mouse, in units (4x3 per screen) per second.
_MOUSE_SPEED = 0.5


class HelpWidget(Gtk.EventBox):
    def __init__(self, icon_file_func, *args, **kwargs):
        super(HelpWidget, self).__init__(*args, **kwargs)

        vbox = Gtk.Box(orientation=Gtk.Orientation.VERTICAL)
        self.add(vbox)

        self._stages = [
            _HelpStage1(icon_file_func),
            _HelpStage2(icon_file_func),
            _HelpStage3(icon_file_func),
            _HelpStage4(icon_file_func),
            _HelpStage5(icon_file_func),
        ]
        self._stage_index = 0
        self._notebook = Gtk.Notebook()
        self._notebook.set_show_tabs(False)
        for stage in self._stages:
            self._notebook.append_page(stage, None)
        vbox.pack_start(self._notebook, True, True, 0)

        self._reset_current_stage()

    def can_prev_stage(self):
        """Returns True if the help widget can move to the previous stage."""
        return (self._stage_index != 0)

    def can_next_stage(self):
        """Returns True if the help widget can move to the next stage."""
        return (self._stage_index < len(self._stages) - 1)

    def prev_stage(self):
        """Moves the help widget to the previous stage."""
        self._stage_index = max(0, self._stage_index - 1)
        self._reset_current_stage()

    def next_stage(self):
        """Moves the help widget to the next stage."""
        self._stage_index = min(len(self._stages) - 1, self._stage_index + 1)
        self._reset_current_stage()

    def replay_stage(self):
        """Replays the current stage."""
        self._stages[self._stage_index].reset()

    def _reload_clicked_cb(self, source):
        self._reset_current_stage()

    def _reset_current_stage(self):
        self._notebook.set_current_page(self._stage_index)
        self._stages[self._stage_index].reset()


class _HelpStage(Gtk.EventBox):
    # An abstract parent class for objects that represent an animated help
    # screen widget with a description.
    def __init__(self, icon_file_func, *args, **kwargs):
        super(_HelpStage, self).__init__(*args, **kwargs)

        hbox = Gtk.Box(orientation=Gtk.Orientation.HORIZONTAL)
        self.add(hbox)

        vbox = Gtk.Box(orientation=Gtk.Orientation.VERTICAL)
        hbox.pack_start(vbox, expand=True, fill=True,
                        padding=_DEFAULT_SPACING)

        self.preview = _PreviewWidget(icon_file_func)
        vbox.pack_start(self.preview, expand=True, fill=False,
                        padding=_DEFAULT_PADDING)

        label = Gtk.Label(label=self.get_message())
        label.set_line_wrap(True)
        vbox.pack_start(label, expand=False, fill=False,
                        padding=_DEFAULT_PADDING)

        self.board = None
        self.undo_stack = []

        self.anim = None
        self._actions = []
        self._action_index = 0

        actions = self._get_actions()
        self._actions = _flatten(actions)

    def get_message(self):
        # Implement to return stage message.
        raise Exception()

    def reset(self):
        # Resets the playback of the animation script.
        self._stop_animation()
        self._action_index = 0
        self.preview.set_cursor_visible(True)
        self.preview.set_click_visible(False)
        self.preview.center_cursor()
        self.next_action()

    def set_board(self, board):
        self.board = board.clone()
        self.preview.board_drawer.set_board(self.board)

    def _stop_animation(self):
        if self.anim:
            self.anim.stop()
            self.anim = None

    def next_action(self):
        # Moves the HelpStage animation script to the next action.
        if self._action_index >= len(self._actions):
            self.preview.set_cursor_visible(False)
            return
        powerd.fake()
        action = self._actions[self._action_index]
        self._action_index += 1
        action(self)

    def _get_actions(self):
        # Implement to return a list stage actions (optionally containing
        # sublists of actions).
        raise Exception()


class _HelpStage1(_HelpStage):
    def __init__(self, *args, **kwargs):
        super(_HelpStage1, self).__init__(*args, **kwargs)

    def get_message(self):
        return _("Goal: Clear the board "
                 "by removing blocks in groups of 3 or more.")

