New Font:render method

API.md

@@ -37,7 +37,7 @@ minetest.register_node("mymod:test_text_node", {
 })
 ```
 
-At this step, your node already displays text form "display_text" (hardcoded) node meta.
+At this step, your node already displays text form "display_text" (by default) node meta. If you want to store your text into another meta data field, add a `meta_text` field to display entity definition.
 
 But it uses defaults (default font, default size, default color). Likely you need something more.
 
@@ -59,6 +59,28 @@ Then specify the char width. Two methods available:
   * `halign`: Horizontal alignment: "left", "center" or "right" (default "center").
   * `valign`: Vertical alignement: "top", "middle" or "bottom" (default "middle").
 
+### Example
+Using blue //botic// font, three lines height, aligned top left. Text stored in "text" node meta.
+```
+minetest.register_node("mymod:test_text_node", {
+	...
+	...
+	display_entities = {
+		["mymod:text"] = {
+			depth = -0.5 - display_api.entity_spacing,
+			on_display_update = font_api.on_display_update
+			meta_text = "text",
+			font_name = "botic",
+			color = "#0000FF",
+			maxlines = 3,
+			aspect_ratio = 0.5,
+			halign = "left",
+			valign = "top",
+			},
+	}
+	...
+})
+```
 ## Provided methods
 ### font_api.get_default_font_name()
 Returns de default font name.
@@ -159,19 +181,13 @@ Returns line(s) height. Takes care of top and bottom margins and line spacing.
 Returns the width of a text line. Beware, if line contains any new line char, they are ignored.
   * `line`: Line of text which the width will be computed.
 
-### font:make_line_texture(line, texturew, x, y)
+### font:renter(text, texturew, textureh, style)
-Create a texture for a text line.
-  * `line`: Line of text to be rendered in texture.
-  * `texturew`: Width of the texture (extra text is not rendered).
-  * `x`: Starting x position in texture.
-	* `y`: Vertical position of the line in texture.
-
-### font:make_text_texture(text, texturew, textureh, maxlines, halign, valign, color)
 Builds texture for a multiline colored text.
   * `text`: Text to be rendered.
   * `texturew`: Width of the texture (extra text will be truncated).
-  * `textureh`: Height of the texture.
+  * `textureh`: Height of the texture (extra text will be truncated).
-  * `maxlines`: Maximum number of lines.
+  * `style`: A table with style indications:
-  * `halign`: Horizontal text align ("left"/"center"/"right") (optional).
+    - `lines` or `maxlines`: Maximum number of lines (default none).
-  * `valign`: Vertical text align ("top"/"center"/"bottom") (optional).
+    - `halign`: Horizontal text align: "left"/"center"/"right" (default "center")
-  * `color`: Color of the text (optional).
+    - `valign`: Vertical text align: "top"/"middle"/"bottom" (default "middle")
+    - `color`: Color of the text (default black)

font.lua

@@ -54,20 +54,6 @@ local function char_to_codepoint(str)
 	end
 end
 
--- Split multiline text into array of lines, with <maxlines> maximum lines.
--- Can not use minetest string.split as it has bug if first line(s) empty
-local function split_lines(text, maxlines)
-	local lines = {}
-	local pos = 1
-	repeat
-		local found = string.find(text, "\n", pos)
-		found = found or #text + 1
-		lines[#lines + 1] = string.sub(text, pos, found - 1)
-		pos = found + 1
-	until (maxlines and (#lines >= maxlines)) or (pos > (#text + 1))
-	return lines
-end
-
 --------------------------------------------------------------------------------
 --- Font class
 
@@ -195,88 +181,86 @@ function Font:get_width(line)
 	return width
 end
 
---- Builds texture part for a text line
+--- Legacy make_text_texture method (replaced by "render" - Dec 2018)
--- @param line Text line to be rendered
--- @param texturew Width of the texture (extra text is not rendered)
--- @param x Starting x position in texture
--- @param y Vertical position of the line in texture
--- @return Texture string
-
-function Font:make_line_texture(line, texturew, x, y)
-	local codepoint
-	local texture = ""
-	line = line or ''
-
-	while line ~= '' do
-		codepoint, line = self:get_next_char(line)
-
-		-- Add image only if it is visible (at least partly)
-		if x + self:get_char_width(codepoint) >= 0 and x <= texturew then
-			texture = texture..
