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if not modules then modules = { } end modules ['luaotfload-colors'] = {
version = "2.5",
comment = "companion to luaotfload.lua (font color)",
author = "Khaled Hosny, Elie Roux, Philipp Gesang",
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 color_callback = config.luaotfload.color_callback
if not color_callback then
--- maybe this would be better as a method: "early" | "late"
color_callback = "pre_linebreak_filter"
-- color_callback = "pre_output_filter" --- old behavior, breaks expansion
end
local newnode = node.new
local nodetype = node.id
local traverse_nodes = node.traverse
local insert_node_before = node.insert_before
local insert_node_after = node.insert_after
local stringformat = string.format
local stringgsub = string.gsub
local stringfind = string.find
local stringsub = string.sub
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 octet = C(digit16 * digit16)
local p_rgb = octet * octet * octet
local p_rgba = p_rgb * octet
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
luaotfload.warning(
"%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 glyph_t = nodetype("glyph")
local hlist_t = nodetype("hlist")
local vlist_t = nodetype("vlist")
local whatsit_t = nodetype("whatsit")
local page_insert_t = nodetype("page_insert")
local sub_box_t = nodetype("sub_box")
--- node -> nil | -1 | color‽
local lookup_next_color
lookup_next_color = function (head) --- paragraph material
for n in traverse_nodes(head) do
local n_id = n.id
if n_id == glyph_t then
local n_font
if identifiers[n_font]
and identifiers[n_font].properties
and identifiers[n_font].properties.color
then
return identifiers[n.font].properties.color
else
return -1
end
elseif n_id == vlist_t or n_id == hlist_t or n_id == sub_box_t then
local r = lookup_next_color(n.list)
if r then
return r
end
elseif n_id == whatsit_t or n_id == page_insert_t then
return -1
end
end
return nil
end
--[[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]]--
local cnt = 0
--- node -> string -> int -> (node * string)
local node_colorize
node_colorize = function (head, current_color, next_color)
for n in traverse_nodes(head) do
local n_id = n.id
local nextnode = n.next
if n_id == hlist_t or n_id == vlist_t or n_id == sub_box_t then
local next_color_in = lookup_next_color(nextnode) or next_color
n.list, current_color = node_colorize(n.list, current_color, next_color_in)
elseif n_id == glyph_t then
cnt = cnt + 1
local tfmdata = identifiers[n.font]
--- colorization is restricted to those fonts
--- that received the “color” property upon
--- loading (see ``setcolor()`` above)
if tfmdata and tfmdata.properties and tfmdata.properties.color then
local font_color = tfmdata.properties.color
-- luaotfload.info(
-- "n: %d; %s; %d %s, %s",
-- cnt, utf.char(n.char), n.font, "<TRUE>", font_color)
if font_color ~= current_color then
local pushcolor = hex_to_rgba(font_color)
local push = newnode(whatsit_t, 8)
push.mode = 1
push.data = pushcolor
head = insert_node_before(head, n, push)
current_color = font_color
end
local next_color_in = lookup_next_color (nextnode) or next_color
if next_color_in ~= font_color then
local _, popcolor = hex_to_rgba(font_color)
local pop = newnode(whatsit_t, 8)
pop.mode = 1
pop.data = popcolor
head = insert_node_after(head, n, pop)
current_color = nil
end
-- else
-- luaotfload.info(
-- "n: %d; %s; %d %s",
-- cnt, utf.char(n.char), n.font, "<FALSE>")
end
end
end
return head, current_color
end
--- node -> node
local color_handler = function (head)
local new_head = node_colorize(head, nil, nil)
-- now append our page resources
if res then
res["1"] = true
local tpr, t = tex.pdfpageresources, ""
for k in pairs(res) do
local str = stringformat("/TransGs%s<</ca %s/CA %s>>", k, k, k)
if not stringfind(tpr,str) then
t = t .. str
end
end
if t ~= "" then
if not stringfind(tpr,"/ExtGState<<.*>>") then
tpr = tpr.."/ExtGState<<>>"
end
tpr = stringgsub(tpr,"/ExtGState<<","%1"..t)
tex.pdfpageresources = tpr
end
res = nil -- reset res
end
return new_head
end
local color_callback_activated = 0
--- unit -> unit
add_color_callback = function ( )
if color_callback_activated == 0 then
luatexbase.add_to_callback(color_callback,
color_handler,
"luaotfload.color_handler")
color_callback_activated = 1
end
end
-- vim:tw=71:sw=4:ts=4:expandtab
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