Skip to content

Commit

Permalink
First steps in using Lua for color
Browse files Browse the repository at this point in the history 
Just PDF mode at the moment, and xform boxes are
not covered.
  • Loading branch information
@josephwright
josephwright committed Jun 4, 2021
1 parent 983203b commit d19fdda
Show file tree
Hide file tree
Showing 22 changed files with 2,602 additions and 391 deletions.
2 changes: 1 addition & 1 deletion l3backend/build.lua
View file
Expand Up @@ -9,7 +9,7 @@ bundle = ""
-- Location of main directory: use Unix-style path separators
maindir = ".."

installfiles = {"*.def", "*.pro"}
installfiles = {"*.def", "l3backend-luatex.lua", "*.pro"}
sourcefiles = {"*.dtx", "*.ins"}
tagfiles = {"*.dtx", "CHANGELOG.md", "README.md", "*.ins"}
typesetfiles = {"l3backend-code.tex"}
Expand Down
346 changes: 342 additions & 4 deletions l3backend/l3backend-color.dtx
View file
Expand Up @@ -411,7 +411,10 @@
% }
% \begin{macro}{\@@_backend_select:nn}
% \begin{macro}{\@@_backend_reset:}
% Store the values then pass to the stack.
% \begin{macro}{\@@_backend_stack_push:nn}
% Store the values then pass to the stack. The abstraction here allows for
% transparency needing the same fundamental approach but with switchable
% code for \LuaTeX{}.
% \begin{macrocode}
\cs_new_protected:Npn \@@_backend_select_cmyk:n #1
{ \@@_backend_select:nn { #1 ~ k } { #1 ~ K } }
Expand All @@ -423,15 +426,17 @@
{
\tl_set:Nn \l_@@_backend_fill_tl {#1}
\tl_set:Nn \l_@@_backend_stroke_tl {#2}
\__kernel_color_backend_stack_push:nn \l_@@_backend_stack_int { #1 ~ #2 }
\@@_backend_stack_push:nn \l_@@_backend_stack_int { #1 ~ #2 }
\group_insert_after:N \@@_backend_reset:
}
\cs_new_protected:Npn \@@_backend_reset:
{ \__kernel_color_backend_stack_pop:n \l_@@_backend_stack_int }
\cs_new_eq:NN \@@_backend_stack_push:nn \__kernel_color_backend_stack_push:nn
% \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macrocode}
%</dvipdfmx|luatex|pdftex|xetex>
Expand Down Expand Up @@ -982,7 +987,7 @@
\cs_new_protected:Npn \@@_backend_fill:n #1
{
\tl_set:Nn \l_@@_backend_fill_tl {#1}
\__kernel_color_backend_stack_push:nn \l_@@_backend_stack_int
\@@_backend_stack_push:nn \l_@@_backend_stack_int
{ #1 ~ \l_@@_backend_stroke_tl }
\group_insert_after:N \@@_backend_reset:
}
Expand All @@ -995,7 +1000,7 @@
\cs_new_protected:Npn \@@_backend_stroke:n #1
{
\tl_set:Nn \l_@@_backend_stroke_tl {#1}
\__kernel_color_backend_stack_push:nn \l_@@_backend_stack_int
\@@_backend_stack_push:nn \l_@@_backend_stack_int
{ \l_@@_backend_fill_tl \c_space_tl #1 }
\group_insert_after:N \@@_backend_reset:
}
Expand Down Expand Up @@ -1248,6 +1253,339 @@
%</package>
% \end{macrocode}
%
% \subsection{Color in \LuaTeX{}}
%
% \begin{macrocode}
%<*lua>
% \end{macrocode}
%
% In \LuaTeX{}, we can use an approach based on attributes to avoid having to
% insert whatsits. That means having the appropriate supporting Lua code. The
% underlying idea comes from Heiko Oberdiek's \pkg{luacolor} package.
%
% \begin{macro}{ltx.color}
% \begin{macro}{ltxcolor}
% The basic table should be set up in \pkg{l3luatex}, but we want a separate
% sub-table for color.
% \begin{macrocode}
ltx = ltx or {color = {}}
ltx.color = ltx.color or {}
local ltxcolor = ltx.color
% \end{macrocode}
% \end{macro}
% \end{macro}
%
% Load basic support and print some information.
% \begin{macrocode}
require("ltluatex")
local luatexbase = luatexbase
luatexbase.provides_module({name = "l3backend-luatex", date = "2021-06-03"})
% \end{macrocode}
%
% \begin{macro}{attr}
% An attribute to track color. There is no need to access this from \TeX{} so
% in contrast to \pkg{luacolor} we just allocate directly in Lua.
% \begin{macrocode}