    def _get_actions(self):
        return [
            _set_board("""..33.
                          .2231
                          12231"""),
            _pause(1),
            _move_to_block(0, 0),
            _pause(0.5),
            _move_to_block(4, 0),
            _pause(0.5),
            _click_to_remove(1, 1),
            _click_to_remove(2, 2),
            _click_to_remove(1, 0, pause=0),
            _show_win(1),
            _pause(1),
        ]


class _HelpStage2(_HelpStage):
    def __init__(self, *args, **kwargs):
        super(_HelpStage2, self).__init__(*args, **kwargs)

    def get_message(self):
        return _("You can't remove groups of one or two blocks.")

    def _get_actions(self):
        return [
            _set_board(""".1..
                          .221
                          1121"""),
            _pause(1),
            _move_to_block(0, 0),
            _pause(1),
            _click(),
            _pause(1),
            _move_to_block(0, 1),
            _move_to_block(1, 2),
            _pause(1),
            _click(),
            _pause(1),
            _move_to_block(2, 2),
            _move_to_block(3, 1),
            _move_to_block(3, 0),
            _pause(1),
            _click(),
            _pause(1),
            _move_to_block(3, 1),
            _move_to_block(2, 2),
            _move_to_block(1, 2),
            _pause(0.5),
            _move_to_block(0, 1),
            _move_to_block(0, 0),
            _move_to_block(1, 0),
            _pause(1),
            _click_to_remove(2, 1),
            _click_to_remove(0, 0, pause=0),
            _show_win(2),
            _pause(1),
        ]


class _HelpStage3(_HelpStage):
    def __init__(self, *args, **kwargs):
        super(_HelpStage3, self).__init__(*args, **kwargs)

    def get_message(self):
        return _("Blocks fall to fill empty gaps, "
                 "and they slide to fill empty columns.")

    def _get_actions(self):
        return [
            _set_board(""".333.
                          1222.
                          12221
                          32223"""),
            _pause(2),
            _click_to_remove(2, 1),
            _pause(1),
            _click_to_remove(1, 0),
            _click_to_remove(0, 1, pause=0),
            _show_win(3),
            _pause(1),
        ]


class _HelpStage4(_HelpStage):
    def __init__(self, *args, **kwargs):
        super(_HelpStage4, self).__init__(*args, **kwargs)

    def get_message(self):
        return _("If you get stuck, you can undo to try again.")

    def _get_actions(self):
        return [
            _set_board("""1211
                          1221"""),
            _pause(2),
            _click_to_remove(2, 1),
            _click_to_remove(1, 1),
            _move_to_block(0, 1),
            _pause(1),
            _click(),
            _pause(1),
            _click(),
            _pause(2),
            _click_to_undo(),
            _click_to_undo(),
            _click_to_remove(1, 1),
            _click_to_remove(0, 0, pause=0),
            _show_win(4),
            _pause(1),
        ]


def _click_to_remove(x, y, pause=2):
    # Returns an array of action functions to remove the block at (x, y).
    return [
        _move_to_block(x, y),
        _pause(1),
        _click(),
        _remove_piece(x, y),
        _pause(pause),
    ]


def _click_to_undo():
    # Returns an array of action functions to undo the last move.
    return [
        _move_to_icon(2),
        _pause(1),
        _click(),
        _undo(),
    ]


class _HelpStage5(_HelpStage):
    def __init__(self, *args, **kwargs):
        super(_HelpStage5, self).__init__(*args, **kwargs)

    def get_message(self):
        return _("There is always a way to clear the board.")

