diff options
| -rw-r--r-- | luaotfload-colors.lua | 91 |
1 files changed, 64 insertions, 27 deletions
diff --git a/luaotfload-colors.lua b/luaotfload-colors.lua index d7b84fc..0bc3f9c 100644 --- a/luaotfload-colors.lua +++ b/luaotfload-colors.lua @@ -20,6 +20,18 @@ 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 @@ -52,7 +64,15 @@ registerotffeature { } } -local function hex2dec(hex,one) + +--[[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 @@ -60,33 +80,41 @@ local function hex2dec(hex,one) end end -local res +--- 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) + 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 = hex2dec(a,true) + a = hex_to_dec(a,true) pageresources(a) end else return nil end - r = hex2dec(r) - g = hex2dec(g) - b = hex2dec(b) + 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' @@ -106,6 +134,7 @@ 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 @@ -122,9 +151,7 @@ local function lookup_next_color(head) 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 == -1 then - return -1 - elseif r then + if r then return r end @@ -135,6 +162,13 @@ local function lookup_next_color(head) 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 @@ -169,28 +203,31 @@ local function node_colorize(head, current_color, next_color) return head, current_color end -local function font_colorize(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 +--- 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 -function add_color_callback() +--- unit -> unit +function add_color_callback () if color_callback_activated == 0 then - luatexbase.add_to_callback( - "pre_output_filter", font_colorize, "luaotfload.colorize") + luatexbase.add_to_callback("pre_output_filter", + color_handler, + "luaotfload.color_handler") color_callback_activated = 1 end end |