From 5b773f9c6d94616316734a0070cae68ce6a67523 Mon Sep 17 00:00:00 2001
From: Philipp Gesang <phg42.2a@gmail.com>
Date: Sun, 14 Dec 2014 12:14:51 +0100
Subject: [letterspace] convert to node.direct
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This is an experiment: The character kerning callback has been converted
in its entirety to utilize the not-so-new direct node API. Since the
translation was mechanical only to a certain extent, this may have
introduced errors. On the other hand, the revised code resembles its
distant ancestor in Context’s ``typo-krn.lua`` much more closely again,
which may come in handy in the future.
---
src/luaotfload-letterspace.lua | 217 ++++++++++++++++++++++++-----------------
1 file changed, 127 insertions(+), 90 deletions(-)
diff --git a/src/luaotfload-letterspace.lua b/src/luaotfload-letterspace.lua
index f1fb234..8956f82 100644
--- a/src/luaotfload-letterspace.lua
+++ b/src/luaotfload-letterspace.lua
@@ -7,7 +7,7 @@ if not modules then modules = { } end modules ['letterspace'] = {
}
local log = luaotfload.log
-local report = log.report
+local logreport = log.report
local getmetatable = getmetatable
local require = require
@@ -17,14 +17,26 @@ local tonumber = tonumber
local next = next
local nodes, node, fonts = nodes, node, fonts
-local find_node_tail = node.tail or node.slide
-local free_node = node.free
-local copy_node = node.copy
-local new_node = node.new
-local insert_node_before = node.insert_before
-
-local nodepool = nodes.pool
-
+--- As of December 2014 the faster ``node.direct.*`` interface is
+--- preferred.
+local nodedirect = nodes.nuts
+local getchar = nodedirect.getchar
+local getfont = nodedirect.getfont
+local getid = nodedirect.getid
+local getnext = nodedirect.getnext
+local getprev = nodedirect.getprev
+local getfield = nodedirect.getfield
+local setfield = nodedirect.setfield
+local find_node_tail = nodedirect.tail
+local todirect = nodedirect.tonut
+local tonode = nodedirect.tonode
+
+local insert_node_before = nodedirect.insert_before
+local free_node = nodedirect.free
+local copy_node = nodedirect.copy
+local new_node = nodedirect.new
+
+local nodepool = nodedirect.pool
local new_kern = nodepool.kern
local new_glue = nodepool.glue
@@ -78,34 +90,24 @@ local userkern_code = kerncodes.userkern
--- node-res
-----------------------------------------------------------------------
-nodes.pool = nodes.pool or { }
-local pool = nodes.pool
-
-local kern = new_node ("kern", kerncodes.userkern)
local glue_spec = new_node "glue_spec"
-pool.kern = function (k)
- local n = copy_node (kern)
- n.kern = k
- return n
-end
-
-pool.glue = function (width, stretch, shrink,
- stretch_order, shrink_order)
- local n = new_node"glue"
+nodepool.glue = function (width, stretch, shrink,
+ stretch_order, shrink_order)
+ local n = new_node "glue"
if not width then
-- no spec
elseif width == false or tonumber(width) then
local s = copy_node(glue_spec)
- if width then s.width = width end
- if stretch then s.stretch = stretch end
- if shrink then s.shrink = shrink end
- if stretch_order then s.stretch_order = stretch_order end
- if shrink_order then s.shrink_order = shrink_order end
- n.spec = s
+ if width then setfield(s, "width" , width ) end
+ if stretch then setfield(s, "stretch" , stretch ) end
+ if shrink then setfield(s, "shrink" , shrink ) end
+ if stretch_order then setfield(s, "stretch_order", stretch_order) end
+ if shrink_order then setfield(s, "shrink_order" , shrink_order ) end
+ setfield(n, "spec", s)
else
-- shared
