The dot language has for nodes regular text labels, for record nodes special record node labels and all type of nodes html style labels which are between <> chars.
Now adding support for html style labels in gml4gtk
version 7.1
In most dot data the html <table> tag is used but that
maybe is not needed in all situations because there is a second
type of simpler html labels like this:
/* html labels with only items, not tables */
digraph "items"
{
/* to specify '&' use & */
"1"[label=<&amp;>];
"2"[label=<this is a &amp;>];
/* point-size set the font size */
"3"[label=<text<font point-size="6">small</font><font point-size="20">big</font>>];
/* wrong font name but no warnings */
"4"[label=<sans-font<font face="xyz">xyz-font</font>>];
/* set font color to "blue" or rgb "#0000ff" */
"5"[label=<<font color="blue">BlueColor</font>>];
/* set background color */
"6"[fillcolor="lightgreen" style="filled" label=<lightgreen>];
/* <o> overline text depends on pango lib version for it to work */
"7"[label=<is <o>overline</o>>];
/* <u> underline text */
"8"[label=<is <u>underline</u>>];
/* <i> italic text */
"9"[label=<is <i>italic</i>>];
1->2->3->4->5->6->7->8->9;
/* <b> bold text */
"10"[label=<is <b>bold</b>>];
/* <sub> subscript text */
"11"[label=<is <sub>subscript</sub>>];
/* <sup> superscript text */
"12"[label=<is <sup>superscript</sup>>];
/* <br/> is newline */
"13"[label=<line 1<br/>line two>];
"14"[label=<line one<br/>line 2>];
"15"[label=<line 1<br/><br/><br/>line 4>];
/* align is parsed but not yet implemented */
"16"[label=<top longer line<br/>line<br align="right"/>l2<br align="center"/>bottom<br align="left"/>end>];
1->10->11->12->13->14->15->16;
}