harfbuzz/docs/features.dot

digraph {
  graph [outputorder=edgefirst];
	node [shape="record", fontname="Noto Sans Mono SemiBold", fontsize=15];
	edge [fontname="Verdana", fontsize=12,labeldistance=7.5 ];
	fontname="Verdana";
  ranksep=0.02; nodesep=0.5;

subgraph {
	ranksep="0.02 equally";
	preprocessing[style=filled,fillcolor="lightgreen",fontname="Verdana",label="Glyph pre-processing"];
	orthographic[style=filled,fillcolor="lightblue",fontname="Verdana",label="Orthographic Unit Shaping"];
	reordering[style=filled, fillcolor="lightcoral",fontname="Verdana",label="Reordering group (USE)"];
	topographic[style=filled,fillcolor="lightgoldenrod",fontname="Verdana",label="Topographical Features‡"];
	typographic[style=filled,fillcolor="lightpink",fontname="Verdana",label="Typographic Presentation"];
	positioning[style=filled,fillcolor="lightsalmon",fontname="Verdana",label="Positioning"];
	preprocessing->reordering->orthographic->topographic->typographic->positioning;
}

	decision1 [shape="diamond", label="Script\ndirection?",fontname="Verdana"];
	rvrn->decision1;

	ltrfeatures [label="{ltra|ltrm}", fillcolor="lightgreen",style="filled"];
	{
	rtlfeatures [label="{rtla|rtlm¹}", fillcolor="lightgreen",style="filled"];
	}
	{
		rank=same;
		fracfeatures [label="frac²|numr³|dnom⁴", fillcolor="lightpink",style="filled"];
		fracnotes [fontname="Verdana",shape=plaintext,label=<<table border="0" cellborder="0" cellspacing="0">
			<tr><td align="left">¹ rtlm is scoped to characters with a Unicode mirroring property</td></tr>
			<tr><td align="left">² frac is scoped to numr + the slash + dnom</td></tr>
			<tr><td align="left">³ numr is scoped to all decimal numbers before a U+2044 FRACTION SLASH.</td></tr>
			<tr><td align="left">⁴ dnom is scoped to all decimal numbers after a U+2044 FRACTION SLASH.</td></tr>
	</table>
		>];

	}
	rand [fillcolor="lightpink",style="filled"];

	decision1 -> ltrfeatures [label="Left-to-right"];
	decision1 -> rtlfeatures [label="Right-to-left"];

	decision1 -> fracfeatures [label="Other"];

	ltrfeatures -> fracfeatures;
	rtlfeatures -> fracfeatures;
	fracfeatures->rand;

	decision2 [shape="diamond", label="Script?",fontname="Verdana"];

{rank=same; HARF [label="{Harf|HARF}"]; notes;}
	rand -> trak -> HARF -> decision2;

	commonfeatures [shape=none,label=<<table border="0" cellspacing="0">
                    <tr>
                    	<td border="1" bgcolor="lightsalmon">abvm</td>
                    	<td border="1" bgcolor="lightsalmon">blwm</td>
                    	<td border="1" bgcolor="lightgreen">ccmp</td>
                    	<td border="1" bgcolor="lightgreen">locl</td>
                    	<td border="1" bgcolor="lightsalmon">mark</td>
                    	<td border="1" bgcolor="lightsalmon">mkmk</td>
                    	<td border="1" bgcolor="lightpink">rlig</td>
                    </tr>
                </table>>
    ];

	decision3 [shape="diamond", label="Script\ndirection?",fontname="Verdana"];

	BUZZ  [label="{Buzz|BUZZ}"];
	BUZZ -> commonfeatures -> decision3;

	horizontalfeatures [
	shape=none,label=<<table border="0" cellspacing="0">
                    <tr><td border="1" bgcolor="lightpink">calt <font face="Verdana">(not Hangul)</font></td></tr>
                    <tr><td border="1" bgcolor="lightpink">clig <font face="Verdana">(not Khmer)</font></td></tr>
                    <tr><td border="1" bgcolor="lightsalmon">curs</td></tr>
                    <tr><td border="1" bgcolor="lightsalmon">dist</td></tr>
                    <tr><td border="1" bgcolor="lightsalmon">kern</td></tr>
                    <tr><td border="1" bgcolor="lightpink">liga <font face="Verdana">(not Khmer)</font></td></tr>
                    <tr><td border="1" bgcolor="lightpink">rclt</td></tr>
                </table>>
                ];
	vert [label="vert",style=filled,fillcolor="lightpink"];

	decision3 -> horizontalfeatures [label="Horizontal"];
	decision3 -> vert [label="Vertical"];

	discretionary [label="User-selected\ndiscretionary\nfeatures",fontname="Verdana"];

	horizontalfeatures -> discretionary;
	vert -> discretionary;

	decision2->stch;