    def _get_actions(self):
        return [
            # Difficult game seed: 5234
            _set_board("""132.1..1.1...4
                          15244.25.1...4
                          12244114.1..44
                          12254314.1..43
                          15251324.1..11
                          15253413.1..14
                          53251213.5..43
                          53252113.5..33
                          53242114.5..33
                          34232114.1..32
                          34115113.51111
                          54131215452221
                          24231423423222
                          24245323423224
                          24245423423244"""),
            _click_to_remove(12, 9),
            _click_to_remove(12, 9),
            _click_to_remove(2, 12),
            _click_to_remove(1, 11),
            _click_to_remove(3, 4),
            _click_to_remove(3, 3),
            _click_to_remove(3, 2),
            _click_to_remove(1, 3),
            _click_to_remove(1, 3),
            _click_to_remove(1, 2),
            _click_to_remove(5, 9),
            _click_to_remove(2, 6),
            _click_to_remove(3, 6),
            _click_to_undo(),
            _click_to_undo(),
            _click_to_remove(3, 7),
            _click_to_remove(2, 7),
            _click_to_remove(3, 6),
            _click_to_remove(6, 1),
            _click_to_remove(6, 4),
            _click_to_remove(5, 4),
            _click_to_remove(6, 4),
            _click_to_remove(6, 3),
            _click_to_remove(2, 5),
            _click_to_remove(3, 4),
            _click_to_remove(4, 3),
            _click_to_remove(1, 4),
            _click_to_undo(),
            _click_to_remove(2, 5),
            _click_to_remove(1, 4),
            _click_to_remove(1, 2),
            _click_to_remove(1, 2),
            _click_to_remove(1, 1),
            _click_to_remove(1, 1),
            _click_to_remove(1, 1),
            _click_to_remove(1, 1),
            _click_to_remove(1, 0),
            _click_to_remove(0, 0, pause=0),
            _show_win(5),
            _pause(1),
        ]

# The following are functions that return a function that, given a HelpStage
# object will set it up to perform the appropriate action.


def _set_board(board_string):
    # Returns a function to reset the game board to a given state.
    board = _make_board(board_string)

    def action(stage):
        stage.set_board(board)
        stage.undo_stack = []
        stage.preview.set_drawer(stage.preview.board_drawer)
        stage.next_action()
    return action


def _pause(delay):
    # Returns a function to delay playback by the given amount of time.
    def action(stage):
        start_time = time.time()

        def update_func():
            delta = time.time() - start_time
            return delta < delay

        def end_anim_func(anim_stopped):
            if not anim_stopped:
                stage.next_action()
        stage.anim = Anim(update_func, end_anim_func)
        stage.anim.start()
    return action


def _move_to_block(x, y):
    # Returns a function to move the mouse cursor to the given block
    # coordinate.
    def coord_func(stage):
        return stage.preview.get_block_coord(x, y)
    return _move_to(coord_func)


def _move_to_icon(index):
    # Returns a function to move the mouse cursor to the given icon.
    def coord_func(stage):
        return stage.preview.get_icon_coord(index)
    return _move_to(coord_func)


def _move_to(coord_func):
    def action(stage):
        # Caveat: This has the potential to get a little messed up if it is an
        # early action in a stage or if the screen changes size as the cursor
        # is moving...  Best to keep a pause before it in the sequence.
        (old_x, old_y) = stage.preview.get_cursor_pos()
        (new_x, new_y) = coord_func(stage)
        delta_x = new_x - old_x
        delta_y = new_y - old_y
        dist = math.sqrt(delta_x * delta_x + delta_y * delta_y)
        move_time = dist * _MOUSE_SPEED
        start_time = time.time()

        def update_func():
            delta = time.time() - start_time
            if delta >= move_time or move_time == 0.0:
                return False
            t = max(0.0, min(1.0, delta / move_time))
            # Use the first half of cosine wave to ease in/out.
            w = 1.0 - (0.5 * math.cos(t * math.pi) + 0.5)
            inv_w = 1.0 - w
            move_x = old_x * inv_w + new_x * w
            move_y = old_y * inv_w + new_y * w
            stage.preview.set_cursor_pos(move_x, move_y)
            return True

