summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--src/luaotfload-auxiliary.lua94
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