SNKRX/engine/graphics/text.lua

277 lines
9.7 KiB
Lua

-- A generic text object.
-- It implements a character based tagging system which should allow you to implement any kind of text effect possible, from setting a character's color to making it become visible, shake and play sounds.
-- You would use it like this:
--[[
yellow_text_tag = TextTag({
init = function(c, i, text)
text.yellow = Color(1, 0.5, 0, 1)
end,
draw = function(c, i, text)
graphics.set_color(text.yellow)
end
})
shaking_text_tag = TextTag({
init = function(c, i, text)
c.shaking_intensity = 8
end,
update = function(c, dt, i, text)
c.ox = random:float(-c.shaking_intensity, c.shaking_intensity)
c.oy = random:float(-c.shaking_intensity, c.shaking_intensity)
end
})
text = Text({
{text: '[yellow]This text is yellow', font: some_font, alignment: 'center', height_offset: -10}
{text: '[shaking]This text is shaking', font: some_other_font, alignment: 'center', height_multiplier: 1.2}
{text: 'This text is normal', font: yet_another_font, alignment: 'center', height_multiplier: 1.2}
{text: '[yellow, shaking]This text is yellow and shaking []while this text is normal', font: some_font, alignment: 'center'}
}, {yellow = yellow_text_tag, shaking = shaking_text_tag})
]]--
-- There are two main things happening in the example above: first we're creating TextTags and then we're creating a text object that uses those tags.
-- The way each tag works is fairly simple: a tag accepts 3 functions, init, update and draw, and each of those functions operates on the text's characters one at a time.
-- In the example above, the text without tags is 'This text is yellow while this text is shaking and this text is normal'
-- For each of the characters in that string, different functions will be applied based on what tags were previously applied to it.
-- init, update and draw functions take in 3 arguments in common:
-- c - the character in question, a table containing .x, .y, .r, .sx, .sy, .ox, .oy and .character attributes.
-- i - the index of character in the string
-- text - the reference to the text object
-- The update function also takes in dt as the second argument.
--
-- After we're done creating TextTags, we have to create the actual text object.
-- The way this is done is by specifying each line of the text object, along with its font, alignment, height multipliers and height offsets.
-- The first argument (text_data) is a table of tables containing all relevant info:
-- text - the actual string containing the text to be displayed, along with any tag information
-- font - the font to be used for the text
-- alignment (optional) - how the text should align itself, possible values are 'center', 'justified', 'right', if not specified then by default it's 'left'
-- height_offset (optional) - how many pixels the line below this one should be offset by
-- height_multiplier (optional) - multiplier over the font's height for placing the line below
-- The text object itself also has .w and .h which corresponds to the width of the biggest line and height of all lines + offsets, respectively.
-- If 'alignment_width' is set to a specific line then that line will be automatically set to that width, and if it is the biggest then .w will also be set to that value.
Text = Object:extend()
function Text:init(text_data, text_tags)
self.trigger = Trigger()
self.text_data = text_data
self.text_tags = text_tags
self.white = Color(1, 1, 1, 1)
self:set_text(text_data)
return self
end
function Text:update(dt)
self.trigger:update(dt)
self:format_text()
for _, line in ipairs(self.lines) do
for i, c in ipairs(line.characters) do
for k, v in pairs(self.text_tags) do
for _, tag in ipairs(c.tags) do
if tag == k then
if v.actions.update then
v.actions.update(c, dt, i, self)
end
end
end
end
end
end
end
-- Draws the text object centered at the specified location.
