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if not modules then modules = { } end modules ['luaotfload-colors'] = {
version = "2.6",
comment = "companion to luaotfload-main.lua (font color)",
author = "Khaled Hosny, Elie Roux, Philipp Gesang, Dohyun Kim",
copyright = "Luaotfload Development Team",
license = "GNU GPL v2.0"
}
--[[doc--
buggy coloring with the pre_output_filter when expansion is enabled
· tfmdata for different expansion values is split over different objects
· in ``initializeexpansion()``, chr.expansion_factor is set, and only
those characters that have it are affected
· in constructors.scale: chr.expansion_factor = ve*1000 if commented out
makes the bug vanish
explanation: http://tug.org/pipermail/luatex/2013-May/004305.html
--doc]]--
local log = luaotfload.log
local logreport = log.report
local nodedirect = node.direct
local newnode = nodedirect.new
local insert_node_before = nodedirect.insert_before
local insert_node_after = nodedirect.insert_after
local todirect = nodedirect.todirect
local tonode = nodedirect.tonode
local setfield = nodedirect.setfield
local getid = nodedirect.getid
local getfont = nodedirect.getfont
local getlist = nodedirect.getlist
local getsubtype = nodedirect.getsubtype
local getnext = nodedirect.getnext
local nodetail = nodedirect.tail
local getattribute = nodedirect.has_attribute
local setattribute = nodedirect.set_attribute
local texset = tex.set
local texget = tex.get
local texsettoks = tex.settoks
local texgettoks = tex.gettoks
local stringformat = string.format
local concat = table.concat
local otffeatures = fonts.constructors.newfeatures("otf")
local identifiers = fonts.hashes.identifiers
local registerotffeature = otffeatures.register
local add_color_callback --[[ this used to be a global‽ ]]
--[[doc--
This converts a single octet into a decimal with three digits of
precision. The optional second argument limits precision to a single
digit.
--doc]]--
--- string -> bool? -> string
local hex_to_dec = function (hex,one) --- one isn’t actually used anywhere ...
if one then
return stringformat("%.1g", tonumber(hex, 16)/255)
else
return stringformat("%.3g", tonumber(hex, 16)/255)
end
end
--[[doc--
Color string validator / parser.
--doc]]--
local lpeg = require"lpeg"
local lpegmatch = lpeg.match
local C, Cg, Ct, P, R, S = lpeg.C, lpeg.Cg, lpeg.Ct, lpeg.P, lpeg.R, lpeg.S
local digit16 = R("09", "af", "AF")
local opaque = S("fF") * S("fF")
local octet = C(digit16 * digit16)
local p_rgb = octet * octet * octet
local p_rgba = p_rgb * (octet - opaque)
local valid_digits = C(p_rgba + p_rgb) -- matches eight or six hex digits
local p_Crgb = Cg(octet/hex_to_dec, "red") --- for captures
* Cg(octet/hex_to_dec, "green")
* Cg(octet/hex_to_dec, "blue")
local p_Crgba = p_Crgb * Cg(octet/hex_to_dec, "alpha")
local extract_color = Ct(p_Crgba + p_Crgb)
--- string -> (string | nil)
local sanitize_color_expression = function (digits)
digits = tostring(digits)
local sanitized = lpegmatch(valid_digits, digits)
if not sanitized then
logreport("both", 0, "color",
"%q is not a valid rgb[a] color expression",
digits)
return nil
end
return sanitized
end
--[[doc--
``setcolor`` modifies tfmdata.properties.color in place
--doc]]--
--- fontobj -> string -> unit
---
--- (where “string” is a rgb value as three octet
--- hexadecimal, with an optional fourth transparency
--- value)
---
local setcolor = function (tfmdata, value)
local sanitized = sanitize_color_expression(value)
local properties = tfmdata.properties
if sanitized then
properties.color = sanitized
add_color_callback()
end
end
registerotffeature {
name = "color",
description = "color",
initializers = {
base = setcolor,
node = setcolor,
}
}
--- something is carried around in ``res``
--- for later use by color_handler() --- but what?
local res = nil
--- float -> unit
local function pageresources(alpha)
res = res or {}
res[alpha] = true
end
--- we store results of below color handler as tuples of
--- push/pop strings
local color_cache = { } --- (string, (string * string)) hash_t
--- string -> (string * string)
local hex_to_rgba = function (digits)
if not digits then
return
end
--- this is called like a thousand times, so some
--- memoizing is in order.
