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diff --git a/Master/texmf-dist/doc/luatex/base/luatex-fontloader.tex b/Master/texmf-dist/doc/luatex/base/luatex-fontloader.tex new file mode 100644 index 00000000000..91f1ac69769 --- /dev/null +++ b/Master/texmf-dist/doc/luatex/base/luatex-fontloader.tex @@ -0,0 +1,1066 @@ +% language=uk + +\environment luatex-style +\environment luatex-logos + +\startcomponent luatex-fontloader + +\startchapter[reference=fontloader,title={The fontloader}] + +The fontloader library is sort of independent of the rest in the sense that it +can load font into a \LUA\ table that then can be converted into a table suitable +for \TEX. The library is an adapted subset of \FONTFORGE\ and as such gives a +similar view on a font (which has advantages when you want to debug.) + +\section{Getting quick information on a font} + +When you want to locate font by name you need some basic information that is +hidden in the font files. For that reason we provide an efficient helper that +gets the basic information without loading all of the font. Normally this helper +is used to create a font (name) database. + +\startfunctioncall +<table> info = + fontloader.info(<string> filename) +\stopfunctioncall + +This function returns either \type {nil}, or a \type {table}, or an array of +small tables (in the case of a \TRUETYPE\ collection). The returned table(s) will +contain some fairly interesting information items from the font(s) defined by the +file: + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC fontname \NC string \NC the \POSTSCRIPT\ name of the font\NC \NR +\NC fullname \NC string \NC the formal name of the font\NC \NR +\NC familyname \NC string \NC the family name this font belongs to\NC \NR +\NC weight \NC string \NC a string indicating the color value of the font\NC \NR +\NC version \NC string \NC the internal font version\NC \NR +\NC italicangle \NC float \NC the slant angle\NC \NR +\NC units_per_em \NC number \NC 1000 for \POSTSCRIPT-based fonts, usually 2048 for \TRUETYPE\NC \NR +\NC pfminfo \NC table \NC (see \in{section}[fontloaderpfminfotable])\NC \NR +\stoptabulate + +Getting information through this function is (sometimes much) more efficient than +loading the font properly, and is therefore handy when you want to create a +dictionary of available fonts based on a directory contents. + +\section{Loading an \OPENTYPE\ or \TRUETYPE\ file} + +If you want to use an \OPENTYPE\ font, you have to get the metric information +from somewhere. Using the \type {fontloader} library, the simplest way to get +that information is thus: + +\starttyping +function load_font (filename) + local metrics = nil + local font = fontloader.open(filename) + if font then + metrics = fontloader.to_table(font) + fontloader.close(font) + end + return metrics +end + +myfont = load_font('/opt/tex/texmf/fonts/data/arial.ttf') +\stoptyping + +The main function call is + +\startfunctioncall +<userdata> f, <table> w = fontloader.open(<string> filename) +<userdata> f, <table> w = fontloader.open(<string> filename, <string> fontname) +\stopfunctioncall + +The first return value is a userdata representation of the font. The second +return value is a table containing any warnings and errors reported by fontloader +while opening the font. In normal typesetting, you would probably ignore the +second argument, but it can be useful for debugging purposes. + +For \TRUETYPE\ collections (when filename ends in 'ttc') and \DFONT\ collections, +you have to use a second string argument to specify which font you want from the +collection. Use the \type {fontname} strings that are returned by \type +{fontloader.info} for that. + +To turn the font into a table, \type {fontloader.to_table} is used on the font +returned by \type {fontloader.open}. + +\startfunctioncall +<table> f = fontloader.to_table(<userdata> font) +\stopfunctioncall + +This table cannot be used directly by \LUATEX\ and should be turned into another +one as described in~\in {chapter} [fonts]. Do not forget to store the \type +{fontname} value in the \type {psname} field of the metrics table to be returned +to \LUATEX, otherwise the font inclusion backend will not be able to find the +correct font in the collection. + +See \in {section} [fontloadertables] for details on the userdata object returned +by \type {fontloader.open()} and the layout of the \type {metrics} table returned +by \type {fontloader.to_table()}. + +The font file is parsed and partially interpreted by the font loading routines +from \FONTFORGE. The file format can be \OPENTYPE, \TRUETYPE, \TRUETYPE\ +Collection, \CFF, or \TYPEONE. + +There are a few advantages to this approach compared to reading the actual font +file ourselves: + +\startitemize + +\startitem + The