diff options
Diffstat (limited to 'src/luaotfload-auxiliary.lua')
| -rw-r--r-- | src/luaotfload-auxiliary.lua | 94 |
1 files changed, 63 insertions, 31 deletions
diff --git a/src/luaotfload-auxiliary.lua b/src/luaotfload-auxiliary.lua index 347d9f8..22f8201 100644 --- a/src/luaotfload-auxiliary.lua +++ b/src/luaotfload-auxiliary.lua @@ -177,40 +177,72 @@ Comment from fontspec: --doc]]-- +local capheight_reference_char = stringbyte "X" -- might be ‘M’, ‘Ж’, or ‘ξ’. + +local determine_capheight = function (fontdata) + local parameters = fontdata.parameters if not parameters then return false end + local characters = fontdata.characters if not characters then return false end + local refchar = characters [capheight_reference_char] + if refchar then + return refchar.height + end + return false +end + +local query_ascender = function (fontdata) + local parameters = fontdata.parameters if not parameters then return false end + local metadata = fontdata.metadata if not metadata then return false end + local ascender = metadata.ascender if not ascender then return false end + local units = metadata.units if units == 0 then return false end + local size = parameters.size if not size then return false end + return ascender * size / units +end + +local query_capheight = function (fontdata) + local parameters = fontdata.parameters if not parameters then return false end + local metadata = fontdata.metadata if not metadata then return false end + local capheight = metadata.capheight if not capheight then return false end + local units = metadata.units if units == 0 then return false end + local size = parameters.size if not size then return false end + return capheight * size / units +end + +local query_fontdimen8 = function (fontdata) + local parameters = fontdata.parameters if not parameters then return false end + local fontdimen8 = parameters [8] + if fontdimen8 then return fontdimen8 end + return false +end + +local caphtfmt = function (ref, ht) + if not ht then return "<none>" end + if not ref then return tostring (ht) end + return stringformat ("%s(δ=%s)", ht, ht - ref) +end + local set_capheight = function (fontdata) - local shared = fontdata.shared - local parameters = fontdata.parameters - local capheight - if shared - and shared.rawdata.metadata - and shared.rawdata.metadata.pfminfo - then - local units_per_em = parameters.units - local size = parameters.size - local os2_capheight = shared.rawdata.metadata.pfminfo.os2_capheight - - if capheight and os2_capheight > 0 then - capheight = os2_capheight / units_per_em * size - else - local X8_str = stringbyte"X" - local X8_chr = fontdata.characters[X8_str] - if X8_chr then - capheight = X8_chr.height - else - capheight = parameters.ascender / units_per_em * size - end - end - else - local X8_str = stringbyte "X" - local X8_chr = fontdata.characters[X8_str] - if X8_chr then - capheight = X8_chr.height - end + if not fontdata then + logreport ("both", 0, "aux", + "error: set_capheight() received garbage") + return end + local capheight_dimen8 = query_fontdimen8 (fontdata) + local capheight_alleged = query_capheight (fontdata) + local capheight_ascender = query_ascender (fontdata) + local capheight_measured = determine_capheight (fontdata) + logreport ("term", 4, "aux", + "capht: param[8]=%s advertised=%s ascender=%s measured=%s", + tostring (capheight_dimen8), + caphtfmt (capheight_dimen8, capheight_alleged), + caphtfmt (capheight_dimen8, capheight_ascender), + caphtfmt (capheight_dimen8, capheight_measured)) + if capheight_dimen8 then --- nothing to do + return + end + + local capheight = capheight_alleged or capheight_ascender or capheight_measured if capheight then - --- is this legit? afaics there’s nothing else on the - --- array part of that table - fontdata.parameters[8] = capheight + fontdata.parameters [8] = capheight end end |