如何在 tikzpicture 中制作由一条线连接的两个移动点的动画

Question 1

经过一些实验，我得出了以下答案。虽然在最终用例中坐标几乎是一条直线，但在这里我使用了三个形成大角度的坐标（出于演示目的）。

案例 a) 不断重复

在代码中我在每个动画开始前添加了 3 秒的延迟：

\usetikzlibrary {animations}
\begin{tikzpicture}
\useasboundingbox (0,0) rectangle (6,4);

\node at (0.5,1) :position = { 0s = "{(0.5,1)}", 3s = "{(0.5,1)}", 5s = "{(1,2.5)}" , 8s = "{(2,2)}", repeat }
[fill = blue!20, draw = blue, ultra thick, circle] (node1) {};

\node at (2,2) :position = { 0s = "{(2,2)}", 3s = "{(2,2)}", 5s = "{(4,3)}", 8s = "{(5,3.5)}", repeat }
[fill = red!20, draw = red, ultra thick, circle] (node2) {};

\draw [green] (node1) -- (node2) :path = { 0s = "{(node1) -- (node2)}", 3s = "{(node1) -- (node2)}",
5s = "{(1,2.5) -- (4,3)}", 8s = "{(2,2) -- (5,3.5)}", repeat };
\end{tikzpicture}

这是 SVG（我希望它能起作用）：

批评：我不喜欢连接线的长度增加到两个圆的中心——我需要减去两个终止圆的半径。

情况 b) 带有开始按钮

\usetikzlibrary {animations}
\begin{tikzpicture}
\draw (5,5) node[minimum height =0cm,draw,scale=1.5] (Go) {Go!};

\node at (0.5,1) :position = { 0s = "{(0.5,1)}", 2s = "{(1,2.5)}" , 5s = "{(2,2)}", begin on={click, of=Go} }
[fill = blue!20, draw = blue, ultra thick, circle] (node1) {};

\node at (2,2) :position = { 0s = "{(2,2)}", 2s = "{(4,3)}", 5s = "{(5,3.5)}", begin on={click, of=Go} }
[fill = red!20, draw = red, ultra thick, circle] (node2) {};

\draw [green] (node1) -- (node2) :path = { 0s = "{(node1) -- (node2)}", 2s = "{(1,2.5) -- (4,3)}",
5s = "{(2,2) -- (5,3.5)}", begin on={click, of=Go} };

\end{tikzpicture}

这是 SVG（抱歉，但是按钮在创建的 SVG 中可以工作）：

批评：如果将node1和node2的坐标提取到一个\begin{scope} [animate = { .... }] .... \end{scope}部分中，则:position参数列表内的坐标begin on={click, of=Go}将被忽略，即动画永远不会启动。

案例 a2) 不断重复

连接节点的逐渐延伸的线（在上面的例子中很难看到）可以使用幻影节点删除。参见：TikZ 动画的幻影节点

\usetikzlibrary {animations}
\begin{tikzpicture}
\useasboundingbox (0,0) rectangle (6,4);

\node at (0.5,1) :position = { 0s = "{(0.5,1)}", 3s = "{(0.5,1)}", 5s = "{(1,2.5)}" , 8s = "{(2.5,1.5)}", 10s = "{(2.5,1.5)}", repeat }
[fill = blue!05, draw = blue, thick, circle, radius = 0.6] (node1) {};

\node at (2,2) :position = { 0s = "{(2,2)}", 3s = "{(2,2)}", 5s = "{(4,3)}", 8s = "{(5,0.5)}", 10s = "{(5,0.5)}", repeat }
[fill = red!05, draw = red, thick, circle, radius = 0.6] (node2) {};

\begin{lrbox}{0}
\node at (1,2.5) [draw, circle, radius = 0.6, opacity = 0.2] (n1) {};
\node at (2.5,1.5) [draw, circle, radius = 0.6, opacity = 0.2] (n2) {};
\node at (4,3) [draw, circle, radius = 0.6, opacity = 0.2] (n3) {};
\node at (5,0.5) [draw, circle, radius = 0.6, opacity = 0.2] (n4) {};
\end{lrbox}

\draw [brown] (node1) -- (node2) :path = { 0s = "{(node1) -- (node2)}", 3s = "{(node1) -- (node2)}", 5s = "{(n1) -- (n3)}", 8s = "{(n2) -- (n4)}", 10s = "{(n2) -- (n4)}", repeat };

\end{tikzpicture}

SVG 在这里：

如果你注释掉的开头和结尾{lrbox}，你会看到幻影节点所在位置的模糊图像：

这是一个很好的解决方案，但编码起来很麻烦。我后来看到（在 Ti 的第 382 页上）钾Z 手册：

所以，总而言之，我对这个解决方案很满意，它.tex无论如何都会使用 Python 来创建文件。如果有人能改进它，我会很高兴看到你的版本。

Answer