2
這是我的代碼:球拍:爲什麼不能設置畫布的背景在Windows
#lang racket
(require racket/gui)
(define-values (screen-width screen-height) (get-display-size))
(define *app-width* 400)
(define *app-height* 125)
(define *vm-frame* (new frame%
[label "Test"]
[width *app-width*]
[height *app-height*]
[x (- (quotient screen-width 2) (quotient *app-width* 2))]
[y (- (quotient screen-height 2) (quotient *app-height* 2))]
))
(define frame-canvas%
(class canvas%
(super-new)
(inherit get-dc)
(define/override (on-paint)
(let ([my-dc (get-dc)])
(send my-dc clear)
(send my-dc set-background "black")))))
(let ([frame-canvas (new frame-canvas% [parent *vm-frame*])])
(send *vm-frame* show #t))
在Mac OS上,這是正常的,顯示出與黑色背景上的應用程序。 但在窗戶上,背景是白色的。 爲什麼?球拍版本是5.3,這是一個5.3的錯誤?
是的,它的工作,非常感謝。 – simmone