DrawingArea.py

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"""
Copyright 2007 Free Software Foundation, Inc.
This file is part of GNU Radio

GNU Radio Companion 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.

GNU Radio Companion 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 Street, Fifth Floor, Boston, MA  02110-1301, USA
"""
##@package grc.gui.DrawingArea
#Drawing area for graphical elements.
#@author Josh Blum

import pygtk
pygtk.require('2.0')
import gtk
from grc.Constants import *

class DrawingArea(gtk.DrawingArea):
        """
        DrawingArea is the gtk pixel map that graphical elements may draw themselves on.
        The drawing area also responds to mouse and key events.
        """

        def __init__(self, main_window):
                """!
                DrawingArea contructor.
                Connect event handlers.
                @param main_window the main_window containing all flow graphs
                """
                self.ctrl_mask = False
                self._main_window = main_window
                #inject drawing area into main_window
                self._main_window.drawing_area = self
                gtk.DrawingArea.__init__(self)
                self.set_size_request(MIN_WINDOW_WIDTH, MIN_WINDOW_HEIGHT)
                self.connect('expose-event', self._handle_window_expose)
                self.connect('motion-notify-event', self._handle_mouse_motion)
                self.connect('button-press-event', self._handle_mouse_button_press)
                self.connect('button-release-event', self._handle_mouse_button_release)
                self.set_events(
                        gtk.gdk.BUTTON_PRESS_MASK | \
                        gtk.gdk.POINTER_MOTION_MASK | \
                        gtk.gdk.BUTTON_RELEASE_MASK | \
                        gtk.gdk.LEAVE_NOTIFY_MASK | \
                        gtk.gdk.ENTER_NOTIFY_MASK
                )
                #setup the focus flag
                self._focus_flag = False
                self.get_focus_flag = lambda: self._focus_flag
                self.connect("leave-notify-event", self._handle_focus_event, False)
                self.connect("enter-notify-event", self._handle_focus_event, True)
                #pixmap for drawing
                self.pixmap = None
                self.gc = None

        def draw(self):
                """!
                Draw the pixmap onto this drawing area.
                """
                self.window.draw_drawable(self.gc, self.pixmap, 0, 0, 0, 0, -1, -1)

        ##########################################################################
        ## Handlers
        ##########################################################################
        def _handle_focus_event(self, widget, event, focus_flag):
                """Record the focus state of the flow graph window."""
                self._focus_flag = focus_flag

        def _handle_mouse_button_press(self, widget, event):
                """!
                Forward button click information to the flow graph.
                """
                self.ctrl_mask = event.state & gtk.gdk.CONTROL_MASK
                self._main_window.get_flow_graph().handle_mouse_button_press(
                        left_click=(event.button == 1),
                        double_click=(event.type == gtk.gdk._2BUTTON_PRESS),
                        coordinate=(event.x, event.y),
                )
                return True

        def _handle_mouse_button_release(self, widget, event):
                """!
                Forward button release information to the flow graph.
                """
                self.ctrl_mask = event.state & gtk.gdk.CONTROL_MASK
                self._main_window.get_flow_graph().handle_mouse_button_release(
                        left_click=(event.button == 1),
                        coordinate=(event.x, event.y),
                )
                return True

        def _handle_mouse_motion(self, widget, event):
                """!
                Forward mouse motion information to the flow graph.
                """
                self.ctrl_mask = event.state & gtk.gdk.CONTROL_MASK
                self._main_window.get_flow_graph().handle_mouse_motion(
                        coordinate=(event.x, event.y),
                )
                return True

        def _handle_window_expose(self, widget, event):
                """!
                Called when the window initially appears or is resized: create a new pixmap, draw the flow graph.
                """
                self.gc = self.window.new_gc()
                width, height = self.get_size_request()
                if not self.pixmap or (width, height) != self.pixmap.get_size():
                        self.pixmap = gtk.gdk.Pixmap(self.window, width, height, -1)
                self._main_window.get_flow_graph().draw()
                return True

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