#lang racket (require racket/gui/base) ;========================= Picture ============================== ; MAKING FRAME WINDOW, CANVAS, and DC (define frame (new frame% [label "Paint George"] [width 747] [height 769])) (define canvas (new canvas% [parent frame] [paint-callback (lambda(cnavas dc) (send dc set-pen red-pen) (send dc set-brush no-brush) (on-paint))])) (define red-pen (make-object pen% "RED" 2 'solid)) (define no-brush (make-object brush% "BLACK" 'transparent)) (define dc (send canvas get-dc)) ; DEFINE CALLBACK PAINT PROCEDURE ;(define (on-paint) (george-mix frame1)) (define (on-paint) (send dc draw-line 1 1 700 700)) ;MAKING THE FRAME VISIBLE (send frame show #t)