local color_attr = luatexbase.new_attribute("color")
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{map}
% A map between color strings and their color_index, plus the tracking number.
% \begin{macrocode}
local map = {n = 0}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{color_index}
% Get the color_index of a color or create a new color_index if necessary.
% \begin{macrocode}
local function color_index(color)
local n = map[color]
if not n then
n = map.n + 1
map[n] = color
map[color] = n
end
return n
end
% \end{macrocode}
% \end{macro}
%
% Local copies of global tables.
% \begin{macrocode}
local node = node
local string = string
local tex = tex
local texio = texio
% \end{macrocode}
%
% Local copies of standard functions.
% \begin{macrocode}
local module_error = luatexbase.module_error
local has_attribute = node.has_attribute
local id = node.id
local insert_before = node.insert_before
local node_new = node.new
local node_traverse = node.traverse
local set_attribute = tex.setattribute
local type = node.type
local subtype = node.subtype
% \end{macrocode}
%
% \begin{macro}{ltx.color.select}
% Get the color_index of a color or create a new color_index if necessary.
% \begin{macrocode}
local function select(color_str)
set_attribute(color_attr,color_index(color_str))
end
ltxcolor.select = select
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{node_map, node_types,literals}
% We abstract the idea of different types of node where it makes sense:
% notice for example that in contrast to \pkg{luacolor} we extract some
% one-off information in the function that needs it. We also use a single
% local \enquote{map} for the node values.
% \begin{macrocode}
local node_map = {
list = 1 ,
list_leaders = 2 ,
list_disc = 3 ,
color = 4 ,
no_color = 5
}
local node_types = {
[id("hlist")] = node_map.list ,
[id("vlist")] = node_map.list ,
[id("rule")] = node_map.color ,
[id("glyph")] = node_map.color ,
[id("disc")] = node_map.list_disc ,
[id("whatsit")] = {
[subtype("pdf_colorstack")] =
function(n) return n.stack == 0 and node_map.no_color or nil end ,
[subtype("special")] = node_map.color ,
[subtype("pdf_literal")] = node_map.color ,
[subtype("pdf_save")] = node_map.color ,
[subtype("pdf_restore")] = node_map.color ,
} ,
[id("glue")] =
function(n)
if n.subtype >= 100 then
if n.leader.id == id("rule") then
return node_map.color
else
return node_map.list_leaders
end
end
end
}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{node_map, node_types,literals}
% We abstract the idea of different types of node where it makes sense:
% notice for example that in contrast to \pkg{luacolor} we extract some
% one-off information in the function that needs it. We also use a single
% local \enquote{map} for the node values.
% \begin{macrocode}
local node_map = {
list = 1 ,
list_leaders = 2 ,
list_disc = 3 ,
color = 4 ,
no_color = 5
}
local node_types = {
[id("hlist")] = node_map.list ,
[id("vlist")] = node_map.list ,
[id("rule")] = node_map.color ,
[id("glyph")] = node_map.color ,
[id("disc")] = node_map.list_disc ,
[id("whatsit")] = {
[subtype("pdf_colorstack")] =
function(n) return n.stack == 0 and node_map.no_color or nil end ,
[subtype("special")] = node_map.color ,
[subtype("pdf_literal")] = node_map.color ,
[subtype("pdf_save")] = node_map.color ,
[subtype("pdf_restore")] = node_map.color
} ,
[id("glue")] =
function(n)
if n.subtype >= 100 then
if n.leader.id == id("rule") then
return node_map.color
else
return node_map.list_leaders
end
end
end
}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{get_type}
% Convert a node into the type, allowing for tables and functions.
% \begin{macrocode}
local function get_type(n)
local ret = node_types[n.id]
if type(ret) == "table" then
