diff options
Diffstat (limited to 'src/luaotfload-database.lua')
| -rw-r--r-- | src/luaotfload-database.lua | 85 |
1 files changed, 66 insertions, 19 deletions
diff --git a/src/luaotfload-database.lua b/src/luaotfload-database.lua index 5e4fd7a..950d126 100644 --- a/src/luaotfload-database.lua +++ b/src/luaotfload-database.lua @@ -928,7 +928,7 @@ local choose_size = function (sizes, askedsize) --- exact match, this is what we were looking for exact = index goto skip - elseif askedsize < low then + elseif askedsize <= low then --- below range, add to the norange table local d = low - askedsize norange [#norange + 1] = { d, index } @@ -938,10 +938,19 @@ local choose_size = function (sizes, askedsize) norange [#norange + 1] = { d, index } else --- range match - local d = ((low + high) / 2) - askedsize + local d = 0 + + -- should always be true. Just in case there's some + -- weried fonts out there + if dsnsize > low and dsnsize < high then + d = dsnsize - askedsize + else + d = ((low + high) / 2) - askedsize + end if d < 0 then d = -d end + inrange [#inrange + 1] = { d, index } end end @@ -1042,26 +1051,54 @@ local lookup_fontname = function (specification, name, style) return nil, nil end -local design_size_dimension -local set_size_dimension +local design_size_dimension --- scale asked size if not using bp +local set_size_dimension --- called from config do - --- cf. TeXbook p. 57 + --- cf. TeXbook p. 57; the index stores sizes pre-scaled from bp to + --- sp. This allows requesting sizes we got from the TeX end + --- without further conversion. For the other options *pt* and *dd* + --- we scale the requested size as though the value in the font was + --- specified in the requested unit. + + --- From @zhouyan: + + --- Let P be the asked size in pt, and Aᵤ = CᵤP, where u is the + --- designed unit, pt, bp, or dd, and + --- + --- Cpt = 1, Cbp = 7200/7227, Cdd = 1157/1238. + --- + --- That is, Aᵤ is the asked size in the desired unit. Let D be the + --- de-sign size (assumed to be in the unit of bp) as reported by + --- the font (divided by 10; in all the following we ignore the + --- factor 2^16 ). + --- + --- For simplicity, consider only the case of exact match to the + --- design size. That is, we would like to have Aᵤ = D. Let A′ᵤ = αᵤP + --- and D′ = βD be the scaled values used in comparisons. For the + --- comparison to work correctly, we need, + --- + --- Aᵤ = D ⟺ A′ᵤ = D′ , + --- + --- and thus αᵤ = βCᵤ. The fix in PR 400 is the case of β = 1. The + --- fix for review is β = 7227/7200, and the value of αᵤ is thus + --- correct for pt, bp, but not for dd. + local dimens = { - pt = function (v) return v end, - bp = function (v) return (v * 7227) / 7200 end, - dd = function (v) return (v * 1238) / 1157 end, + bp = false, + pt = 7227 / 7200, + dd = (7227 / 7200) * (1157 / 1238), } design_size_dimension = dimens.bp set_size_dimension = function (dim) - local f = dimens [dim] - if f then + local conv = dimens [dim] + if conv ~= nil then logreport ("both", 4, "db", "Interpreting design sizes as %q, factor %.6f.", - dim, f (1.000000)) - design_size_dimension = f + dim, conv) + design_size_dimension = conv return end logreport ("both", 0, "db", @@ -1135,7 +1172,10 @@ lookup_font_name = function (specification) askedsize = 0 end end - askedsize = design_size_dimension (askedsize) + + if design_size_dimension ~= false then + askedsize = design_size_dimension * askedsize + end resolved, subfont = lookup_familyname (specification, name, @@ -1350,9 +1390,16 @@ local load_font_file = function (filename, subfont) return ret end +--- Design sizes in the fonts are specified in decipoints. For the +--- index these values are prescaled to sp which is what we’re dealing +--- with at the TeX end. + local get_size_info do --- too many upvalues :/ --- rawdata -> (int * int * int | bool) + local sp = 2^16 -- pt + local bp = 7227 / 7200 -- pt + get_size_info = function (rawinfo) local design_size = rawinfo.design_size local design_range_top = rawinfo.design_range_top @@ -1363,13 +1410,13 @@ local get_size_info do --- too many upvalues :/ or design_range_top ~= 0 and design_range_top if fallback_size then - design_size = ((design_size or fallback_size) * 2^16) / 10 - design_range_top = ((design_range_top or fallback_size) * 2^16) / 10 - design_range_bottom = ((design_range_bottom or fallback_size) * 2^16) / 10 + design_size = ((design_size or fallback_size) * sp) / 10 + design_range_top = ((design_range_top or fallback_size) * sp) / 10 + design_range_bottom = ((design_range_bottom or fallback_size) * sp) / 10 - design_size = (design_size * 7227) / 7200 - design_range_top = (design_range_top * 7227) / 7200 - design_range_bottom = (design_range_bottom * 7227) / 7200 + design_size = design_size * bp + design_range_top = design_range_top * bp + design_range_bottom = design_range_bottom * bp return { design_size, design_range_top, design_range_bottom, |