rounded rectangle in pygtk

Question

what is the best way to draw a rounded rectangle in a pygtk application

Answer 1

Probably pycairo

Answer 2

#!/usr/bin/env python

import gtk

def rounded_rectangle(cr, x, y, w, h, r=20):
    # This is just one of the samples from 
    # http://www.cairographics.org/cookbook/roundedrectangles/
    #   A****BQ
    #  H      C
    #  *      *
    #  G      D
    #   F****E

    cr.move_to(x+r,y)                      # Move to A
    cr.line_to(x+w-r,y)                    # Straight line to B
    cr.curve_to(x+w,y,x+w,y,x+w,y+r)       # Curve to C, Control points are both at Q
    cr.line_to(x+w,y+h-r)                  # Move to D
    cr.curve_to(x+w,y+h,x+w,y+h,x+w-r,y+h) # Curve to E
    cr.line_to(x+r,y+h)                    # Line to F
    cr.curve_to(x,y+h,x,y+h,x,y+h-r)       # Curve to G
    cr.line_to(x,y+r)                      # Line to H
    cr.curve_to(x,y,x,y,x+r,y)             # Curve to A

def expose(canvas, event):
    # Create cairo context
    cr = canvas.window.cairo_create()

    # Restrict drawing to the exposed area, so that
    # no unnecessary drawing is done
    cr.rectangle(event.area.x, event.area.y, 
                 event.area.width, event.area.height)
    cr.clip()

    rounded_rectangle(cr, 100, 100, 100, 100)
    cr.set_line_width(4.0)
    cr.set_source_rgb(1.0, 0.0, 0.0)
    cr.stroke_preserve()
    cr.set_source_rgb(1.0, 0.5, 0.5)
    cr.fill()

# Construct window
window = gtk.Window()
canvas = gtk.DrawingArea()
canvas.set_size_request(300, 300)
canvas.connect('expose-event', expose)
window.connect('delete-event', gtk.main_quit)
window.add(canvas)
window.show_all()

gtk.main()