ret = ret[n.subtype]
end
if type(ret) == "function" then
ret = ret(n)
end
return ret
end
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{create_node}
% Create the the node containing color data. The mode is hard-coded as $2$:
% a PDF literal.
% \begin{macrocode}
local function create_node(color)
local color_node = node_new(id("whatsit"),subtype("pdf_literal"))
color_node.mode = 2
color_node.data = color
return color_node
end
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{traverse}
% The business end of the process: transverse the node list.
% \begin{macrocode}
local function traverse(list,color,dry_run)
% \end{macrocode}
% We start with a sanity check: do we have a list at all.
% \begin{macrocode}
if not list then
return color
end
% \end{macrocode}
% Work out the type of head we have: should be a |list| or |list_disc|.
% \begin{macrocode}
local head
if get_type(list) == node_map.list then
head = list.head
elseif get_type(list) == node_map.list_disc then
head = list.replace
else
module_error("l3color","Wrong list type: " .. type(list.id))
return color
end
% \end{macrocode}
% The main loop. We have various bits of recursion to do to map over
% the lists, before we get to the business end: color nodes.
% \begin{macrocode}
for n in node_traverse(head) do
local t = get_type(n)
if t == node_map.list or t == node_map.list_disc then
color = traverse(n,color,dry_run)
elseif t == node_map.list_leaders then
local color_after = traverse(n.leader,color,true)
if color == color_after then
traverse(n.leader,color,dry_run)
else
traverse(n.leader,"",dry_run)
color = ""
end
elseif t == node_map.color then
local c = has_attribute(n,color_attr)
if c then
local new_color = map[c]
if new_color ~= color then
color = new_color
if not dry_run then
print("NEW NODE")
head = insert_before(head,n,create_node(color))
end
end
end
elseif t == node_map.no_color then
color = ""
end
end
% \end{macrocode}
% Loop done, set up the list.
% \begin{macrocode}
if get_type(list) == node_map.list then
list.head = head
else
list.replace = head
end
return color
end
% \end{macrocode}
% \end{macro}
%
% Activate the code: we assume that the |pre_shipout_filter| callback is
% available as this is pretty burning-edge stuff.
% \begin{macrocode}
if luatexbase.callbacktypes.pre_shipout_filter then
luatexbase.add_to_callback(
"pre_shipout_filter",
function(list)
traverse(list,"")
return true
end,
"color")
end
% \end{macrocode}
%
% For recent versions of \pkg{luaotfload}, we can register a callback to
% control how coloring glyph is handled for the color feature.
% \begin{macrocode}
if luaotfload and luaotfload.set_colorhandler then
local set_attribute = node.direct.set_attribute
luaotfload.set_colorhandler(function(head,n,color)
set_attribute(n,attribute,color_index(color))
return head,n
end)
end
% \end{macrocode}
%
% \begin{macrocode}
%</lua>
% \end{macrocode}
%
% \begin{macrocode}
%<*package>
% \end{macrocode}
%
% At present we only set up for \LuaTeX{} in PDF mode: later we will expand
% on that!
%
% \begin{macrocode}
%<*luatex>
% \end{macrocode}
%
% \begin{macrocode}
\lua_now:n { require("l3backend-luatex") }
% \end{macrocode}
%
% \begin{macro}{\@@_backend_stack_push:nn}
% \begin{macro}{\@@_backend_reset:}
% A simple reworking: we may need to check about transparency here.
% \begin{macrocode}
\cs_gset_protected:Npn \@@_backend_stack_push:nn #1#2
{
\lua_now:e { ltx.color.select(" \lua_escape:n {#2} ") }
}
\cs_gset_protected:Npn \@@_backend_reset: { }
% \end{macrocode}
% \end{macro}
%
% \begin{macrocode}
%</luatex>
% \end{macrocode}
%
% \begin{macrocode}
%</package>
% \end{macrocode}
%
% \end{implementation}
%
% \PrintIndex

0 comments on commit d19fdda

Please sign in to comment.