        def end_anim_func(anim_stopped):
            if not anim_stopped:
                stage.next_action()
        stage.anim = Anim(update_func, end_anim_func)
        stage.anim.start()
    return action


def _click():
    # Returns a function to play the mouse-click animation.
    def action(stage):
        start_time = time.time()
        stage.preview.set_click_visible(True)

        def update_func():
            delta = time.time() - start_time
            return (delta < _CLICK_SPEED)

        def end_anim_func(anim_stopped):
            stage.preview.set_click_visible(False)
            if not anim_stopped:
                stage.next_action()
        stage.anim = Anim(update_func, end_anim_func)
        stage.anim.start()
    return action


def _remove_piece(x, y):
    # Returns a function to animate the removal of the given piece.
    def action(stage):
        contiguous = stage.board.get_contiguous(x, y)
        removal_drawer = stage.preview.removal_drawer
        stage.preview.set_drawer(removal_drawer)
        removal_drawer.init(stage.board, contiguous)
        removal_drawer.set_anim_time(0.0)
        start_time = time.time()

        def update_func(start_time_ref=[start_time]):
            delta = time.time() - start_time_ref[0]
            length = removal_drawer.get_anim_length()
            if delta > length:
                if not removal_drawer.next_stage():
                    return False
                start_time_ref[0] = time.time()
                delta = 0.0
            removal_drawer.set_anim_time(delta)
            return True

        def local_end_anim_func(anim_stopped):
            stage.preview.set_drawer(stage.preview.board_drawer)
            stage.undo_stack.append(stage.board)
            board = stage.board.clone()
            board.clear_pieces(contiguous)
            board.drop_pieces()
            board.remove_empty_columns()
            stage.set_board(board)
            if not anim_stopped:
                stage.next_action()
        stage.anim = Anim(update_func, local_end_anim_func)
        stage.anim.start()
    return action


def _show_win(color):
    # Returns a function to animate a win.
    def action(stage):
        win_drawer = stage.preview.win_drawer
        stage.preview.set_drawer(win_drawer)
        win_drawer.set_win_state(True, color)
        length = win_drawer.get_anim_length()
        start_time = time.time()

        def update_func():
            delta = time.time() - start_time
            win_drawer.set_anim_time(min(delta, length))
            return (delta <= length)

        def local_end_anim_func(anim_stopped):
            win_drawer.set_anim_time(length)
            if not anim_stopped:
                stage.next_action()

        stage.anim = Anim(update_func, local_end_anim_func)
        stage.anim.start()
    return action


def _undo():
    # Returns a function that undoes the previous move.
    def action(stage):
        board = stage.undo_stack.pop()
        stage.set_board(board)
        stage.next_action()
    return action


class _PreviewWidget(Gtk.DrawingArea):
    def __init__(self, icon_file_func, *args, **kwargs):
        super(_PreviewWidget, self).__init__(*args, **kwargs)

        self.board_drawer = \
            BoardDrawer(get_size_func=self._get_drawer_size,
                        invalidate_rect_func=self._invalidate_drawer_rect)
        self.removal_drawer = \
            RemovalDrawer(get_size_func=self._get_drawer_size,
                          invalidate_rect_func=self._invalidate_drawer_rect)
        self.win_drawer = \
            WinDrawer(get_size_func=self._get_drawer_size,
                      invalidate_rect_func=self._invalidate_drawer_rect)

        self._icon_file_func = icon_file_func

        self._preview_rect = Gdk.Rectangle()
        self._preview_rect.x = self._preview_rect.y = \
            self._preview_rect.width = self._preview_rect.height = 0

        self._toolbar_rect = Gdk.Rectangle()
        self._toolbar_rect.x = self._toolbar_rect.y = \
            self._toolbar_rect.width = self._toolbar_rect.height = 0

        self._drawer_rect = Gdk.Rectangle()
        self._drawer_rect.x = self._drawer_rect.y = \
            self._drawer_rect.width = self._drawer_rect.height = 0

        self._drawer = self.board_drawer

        # Mouse position as a floating point value over the 4x3 unit preview
        # area.
        self._cursor_pos = (0.0, 0.0)

