Added support for linebreaks

Author: britzl

README.md

@@ -63,6 +63,9 @@ The following named colors are supported:
 | white     | `#ffffffff` | ![](https://placehold.it/15/ffffff/000000?text=+) |
 | yellow    | `#ffff00ff` | ![](https://placehold.it/15/ffff00/000000?text=+) |
 
+## Line breaks
+There is no need for the HTML `<br>` tag since line breaks (i.e. `\n`) are parsed and presented by the system.
+
 # Usage
 The RichText library will create gui text nodes representing the markup in the text passed to the library. It will search for tags and split the entire text into words, where each word contains additional meta-data that is used to create and configure text nodes. This means that the library will create as many text nodes as there are words in the text. Example:
 

example/example.gui_script

@@ -1,6 +1,6 @@
 local richtext = require "richtext.richtext"
 
-local TEXT = "<size=3>RichText</size>Lorem <color=0,0.5,0,1>ipsum </color>dolor <color=red>sit </color><color=#ff00ffff>amet, </color><size=1.15><font=Nanum>consectetur </font></size>adipiscing elit. <b>Nunc </b>tincidunt <b><i>mattis</i> libero</b> <i>non viverra</i>. Nullam ornare accumsan rhoncus. Nunc placerat nibh a purus auctor, id scelerisque massa rutrum."
+local TEXT = "<size=3>RichText</size>Lorem <color=0,0.5,0,1>ipsum </color>dolor <color=red>sit </color><color=#ff00ffff>amet, </color><size=1.15><font=Nanum>consectetur </font></size>adipiscing elit. <b>Nunc </b>tincidunt <b><i>mattis</i> libero</b> <i>non viverra</i>.\n\nNullam ornare accumsan rhoncus.\n\nNunc placerat nibh a purus auctor, id scelerisque massa rutrum."
 
 function init(self)
 	local settings = {

richtext/parse.lua

@@ -59,7 +59,7 @@ local function parse_tag(tag, params)
 	return settings
 end
 
-
+-- add a single word to the list of words
 local function add_word(text, settings, words)
 	local data = { text = text }
 	for k,v in pairs(settings) do
@@ -68,21 +68,41 @@ local function add_word(text, settings, words)
 	words[#words + 1] = data
 end
 
-local function split_and_add(text, settings, words)
-	local ws_start, trimmed_text, ws_end = text:match("^(%s*)(.-)(%s*)$")
+-- split a line into words
+local function split_line(line, settings, words)
+	local ws_start, trimmed_text, ws_end = line:match("^(%s*)(.-)(%s*)$")
 	if trimmed_text == "" then
 		add_word(ws_start .. ws_end, settings, words)
 	else
 		local wi = #words
-		for word in text:gmatch("%S+") do
+		for word in trimmed_text:gmatch("%S+") do
 			add_word(word .. " ", settings, words)
 		end
-		if #words > wi then
-			local first = words[wi + 1]
-			first.text = ws_start .. first.text
-			local last = words[#words]
-			last.text = last.text:sub(1,#last.text - 1) .. ws_end
-		end
+		local first = words[wi + 1]
+		first.text = ws_start .. first.text
+		local last = words[#words]
+		last.text = last.text:sub(1,#last.text - 1) .. ws_end
+	end
+end
+
+-- split text
+-- split by lines first
+local function split_text(text, settings, words)
+	local added_linebreak = false
+	if text:sub(-1)~="\n" then
+		added_linebreak = true
+		text = text .. "\n"
+	end
+
+	for line in text:gmatch("(.-)\n") do
+		split_line(line, settings, words)
+		local last = words[#words]
+		last.linebreak = true
+	end
+
+	if added_linebreak then
+		local last = words[#words]
+		last.linebreak = false
 	end
 end
 
@@ -114,13 +134,13 @@ function M.parse(s, parent_settings)
 		local before, tag, params, text, after = find_tag(s)
 		-- no more tags? Split and add the entire string
 		if not tag then
-			split_and_add(s, parent_settings, all_words)
+			split_text(s, parent_settings, all_words)
 			break
 		end
 
 		-- split and add text before the encountered tag
 		if before ~= "" then
-			split_and_add(before, parent_settings, all_words)
+			split_text(before, parent_settings, all_words)
 		end
 
 		-- parse the tag and merge it with settings for the parent tag

richtext/richtext.lua

@@ -46,7 +46,7 @@ function M.create(text, font, settings)
 	settings.position = settings.position or vmath.vector3()
 
 	-- cache length of a single space, per font
-	local space_widths = {}
+	local font_sizes = {}
 
 	local position = vmath.vector3(settings.position)
 
@@ -74,26 +74,39 @@ function M.create(text, font, settings)
 		gui.set_scale(node, vmath.vector3(1) * (word.size or 1))
 
 		-- measure width of a single space for current font
-		if not space_widths[font] then
-			space_widths[font] = gui.get_text_metrics(font, " _").width - gui.get_text_metrics(font, "_").width
+		if not font_sizes[font] then
+			font_sizes[font] = {
+				space = gui.get_text_metrics(font, " _").width - gui.get_text_metrics(font, "_").width,
+				height = gui.get_text_metrics(font, "Ij").height,
+			}
 		end
 
 		-- get metrics of node
 		word.metrics = gui.get_text_metrics_from_node(node)
-		word.metrics.total_width = (word.metrics.width + #get_trailing_whitespace(word.text) * space_widths[font]) * word.size
+		word.metrics.total_width = (word.metrics.width + #get_trailing_whitespace(word.text) * font_sizes[font].space) * word.size
 		word.metrics.width = word.metrics.width * word.size
 		word.metrics.height = word.metrics.height * word.size
 		highest_word = math.max(highest_word, word.metrics.height)
 
-		-- adjust position and position node
+		-- move word to next row if it overflows the width
 		local width = position.x + word.metrics.width - settings.position.x
 		if settings.width and width > settings.width then
 			position.y = position.y - highest_word
 			position.x = settings.position.x
-			highest_word = 0
+			highest_word = font_sizes[font].height
 		end
+
+		-- position word
 		gui.set_position(node, position)
-		position.x = position.x + word.metrics.total_width
+
+		-- handle linebreak or advance on same line
+		if word.linebreak then
+			position.y = position.y - highest_word
+			position.x = settings.position.x
+			highest_word = font_sizes[font].height
+		else
+			position.x = position.x + word.metrics.total_width
+		end
 	end
 
 	return nodes