- n.spec = copy_node(width)
+ setfield(n, "spec", copy_node(width))
end
return n
end
@@ -187,13 +189,12 @@ end
local kern_injector = function (fillup, kern)
if fillup then
local g = new_glue(kern)
- local s = g.spec
- s.stretch = kern
- s.stretch_order = 1
+ local s = getfield(g, "spec")
+ setfield(s, "stretch", kern)
+ setfield(s, "stretch_order", 1)
return g
- else
- return new_kern(kern)
end
+ return new_kern(kern)
end
--[[doc--
@@ -223,12 +224,12 @@ kerncharacters = function (head)
local firstkern = true
while start do
- local id = start.id
+ local id = getid(start)
if id == glyph_code then
--- 1) look up kern factor (slow, but cached rudimentarily)
local krn
- local fontid = start.font
+ local fontid = getfont(start)
do
krn = kernfactors[fontid]
if not krn then
@@ -249,7 +250,7 @@ kerncharacters = function (head)
goto nextnode
elseif firstkern then
firstkern = false
- if (id ~= disc_code) and (not start.components) then
+ if (id ~= disc_code) and (not getfield(start, "components")) then
--- not a ligature, skip node
goto nextnode
end
@@ -266,7 +267,7 @@ kerncharacters = function (head)
lastfont = fontid
--- 2) resolve ligatures
- local c = start.components
+ local c = getfield(start, "components")
if c then
if keepligature and keepligature(start) then
@@ -274,20 +275,20 @@ kerncharacters = function (head)
else
--- c = kerncharacters (c) --> taken care of after replacing
local s = start
- local p, n = s.prev, s.next
+ local p, n = getprev(s), s.next
local tail = find_node_tail(c)
if p then
- p.next = c
- c.prev = p
+ setfield(p, "next", c)
+ p = getprev(c)
else
head = c
end
if n then
- n.prev = tail
+ tail = getprev(n)
end
- tail.next = n
+ setnext(tail, "next", n)
start = c
- s.components = nil
+ setfield(s, "components", nil)
-- we now leak nodes !
-- free_node(s)
done = true
@@ -295,30 +296,40 @@ kerncharacters = function (head)
end -- kern ligature
--- 3) apply the extra kerning
- local prev = start.prev
+ local prev = getprev(start)
if prev then
- local pid = prev.id
+ local pid = getid(prev)
if not pid then
-- nothing
elseif pid == kern_code then
- if prev.subtype == kerning_code --- context does this by means of an
- or prev.subtype == userkern_code --- attribute; we may need a test
+ local prev_subtype = getsubtype(prev)
+ if prev_subtype == kerning_code --- context does this by means of an
+ or prev_subtype == userkern_code --- attribute; we may need a test
then
- if keeptogether and prev.prev.id == glyph_code and keeptogether(prev.prev,start) then
+
+ local pprev = getprev(prev)
+ local pprev_id = getid(pprev)
+
+ if keeptogether
+ and pprev_id == glyph_code
+ and keeptogether(pprev, start)
+ then
-- keep
else
- prev.subtype = userkern_code
- prev.kern = prev.kern + quaddata[lastfont]*krn -- here
+ prev_subtype = userkern_code
+ local prev_kern = getfield(prev, "kern")
+ prev_kern = prev_kern + quaddata[lastfont] * krn
done = true
end
end
elseif pid == glyph_code then
- if prev.font == lastfont then
- local prevchar, lastchar = prev.char, start.char
- if keeptogether and keeptogether(prev,start) then
+ if getfont(prev) == lastfont then
+ local prevchar = getchar(prev)
+ local lastchar = getchar(start)
+ if keeptogether and keeptogether(prev, start) then
-- keep 'm
elseif identifiers[lastfont] then
local kerns = chardata[lastfont] and chardata[lastfont][prevchar].kerns
@@ -337,31 +348,34 @@ kerncharacters = function (head)
-- a bit too complicated, we can best not copy and just calculate
-- but we could have multiple glyphs involved so ...