        # Cursor size in pixels.
        self._cursor_size = (0, 0)

        self._click_visible = False
        self._cursor_visible = False

        self.connect('draw', self._draw_event_cb)
        self.connect('configure-event', self._configure_event_cb)
        # self.connect('size-allocate', self._configure_event_cb)

    def _get_drawer_size(self):
        return (self._drawer_rect.width, self._drawer_rect.height)

    def _invalidate_drawer_rect(self, rect):
        if self.get_window():
            (x, y) = (self._drawer_rect.x, self._drawer_rect.y)
            offset_rect = Gdk.Rectangle()
            offset_rect.x, offset_rect.y, = (rect.x + x, rect.y + y)
            offset_rect.width, offset_rect.height = (rect.width, rect.height)
            self.get_window().invalidate_rect(offset_rect, True)

    def set_drawer(self, drawer):
        self._drawer = drawer
        r = self._preview_rect
        self._invalidate_client_rect(0, 0, r.width, r.height)

    def center_cursor(self):
        self.set_cursor_pos(2.0, 1.5)

    def set_cursor_pos(self, x, y):
        self._invalidate_cursor()
        self._cursor_pos = (x, y)
        self._invalidate_cursor()
        self._update_mouse_position()

    def get_cursor_pos(self):
        return self._cursor_pos

    def set_click_visible(self, click_visible):
        self._click_visible = click_visible
        self._invalidate_click()

    def set_cursor_visible(self, cursor_visible):
        self._cursor_visible = cursor_visible
        self._invalidate_cursor()

    def get_block_coord(self, x, y):
        # Returns the coordinate of the given board block in terms of
        # 4x3 units.
        if (self._preview_rect.width == 0 or self._preview_rect.height == 0):
            return (0, 0)
        (drawer_x, drawer_y) = self.board_drawer.get_block_coord(x, y)
        preview_x = drawer_x
        preview_y = drawer_y + self._toolbar_rect.height
        out_x = preview_x * 4.0 / self._preview_rect.width
        out_y = preview_y * 3.0 / self._preview_rect.height
        return (out_x, out_y)

    def get_icon_coord(self, index):
        # Returns the coordinate of the given icon in terms of 4x3 units.
        icon_height = self._toolbar_rect.height
        preview_x = icon_height * (index + 0.5)
        preview_y = icon_height * 0.5
        out_x = preview_x * 4.0 / self._preview_rect.width
        out_y = preview_y * 3.0 / self._preview_rect.height
        return (out_x, out_y)

    def _get_cursor_pixel_coords(self):
        (x, y) = self._cursor_pos
        pixel_x = x * self._preview_rect.width / 4
        pixel_y = y * self._preview_rect.height / 3
        return (pixel_x, pixel_y)

    def _invalidate_cursor(self):
        (pixel_x, pixel_y) = self._get_cursor_pixel_coords()
        self._invalidate_client_rect(pixel_x, pixel_y, *self._cursor_size)

        if self._click_visible:
            self._invalidate_click()

    def _invalidate_click(self):
        (pixel_x, pixel_y) = self._get_cursor_pixel_coords()
        r = self._cursor_size[0] * _CLICK_OUTER_RADIUS
        r2 = r * 2
        self._invalidate_client_rect(pixel_x - r, pixel_y - r, r2, r2)

