不使用 Shade 的 Tikz Sphere

Question

我在投影仪幻灯片中使用了以下图形

我使用 evince pdf viewer，发现 pdf 显示非常慢。当我点击下一页时，大约需要 15-20 秒才会显示。我的处理器很快（英特尔 i7，4GB RAM）。

所以我要么更换查看器，要么停止使用着色。我现在不想从 Evince 切换。我是否可以不使用着色来绘制球体？或者我应该只使用普通的圆圈？

代码如下

\documentclass[compress,red,xcolor={table},10pt]{beamer}
\usepackage{tikz}
\usetikzlibrary{arrows,automata,calc,shapes, positioning,shadows,shadows.blur,patterns,plotmarks,shapes.geometric,decorations.pathmorphing,patterns,intersections,decorations.markings,circuits.logic.US}
\begin{document}

\begin{frame}{}

\begin{tikzpicture}
\pgfmathsetseed{3}

\onslide<3->
{
\draw[draw=none,black!40,fill=green!40] (1.35,2.65) circle (35pt);
\draw[draw=none,black!40,fill=red!40] (3.5,3.5) circle (25pt);
\draw[draw=none,black!40,fill=black!40] (2.0,5.25) circle (40pt);
\draw[draw=none,black!40,fill=blue!40] (4.75,5.45) circle (35pt);
}

\onslide<2->
{
    % Axis
    \draw[thick] (-0.5,0) -- (7,0);
    \draw[thick] (0,-0.5) -- (0,7);

  \foreach \i in {1,2,...,70}{

    \pgfmathsetmacro{\x}{1.35 + rand*0.90}
    \pgfmathsetmacro{\y}{2.65+rand*0.90}

     \shade [ball color = black!70] (\x,\y) circle (0.1);
}

\foreach \i in {1,2,...,60}{
    \pgfmathsetmacro{\x}{3.5 + rand*0.70}
    \pgfmathsetmacro{\y}{3.5+rand*0.70}
     \shade [ball color = black!70] (\x,\y) circle (0.1);
}

\foreach \i in {1,2,...,70}{
    \pgfmathsetmacro{\x}{2.0 + rand*0.90}
    \pgfmathsetmacro{\y}{5.25+rand*0.90}
     \shade [ball color = black!70] (\x,\y) circle (0.1);
}

\foreach \i in {1,2,...,70}{
    \pgfmathsetmacro{\x}{4.75 + rand*0.90}
    \pgfmathsetmacro{\y}{5.45+rand*0.90}
     \shade [ball color = black!70] (\x,\y) circle (0.1);
}
}

\onslide<4->
{
\shade [ball color=blue] (1.45,3.30) circle (0.1);
\shade [ball color=blue] (3.45,3.30) circle (0.1);
\shade [ball color=blue] (4.45,6.20) circle (0.1);
\shade [ball color=blue] (2.25,4.40) circle (0.1);
}

\end{tikzpicture}
\end{frame}
\end{document}