非常简单的点文件不能通过Graphviz twopi转换为png

我正在使用graphviz twopi生成一个png文件。我有很多点文件，但只有三个不能转换为png。下面是一个无法转换的简化示例：

digraph G{
    overlap = false;
    splines = true;
    root = "a";
    "a" [label ="ATCC 12633"];
    "b" [label = "R M Egan",fontsize=25];
    "a" -> "b" [label = "paper:1",penwidth = 4,color = black ,len=2];
    "c" [fontsize=25, label = "ATCC 8014"];
    "b" -> "c" [label = "paper:1"];
}

我使用-v查看详细信息，具体如下：

mongodb@mongodb:/home/wuchang/newStore/allYear$ sudo twopi ATCC_12633_1977.dot -Tpng -o 77.png -v
twopi - graphviz version 2.26.3 (20100126.1600)
Activated plugin library: libgvplugin_pango.so.6
Using textlayout: textlayout:cairo
Activated plugin library: libgvplugin_neato_layout.so.6
Using layout: twopi:neato_layout
Using render: cairo:cairo
Using device: png:cairo:cairo
The plugin configuration file:
        /usr/lib/graphviz/config6
                was successfully loaded.
    render      :  cairo dot fig gd map ps svg tk vml vrml xdot
    layout      :  circo dot fdp neato nop nop1 nop2 osage patchwork sfdp twopi
    textlayout  :  textlayout
    device      :  canon cmap cmapx cmapx_np dot eps fig gd gd2 gif gv imap imap_np ismap jpe jpeg jpg pdf plain plain-ext png ps ps2 svg svgz tk vml vmlz vrml wbmp x11 xdot xlib
    loadimage   :  (lib) eps gd gd2 gif jpe jpeg jpg png ps svg
fontname: "Times-Roman" resolved to: (ps:pango  Times Roman,) (PangoCairoFcFont) "DejaVu Sans 14" 
root = a
Rank separation = 0.000 1.000 2.000 
Adjusting G using Voronoi
Node separation: add=1 (4.000000,4.000000)

我怀疑这只是graphviz中的一个bug。我的graphviz版本是2.26.3，我的操作系统是Ubuntu 12.04.3

与转换输出为的成功转换的点文件相比：

mongodb@mongodb:/home/wuchang/newStore/allYear$ sudo twopi ATCC_12633_1988.dot -Tpng -o 88.png -v
twopi - graphviz version 2.26.3 (20100126.1600)
Activated plugin library: libgvplugin_pango.so.6
Using textlayout: textlayout:cairo
Activated plugin library: libgvplugin_neato_layout.so.6
Using layout: twopi:neato_layout
Using render: cairo:cairo
Using device: png:cairo:cairo
The plugin configuration file:
        /usr/lib/graphviz/config6
                was successfully loaded.
    render      :  cairo dot fig gd map ps svg tk vml vrml xdot
    layout      :  circo dot fdp neato nop nop1 nop2 osage patchwork sfdp twopi
    textlayout  :  textlayout
    device      :  canon cmap cmapx cmapx_np dot eps fig gd gd2 gif gv imap imap_np ismap jpe jpeg jpg pdf plain plain-ext png ps ps2 svg svgz tk vml vmlz vrml wbmp x11 xdot xlib
    loadimage   :  (lib) eps gd gd2 gif jpe jpeg jpg png ps svg
fontname: "Times New Roman Bold" resolved to: (PangoCairoFcFont) "DejaVu Sans Bold 30" 
fontname: "Times-Roman" resolved to: (ps:pango  Times Roman,) (PangoCairoFcFont) "DejaVu Sans 24.9990234375" 
root = -290487096
Rank separation = 0.000 1.000 2.000 
Adjusting G using Voronoi
Node separation: add=1 (4.000000,4.000000)
Number of iterations = 5
Number of increases = 3
Edge separation: add=1 (3.200000,3.200000)
Creating edges using splines
Using render: cairo:cairo
Using device: png:cairo:cairo
twopi: allocating a 1477K cairo image surface (907 x 417 pixels)

我尝试了许多修改，例如：

如果我删除

overlap=false

，它可以生成png文件，但 生成的图形的节点重叠，这不符合我的要求 要求

当我删除节点“c”的

fontsize=23

时，它也 可以生成png文件，但png文件完全 错

---

我建议更新到Graphviz的新版本。在过去的四年里有了很大的发展。因为您的详细输出在显示迭代次数之前结束，所以我强烈怀疑您正在使用的Graphviz版本是一个bug（可能是一个无限循环）

使用OS X下的2.36.0，您的文件提供了以下信息（这显然不是您想要的）：

如果我注释掉行

root=“a”我得到这个：