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if not modules then modules = { } end modules ['luaotfload-colors'] = {
version = 2.200,
comment = "companion to luaotfload.lua (font color)",
author = "Khaled Hosny, Elie Roux, Philipp Gesang",
copyright = "Luaotfload Development Team",
license = "GNU GPL v2"
}
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 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--
``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 function setcolor(tfmdata,value)
local sanitized
local properties = tfmdata.properties
if value then
value = tostring(value)
if #value == 6 or #value == 8 then
sanitized = value
elseif #value == 7 then
_, _, sanitized = stringfind(value, "(......)")
elseif #value > 8 then
_, _, sanitized = stringfind(value, "(........)")
else
-- broken color code ignored, issue a warning?
end
end
if sanitized then
tfmdata.properties.color = sanitized
add_color_callback()
end
end
registerotffeature {
name = "color",
description = "color",
initializers = {
base = setcolor,
node = setcolor,
}
}
--[[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? -> float
local function hex_to_dec(hex,one)
if one then
return stringformat("%.1g", tonumber(hex, 16)/255)
else
return stringformat("%.3g", tonumber(hex, 16)/255)
end
end
--- something is carried around in ``res``
--- for later use by color_handler() --- but what?
local res --- <- state of what?
--- float -> unit
local function pageresources(a)
local res2
if not res then
res = "/TransGs1<</ca 1/CA 1>>"
end
res2 = stringformat("/TransGs%s<</ca %s/CA %s>>", a, a, a)
res = stringformat("%s%s",
res,
stringfind(res, res2) and "" or res2)
end
--- string -> (string * string)
local function hex_to_rgba(hex)
local r, g, b, a, push, pop, res3
if hex then
--- TODO lpeg this mess
if #hex == 6 then
_, _, r, g, b = stringfind(hex, '(..)(..)(..)')
elseif #hex == 8 then
_, _, r, g, b, a = stringfind(hex, '(..)(..)(..)(..)')
a = hex_to_dec(a,true)
pageresources(a)
end
else
return nil
end
r = hex_to_dec(r)
g = hex_to_dec(g)
b = hex_to_dec(b)
if a then
push = stringformat('/TransGs%g gs %s %s %s rg', a, r, g, b)
pop = '0 g /TransGs1 gs'
else
push = stringformat('%s %s %s rg', r, g, b)
pop = '0 g'
end
return push, pop
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 function lookup_next_color(head)
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]]--
--- node -> string -> int -> (node * string)
local function node_colorize(head, current_color, next_color)
for n in traverse_nodes(head) do
local n_id = n.id
if n_id == hlist_t or n_id == vlist_t or n_id == sub_box_t then
local next_color_in = lookup_next_color(n.next) or next_color
n.list, current_color = node_colorize(n.list, current_color, next_color_in)
elseif n_id == glyph_t then
local tfmdata = identifiers[n.font]
if tfmdata and tfmdata.properties and tfmdata.properties.color then
if tfmdata.properties.color ~= current_color then
local pushcolor = hex_to_rgba(tfmdata.properties.color)
local push = newnode(whatsit_t, 8)
push.mode = 1
push.data = pushcolor
head = insert_node_before(head, n, push)
current_color = tfmdata.properties.color
end
local next_color_in = lookup_next_color (n.next) or next_color
if next_color_in ~= tfmdata.properties.color then
local _, popcolor = hex_to_rgba(tfmdata.properties.color)
local pop = newnode(whatsit_t, 8)
pop.mode = 1
pop.data = popcolor
head = insert_node_after(head, n, pop)
current_color = nil
end
end
end
end
return head, current_color
end
--- node -> node
local function color_handler (head)
-- check if our page resources existed in the previous run
-- and remove it to avoid duplicating it later
if res then
local r = "/ExtGState<<"..res..">>"
tex.pdfpageresources = stringgsub(tex.pdfpageresources, r, "")
end
local new_head = node_colorize(head, nil, nil)
-- now append our page resources
if res and stringfind(res, "%S") then -- test for non-empty string
local r = "/ExtGState<<"..res..">>"
tex.pdfpageresources = tex.pdfpageresources..r
end
return new_head
end
local color_callback_activated = 0
--- unit -> unit
function add_color_callback ()
if color_callback_activated == 0 then
luatexbase.add_to_callback("pre_output_filter",
color_handler,
"luaotfload.color_handler")
color_callback_activated = 1
end
end
-- vim:tw=71:sw=4:ts=4:expandtab
|