-				string.format(":%d,%d=font_%s_%04x.png",
-				              x, y, self.name, codepoint)
-		end
-		x = x + self:get_char_width(codepoint)
-	end
-
-	return texture
-end
-
---- Builds texture for a multiline colored text
--- @param text Text to be rendered
--- @param texturew Width of the texture (extra text will be truncated)
--- @param textureh Height of the texture
--- @param maxlines Maximum number of lines
--- @param halign Horizontal text align ("left"/"center"/"right") (optional)
--- @param valign Vertical text align ("top"/"center"/"bottom") (optional)
--- @param color Color of the text (optional)
--- @return Texture string
 
 function Font:make_text_texture(text, texturew, textureh, maxlines,
 		halign, valign, color)
-	local texture = ""
+		return self:render(text, texturew, textureh, {
-	local lines = {}
+			lines = maxlines,
-	local textheight = 0
+			valign = valign,
-	local y
+			halign = halign,
+			color = color
+		})
+end
 
-	-- Split text into lines (limited to maxlines fist lines)
+--- Render text with the font in a view
-	for num, line in pairs(split_lines(text, maxlines)) do
+-- @param text Text to be rendered
-		lines[num] = { text = line, width = self:get_width(line) }
+-- @param texturew Width (in pixels) of the texture (extra text will be truncated)
+-- @param textureh Height (in pixels) of the texture (extra text will be truncated)
+-- @param style Style of the rendering:
+--		- lines: maximum number of text lines (if text is limited)
+--		- halign: horizontal align ("left"/"center"/"right")
+--		- valign: vertical align ("top"/"center"/"bottom")
+--		- color: color of the text ("#rrggbb")
+-- @return Texture string
+
+function Font:render(text, texturew, textureh, style)
+	local style = style or {}
+
+	-- Split text into lines (and limit to style.lines # of lines)
+	local lines = {}
+	local pos = 1
+	local found, line
+	repeat
+		found = string.find(text, "\n", pos) or (#text + 1)
+		line = string.sub(text, pos, found - 1)
+		lines[#lines + 1] = { text = line, width = self:get_width(line) }
+		pos = found + 1
+	until (style.lines and (#lines >= style.lines)) or (pos > (#text + 1))
+
+	if not #lines then
+		return ""
 	end
 
-	textheight = self:get_height(#lines)
+	local x, y, codepoint
+	local texture = ""
+	local textheight = self:get_height(#lines)
 
-	if #lines then
+	if style.valign == "top" then
-		if valign == "top" then
+		y = 0
-			y = 0
+	elseif style.valign == "bottom" then
-		elseif valign == "bottom" then
+		y = textureh - textheight
-			y = textureh - textheight
+	else
-		else
+		y = (textureh - textheight) / 2
-			y = (textureh - textheight) / 2
-		end
 	end
 
 	y = y + (self.margintop or 0)
 
 	for _, line in pairs(lines) do
-		if halign == "left" then
+		if style.halign == "left" then
-			texture = texture..
+			x = 0
-				self:make_line_texture(line.text, texturew,
+		elseif style.halign == "right" then
-				0, y)
+			x = texturew - line.width
-		elseif halign == "right" then
-			texture = texture..
-				self:make_line_texture(line.text, texturew,
-				texturew - line.width, y)
 		else
-			texture = texture..
