Populate MathConstants table

A temporary fix.

2 files changed, 50 insertions, 7 deletions

diff --git a/luaotfload.dtx b/luaotfload.dtx
index 12aae2a..0918a4b 100644
--- a/luaotfload.dtx
+++ b/luaotfload.dtx
@@ -556,9 +556,18 @@ luaotfload.loadmodule('font-clr.lua')
 
 %    \end{macrocode}
 %
-% \subsection{Emulating font dimensions}
+% \subsection{Post-processing TFM table}
 %
-% And here add some code to emulate \XeTeX's \cs{fontdimen8},
+% Here we do some final touches to the loaded TFM table before passing it
+% to the \TeX\ end.
+%
+%    \begin{macrocode}
+local function def_font(...)
+    local fontdata = fonts.define.read(...)
+    if type(fontdata) == "table" and fontdata.shared then
+%    \end{macrocode}
+%
+% First, we add some code to emulate \XeTeX's \cs{fontdimen8},
 % which stores the caps-height of the font. (Cf.\ \cs{fontdimen5} which
 % stores the x-height.)
 %
@@ -567,24 +576,38 @@ luaotfload.loadmodule('font-clr.lua')
 % This needs to be extended for fonts that don't contain an `X'.
 %
 %    \begin{macrocode}
-local function def_font(...)
-    local fontdata = fonts.define.read(...)
-    if type(fontdata) == "table" and fontdata.shared then
         local capheight
         local units     = fontdata.units
         local size      = fontdata.size
         local otfdata   = fontdata.shared.otfdata
 
         if otfdata.pfminfo.os2_capheight > 0 then
-            capheight = otfdata.pfminfo.os2_capheight/units*size
+            capheight = otfdata.pfminfo.os2_capheight / units * size
         else
             if fontdata.characters[string.byte("X")] then
                 capheight = fontdata.characters[string.byte("X")].height
             else
-                capheight = otfdata.metadata.ascent/units*size
+                capheight = otfdata.metadata.ascent / units * size
             end
         end
         fontdata.parameters[8] = capheight
+%    \end{macrocode}
+%
+% Then we populate \texttt{MathConstants} table, which is required for
+% OpenType math.
+%
+%    \begin{macrocode}
+        if otfdata.metadata.math then
+            for k,v in next, otfdata.metadata.math do
+                if k == "RadicalDegreeBottomRaisePercent" then
+                    -- this is a percent
+                    fontdata.MathConstants[k] = v
+                else
+                    fontdata.MathConstants[k] = v / units * size
+                end
+            end
+        end
+
     end
     return fontdata
 end
diff --git a/tests/math.tex b/tests/math.tex
new file mode 100644
index 0000000..6157fd5
--- /dev/null
+++ b/tests/math.tex
@@ -0,0 +1,20 @@
+% start out with plain.tex,
+% having TFM-based CM fonts preloaded in \fam 0...3
+
+% load OT math font in \fam 4
+\input luaotfload.sty
+\font\4={name:XITS Math:mode=base;script=math} at 10pt
+\font\5={name:XITS Math:mode=base;script=math;+ssty=0} at 7pt
+\font\6={name:XITS Math:mode=node;script=math;+ssty=1} at 5pt
+\textfont4=\4 \scriptfont4=\5 \scriptscriptfont4=\6
+
+% set up macros to use math font in \fam 4, just enough for this test
+\def\x{\Umathchar"7 "4 "1D465 }
+\def\y{\Umathchar"7 "4 "1D465 }
+\def\3{\Umathchar"7 "4 "0033 }
+
+%\tracingall
+$$\Uradical "4 "221A {\x}$$
+$$\Uroot    "4 "221A {\3}{\x^\3+\y^\3}$$
+\bye
+