From 9a1b9756939e12e328dea3633d9fe3cbde8f154b Mon Sep 17 00:00:00 2001
From: Hans Hagen <pragma@wxs.nl>
Date: Wed, 8 Apr 2020 15:36:51 +0200
Subject: 2020-04-08 14:37:00

---
 .../sources/general/manuals/luatex/luatex-fonts.tex | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

(limited to 'doc/context/sources/general/manuals/luatex/luatex-fonts.tex')

diff --git a/doc/context/sources/general/manuals/luatex/luatex-fonts.tex b/doc/context/sources/general/manuals/luatex/luatex-fonts.tex
index 400550a96..e944b2c5b 100644
--- a/doc/context/sources/general/manuals/luatex/luatex-fonts.tex
+++ b/doc/context/sources/general/manuals/luatex/luatex-fonts.tex
@@ -861,6 +861,27 @@ value is the index in \type {font.fonts}, the second the font itself, as a \LUA\
 table. The indices are listed incrementally, but they do not always form an array
 of consecutive numbers: in some cases there can be holes in the sequence.
 
+\startsubsection[title={\type{\glyphdimensionsmode}}]
+
+Already in the early days of \LUATEX\ the decision was made to calculate the
+effective height and depth of glyphs in a way that reflected the applied vertical
+offset. The height got that offset added, the depth only when the offset was
+larger than zero. We can now control this in more detail with this mode
+parameter. An offset is added to the height and|/|or subtracted from the depth.
+The effective values are never negative. The zero mode is the default.
+
+\starttabulate[|l|pl|]
+\DB value     \BC effect \NC\NR
+\TB
+\NC \type {0} \NC the old behavior: add the offset to the height and only subtract
+                  the offset only from the depth when it is positive \NC \NR
+\NC \type {1} \NC add the offset to the height and subtract it from the depth \NC \NR
+\NC \type {2} \NC add the offset to the height and subtract it from the depth but
+                  keep the maxima of the current and previous results \NC \NR
+\NC \type {3} \NC use the height and depth of the glyph, so no offset is applied \NC \NR
+\LL
+\stoptabulate
+
 \stopsection
 
 \stopchapter
-- 
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