local cached = color_cache[digits]
if not cached then
local push, pop
local rgb = lpegmatch(extract_color, digits)
if rgb.alpha then
pageresources(rgb.alpha)
push = stringformat(
"/TransGs%g gs %s %s %s rg",
rgb.alpha,
rgb.red,
rgb.green,
rgb.blue)
pop = "0 g /TransGs1 gs"
else
push = stringformat(
"%s %s %s rg",
rgb.red,
rgb.green,
rgb.blue)
pop = "0 g"
end
color_cache[digits] = { push, pop }
return push, pop
end
return cached[1], cached[2]
end
--- Luatex internal types
local nodetype = node.id
local glyph_t = nodetype("glyph")
local hlist_t = nodetype("hlist")
local vlist_t = nodetype("vlist")
local whatsit_t = nodetype("whatsit")
local disc_t = nodetype("disc")
local pdfliteral_t = node.subtype("pdf_literal")
local colorstack_t = node.subtype("pdf_colorstack")
local color_callback
local color_attr = luatexbase.new_attribute("luaotfload_color_attribute")
-- (node * node * string * bool * (bool | nil)) -> (node * node * (string | nil))
local color_whatsit
color_whatsit = function (head, curr, color, push, tail)
local pushdata = hex_to_rgba(color)
local colornode = newnode(whatsit_t, colorstack_t)
setfield(colornode, "stack", 0)
setfield(colornode, "command", push and 1 or 2) -- 1: push, 2: pop
setfield(colornode, "data", push and pushdata or nil)
if tail then
head, curr = insert_node_after (head, curr, colornode)
else
head = insert_node_before(head, curr, colornode)
end
if not push and color:len() > 6 then
local colornode = newnode(whatsit_t, pdfliteral_t)
setfield(colornode, "mode", 2)
setfield(colornode, "data", "/TransGs1 gs")
if tail then
head, curr = insert_node_after (head, curr, colornode)
else
head = insert_node_before(head, curr, colornode)
end
end
color = push and color or nil
return head, curr, color
end
-- number -> string | nil
local get_font_color = function (font_id)
local tfmdata = identifiers[font_id]
local font_color = tfmdata and tfmdata.properties and tfmdata.properties.color
return font_color
end
local cnt = 0
--[[doc--
While the second argument and second returned value are apparently
always nil when the function is called, they temporarily take string
values during the node list traversal.
--doc]]--
--- (node * (string | nil)) -> (node * (string | nil))
local node_colorize
node_colorize = function (head, current_color)
local n = head
while n do
local n_id = getid(n)
if n_id == hlist_t or n_id == vlist_t then
cnt = cnt + 1
local n_list = getlist(n)
if getattribute(n_list, color_attr) then
if current_color then
head, n, current_color = color_whatsit(head, n, current_color, false)
end
else
n_list, current_color = node_colorize(n_list, current_color)
if current_color and getsubtype(n) == 1 then -- created by linebreak
n_list, _, current_color = color_whatsit(n_list, nodetail(n_list), current_color, false, true)
end
setfield(n, "head", n_list)
end
cnt = cnt - 1
elseif n_id == glyph_t then
--- colorization is restricted to those fonts
--- that received the “color” property upon
--- loading (see ``setcolor()`` above)
local font_color = get_font_color(getfont(n))
if font_color ~= current_color then
if current_color then
head, n, current_color = color_whatsit(head, n, current_color, false)
end
if font_color then
head, n, current_color = color_whatsit(head, n, font_color, true)
end
end
if current_color and color_callback == "pre_linebreak_filter" then
local nn = getnext(n)
while nn and getid(nn) == glyph_t do
local font_color = get_font_color(getfont(nn))
if font_color == current_color then
n = nn
else
break
end
nn = getnext(nn)
end
if getid(nn) == disc_t then
head, n, current_color = color_whatsit(head, nn, current_color, false, true)
else
head, n, current_color = color_whatsit(head, n, current_color, false, true)
end
end
elseif n_id == whatsit_t then
if current_color then
head, n, current_color = color_whatsit(head, n, current_color, false)
end
end
n = getnext(n)
end
if cnt == 0 and current_color then
head, _, current_color = color_whatsit(head, nodetail(head), current_color, false, true)
end
setattribute(head, color_attr, 1)
return head, current_color
end
--- node -> node
local color_handler = function (head)
head = todirect(head)
head = node_colorize(head)
head = tonode(head)
-- now append our page resources
if res then
res["1"] = true
local tpr = texget("pdfpageresources")
local no_extgs = not tpr:find("/ExtGState<<.*>>")
local pgf_loaded = no_extgs and luaotfload.pgf_loaded
if pgf_loaded then
tpr = texgettoks(pgf_loaded)
end
local t = ""
for k in pairs(res) do
local str = stringformat("/TransGs%s<</ca %s>>", k, k) -- don't touch stroking elements
if not tpr:find(str) then
t = t .. str
end
end
if t ~= "" then
if pgf_loaded then
texsettoks("global", pgf_loaded, tpr..t)
else
if no_extgs then
tpr = tpr .. "/ExtGState<<>>"
end
tpr = tpr:gsub("/ExtGState<<", "%1"..t)
texset("global", "pdfpageresources", tpr)
end
end
res = nil -- reset res
end
return head
end
local color_callback_activated = 0
--- unit -> unit
add_color_callback = function ( )
color_callback = config.luaotfload.run.color_callback
if not color_callback then
color_callback = "post_linebreak_filter"
end
if color_callback_activated == 0 then
luatexbase.add_to_callback(color_callback,
color_handler,
"luaotfload.color_handler")
luatexbase.add_to_callback("hpack_filter",
function (head, groupcode)
if groupcode == "hbox" or
groupcode == "adjusted_hbox" or
groupcode == "align_set" then
head = color_handler(head)
end
return head
end,
"luaotfload.color_handler")
color_callback_activated = 1
end
end
-- vim:tw=71:sw=4:ts=4:expandtab
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