    def _invalidate_client_rect(self, x, y, width, height):
        if self.get_window():
            rect = Gdk.Rectangle()
            rect.x, rect.y, rect.width, rect.height = (
                int(math.floor(x)) + self._preview_rect.x,
                int(math.floor(y)) + self._preview_rect.y,
                int(math.ceil(width)) + 1,
                int(math.ceil(height)) + 1)

            self.get_window().invalidate_rect(rect, True)

    def _update_mouse_position(self):
        (pixel_x, pixel_y) = self._get_cursor_pixel_coords()
        (x, y) = (pixel_x, pixel_y - self._toolbar_rect.height)
        self.board_drawer.set_mouse_selection(x, y)

    def _size_allocate_cb(self, widget, rect):
        self.width = rect.width
        self.height = rect.height

    def _draw_event_cb(self, widget, cr):
        alloc = self.get_allocation()
        cr.rectangle(0, 0, alloc.width, alloc.height)
        self._draw(cr, alloc.width, alloc.height)

    def _draw(self, cr, width, height):
        cr.set_source_rgb(*_BG_COLOR)
        cr.rectangle(0, 0, width, height)
        cr.fill()

        cr.save()
        cr.rectangle(self._preview_rect.x,
                     self._preview_rect.y,
                     self._preview_rect.width,
                     self._preview_rect.height)
        cr.clip()

        self._draw_toolbar(cr)
        self._draw_grid(cr)
        if self._click_visible:
            self._draw_click(cr)
        if self._cursor_visible:
            self._draw_cursor(cr)

        cr.restore()

    def _draw_toolbar(self, cr):
        cr.set_source_rgb(*_TOOLBAR_COLOR)
        cr.rectangle(self._toolbar_rect.x,
                     self._toolbar_rect.y,
                     self._toolbar_rect.width,
                     self._toolbar_rect.height)
        cr.fill()

        icon_height = self._toolbar_rect.height
        scale = icon_height / 55.0
        for (i, icon_name) in enumerate(['new-game',
                                         'replay-game',
                                         'edit-undo',
                                         'edit-redo',
                                         'easy-level',
                                         'medium-level',
                                         'hard-level', ]):
            file_path = self._icon_file_func(icon_name)
            handle = _get_icon_handle(file_path)
            cr.save()
            cr.translate(self._toolbar_rect.x + i * icon_height,
                         self._toolbar_rect.y)
            cr.scale(scale, scale)
            handle.render_cairo(cr)
            cr.restore()

    def _draw_grid(self, cr):
        cr.save()
        cr.translate(self._drawer_rect.x, self._drawer_rect.y)
        self._drawer.draw(cr, self._drawer_rect.width,
                          self._drawer_rect.height)
        cr.restore()

    def _draw_click(self, cr):
        width = self._cursor_size[0]
        weight = width * _CLICK_WEIGHT_SCALE
        outline_weight = width * _CLICK_OUTLINE_WEIGHT_SCALE
        r1 = width * _CLICK_INNER_RADIUS + outline_weight
        r2 = width * _CLICK_OUTER_RADIUS - outline_weight
        (pixel_x, pixel_y) = self._get_cursor_pixel_coords()
        x = pixel_x + self._preview_rect.x
        y = pixel_y + self._preview_rect.y

        cr.save()
        cr.translate(x, y)
        cr.set_line_cap(cairo.LINE_CAP_ROUND)
        angle_inc = math.pi * 2.0 / 6
        cr.rotate(angle_inc * 0.75)
        for i in range(6):
            cr.set_line_width(outline_weight)
            cr.set_source_rgb(*_CURSOR_OUTLINE_COLOR)
            cr.move_to(r1, 0)
            cr.line_to(r2, 0)
            cr.stroke()

            cr.set_line_width(weight)
            cr.set_source_rgb(*_CURSOR_COLOR)
            cr.move_to(r1, 0)
            cr.line_to(r2, 0)
            cr.stroke()

            cr.rotate(angle_inc)

