我想设计一个名为add-frame的函数,它需要一个图像,并在所有四边都用一个像素的黑色边框包围它。这里是我所拥有的:覆盖在方案(球拍)
(define (horizontal-line x)
(line x 0 "black"))
(define (vertical-line x)
(line 0 x "black"))
(define (add-left-border height design color)
(overlay/align "left" "top"
(vertical-line height)
(square height design color)))
(define (add-right-border height design color)
(overlay/align "right" "top"
(vertical-line height)
(square height design color)))
(define (add-top-border height design color)
(overlay/align "right" "top"
(horizontal-line height)
(square height design color)))
(define (add-bottom-border height design color)
(overlay/align "right" "bottom"
(horizontal-line height)
(square height design color)))
(define (add-frame height design color)
(overlay (square height design color)
(add-left-border height design color)
(add-right-border height design color)
(add-top-border height design color)
(add-bottom-border height design color)))
当我运行“添加框架”时,我返回一个带有左边框的正方形图像。如何让边框的其余部分出现在返回的广场上?
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出于好奇,这是一个功课题吗? –
如何定义“垂直线”和“水平线”? (我无法让你的程序运行) – soegaard