from Gui import *

class DraggableItem(Item):
    """DraggableItem extends Item with basic drag-and-drop capability"""
    def __init__(self, canvas, tag):
        Item.__init__(self, canvas, tag)
        self.handles = []
        self.bind('<Button-1>', self.select)
        self.bind('<B1-Motion>', self.drag)
        self.bind('<ButtonRelease-1>', self.release)

    # the following event handlers take an event object as a parameter

    def select(self, event):
        print 'Item.select', self
        self.config(fill='red')
        self.set_drag(event)
        
    def drag(self, event):
        """move this item (and its handles) using the pixel
        coordinates in the event object."""

        # see how far we have moved
        dx, dy = self.sub_drag(event, self.drag)

        # save the current drag coordinates
        self.set_drag(event)

        # move the item and its handles
        self.move(dx, dy)
        return dx, dy

    def release(self, event):
        print 'Item.release', self
        self.config(fill='blue')

    # the following methods are for dealing with events and drag
    # coordinates
        
    def get_drag(self, event):
        """get the drag coordinates from this event and translate
        them into canvas coordinates"""
        #x, y = self.canvas.trans([event.x, event.y])
        x, y = event.x, event.y
        return x, y

    def set_drag(self, event):
        """store the current drag coordinates"""
        self.drag = self.get_drag(event)

    def sub_drag(self, event, d2):
        """subtract d2 from the drag coordinates in event"""
        d1 = self.get_drag(event)
        return d1[0] - d2[0], d1[1] - d2[1]
        

class Hello(Gui):
    def __init__(self):
        Gui.__init__(self)
        self.ca_width = 400
        self.ca_height = 400
        self.setup()

    def setup(self):
        self.canvas = self.ca(width=self.ca_width, height=self.ca_height,
                              bg='white')
        self.canvas.bind('<Button-1>', self.click)

        self.row([1,1,1])
        self.bu(text='Hello', command=self.hello)
        self.bu(text='Circle', command=self.circle)
        self.bu(text='Quit', command=self.quit)
        self.endrow()
   
    def hello(self):
        font = ('Helvetica', 36)
        item = self.canvas.text([0, 0], 'Hello', font=font, fill='blue')
        item = DraggableItem(item.canvas, item.tag)

    def circle(self):
        item = self.canvas.circle([0, 0], 100, 'yellow')
        item = DraggableItem(item.canvas, item.tag)

    def click(self, event):
        """this event handler gets invoked when the user clicks
        on the canvas."""
        print 'Hello.click', event.type, event.num, event.x, event.y


if __name__ == '__main__':
    h = Hello()
    h.mainloop()