canvas.py 文件源码

def __init__(self):
        gtk.DrawingArea.__init__(self)
        self.set_double_buffered(False)
        self.add_events(
            gtk.gdk.BUTTON_PRESS_MASK| 
            gtk.gdk.BUTTON_RELEASE_MASK| 
            gtk.gdk.BUTTON1_MOTION_MASK| 
            gtk.gdk.BUTTON2_MOTION_MASK| 
            gtk.gdk.BUTTON3_MOTION_MASK| 
            gtk.gdk.SCROLL_MASK| 
            gtk.gdk.KEY_PRESS_MASK| 
            gtk.gdk.KEY_RELEASE_MASK)

        # foregorund, background
        self.fg = (0, 0, 0)
        self.bg = (0, 0, 0)

        # list of layers
        self.layers = []

        # visible are used for speedup as list
        self.visible = None

        # canvas bindings
        self.bindings = {}

        # last item which had some event
        self.current_item = None

        # cairo context
        self.cr = None

        # cached cairo image surfaces using filenames/images as keys
        self.cache_filenames = {}
        self.cache_images = {}

        # connect event callbacks
        gtk.DrawingArea.connect(self, 'configure-event', self.drawingarea_configure_event_cb)
        gtk.DrawingArea.connect(self, 'expose-event', self.drawingarea_expose_event_cb)
        gtk.DrawingArea.connect(self, 'button-press-event', self.drawingarea_button_press_event_cb)
        gtk.DrawingArea.connect(self, 'button-release-event', self.drawingarea_button_release_event_cb)
        gtk.DrawingArea.connect(self, 'motion-notify-event', self.drawingarea_motion_notify_event_cb)
        gtk.DrawingArea.connect(self, 'scroll-event', self.drawingarea_scroll_event_cb)