Write a program that allows the user to draw a rectangle by dragging the mouse on a Can- vas. The drawing should begin when the user holds the left-mouse button down. With this button held down, the user should be able to resize the rectangle. The drawing ends when the user releases the left button. When the user next clicks on the Canvas, the rectangle should be deleted.

Question

What will be an ideal response?

Answer 1

```
# Draw a rectangle on a Canvas using the mouse.

from Tkinter import *

class DrawRectangle( Frame ):
"""Demonstrate drawing on a Canvas with mouse"""

def __init__( self ):
"""Create Canvas and bind events"""

Frame.__init__( self )
self.pack( expand = YES, fill = BOTH )
self.master.title( "Drag to Draw a Rectangle" )
self.master.geometry( "300x200" )

self.display = Canvas( self, bg = "white" )
self.display.pack( expand = YES, fill = BOTH )

# coordinates of the rectangle
self.x1, self.x2 = 0, 0
self.x2, self.y2 = 0, 0

# bind events to the canvas
self.display.bind( "", self.setStart )
self.display.bind( "", self.setEnd )
self.display.bind( "", self.setEnd )

def setStart( self, event ):
"""Set start points for rectangle"""

self.x1 = event.x
self.y1 = event.y

def setEnd( self, event ):
"""Set end points for rectangle and draw"""

self.x2 = event.x
self.y2 = event.y
self.draw()

def draw( self ):
"""Remove rectangle and redraw"""

self.display.delete( "rectangle" )
self.display.create_rectangle( self.x1, self.y1, self.x2,
self.y2, fill = "white", tags = "rectangle" )

def main():
DrawRectangle().mainloop()

if __name__ == "__main__":
main()
```