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# Copyright 2008 by Peter Moxhay and Wade Brainerd.
# This file is part of Math.
#
# Math 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 3 of the License, or
# (at your option) any later version.
#
# Math 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 Math. If not, see <http://www.gnu.org/licenses/>.
from objectarea import Object
from vector import Vector
from movableobject import MovableObject
import gtk, math
class ShapeObject(MovableObject):
"""Movable convex shape object."""
def __init__(self, color, symbol, points, pos, angle):
MovableObject.__init__(self)
self.color = color
self.symbol = symbol
self.points = points
self.pos = pos
self.angle = angle
self.area = 0
self.centroid = Vector(0, 0)
self.bounds_min = Vector(0, 0)
self.bounds_max = Vector(0, 0)
self.selectable = True
# Calculate the area and centroid of the shape
self.calculate_area_and_centroid()
# Transform the points of the polygon to center-of-mass coordinates
self.points = [p - self.centroid for p in self.points]
# Get the current bounding rectangle.
self.calculate_bounds()
self.symbol_visible = True
def calculate_area_and_centroid(self):
# Calculate the area.
self.area = 0
for i in range (0, len(self.points) ):
p1 = self.points[i]
p2 = self.points[(i+1) % len(self.points)]
self.area += (p1.x*p2.y - p2.x*p1.y)/2
# Need to take absolute value?
#self.area = abs(self.area)
# Calculate the centroid (center of mass).
self.centroid = Vector(1, 1)
for i in range (0, len(self.points) ):
p1 = self.points[i]
p2 = self.points[(i+1) % len(self.points)]
self.centroid += (p1+p2) * (p1.x*p2.y - p2.x*p1.y) / (6 * self.area)
# Calculate the "move only" radius (the radius of a circle whose area is half the area of the shape).
# (Modify for a long, thin object?)
self.move_only_radius = math.sqrt(self.area/(2 * math.pi))
def calculate_bounds(self):
# Get the current width and height of the bounding rectangle.
self.bounds_min = Vector(float('inf'), float('inf'))
self.bounds_max = Vector(float('-inf'), float('-inf'))
for p in self.points:
p = self.transform_point(p)
self.bounds_min = self.bounds_min.min(p)
self.bounds_max = self.bounds_max.max(p)
# Bump the bounds a little bit to account for the outline edge.
self.bounds_min -= Vector(2, 2)
self.bounds_max += Vector(2, 2)
def get_bounds(self):
#print "ShapeObject get_bounds: ", self.bounds_min, self.bounds_max
return self.bounds_min, self.bounds_max
def transform_point(self, p):
return p.rotate(self.angle) + self.pos
def inside_move_area(self, point):
self.point = point
boolean = False
# If the point is near the center of the object, return True.
if ((self.point - self.pos).length() < self.move_only_radius):
boolean = True
return boolean
# Enables user to "see both areas" in answer box by clicking.
def select_by_button_press(self):
other = None
self.container.select_object(self)
if self.in_answer_box and (self.container.problem_type == 'area' or self.container.problem_type == 'cutting'):
i = 0
for o in self.container.objects:
if isinstance(o, ShapeObject):
if not o == self:
other = o
i += 1
if not self.selected:
self.container.select_object(self)
else:
self.container.select_object(other)
# Switch self and other to make selection work correctly in answer box?
#if not self.selected:
# self.container.select_object(other)
#else:
# self.container.select_object(self)
self.container.adjust_tab_order()
else:
self.container.select_object(self)
def draw(self, cr):
cr.scale(self.scale, self.scale)
# Transform the points.
points = [self.transform_point(p) for p in self.points]
# Generate the shape.
cr.move_to(points[0].x, points[0].y)
for p in points:
cr.line_to(p.x, p.y)
cr.line_to(points[0].x, points[0].y)
cr.close_path()
# Draw the fill.
if self.selected:
cr.set_source_rgb(self.color[0]*1.6, self.color[1]*1.6, self.color[2]*1.6)
else:
cr.set_source_rgb(self.color[0], self.color[1], self.color[2])
cr.fill_preserve()
# Draw the outline.
if self.selected:
cr.set_dash((10, 10), 0)
cr.set_source_rgb(self.color[0]*0.75, self.color[1]*0.75, self.color[2]*0.75)
cr.set_line_width(4.0)
cr.stroke()
# Draw the symbol (capital letter representing the shapes's area).
if self.symbol_visible:
cr.set_source_rgb(0, 0, 0)
cr.set_font_size(50)
x_bearing, y_bearing, width, height = cr.text_extents(self.symbol)[:4]
cr.move_to(self.pos.x - x_bearing - width/2, self.pos.y - y_bearing - height/2)
cr.show_text(self.symbol)
# Algorithm to test whether point is inside the polygon
def contains_point(self, pos):
n = 0
p = pos
for i in range (0, len(self.points) ):
p1 = self.points[i]
p2 = self.points[(i+1) % len(self.points)]
p1 = self.transform_point(p1)
p2 = self.transform_point(p2)
if p.y > min(p1.y, p2.y):
if p.y <= max(p1.y, p2.y):
if p.x <= max(p1.x, p2.x):
if p1.y != p2.y:
x = (p.y-p1.y)*(p2.x-p1.x)/(p2.y-p1.y)+p1.x
if p1.x == p2.x or p.x <= x:
n = n + 1
if n % 2 == 0:
return(False)
else:
return(True)
def is_in_container(self):
for p in self.points:
p = self.transform_point(p)
if p.x < -2 or p.x > self.container.DRAGGING_RECT_WIDTH + 2 or \
p.y < -1 or p.y > self.container.DRAGGING_RECT_HEIGHT:
return False
return True
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