+			x = (texturew - line.width) / 2
-				self:make_line_texture(line.text, texturew,
+		end
-				(texturew - line.width) / 2, y)
+
+		while line.text ~= '' do
+			codepoint, line.text = self:get_next_char(line.text)
+
+			-- Add image only if it is visible (at least partly)
+			if x + self.widths[codepoint] >= 0 and x <= texturew then
+				texture = texture..
+					string.format(":%d,%d=font_%s_%04x.png", x, y, self.name, codepoint)
+			end
+			x = x + self.widths[codepoint]
 		end
 
 		y = y + self:get_height() + (self.linespacing or 0)
 	end
-
 	texture = string.format("[combine:%dx%d", texturew, textureh)..texture
-	if color then texture = texture.."^[colorize:"..color end
+	if style.color then
+		texture = texture.."^[colorize:"..style.color
+	end
 	return texture
 end

init.lua

@@ -39,43 +39,49 @@ dofile(font_api.path.."/fontform.lua")
 
 function font_api.on_display_update(pos, objref)
 	local meta = minetest.get_meta(pos)
-	local text = meta:get_string("display_text")
 	local ndef = minetest.registered_nodes[minetest.get_node(pos).name]
 	local entity = objref:get_luaentity()
 
-	if entity and ndef.display_entities[entity.name] then
+	if not entity or not ndef.display_entities[entity.name] then
-		local def = ndef.display_entities[entity.name]
+		return
-		local font = font_api.get_font(meta:get_string("font") ~= ""
-			and meta:get_string("font") or def.font_name)
-
-		-- Compute entity resolution accroding to given attributes
-		local texturew, textureh
-		textureh = font:get_height(def.lines or def.maxlines or 1)
-
-		if def.columns then
-			if font.fixedwidth then
-				texturew = def.columns * font.fixedwidth
-				if def.aspect_ratio then
-					minetest.log('warning', "[font_api] 'aspect_ratio' ignored because 'columns' is specified")
-				end
-			else
-				minetest.log('warning', "[font_api] 'columns' ignored because '"..font.name.."' is not a fixed width font.")
-			end
-		end
-
-		if not texturew then
-			if not def.aspect_ratio then
-				minetest.log('warning', "[font_api] No 'aspect_ratio' specified, using default 1.")
-			end
-			texturew = textureh * def.size.x / def.size.y	/ (def.aspect_ratio or 1)
-		end
-
-		objref:set_properties({
-			textures={font:make_text_texture(text, texturew, textureh,
-				def.maxlines, def.halign, def.valign, def.color)},
-			visual_size = def.size
-		})
 	end
+
+	local def = ndef.display_entities[entity.name]
+	local font = font_api.get_font(meta:get_string("font") ~= ""
+		and meta:get_string("font") or def.font_name)
+
+	local text = meta:get_string(def.meta_text or "display_text")
+
+	-- Compute entity resolution accroding to given attributes
+	local texturew, textureh
+	textureh = font:get_height(def.lines or def.maxlines or 1)
+
+	if def.columns then
+		if font.fixedwidth then
+			texturew = def.columns * font.fixedwidth
+			if def.aspect_ratio then
+				minetest.log('warning', "[font_api] 'aspect_ratio' ignored because 'columns' is specified")
+			end
+		else
+			minetest.log('warning', "[font_api] 'columns' ignored because '"..font.name.."' is not a fixed width font.")
+		end
+	end
+
+	if not texturew then
+		if not def.aspect_ratio then
+			minetest.log('warning', "[font_api] No 'aspect_ratio' specified, using default 1.")
+		end
+		texturew = textureh * def.size.x / def.size.y	/ (def.aspect_ratio or 1)
+	end
+
+	objref:set_properties({
+		textures={ font:render(text, texturew, textureh, {
+			lines = def.maxlines or def.lines,
+			halign = def.halign,
+			valign = def.valign,
+			color = def.color} ) },
+		visual_size = def.size,
+	})
 end
 
 -- Compatibility