	BUZZ;

subgraph shapers {
	subgraph cluster_arabic {
		bgcolor="lightyellow"
		label="Arabic, Syriac";
	stch [ style="filled", fillcolor="lightgreen",label="stch"];
	ccmplocl [ style="filled", label="ccmp|locl", fillcolor="lightgreen"];
	arabicfeatures [label="isol|fina|fin2|fin3|medi|med2|init", style="filled", fillcolor="lightgoldenrod"];
	arabicfeatures2 [label="rclt|calt", style="filled",fillcolor="lightpink"];
rlig[style="filled",fillcolor="lightpink"];
mset [fillcolor="lightpink",style="filled"]
	stch->ccmplocl->arabicfeatures->rlig->arabicfeatures2->mset;
	}
	mset->BUZZ:n;

	subgraph cluster_hangul {
		bgcolor="lightyellow"
		label="Hangul";
		hangulfeatures [label="ljmo|vjmo|tjmo", style="filled",fillcolor="lightgoldenrod"]
	}
	  hangulfeatures->BUZZ:n;

	subgraph cluster_indic {
		label="Indic";
		bgcolor="lightyellow"
		// Preprocessing
		loclccmpindic [label="locl†|ccmp†",style=filled,fillcolor="lightgreen"];
		node[style=filled,fillcolor="lightgreen"];
		nukt [label="nukt†"];
		akhn [label="akhn†"];
		loclccmpindic->indic_reorder_1->nukt->akhn;
		indic_reorder_1[label="Initial reordering", fontname="Verdana",fillcolor="lightgrey",shape=ellipse,style=filled]

		// Orthographic
		node[style=filled,fillcolor="lightblue"]
		rphf [label="rphf⁵"];
		rkpf [label="rkpf†"];
		pref [label="pref⁶"];
		blwf [label="blwf⁷"];
		abvf [label="abvf⁸"];
		half [label="half⁹"];
		pstf [label="pstf⁸"];
		vatu [label="vatu†"];
		cjct [label="cjct†"];
		akhn ->rphf -> rkpf -> pref -> blwf -> abvf -> half -> pstf -> vatu -> cjct;
		// Typographic presentation
		indic_typographic[style=filled,fillcolor="lightpink",label="init|pres|abvs|blws|psts|haln"]
		indic_reorder_2[label="Final reordering",fillcolor="lightgrey",fontname="Verdana", shape=ellipse,style=filled]
		cjct->indic_reorder_2->indic_typographic;

	notes2 [fontname="Verdana",shape=plaintext,style="",label=<<table border="0" cellborder="0" cellspacing="0">
<tr><td align="right">⁵ rphf is scoped to pre-base ra+halant sequences</td></tr>
<tr><td align="right">⁶ pref is scoped to the two glyphs after the base; outputs are reordered</td></tr>
<tr><td align="right">⁷ blwf is usually scoped to the whole syllable, except in Telugu and Kannada where it is post-base</td></tr>
<tr><td align="right">⁸ abvf and pstf are scoped to post-base</td></tr>
<tr><td align="right">⁹ half is scoped to pre-base</td></tr>
</table>
>];
		indic_typographic -> notes2 [style=invis];
	}


	subgraph cluster_khmer {
		label="Khmer";
		bgcolor="lightyellow"

		khmerbasic [style=filled,fillcolor="lightgreen",label="locl†|ccmp†|pref†|bwlf†|abvf†|pstf†|cfar†"]
		khmerother [style=filled,fillcolor="lightpink",label="pres|abvs|blws|psts"]
		khmerbasic -> khmerother -> khmerclig;
				khmerclig [label="clig",style=filled,fillcolor="lightpink"];
	}

