sugar-toolkit-gtk3/shell/view/home/spreadlayout.py

# Copyright (C) 2007 Red Hat, Inc.
#
# 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 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.

from numpy import array
from random import random

import hippo
import gobject
import gtk

from sugar.graphics import style

_PLACE_TRIALS = 20
_MAX_WEIGHT = 255
_CELL_SIZE = 4

class _Grid(gobject.GObject):
    __gsignals__ = {
        'child-changed' : (gobject.SIGNAL_RUN_FIRST,
                           gobject.TYPE_NONE,
                           ([gobject.TYPE_PYOBJECT]))
    }
    def __init__(self, width, height):
        gobject.GObject.__init__(self)

        self.width = width
        self.height = height
        self._children = []
        self._collisions = []
        self._collisions_sid = 0

        self._array = array([0], dtype='b')
        self._array.resize(width * height)

    def add(self, child, width, height):
        trials = _PLACE_TRIALS
        weight = _MAX_WEIGHT
        while trials > 0 and weight:
            x = int(random() * (self.width - width))
            y = int(random() * (self.height - height))

            rect = gtk.gdk.Rectangle(x, y, width, height)
            new_weight = self._compute_weight(rect)
            if weight > new_weight:
                weight = new_weight

            trials -= 1

        child.grid_rect = rect
        child.locked = False

        self._add_child(child)

        if weight > 0:
            self._detect_collisions(child)

    def remove(self, child):
        self._children.remove(child)
        self._remove_weight(child.grid_rect)
        child.grid_rect = None

    def _add_child(self, child):
        self._children.append(child)
        self.add_weight(child.grid_rect)

    def _move_child(self, child, new_rect):
        self._remove_weight(child.grid_rect)
        self.add_weight(new_rect)

        child.grid_rect = new_rect

        self.emit('child-changed', child)

    def _shift_child(self, child):
        rect = child.grid_rect
        weight = self._compute_weight(rect)
        new_rects = []

        if (rect.x + rect.width < self.width - 1):
            new_rects.append(gtk.gdk.Rectangle(rect.x + 1, rect.y,
                                               rect.width, rect.height))

        if (rect.x - 1 > 0):
            new_rects.append(gtk.gdk.Rectangle(rect.x - 1, rect.y,
                                               rect.width, rect.height))

        if (rect.y + rect.height < self.height - 1):
            new_rects.append(gtk.gdk.Rectangle(rect.x, rect.y + 1,
                                               rect.width, rect.height))

        if (rect.y - 1 > 0):
            new_rects.append(gtk.gdk.Rectangle(rect.x, rect.y - 1,
                                               rect.width, rect.height))

        best_rect = None
        for new_rect in new_rects:
            new_weight = self._compute_weight(new_rect)
            if new_weight < weight:
                best_rect = new_rect
                weight = new_weight
        
        if best_rect:
            self._move_child(child, best_rect)

        return weight
            

    def _solve_collisions(self):
        for collision in self._collisions[:]:
            weight = self._shift_child(collision)
            if not weight:
                self._collisions.remove(collision)

        return (len(self._collisions) > 0)

    def _detect_collisions(self, child):
        collision_found = False
        for c in self._children:
            intersection = child.grid_rect.intersect(c.grid_rect)
            if c != child and intersection.width > 0:
                if c not in self._collisions:
                    collision_found = True
                    self._collisions.append(c)

        if collision_found:
            if child not in self._collisions:
                self._collisions.append(child)

#        if len(self._collisions) and not self._collisions_sid:
#            self._collisions_sid = gobject.idle_add(self._solve_collisions)

    def add_weight(self, rect):
        for i in range(rect.x, rect.x + rect.width):
            for j in range(rect.y, rect.y + rect.height):
                self[j, i] += 1

    def _remove_weight(self, rect):
        for i in range(rect.x, rect.x + rect.width):
            for j in range(rect.y, rect.y + rect.height):
                self[j, i] -= 1

    def _compute_weight(self, rect):
        weight = 0

        for i in range(rect.x, rect.x + rect.width):
            for j in range(rect.y, rect.y + rect.height):
                weight += self[j, i]

        return weight
    
    def __getitem__(self, (row, col)):
        return self._array[col + row * self.width]

    def __setitem__(self, (row, col), value):
        self._array[col + row * self.width] = value


class SpreadLayout(gobject.GObject, hippo.CanvasLayout):
    __gtype_name__ = 'SugarSpreadLayout'
    def __init__(self):
        gobject.GObject.__init__(self)

        min_width, width = self.do_get_width_request()
        min_height, height = self.do_get_height_request(width)

        self._grid = _Grid(width / _CELL_SIZE, height / _CELL_SIZE)
        self._grid.connect('child-changed', self._grid_child_changed_cb)

    def add_center(self, child, vertical_offset=0):
        self._box.append(child)

        width, height = self._get_child_grid_size(child)
        rect = gtk.gdk.Rectangle(int((self._grid.width - width) / 2),
                                 int((self._grid.height - height) / 2),
                                 width + 1, height + 1)
        self._grid.add_weight(rect)

        box_child = self._box.find_box_child(child)
        box_child.grid_rect = None
        box_child.vertical_offset = vertical_offset

    def add(self, child):
        self._box.append(child)

        width, height = self._get_child_grid_size(child)
        box_child = self._box.find_box_child(child)
        self._grid.add(box_child, width, height)

    def remove(self, child):
        box_child = self._box.find_box_child(child)
        self._grid.remove(box_child)

        self._box.remove(child)

    def do_set_box(self, box):
        self._box = box

    def do_get_height_request(self, for_width):
        return 0, gtk.gdk.screen_height() - style.GRID_CELL_SIZE

    def do_get_width_request(self):
        return 0, gtk.gdk.screen_width()

    def do_allocate(self, x, y, width, height,
                    req_width, req_height, origin_changed):
        for child in self._box.get_layout_children():
            rect = child.grid_rect
            if child.grid_rect:
                child.allocate(rect.x * _CELL_SIZE,
                               rect.y * _CELL_SIZE,
                               rect.width * _CELL_SIZE,
                               rect.height * _CELL_SIZE,
                               origin_changed)
            else:
                vertical_offset = child.vertical_offset
                min_w, child_width = child.get_width_request()
                min_h, child_height = child.get_height_request(child_width)
                child_x = x + (width - child_width) / 2
                child_y = y + (height - child_height + vertical_offset) / 2
                child.allocate(child_x, child_y, child_width, child_height,
                               origin_changed)

    def _get_child_grid_size(self, child):
        min_width, width = child.get_width_request()
        min_height, height = child.get_height_request(width)

        return int(width / _CELL_SIZE), int(height / _CELL_SIZE)

    def _grid_child_changed_cb(self, grid, box_child):
        box_child.item.emit_request_changed()