smalltalk - 如何在Morphic中制作行进的 Ant 边框？

Question

我正在寻找 Morphic 中的行进 Ant 边界或线:

Wikipedia describes a possbile algorithm :

The easiest way to achieve this animation is by drawing the selection using a pen pattern that contains diagonal lines. If the selection outline is only one pixel thick, the slices out of the pattern will then look like a dashed line, and the animation can easily be achieved by simply shifting the pattern one pixel sideways and redrawing the outline.

由于可能没有现成的，有人提示我如何创建这样的边框或线条吗？

(行进的 Ant 图案作为 GIF 动画是 licensed under CC by Uli Kusterer )

Answer 1

事实上，Morphic 确实有:

(PolygonMorph
    vertices: Rectangle fromUser corners
    color: Color transparent
    borderWidth: 2
    borderColor: Color black)
            dashedBorder: {10. 10. Color white. 0. 1};
            openInHand

由于这是基于多边形的，因此它不仅可以是矩形，还可以是任何形状。