font is automatically re|-|encoded, so that the \type {metrics} table for + \TRUETYPE\ and \OPENTYPE\ fonts is using \UNICODE\ for the character indices. +\stopitem + +\startitem + Many features are pre|-|processed into a format that is easier to handle than + just the bare tables would be. +\stopitem + +\startitem + \POSTSCRIPT|-|based \OPENTYPE\ fonts do not store the character height and + depth in the font file, so the character boundingbox has to be calculated in + some way. +\stopitem + +\startitem + In the future, it may be interesting to allow \LUA\ scripts access to + the font program itself, perhaps even creating or changing the font. +\stopitem + +\stopitemize + +A loaded font is discarded with: + +\startfunctioncall +fontloader.close(<userdata> font) +\stopfunctioncall + +\section{Applying a \quote{feature file}} + +You can apply a \quote{feature file} to a loaded font: + +\startfunctioncall +<table> errors = fontloader.apply_featurefile(<userdata> font, <string> filename) +\stopfunctioncall + +A \quote {feature file} is a textual representation of the features in an +\OPENTYPE\ font. See + +\starttyping +http://www.adobe.com/devnet/opentype/afdko/topic_feature_file_syntax.html +\stoptyping + +and + +\starttyping +http://fontforge.sourceforge.net/featurefile.html +\stoptyping + +for a more detailed description of feature files. + +If the function fails, the return value is a table containing any errors reported +by fontloader while applying the feature file. On success, \type {nil} is +returned. + +\section{Applying an \quote{\AFM\ file}} + +You can apply an \quote {\AFM\ file} to a loaded font: + +\startfunctioncall +<table> errors = fontloader.apply_afmfile(<userdata> font, <string> filename) +\stopfunctioncall + +An \AFM\ file is a textual representation of (some of) the meta information +in a \TYPEONE\ font. See + +\starttyping +ftp://ftp.math.utah.edu/u/ma/hohn/linux/postscript/5004.AFM_Spec.pdf +\stoptyping + +for more information about \AFM\ files. + +Note: If you \type {fontloader.open()} a \TYPEONE\ file named \type {font.pfb}, +the library will automatically search for and apply \type {font.afm} if it exists +in the same directory as the file \type {font.pfb}. In that case, there is no +need for an explicit call to \type {apply_afmfile()}. + +If the function fails, the return value is a table containing any errors reported +by fontloader while applying the AFM file. On success, \type {nil} is returned. + +\section[fontloadertables]{Fontloader font tables} + +As mentioned earlier, the return value of \type {fontloader.open()} is a userdata +object. One way to have access to the actual metrics is to call \type +{fontloader.to_table()} on this object, returning the table structure that is +explained in the following sections. In teh following sections we will not +explain each field in detail. Most fields are self descriptive and for the more +technical aspects you need to consult the relevant font references. + +It turns out that the result from \type {fontloader.to_table()} sometimes needs +very large amounts of memory (depending on the font's complexity and size) so it +is possible to access the userdata object directly. + +\startitemize +\startitem + All top|-|level keys that would be returned by \type {to_table()} + can also be accessed directly. +\stopitem +\startitem + The top|-|level key \quote {glyphs} returns a {\it virtual\/} array that + allows indices from \type {f.glyphmin} to (\type {f.glyphmax}). +\stopitem +\startitem + The items in that virtual array (the actual glyphs) are themselves also + userdata objects, and each has accessors for all of the keys explained in the + section \quote {Glyph items} below. +\stopitem +\startitem + The top|-|level key \quote {subfonts} returns an {\it actual} array of userdata + objects, one for each of the subfonts (or nil, if there are no subfonts). +\stopitem +\stopitemize + +A short example may be helpful. This code generates a printout of all +the glyph names in the font \type {PunkNova.kern.otf}: + +\starttyping +local f = fontloader.open('PunkNova.kern.otf') +print (f.fontname) +local i = 0 +if f.glyphcnt > 0 then + for i=f.glyphmin,f.glyphmax do + local g = f.glyphs[i] + if g then + print(g.name) + end + i = i + 1 + end +end +fontloader.close(f) +\stoptyping + +In this case, the \LUATEX\ memory requirement stays below 100MB on the test +computer, while the internal structure generated by \type {to_table()} needs more +than 2GB of memory (the font itself is 6.9MB in disk size). + +Only the top|-|level font, the subfont table entries, and the glyphs are virtual +objects, everything else still produces normal \LUA\ values and tables. + +If you want to know the valid fields in a font or glyph structure, call the \type +{fields} function on an object of a particular type (either glyph or font): + +\startfunctioncall +<table> fields = fontloader.fields(<userdata> font) +<table> fields = fontloader.fields(<userdata> font_glyph) +\stopfunctioncall + +For instance: + +\startfunctioncall +local fields = fontloader.fields(f) +local fields = fontloader.fields(f.glyphs[0]) +\stopfunctioncall + +\subsection{Table types} + +\subsubsection{Top-level} + +The top|-|level keys in the returned table are (the explanations in this part of +the documentation are not yet finished): + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC table_version \NC number \NC indicates the metrics version (currently~0.3)\NC \NR +\NC fontname \NC string \NC \POSTSCRIPT\ font name\NC \NR +\NC fullname \NC string \NC official (human-oriented) font name\NC \NR +\NC familyname \NC string \NC family name\NC \NR +\NC weight \NC string \NC weight indicator\NC \NR +\NC copyright \NC string \NC copyright information\NC \NR +\NC filename \NC string \NC the file name\NC \NR +\NC version \NC string \NC font version\NC \NR +\NC italicangle \NC float \NC slant angle\NC \NR +\NC units_per_em \NC number \NC 1000 for \POSTSCRIPT-based fonts, usually 2048 for \TRUETYPE\NC \NR +\NC ascent \NC number \NC height of ascender in \type {units_per_em}\NC \NR +\NC descent \NC number \NC depth of descender in \type {units_per_em}\NC \NR +\NC upos \NC float \NC \NC \NR +\NC uwidth \NC float \NC \NC \NR +\NC uniqueid \NC number \NC \NC \NR +\NC glyphs \NC array \NC \NC \NR +\NC glyphcnt \NC number \NC number of included glyphs\NC \NR +\NC glyphmax \NC number \NC maximum used index the glyphs array\NC \NR +\NC glyphmin \NC number \NC minimum used index the glyphs array\NC \NR +\NC notdef_loc \NC number \NC location of the \type {.notdef} glyph + or \type {-1} when not present \NC \NR +\NC hasvmetrics \NC number \NC \NC \NR +\NC onlybitmaps \NC number \NC \NC \NR +\NC serifcheck \NC number \NC \NC \NR +\NC isserif \NC number \NC \NC \NR +\NC issans \NC number \NC \NC \NR +\NC encodingchanged \NC number \NC \NC \NR +\NC strokedfont \NC number \NC \NC \NR +\NC use_typo_metrics \NC number \NC \NC \NR +\NC weight_width_slope_only \NC number \NC \NC \NR +\NC head_optimized_for_cleartype \NC number \NC \NC \NR +\NC uni_interp \NC enum \NC \type {unset}, \type {none}, \type {adobe}, + \type {greek}, \type {japanese}, \type {trad_chinese}, + \type {simp_chinese}, \type {korean}, \type {ams}\NC \NR +\NC origname \NC string \NC the file name, as supplied by the user\NC \NR +\NC map \NC table \NC \NC \NR +\NC private \NC table \NC \NC \NR +\NC xuid \NC string \NC \NC \NR +\NC pfminfo \NC table \NC \NC \NR +\NC names \NC table \NC \NC \NR +\NC cidinfo \NC table \NC \NC \NR +\NC subfonts \NC array \NC \NC \NR +\NC commments \NC string \NC \NC \NR +\NC fontlog \NC string \NC \NC \NR +\NC cvt_names \NC string \NC \NC \NR +\NC anchor_classes \NC table \NC \NC \NR +\NC ttf_tables \NC table \NC \NC \NR +\NC ttf_tab_saved \NC table \NC \NC \NR +\NC kerns \NC table \NC \NC \NR +\NC vkerns \NC table \NC \NC \NR +\NC texdata \NC table \NC \NC \NR +\NC lookups \NC table \NC \NC \NR +\NC gpos \NC table \NC \NC \NR +\NC gsub \NC table \NC \NC \NR +\NC mm \NC table \NC \NC \NR +\NC chosenname \NC string \NC \NC \NR +\NC macstyle \NC number \NC \NC \NR +\NC fondname \NC string \NC \NC \NR +%NC design_size \NC number \NC \NC \NR +\NC fontstyle_id \NC number \NC \NC \NR +\NC fontstyle_name \NC table \NC \NC \NR +%NC design_range_bottom \NC number \NC \NC \NR +%NC design_range_top \NC number \NC \NC \NR +\NC strokewidth \NC float \NC \NC \NR +\NC mark_classes \NC table \NC \NC \NR +\NC creationtime \NC number \NC \NC \NR +\NC modificationtime \NC number \NC \NC \NR +\NC os2_version \NC number \NC \NC \NR +\NC sfd_version \NC number \NC \NC \NR +\NC math \NC table \NC \NC \NR +\NC validation_state \NC table \NC \NC \NR +\NC horiz_base \NC table \NC \NC \NR +\NC vert_base \NC table \NC \NC \NR +\NC extrema_bound \NC number \NC \NC \NR +\NC truetype \NC boolean \NC signals a \TRUETYPE\ font \NC \NR +\stoptabulate + +\subsubsection{Glyph items} + +The \type {glyphs} is an array containing the per|-|character +information (quite a few of these are only present if nonzero). + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC name \NC string \NC the glyph name \NC \NR +\NC unicode \NC number \NC unicode code point, or -1 \NC \NR +\NC boundingbox \NC array \NC array of four numbers, see note below \NC \NR +\NC width \NC number \NC only for horizontal fonts \NC \NR +\NC vwidth \NC number \NC only for vertical fonts \NC \NR +\NC tsidebearing \NC number \NC only for vertical ttf/otf fonts, and only if nonzero \NC \NR +\NC lsidebearing \NC number \NC only if nonzero and not equal to boundingbox[1] \NC \NR +\NC class \NC string \NC one of "none", "base", "ligature", "mark", "component" + (if not present, the glyph class is \quote {automatic}) \NC \NR +\NC kerns \NC array \NC only for horizontal fonts, if set \NC \NR +\NC vkerns \NC array \NC only for vertical fonts, if set \NC \NR +\NC dependents \NC array \NC linear array of glyph name strings, only if nonempty\NC \NR +\NC lookups \NC table \NC only if nonempty \NC \NR +\NC ligatures \NC table \NC only if nonempty \NC \NR +\NC anchors \NC table \NC only if set \NC \NR +\NC comment \NC string \NC only if set \NC \NR +\NC tex_height \NC number \NC only if set \NC \NR +\NC tex_depth \NC number \NC only if set \NC \NR +\NC italic_correction \NC number \NC only if set \NC \NR +\NC top_accent \NC number \NC only if set \NC \NR +\NC is_extended_shape \NC number \NC only if this character is part of a math extension list \NC \NR +\NC altuni \NC table \NC alternate \UNICODE\ items \NC \NR +\NC vert_variants \NC table \NC \NC \NR +\NC horiz_variants \NC table \NC \NC \NR +\NC mathkern \NC table \NC \NC \NR +\stoptabulate + +On \type {boundingbox}: The boundingbox information for \TRUETYPE\ fonts and +\TRUETYPE-based \OTF\ fonts is read directly from the font file. +\POSTSCRIPT-based fonts do not have this information, so the boundingbox of +traditional \POSTSCRIPT\ fonts is generated by interpreting the actual bezier +curves to find the exact boundingbox. This can be a slow process, so the +boundingboxes of \POSTSCRIPT-based \OTF\ fonts (and raw \CFF\ fonts) are +calculated using an approximation of the glyph shape based on the actual glyph +points only, instead of taking the whole curve into account. This means that +glyphs that have missing points at extrema will have a too|-|tight boundingbox, +but the processing is so much faster that in our opinion the tradeoff is worth +it. + +The \type {kerns} and \type {vkerns} are linear arrays of small hashes: + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC char \NC string \NC \NC \NR +\NC off \NC number \NC \NC \NR +\NC lookup \NC string \NC \NC \NR +\stoptabulate + +The \type {lookups} is a hash, based on lookup subtable names, with +the value of each key inside that a linear array of small hashes: + +% TODO: fix this description +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC type \NC enum \NC \type {position}, \type {pair}, \type + {substitution}, \type {alternate}, \type + {multiple}, \type {ligature}, \type {lcaret}, + \type {kerning}, \type {vkerning}, \type + {anchors}, \type {contextpos}, \type + {contextsub}, \type {chainpos}, \type + {chainsub}, \type {reversesub}, \type {max}, + \type {kernback}, \type {vkernback} \NC \NR +\NC specification \NC table \NC extra data \NC \NR +\stoptabulate + +For the first seven values of \type {type}, there can be additional +sub|-|information, stored in the sub-table \type {specification}: + +\starttabulate[|lT|l|p|] +\NC \rmbf value \NC \bf type \NC \bf explanation \NC \NR +\NC position \NC table \NC a table of the \type {offset_specs} type \NC \NR +\NC pair \NC table \NC one string: \type {paired}, and an array of one + or two \type {offset_specs} tables: \type + {offsets} \NC \NR +\NC substitution \NC table \NC one string: \type {variant} \NC \NR +\NC alternate \NC table \NC one string: \type {components} \NC \NR +\NC multiple \NC table \NC one string: \type {components} \NC \NR +\NC ligature \NC table \NC two strings: \type {components}, \type {char} \NC \NR +\NC lcaret \NC array \NC linear array of numbers \NC \NR +\stoptabulate + +Tables for \type {offset_specs} contain up to four number|-|valued fields: \type +{x} (a horizontal offset), \type {y} (a vertical offset), \type {h} (an advance +width correction) and \type {v} (an advance height correction). + +The \type {ligatures} is a linear array of small hashes: + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC lig \NC table \NC uses the same substructure as a single item in + the \type {lookups} table explained above \NC \NR +\NC char \NC string \NC \NC \NR +\NC components \NC array \NC linear array of named components \NC \NR +\NC ccnt \NC number \NC \NC \NR +\stoptabulate + +The \type {anchor} table is indexed by a string signifying the anchor type, which +is one of + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC mark \NC table \NC placement mark \NC \NR +\NC basechar \NC table \NC mark for attaching combining items to a base char \NC \NR +\NC baselig \NC table \NC mark for attaching combining items to a ligature \NC \NR +\NC basemark \NC table \NC generic mark for attaching combining items to connect to \NC \NR +\NC centry \NC table \NC cursive entry point \NC \NR +\NC cexit \NC table \NC cursive exit point \NC \NR +\stoptabulate + +The content of these is a short