Merge pull request #197 from phi-gamma/texlive2014

source tree structure

1 files changed, 312 insertions, 0 deletions

diff --git a/src/luaotfload-colors.lua b/src/luaotfload-colors.lua
new file mode 100644
index 0000000..d999df6
--- /dev/null
+++ b/src/luaotfload-colors.lua
@@ -0,0 +1,312 @@
+if not modules then modules = { } end modules ['luaotfload-colors'] = {
+    version   = "2.5",
+    comment   = "companion to luaotfload-main.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
+