local disc = prev -- disc
- local pre, post, replace = disc.pre, disc.post, disc.replace
- local prv, nxt = disc.prev, disc.next
+ local pre = getfield(disc, "pre")
+ local post = getfield(disc, "post")
+ local replace = getfield(disc, "replace")
+ local prv = getprev(disc)
+ local nxt = getnext(disc)
if pre and prv then -- must pair with start.prev
-- this one happens in most cases
local before = copy_node(prv)
- pre.prev = before
- before.next = pre
- before.prev = nil
+ setfield(pre, "prev", before)
+ setfield(before, "next", pre)
+ setfield(before, "prev", nil)
pre = kerncharacters (before)
- pre = pre.next
- pre.prev = nil
- disc.pre = pre
+ pre = getnext(pre)
+ setfield(pre, "prev", nil)
+ setfield(disc, "pre", pre)
free_node(before)
end
if post and nxt then -- must pair with start
local after = copy_node(nxt)
local tail = find_node_tail(post)
- tail.next = after
- after.prev = tail
- after.next = nil
+ setfield(tail, "next", after)
+ setfield(after, "prev", tail)
+ setfield(after, "next", nil)
post = kerncharacters (post)
- tail.next = nil
- disc.post = post
+ setfield(tail, "next", nil)
+ setfield(disc, "post", post)
free_node(after)
end
@@ -369,29 +383,34 @@ kerncharacters = function (head)
local before = copy_node(prv)
local after = copy_node(nxt)
local tail = find_node_tail(replace)
- replace.prev = before
- before.next = replace
- before.prev = nil
- tail.next = after
- after.prev = tail
- after.next = nil
+ setfield(replace, "prev", before)
+ setfield(before, "next", replace)
+ setfield(before, "prev", nil)
+ setfield(tail, "next", after)
+ setfield(after, "prev", tail)
+ setfield(after, "next", nil)
replace = kerncharacters (before)
- replace = replace.next
- replace.prev = nil
- after.prev.next = nil
- disc.replace = replace
+ replace = getnext(replace)
+ setfield(replace, "prev", nil)
+ setfield(after, "prev.next", nil)
+ setfield(disc, "replace", replace)
free_node(after)
free_node(before)
+
elseif identifiers[lastfont] then
- if prv and prv.id == glyph_code and prv.font == lastfont then
- local prevchar, lastchar = prv.char, start.char
+ if prv
+ and getid(prv) == glyph_code
+ and getfont(prv) == lastfont
+ then
+ local prevchar = getchar(prv)
+ local lastchar = getchar(start)
local kerns = chardata[lastfont] and chardata[lastfont][prevchar].kerns
local kern = kerns and kerns[lastchar] or 0
krn = kern + quaddata[lastfont]*krn -- here
else
krn = quaddata[lastfont]*krn -- here
end
- disc.replace = kern_injector(false,krn) -- only kerns permitted, no glue
+ setfield(disc, "replace", kern_injector(false, krn))
end
end
@@ -400,7 +419,7 @@ kerncharacters = function (head)
::nextnode::
if start then
- start = start.next
+ start = getnext(start)
end
end
return head, done
@@ -439,19 +458,37 @@ local remove_processor = function (name)
return false --> unregistered
end
---- now for the simplistic variant
+--- When font kerning is requested, usually by defining a font with the
+--- ``letterspace`` parameter, we inject a wrapper for the
+--- ``kerncharacters()`` node processor in the relevant callbacks. This
+--- wrapper initially converts the received head node into its “direct”
+--- counterpart. Likewise, the callback result is converted back to an
+--- ordinary node prior to returning. Internally, ``kerncharacters()``
+--- performs all node operations on direct nodes.
+
--- unit -> bool
local enablefontkerning = function ( )
- return add_processor( kerncharacters
+
+ local handler = function (hd)
+ local direct_hd = todirect (hd)
+ local hd, _done = kerncharacters (hd)
+ if not hd then --- bad
+ logreport ("both", 0, "letterspace",
+ "kerncharacters() failed to return a valid new head")
+ end
+ return tonode (hd)
+ end
+
+ return add_processor( handler
, "luaotfload.letterspace"
, "pre_linebreak_filter"
, "hpack_filter")
end
--- unit -> bool
-local disablefontkerning = function ( )
- return remove_processor "luaotfload.letterspace"
-end
+---al disablefontkerning = function ( )
+---eturn remove_processor "luaotfload.letterspace"
+---
--[[doc--
@@ -515,10 +552,10 @@ otffeatures.register {
local initializecompatfontkerning = function (tfmdata, percentage)
local factor = tonumber (percentage)
if not factor then
- report ("both", 0, "letterspace",
- "Invalid argument to letterspace: %s (type %q), " ..
- "was expecting percentage as Lua number instead.",
- percentage, type (percentage))
+ logreport ("both", 0, "letterspace",
+ "Invalid argument to letterspace: %s (type %q), " ..
+ "was expecting percentage as Lua number instead.",
+ percentage, type (percentage))
return
end
return initializefontkerning (tfmdata, factor * 0.01)
--
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