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多帧的第一帧之后图形跳转

tag-icon • tag-icon tikz-pgf animate
多帧的第一帧之后图形跳转

我正在尝试为我的讲座创建一个倒数计时器。除了多帧的第一帧之后的小幅延伸外，一切正常。这是 MWE：

\documentclass{standalone}
\usepackage{tikz}
\usepackage{animate}

\def\R{1cm} % radius
\newcommand{\timer}[1]{% input = number of second
    \begin{animateinline}[autoplay]{1}
    \pgfmathtruncatemacro\Nseconds{#1}
    \pgfmathtruncatemacro\Nframes{\Nseconds+1}
    \multiframe{\Nframes}{i=0+1}{%
        \pgfmathtruncatemacro\Nseconds{#1} % dont know why it is necessary to recalculate
        \pgfmathtruncatemacro\Nframes{\Nseconds+1} % -//-
        \pgfmathsetmacro\dT{360/\Nseconds} % one time step
        \pgfmathsetmacro\x{90+(\i*\dT)} % angle of already spent time
        \pgfmathtruncatemacro\y{\Nseconds-\i} % remaining time
        \begin{tikzpicture}[line cap=rect]
            % background color
            \filldraw[fill=red, draw = none, line width = 3pt] (0,0) circle [radius=\R];
            % white color of spent time
            \filldraw[fill opacity=0.5,fill=white,draw = none] (0,0) -- (0, \R) arc (90:\x:\R) -- cycle;
            % border circle
            \draw[draw = black, line width = 3pt] (0,0) circle [radius=\R];
            % small ticks
            \foreach \angle in {60,30,...,-270}\draw[line width=1pt] (\angle:0.9*\R) -- (\angle:\R);
            % large ticks
            \foreach \angle in {0,90,180,270}\draw[line width=2pt] (\angle:0.8*\R) -- (\angle:\R);
            % remaining time
            \node[font=\Large] at (0, 0) {\y};%
        \end{tikzpicture}%
    }%
    \end{animateinline}
}

\begin{document}
\timer{90}
\end{document}

我有三个问题：1）如何避免这种“跳跃”？2）为什么文档的大小不是正方形？3）是什么原因导致图片左右两侧出现空白？

答案1

  1. TikZ 根据其内容计算大小tikzpicture，每个帧的大小可能不同。因此，对所有帧强制使用一个公共边界框：\useasboundingbox ...
  2. \pgfmath...(&3) 由于包含结尾未得到正确注释的行，动画帧前后出现了大量虚假空白。
\documentclass{standalone}
\usepackage{tikz}
\usepackage{animate}

\def\R{1cm} % radius
\newcommand{\timer}[1]{% input = number of second
    \begin{animateinline}[autoplay]{1}
    \pgfmathtruncatemacro\Nseconds{#1}%
    \pgfmathtruncatemacro\Nframes{\Nseconds+1}%
    \multiframe{\Nframes}{i=0+1}{%
        \pgfmathtruncatemacro\Nseconds{#1}% dont know why it is necessary to recalculate
        \pgfmathtruncatemacro\Nframes{\Nseconds+1}% -//-
        \pgfmathsetmacro\dT{360/\Nseconds}% one time step
        \pgfmathsetmacro\x{90+(\i*\dT)}% angle of already spent time
        \pgfmathtruncatemacro\y{\Nseconds-\i}% remaining time
        \begin{tikzpicture}[line cap=rect]
            \useasboundingbox [draw = black, line width = 3pt] (0,0) circle [radius=\R];
            % background color
            \filldraw[fill=red, draw = none, line width = 3pt] (0,0) circle [radius=\R];
            % white color of spent time
            \filldraw[fill opacity=0.5,fill=white,draw = none] (0,0) -- (0, \R) arc (90:\x:\R) -- cycle;
            % border circle
            \draw[draw = black, line width = 3pt] (0,0) circle [radius=\R];
            % small ticks
            \foreach \angle in {60,30,...,-270}\draw[line width=1pt] (\angle:0.9*\R) -- (\angle:\R);
            % large ticks
            \foreach \angle in {0,90,180,270}\draw[line width=2pt] (\angle:0.8*\R) -- (\angle:\R);
            % remaining time
            \node[font=\Large] at (0, 0) {\y};%
        \end{tikzpicture}%
    }%
    \end{animateinline}% <== line terminated with `%'
}

\begin{document}
\timer{90}
\end{document}

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