	subgraph cluster_myanmar {
		label="Myanmar";
		bgcolor="lightyellow"
		loclccmpmyanmar [label="locl†|ccmp†",style=filled,fillcolor="lightgreen"];
		rphfmymr [label="rphf†",style=filled,fillcolor="lightblue"]
		prefmymr [label="pref†",style=filled,fillcolor="lightblue"]
		blwfmymr [label="blwf†",style=filled,fillcolor="lightblue"]
		pstfmymr [label="pstf†",style=filled,fillcolor="lightblue"]
		myanmarother [label="pres|abvs|blws|psts",style=filled,fillcolor="lightpink"];
		reorder_myanmar[label="Reordering", shape=ellipse,style=filled,fontname="Verdana"]
		loclccmpmyanmar -> reorder_myanmar-> rphfmymr -> prefmymr -> blwfmymr -> pstfmymr -> myanmarother;
	}

	subgraph cluster_use {
		label="Universal Shaping Engine"
		bgcolor="lightyellow"
		use_preprocessing [style=filled, label="locl†|ccmp†|nukt†|akhn†", fillcolor="lightgreen"];
		// Reoredering
		rphfuse [label="rphf¹⁰", style=filled, fillcolor="lightcoral"];
		prefuse [label="pref¹¹", style=filled, fillcolor="lightcoral"];
		// Orthographic
		orthographicuse [label="rkrf†|abvf†|blwf†|half†|pstf†|vatu†|cjct†", style="filled", fillcolor="lightblue"];
		topographicaluse [label="isol|init|medi|fina", style="filled", fillcolor="lightgoldenrod"];
		typographicaluse [label="abvs|blws|haln|pres|psts", style="filled", fillcolor="lightpink"];
		reorder_use[label="Reordering", shape=ellipse,style=filled,fontname="Verdana"]
		use_preprocessing -> rphfuse -> prefuse->orthographicuse ->reorder_use -> topographicaluse -> typographicaluse;
			notes3 [fontname="Verdana",shape=plaintext,label=<<table border="0" cellborder="0" cellspacing="0">
		<tr><td align="left">¹⁰ Outputs are reordered as category R</td></tr>
		<tr><td align="left">¹¹ Outputs are reordered to before base</td></tr>
		</table>
		>];
		typographicaluse -> notes3 [style=invis];
	}

}

	indic_typographic->BUZZ:n;
	typographicaluse->BUZZ:n;
	khmerclig -> BUZZ:n;
	myanmarother -> BUZZ:n;


	decision2->hangulfeatures;
	decision2->loclccmpindic;
	decision2->khmerbasic;
	decision2->loclccmpmyanmar;
	decision2->use_preprocessing;
	decision2->BUZZ [label="  Hebrew, Thai,\n  Lao, other"];

notes [fontname="Verdana",shape=box,label=<<table border="0" cellborder="0" cellspacing="0">
	<tr><td align="left">
<b>Indic</b> scripts are: Bengali, Devanagari,
 Gujarati, Gurmukhi, Kannada,
 Malayalam, Oriya, Tamil,
 Telugu, Sinhala
</td></tr>

	<tr><td align="left">
<b>USE</b> scripts are:
 Adlam, Ahom, Balinese, Batak, Bhaiksuki, Brahmi, Buginese,
 Buhid, Chakma, Cham, Chorasmian, Dives Akuru, Dogra, Duployan,
</td></tr>
	<tr><td align="left">
Egyptian hieroglyphs, Elymaic, Grantha, Gunjala Ggondi, Hanifi Rohingya,
 Hanunoo, Javanese, Kaithi, Kayah li, Kharoshthi, Khojki,
</td></tr>
	<tr><td align="left">
Khudawadi, Lepcha, Limbu, Mahajani, Makasar, Mandaic, Manichaean,
 Marchen, Masaram Gondi, Medefaidrin, Meetei Mayek, Miao, Modi,
</td></tr>
	<tr><td align="left">
Mongolian, Multani, Nandinagari, Newa, Nko, Nyiakeng Puachue Hmong,
 Old Sogdian, Pahawh Hmong, Phags Pa, Psalter Pahlavi, Rejang,
</td></tr>
	<tr><td align="left">
Saurashtra, Sharada, Siddham, Sogdian, Soyombo, Sundanese,
 Syloti Nagri, Tagalog, Tagbanwa, Tai Le, Tai Tham, Tai Viet,
</td></tr>
	<tr><td align="left">
Takri, Tibetan, Tifinagh, Tirhuta, Wancho, Zanabazar square,
</td></tr>

</table>>]


	footnote[fontname="Verdana",label=<<table border="0" cellborder="0" cellspacing="0">
		<tr><td align="left">† Feature is scoped to each syllable</td></tr>
		<tr><td align="left">‡ All topographic features are scoped based on topographic position</td></tr>
		</table>>];
	notes3->footnote[style=invis];

}