array of defined anchors, with the +entry keys being the anchor names. For all except \type {baselig}, the +value is a single table with this definition: + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC x \NC number \NC x location \NC \NR +\NC y \NC number \NC y location \NC \NR +\NC ttf_pt_index \NC number \NC truetype point index, only if given \NC \NR +\stoptabulate + +For \type {baselig}, the value is a small array of such anchor sets sets, one for +each constituent item of the ligature. + +For clarification, an anchor table could for example look like this : + +\starttyping +['anchor'] = { + ['basemark'] = { + ['Anchor-7'] = { ['x']=170, ['y']=1080 } + }, + ['mark'] ={ + ['Anchor-1'] = { ['x']=160, ['y']=810 }, + ['Anchor-4'] = { ['x']=160, ['y']=800 } + }, + ['baselig'] = { + [1] = { ['Anchor-2'] = { ['x']=160, ['y']=650 } }, + [2] = { ['Anchor-2'] = { ['x']=460, ['y']=640 } } + } + } +\stoptyping + +Note: The \type {baselig} table can be sparse! + +\subsubsection{map table} + +The top|-|level map is a list of encoding mappings. Each of those is a table +itself. + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC enccount \NC number \NC \NC \NR +\NC encmax \NC number \NC \NC \NR +\NC backmax \NC number \NC \NC \NR +\NC remap \NC table \NC \NC \NR +\NC map \NC array \NC non|-|linear array of mappings\NC \NR +\NC backmap \NC array \NC non|-|linear array of backward mappings\NC \NR +\NC enc \NC table \NC \NC \NR +\stoptabulate + +The \type {remap} table is very small: + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC firstenc \NC number \NC \NC \NR +\NC lastenc \NC number \NC \NC \NR +\NC infont \NC number \NC \NC \NR +\stoptabulate + +The \type {enc} table is a bit more verbose: + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC enc_name \NC string \NC \NC \NR +\NC char_cnt \NC number \NC \NC \NR +\NC char_max \NC number \NC \NC \NR +\NC unicode \NC array \NC of \UNICODE\ position numbers\NC \NR +\NC psnames \NC array \NC of \POSTSCRIPT\ glyph names\NC \NR +\NC builtin \NC number \NC \NC \NR +\NC hidden \NC number \NC \NC \NR +\NC only_1byte \NC number \NC \NC \NR +\NC has_1byte \NC number \NC \NC \NR +\NC has_2byte \NC number \NC \NC \NR +\NC is_unicodebmp \NC number \NC only if nonzero\NC \NR +\NC is_unicodefull \NC number \NC only if nonzero\NC \NR +\NC is_custom \NC number \NC only if nonzero\NC \NR +\NC is_original \NC number \NC only if nonzero\NC \NR +\NC is_compact \NC number \NC only if nonzero\NC \NR +\NC is_japanese \NC number \NC only if nonzero\NC \NR +\NC is_korean \NC number \NC only if nonzero\NC \NR +\NC is_tradchinese \NC number \NC only if nonzero [name?]\NC \NR +\NC is_simplechinese \NC number \NC only if nonzero\NC \NR +\NC low_page \NC number \NC \NC \NR +\NC high_page \NC number \NC \NC \NR +\NC iconv_name \NC string \NC \NC \NR +\NC iso_2022_escape \NC string \NC \NC \NR +\stoptabulate + +\subsubsection{private table} + +This is the font's private \POSTSCRIPT\ dictionary, if any. Keys and values are +both strings. + +\subsubsection{cidinfo table} + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC registry \NC string \NC \NC \NR +\NC ordering \NC string \NC \NC \NR +\NC supplement \NC number \NC \NC \NR +\NC version \NC number \NC \NC \NR +\stoptabulate + +\subsubsection[fontloaderpfminfotable]{pfminfo table} + +The \type {pfminfo} table contains most of the OS/2 information: + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC pfmset \NC number \NC \NC \NR +\NC winascent_add \NC number \NC \NC \NR +\NC windescent_add \NC number \NC \NC \NR +\NC hheadascent_add \NC number \NC \NC \NR +\NC hheaddescent_add \NC number \NC \NC \NR +\NC typoascent_add \NC number \NC \NC \NR +\NC typodescent_add \NC number \NC \NC \NR +\NC subsuper_set \NC number \NC \NC \NR +\NC panose_set \NC number \NC \NC \NR +\NC hheadset \NC number \NC \NC \NR +\NC vheadset \NC number \NC \NC \NR +\NC pfmfamily \NC number \NC \NC \NR +\NC weight \NC number \NC \NC \NR +\NC width \NC number \NC \NC \NR +\NC avgwidth \NC number \NC \NC \NR +\NC firstchar \NC number \NC \NC \NR +\NC lastchar \NC number \NC \NC \NR +\NC fstype \NC number \NC \NC \NR +\NC linegap \NC number \NC \NC \NR +\NC vlinegap \NC number \NC \NC \NR +\NC hhead_ascent \NC number \NC \NC \NR +\NC hhead_descent \NC number \NC \NC \NR +\NC os2_typoascent \NC number \NC \NC \NR +\NC os2_typodescent \NC number \NC \NC \NR +\NC os2_typolinegap \NC number \NC \NC \NR +\NC os2_winascent \NC number \NC \NC \NR +\NC os2_windescent \NC number \NC \NC \NR +\NC os2_subxsize \NC number \NC \NC \NR +\NC os2_subysize \NC number \NC \NC \NR +\NC os2_subxoff \NC number \NC \NC \NR +\NC os2_subyoff \NC number \NC \NC \NR +\NC os2_supxsize \NC number \NC \NC \NR +\NC os2_supysize \NC number \NC \NC \NR +\NC os2_supxoff \NC number \NC \NC \NR +\NC os2_supyoff \NC number \NC \NC \NR +\NC os2_strikeysize \NC number \NC \NC \NR +\NC os2_strikeypos \NC number \NC \NC \NR +\NC os2_family_class \NC number \NC \NC \NR +\NC os2_xheight \NC number \NC \NC \NR +\NC os2_capheight \NC number \NC \NC \NR +\NC os2_defaultchar \NC number \NC \NC \NR +\NC os2_breakchar \NC number \NC \NC \NR +\NC os2_vendor \NC string \NC \NC \NR +\NC codepages \NC table \NC A two-number array of encoded code pages\NC \NR +\NC unicoderages \NC table \NC A four-number array of encoded unicode ranges\NC \NR +\NC panose \NC table \NC \NC \NR +\stoptabulate + +The \type {panose} subtable has exactly 10 string keys: + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC familytype \NC string \NC Values as in the \OPENTYPE\ font + specification: \type {Any}, \type {No Fit}, + \type {Text and Display}, \type {Script}, + \type {Decorative}, \type {Pictorial} \NC + \NR +\NC serifstyle \NC string \NC See the \OPENTYPE\ font specification for + values \NC \NR +\NC weight \NC string \NC id. \NC \NR +\NC proportion \NC string \NC id. \NC \NR +\NC contrast \NC string \NC id. \NC \NR +\NC strokevariation \NC string \NC id. \NC \NR +\NC armstyle \NC string \NC id. \NC \NR +\NC letterform \NC string \NC id. \NC \NR +\NC midline \NC string \NC id. \NC \NR +\NC xheight \NC string \NC id. \NC \NR +\stoptabulate + +\subsubsection[fontloadernamestable]{names table} + +Each item has two top|-|level keys: + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC lang \NC string \NC language for this entry \NC \NR +\NC names \NC table \NC \NC \NR +\stoptabulate + +The \type {names} keys are the actual \TRUETYPE\ name strings. The possible keys +are: + +\starttabulate[|lT|p|] +\NC \rmbf key \NC \bf explanation \NC \NR +\NC copyright \NC \NC \NR +\NC family \NC \NC \NR +\NC subfamily \NC \NC \NR +\NC uniqueid \NC \NC \NR +\NC fullname \NC \NC \NR +\NC version \NC \NC \NR +\NC postscriptname \NC \NC \NR +\NC trademark \NC \NC \NR +\NC manufacturer \NC \NC \NR +\NC designer \NC \NC \NR +\NC descriptor \NC \NC \NR +\NC venderurl \NC \NC \NR +\NC designerurl \NC \NC \NR +\NC license \NC \NC \NR +\NC licenseurl \NC \NC \NR +\NC idontknow \NC \NC \NR +\NC preffamilyname \NC \NC \NR +\NC prefmodifiers \NC \NC \NR +\NC compatfull \NC \NC \NR +\NC sampletext \NC \NC \NR +\NC cidfindfontname \NC \NC \NR +\NC wwsfamily \NC \NC \NR +\NC wwssubfamily \NC \NC \NR +\stoptabulate + +\subsubsection{anchor_classes table} + +The anchor_classes classes: + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC name \NC string \NC a descriptive id of this anchor class\NC \NR +\NC lookup \NC string \NC \NC \NR +\NC type \NC string \NC one of \type {mark}, \type {mkmk}, \type {curs}, \type {mklg} \NC \NR +\stoptabulate + +% type is actually a lookup subtype, not a feature name. Officially, these +% strings should be gpos_mark2mark etc. + +\subsubsection{gpos table} + +The \type {gpos} table has one array entry for each lookup. (The \type {gpos_} +prefix is somewhat redundant.) + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC type \NC string \NC one of \type {gpos_single}, \type {gpos_pair}, + \type {gpos_cursive}, \type {gpos_mark2base},\crlf + \type {gpos_mark2ligature}, \type + {gpos_mark2mark}, \type {gpos_context},\crlf \type + {gpos_contextchain} \NC \NR +\NC flags \NC table \NC \NC \NR +\NC name \NC string \NC \NC \NR +\NC features \NC array \NC \NC \NR +\NC subtables \NC array \NC \NC \NR +\stoptabulate + +The flags table has a true value for each of the lookup flags that is actually +set: + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC r2l \NC boolean \NC \NC \NR +\NC ignorebaseglyphs \NC boolean \NC \NC \NR +\NC ignoreligatures \NC boolean \NC \NC \NR +\NC ignorecombiningmarks \NC boolean \NC \NC \NR +\NC mark_class \NC string \NC \NC \NR +\stoptabulate + +The features subtable items of gpos have: + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC tag \NC string \NC \NC \NR +\NC scripts \NC table \NC \NC \NR +\stoptabulate + +The scripts table within features has: + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC script \NC string \NC \NC \NR +\NC langs \NC array of strings \NC \NC \NR +\stoptabulate + +The subtables table has: + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC name \NC string \NC \NC \NR +\NC suffix \NC string \NC (only if used)\NC \NR % used by gpos_single to get a default +\NC anchor_classes \NC number \NC (only if used)\NC \NR +\NC vertical_kerning \NC number \NC (only if used)\NC \NR +\NC kernclass \NC table \NC (only if used)\NC \NR +\stoptabulate + +The kernclass with subtables table has: + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC firsts \NC array of strings \NC \NC \NR +\NC seconds \NC array of strings \NC \NC \NR +\NC lookup \NC string or array \NC associated lookup(s) \NC \NR +\NC offsets \NC array of numbers \NC \NC \NR +\stoptabulate + +Note: the kernclass (as far as we can see) always has one entry so it could be one level +deep instead. Also the seconds start at \type {[2]} which is close to the fontforge +internals so we keep that too. + +\subsubsection{gsub table} + +This has identical layout to the \type {gpos} table, except for the +type: + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC type \NC string \NC one of \type {gsub_single}, \type {gsub_multiple}, + \type {gsub_alternate}, \type + {gsub_ligature},\crlf \type {gsub_context}, \type + {gsub_contextchain}, \type + {gsub_reversecontextchain} \NC \NR +\stoptabulate + +\subsubsection{ttf_tables and ttf_tab_saved tables} + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC tag \NC string \NC \NC \NR +\NC len \NC number \NC \NC \NR +\NC maxlen \NC number \NC \NC \NR +\NC data \NC number \NC \NC \NR +\stoptabulate + +\subsubsection{mm table} + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC axes \NC table \NC array of axis names \NC \NR +\NC instance_count \NC number \NC \NC \NR +\NC positions \NC table \NC array of instance positions + (\#axes * instances )\NC \NR +\NC defweights \NC table \NC array of default weights for instances \NC \NR +\NC cdv \NC string \NC \NC \NR +\NC ndv \NC string \NC \NC \NR +\NC axismaps \NC table \NC \NC \NR +\stoptabulate + +The \type {axismaps}: + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC blends \NC table \NC an array of blend points \NC \NR +\NC designs \NC table \NC an array of design values \NC \NR +\NC min \NC number \NC \NC \NR +\NC def \NC number \NC \NC \NR +\NC max \NC number \NC \NC \NR +\stoptabulate + +\subsubsection{mark_classes table} + +The keys in this table are mark class names, and the values are a +space|-|separated string of glyph names in this class. + +\subsubsection{math table} + +\starttabulate[|lT|p|] +\NC ScriptPercentScaleDown \NC \NC \NR +\NC ScriptScriptPercentScaleDown \NC \NC \NR +\NC DelimitedSubFormulaMinHeight \NC \NC \NR +\NC DisplayOperatorMinHeight \NC \NC \NR +\NC MathLeading \NC \NC \NR +\NC AxisHeight \NC \NC \NR +\NC AccentBaseHeight \NC \NC \NR +\NC FlattenedAccentBaseHeight \NC \NC \NR +\NC SubscriptShiftDown \NC \NC \NR +\NC SubscriptTopMax \NC \NC \NR +\NC SubscriptBaselineDropMin \NC \NC \NR +\NC SuperscriptShiftUp \NC \NC \NR +\NC SuperscriptShiftUpCramped \NC \NC \NR +\NC SuperscriptBottomMin \NC \NC \NR +\NC SuperscriptBaselineDropMax \NC \NC \NR +\NC SubSuperscriptGapMin \NC \NC \NR +\NC SuperscriptBottomMaxWithSubscript \NC \NC \NR +\NC SpaceAfterScript \NC \NC \NR +\NC UpperLimitGapMin \NC \NC \NR +\NC UpperLimitBaselineRiseMin \NC \NC \NR +\NC LowerLimitGapMin \NC \NC \NR +\NC LowerLimitBaselineDropMin \NC \NC \NR +\NC StackTopShiftUp \NC \NC \NR +\NC StackTopDisplayStyleShiftUp \NC \NC \NR +\NC StackBottomShiftDown \NC \NC \NR +\NC StackBottomDisplayStyleShiftDown \NC \NC \NR +\NC StackGapMin \NC \NC \NR +\NC StackDisplayStyleGapMin \NC \NC \NR +\NC StretchStackTopShiftUp \NC \NC \NR +\NC StretchStackBottomShiftDown \NC \NC \NR +\NC StretchStackGapAboveMin \NC \NC \NR +\NC StretchStackGapBelowMin \NC \NC \NR +\NC FractionNumeratorShiftUp \NC \NC \NR +\NC FractionNumeratorDisplayStyleShiftUp \NC \NC \NR +\NC FractionDenominatorShiftDown \NC \NC \NR +\NC FractionDenominatorDisplayStyleShiftDown \NC \NC \NR +\NC FractionNumeratorGapMin \NC \NC \NR +\NC FractionNumeratorDisplayStyleGapMin \NC \NC \NR +\NC FractionRuleThickness \NC \NC \NR +\NC FractionDenominatorGapMin \NC \NC \NR +\NC FractionDenominatorDisplayStyleGapMin \NC \NC \NR +\NC SkewedFractionHorizontalGap \NC \NC \NR +\NC SkewedFractionVerticalGap \NC \NC \NR +\NC OverbarVerticalGap \NC \NC \NR +\NC OverbarRuleThickness \NC \NC \NR +\NC OverbarExtraAscender \NC \NC \NR +\NC UnderbarVerticalGap \NC \NC \NR +\NC UnderbarRuleThickness \NC \NC \NR +\NC UnderbarExtraDescender \NC \NC \NR +\NC RadicalVerticalGap \NC \NC \NR +\NC RadicalDisplayStyleVerticalGap \NC \NC \NR +\NC RadicalRuleThickness \NC \NC \NR +\NC RadicalExtraAscender \NC \NC \NR +\NC RadicalKernBeforeDegree \NC \NC \NR +\NC RadicalKernAfterDegree \NC \NC \NR +\NC RadicalDegreeBottomRaisePercent \NC \NC \NR +\NC MinConnectorOverlap \NC \NC \NR +\NC FractionDelimiterSize \NC \NC \NR +\NC FractionDelimiterDisplayStyleSize \NC \NC \NR +\stoptabulate + +\subsubsection{validation_state table} + +\starttabulate[|lT|p|] +\NC \rmbf key \NC \bf explanation \NC \NR +\NC bad_ps_fontname \NC \NC \NR +\NC bad_glyph_table \NC \NC \NR +\NC bad_cff_table \NC \NC \NR +\NC bad_metrics_table \NC \NC \NR +\NC bad_cmap_table \NC \NC \NR +\NC bad_bitmaps_table \NC \NC \NR +\NC bad_gx_table \NC \NC \NR +\NC bad_ot_table \NC \NC \NR +\NC bad_os2_version \NC \NC \NR +\NC bad_sfnt_header \NC \NC \NR +\stoptabulate + +\subsubsection{horiz_base and vert_base table} + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC tags \NC table \NC an array of script list tags\NC \NR +\NC scripts \NC table \NC \NC \NR +\stoptabulate + +The \type {scripts} subtable: + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC baseline \NC table \NC \NC \NR +\NC default_baseline \NC number \NC \NC \NR +\NC lang \NC table \NC \NC \NR +\stoptabulate + + +The \type {lang} subtable: + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC tag \NC string \NC a script tag \NC \NR +\NC ascent \NC number \NC \NC \NR +\NC descent \NC number \NC \NC \NR +\NC features \NC table \NC \NC \NR +\stoptabulate + +The \type {features} points to an array of tables with the same layout except +that in those nested tables, the tag represents a language. + +\subsubsection{altuni table} + +An array of alternate \UNICODE\ values. Inside that array are hashes with: + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC unicode \NC number \NC this glyph is also used for this unicode \NC \NR +\NC variant \NC number \NC the alternative is driven by this unicode selector \NC \NR +\stoptabulate + +\subsubsection{vert_variants and horiz_variants table} + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC variants \NC string \NC \NC \NR +\NC italic_correction \NC number \NC \NC \NR +\NC parts \NC table \NC \NC \NR +\stoptabulate + +The \type {parts} table is an array of smaller tables: + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC component \NC string \NC \NC \NR +\NC extender \NC number \NC \NC \NR +\NC start \NC number \NC \NC \NR +\NC end \NC number \NC \NC \NR +\NC advance \NC number \NC \NC \NR +\stoptabulate + + +\subsubsection{mathkern table} + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC top_right \NC table \NC \NC \NR +\NC bottom_right \NC table \NC \NC \NR +\NC top_left \NC table \NC \NC \NR +\NC bottom_left \NC table \NC \NC \NR +\stoptabulate + +Each of the subtables is an array of small hashes with two keys: + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC height \NC number \NC \NC \NR +\NC kern \NC number \NC \NC \NR +\stoptabulate + +\subsubsection{kerns table} + +Substructure is identical to the per|-|glyph subtable. + +\subsubsection{vkerns table} + +Substructure is identical to the per|-|glyph subtable. + +\subsubsection{texdata table} + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC type \NC string \NC \type {unset}, \type {text}, \type {math}, \type {mathext} \NC \NR +\NC params \NC array \NC 22 font numeric parameters \NC \NR +\stoptabulate + +\subsubsection{lookups table} + +Top|-|level \type {lookups} is quite different from the ones at character level. +The keys in this hash are strings, the values the actual lookups, represented as +dictionary tables. + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC type \NC string \NC \NC \NR +\NC format \NC enum \NC one of \type {glyphs}, \type {class}, \type {coverage}, \type {reversecoverage} \NC \NR +\NC tag \NC string \NC \NC \NR +\NC current_class \NC array \NC \NC \NR +\NC before_class \NC array \NC \NC \NR +\NC after_class \NC array \NC \NC \NR +\NC rules \NC array \NC an array of rule items\NC \NR +\stoptabulate + +Rule items have one common item and one specialized item: + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC lookups \NC array \NC a linear array of lookup names\NC \NR +\NC glyphs \NC array \NC only if the parent's format is \type {glyphs}\NC \NR +\NC class \NC array \NC only if the parent's format is \type {class}\NC \NR +\NC coverage \NC array \NC only if the parent's format is \type {coverage}\NC \NR +\NC reversecoverage \NC array \NC only if the parent's format is \type {reversecoverage}\NC \NR +\stoptabulate + +A glyph table is: + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC names \NC string \NC \NC \NR +\NC back \NC string \NC \NC \NR +\NC fore \NC string \NC \NC \NR +\stoptabulate + +A class table is: + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC current \NC array \NC of numbers \NC \NR +\NC before \NC array \NC of numbers \NC \NR +\NC after \NC array \NC of numbers \NC \NR +\stoptabulate + +coverage: + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC current \NC array \NC of strings \NC \NR +\NC before \NC array \NC of strings\NC \NR +\NC after \NC array \NC of strings \NC \NR +\stoptabulate + +reversecoverage: + +\starttabulate[|lT|l|p|] +\NC \rmbf key \NC \bf type \NC \bf explanation \NC \NR +\NC current \NC array \NC of strings \NC \NR +\NC before \NC array \NC of strings\NC \NR +\NC after \NC array \NC of strings \NC \NR +\NC replacements \NC string \NC \NC \NR +\stoptabulate + +\stopcomponent |