function Text:draw(x, y, r, sx, sy)
for _, line in ipairs(self.lines) do
for i, c in ipairs(line.characters) do
for k, v in pairs(self.text_tags) do
for _, tag in ipairs(c.tags) do
if tag == k then
if v.actions.draw then
v.actions.draw(c, i, self)
end
end
end
end
graphics.push(x, y, r, sx, sy)
graphics.print(c.character, line.font, x + c.x - self.w/2, y + c.y - self.h/2, c.r or 0, c.sx or 1, c.sy or c.sx or 1, c.ox or 0, c.oy or 0)
graphics.pop()
graphics.set_color(self.white)
end
end
end
function Text:format_text()
self.w = 0
for i, line in ipairs(self.lines) do
local line_width = math.max(line.font:get_text_width(line.raw_text), line.alignment_width or 0)
if line_width > self.w then
self.w = line_width
end
end
local x, y = 0, 0
for j, line in ipairs(self.lines) do
local h = (line.font.h*(line.height_multiplier or 1) + (line.height_offset or 0))*(line.sy or 1)
for i, c in ipairs(line.characters) do
c.x = x
c.y = y
c.sx = line.sx or 1
c.sy = line.sy or 1
x = x + line.font:get_text_width(c.character)
end
y = y + h
x = 0
end
self.h = y
for i, line in ipairs(self.lines) do
if line.alignment == "right" then
local text_width = 0
for _, c in ipairs(line.characters) do text_width = text_width + line.font:get_text_width(c.character) end
local left_over_width = self.w - (line.alignment_width or text_width)
for _, c in ipairs(line.characters) do c.x = c.x + left_over_width end
elseif line.alignment == "center" then
local text_width = 0
for _, c in ipairs(line.characters) do text_width = text_width + line.font:get_text_width(c.character) end
local left_over_width = self.w - (line.alignment_width or text_width)
for _, c in ipairs(line.characters) do c.x = c.x + left_over_width/2 end
elseif line.alignment == "justified" then
local text_width = 0
for _, c in ipairs(line.characters) do text_width = text_width + line.font:get_text_width(c.character) end
local left_over_width = self.w - (line.alignment_width or text_width)
local spaces_count = 0
for _, c in ipairs(line.characters) do
if c.character == " " then
spaces_count = spaces_count + 1
end
end
local added_width_to_each_space = math.floor(left_over_width/spaces_count)
local total_added_width = 0
for _, c in ipairs(characters) do
if c.character == " " then
c.x = c.x + added_width_to_each_space
total_added_width = total_added_width + added_width_to_each_space
else
c.x = c.x + total_added_width
end
end
end
end
end
function Text:parse(text_data)
for _, line in ipairs(text_data) do
local tags = {}
for i, tags_text, j in line.text:gmatch("()%[(.-)%]()") do
if tags_text == "" then
table.insert(tags, {i = tonumber(i), j = tonumber(j)-1})
line.tags = tags
else
local local_tags = {}
for tag in tags_text:gmatch("[%w_]+") do table.insert(local_tags, tag) end
table.insert(tags, {i = tonumber(i), j = tonumber(j)-1, tags = local_tags})
line.tags = tags
end
end
if not line.tags then line.tags = {} end
end
for _, line in ipairs(text_data) do
line.characters = {}
local current_tags = nil
for i = 1, #line.text do
local c = line.text:sub(i, i)
local inside_tags = false
for _, tag in ipairs(line.tags) do
if i >= tag.i and i <= tag.j then
inside_tags = true
current_tags = tag.tags
break
end
end
if not inside_tags then
table.insert(line.characters, {character = c, visible = true, tags = current_tags or {}})
end
end
end
for _, line in ipairs(text_data) do
local raw_text = ""
for _, character in ipairs(line.characters) do
raw_text = raw_text .. character.character
end
line.raw_text = raw_text
end
return text_data
end
-- Sets new text.
-- Reapplies all modifications (wrap width, justification, etc).
function Text:set_text(text_data)
self.lines = self:parse(text_data)
self:format_text()
for _, line in ipairs(self.lines) do
for i, c in ipairs(line.characters) do
for k, v in pairs(self.text_tags) do
for _, tag in ipairs(c.tags) do
if tag == k then
if v.actions.init then
v.actions.init(c, i, self)
end
end
end
end
end
end
end
-- Sets the line's alignment width.
-- This is used to align the text according to the alignment option
-- For instance, if the alignment width is 200 and the alignment is 'right', then the right edge used for this alignment will be 200 units to the right
function Text:set_alignment_width(line, alignment_width)
self.alignment_width = alignment_width
self:format_text()
return self
end
-- Sets the text's line height.
-- Lines are automatically placed vertically using the font's height for spacing, but you can increase or decrease this distance by setting these values.
function Text:set_line_height_data(line, offset, multiplier)
self.lines[line].height_offset = offset or 0
self.lines[line].height_multiplier = multiplier or 1
self:format_text()
return self
end
-- Sets the text's font. By default texts use the global font.
function Text:set_font(line, font)
self.lines[line].font = font
self:format_text()
return self
end
-- Sets the alignment behavior for the given line.
-- Possible behaviors are: 'right', 'center' and 'justified'
function Text:set_alignment(line, alignment)
self.lines[line].alignment = alignment
self:format_text()
return self
end
-- The text tag objects to be used with text instances.
TextTag = Object:extend()
function TextTag:init(actions)
self.actions = actions
end