        cr.restore()

    def _draw_cursor(self, cr):
        (pixel_x, pixel_y) = self._get_cursor_pixel_coords()
        x = pixel_x + self._preview_rect.x
        y = pixel_y + self._preview_rect.y
        (width, height) = self._cursor_size
        weight = width * _CURSOR_WEIGHT_SCALE
        outline_weight = width * _CURSOR_OUTLINE_WEIGHT_SCALE
        hw = outline_weight / 2.0

        def draw_arrow():
            cr.move_to(x + width * 0.9 - hw, y + hw)
            cr.line_to(x + hw, y + hw)
            cr.line_to(x + hw, y + height * 0.9 - hw)
            cr.move_to(x + hw, y + hw)
            cr.line_to(x + width - hw, y + height - hw)
            cr.stroke()

        cr.save()
        cr.set_line_cap(cairo.LINE_CAP_ROUND)
        cr.set_line_join(cairo.LINE_JOIN_ROUND)

        cr.set_line_width(outline_weight)
        cr.set_source_rgb(*_CURSOR_OUTLINE_COLOR)
        draw_arrow()

        cr.set_line_width(weight)
        cr.set_source_rgb(*_CURSOR_COLOR)
        draw_arrow()

        cr.restore()

    def _configure_event_cb(self, widget, event):
        (width, height) = (event.width, event.height)

        actual_width = width - _PREVIEW_TRIM_WIDTH
        actual_height = actual_width * 3 // 4

        self.set_size_request(actual_width, actual_height)

        icon_height = int(math.ceil(actual_height * _ICON_HEIGHT))
        board_height = actual_height - icon_height

        x_offset = (width - actual_width) // 2
        y_offset = (height - actual_height) // 2

        self._preview_rect = Gdk.Rectangle()
        self._preview_rect.x = x_offset
        self._preview_rect.y = y_offset
        self._preview_rect.width = actual_width
        self._preview_rect.height = actual_height

        self._toolbar_rect = Gdk.Rectangle()
        self._toolbar_rect.x = x_offset
        self._toolbar_rect.y = y_offset
        self._toolbar_rect.width = actual_width
        self._toolbar_rect.height = icon_height

        self._drawer_rect = Gdk.Rectangle()
        self._drawer_rect.x = x_offset
        self._drawer_rect.y = y_offset + icon_height
        self._drawer_rect.width = actual_width
        self._drawer_rect.height = board_height

        self.board_drawer.resize(actual_width, board_height)
        self.removal_drawer.resize(actual_width, board_height)
        self.win_drawer.resize(actual_width, board_height)

        cursor_width = actual_height * _CURSOR_SCALE
        self._cursor_size = (cursor_width, cursor_width)

        self._update_mouse_position()


def _make_board(board_string):
    # Given a string with numbers representing colors, periods representing
    # spaces, and lines separated by whitespace, returns a board object.
    b = board.Board()
    lines = [x.strip() for x in board_string.strip().split()]

    val_map = dict([('.', None)] + [(str(i), i) for i in range(1, 10)])

    for (i, line) in enumerate(reversed(lines)):
        for (j, ch) in enumerate(line):
            b.set_value(j, i, val_map[ch])

    return b


def _flatten(items):
    # Returns a flattened list of items.
    out = []
    for item in items:
        if isinstance(item, list):
            out.extend(_flatten(item))
        else:
            out.append(item)
    return out


# Simple caching mechanism for getting rsvg rendering handles for icons.  (The
# sugar.graphics.icon package doesn't seem to provide an easy way to get at
# them, so we do a little reimplementing here).
_icon_handles = {}


def _get_icon_handle(file_path):
    global _icon_handles

    if file_path not in _icon_handles:
        with open(file_path, 'rb') as f:
            data = f.read()
        _icon_handles[file_path] = Rsvg.Handle.new_from_data(data)

    return _icon_handles[file_path]