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Fix line layout when using combine_words (#36)
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* Fix word spacing metrics with combine_words = true

* Don't combine words with different tags

* Respect kerning in richtext.characters()

This also fixes running richtext.characters() on combined words
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@dapetcu21 @britzl
dapetcu21 authored and britzl committed Aug 23, 2019
1 parent 046ee3f commit b8792e7
Showing 1 changed file with 121 additions and 77 deletions.
198 changes: 121 additions & 77 deletions richtext/richtext.lua
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Original file line number Diff line number Diff line change
Expand Up @@ -11,8 +11,6 @@ M.ALIGN_RIGHT = hash("ALIGN_RIGHT")
local V3_ZERO = vmath.vector3(0)
local V3_ONE = vmath.vector3(1)

local TEXT_NODE_CACHE = {}

local id_counter = 0

local function new_id(prefix)
Expand Down Expand Up @@ -88,46 +86,35 @@ local function get_layer(word, layers)
return layers.fonts[gui.get_font(node)]
end

-- compare two words and check that they have the same size, color and font
-- compare two words and check that they have the same size, color, font and tags
local function compare_words(one, two)
return one ~= nil and two ~= nil and one.size == two.size and one.color == two.color and one.font == two.font
end


-- combine a list of words to reduce node count as much as possible
-- this will only combine text nodes
-- combined words will be removed from the list and their nodes added
-- to a node cache for reuse
-- @param words The words to combine
-- @param cache The cache to add combined words to
local function combine_words(words)
local previous_word = nil
local i = 1
while i <= #words do
word = words[i]
if previous_word and word.text and previous_word.text and compare_words(word, previous_word) then
local previous_metrics = previous_word.metrics
local current_metrics = word.metrics
previous_word.text = previous_word.text .. word.text
previous_metrics.width = previous_metrics.width + current_metrics.width
previous_metrics.height = math.max(previous_metrics.height, current_metrics.height)
gui.set_size(previous_word.node, vmath.vector3(previous_metrics.width, previous_metrics.height, 0))
gui.set_text(previous_word.node, previous_word.text)
table.remove(words, i)
TEXT_NODE_CACHE[#TEXT_NODE_CACHE + 1] = word.node
else
previous_word = word
i = i + 1
if one == nil or two == nil or one.size ~= two.size or one.color ~= two.color or one.font ~= two.font then
return false
end
local one_tags, two_tags = one.tags, two.tags
if one_tags == two_tags then
return true
end
if one_tags == nil or two_tags == nil then
return false
end
for k, v in pairs(one_tags) do
if two_tags[k] ~= v then
return false
end
end
for k, v in pairs(two_tags) do
if one_tags[k] ~= v then
return false
end
end
return true
end


-- position all words according to the line alignment and line width
-- the list of words will be empty after this function is called
local function position_words(words, line_width, line_height, position, settings)
if settings.combine_words then
combine_words(words)
end
if settings.align == M.ALIGN_RIGHT then
position.x = position.x - line_width
elseif settings.align == M.ALIGN_CENTER then
Expand Down Expand Up @@ -234,34 +221,41 @@ local function get_text_metrics(word, font, text)
end


local function create_text_node(word, font)
local node = table.remove(TEXT_NODE_CACHE)
if node then
gui.set_text(node, word.text)
else
node = gui.new_text_node(V3_ZERO, word.text)
end
local function create_text_node(word, font, metrics)
local node = gui.new_text_node(V3_ZERO, word.text)
gui.set_id(node, new_id("textnode"))
gui.set_font(node, font)
gui.set_color(node, word.color)
gui.set_outline(node, word.color)
gui.set_scale(node, V3_ONE * word.size)

local metrics = get_text_metrics(word, font)
metrics = metrics or get_text_metrics(word, font)
gui.set_size_mode(node, gui.SIZE_MODE_MANUAL)
gui.set_size(node, vmath.vector3(metrics.width, metrics.height, 0))
return node, metrics
end


local function create_node(word, parent, font)
local node, metrics
local function combine_node(previous_word, word, metrics)
local text = previous_word.text .. word.text
previous_word.text = text
previous_word.metrics = metrics
gui.set_size(previous_word.node, vmath.vector3(metrics.width, metrics.height, 0))
gui.set_text(previous_word.node, text)
end


local function create_node(word, parent, font, node, metrics)
if word.image then
node, metrics = create_box_node(word)
if not node then
node, metrics = create_box_node(word)
end
elseif word.spine then
node, metrics = create_spine_node(word)
if not node then
node, metrics = create_spine_node(word)
end
else
node, metrics = create_text_node(word, font)
node, metrics = create_text_node(word, font, metrics)
end
gui.set_pivot(node, gui.PIVOT_NW)
gui.set_parent(node, parent)
Expand All @@ -270,6 +264,22 @@ local function create_node(word, parent, font)
end


local function measure_node(word, font, previous_word)
local node, metrics, combined_metrics
if word.image then
node, metrics = create_box_node(word)
elseif word.spine then
node, metrics = create_spine_node(word)
else
metrics = get_text_metrics(word, font)
if previous_word then
combined_metrics = get_text_metrics(word, font, previous_word.text .. word.text)
end
end
return metrics, combined_metrics, node
end



--- Create rich text gui nodes from text
-- @param text The text to create rich text nodes from
Expand Down Expand Up @@ -311,24 +321,33 @@ function M.create(text, font, settings)
local line_width = 0
local line_height = 0
local position = vmath.vector3(settings.position)
for i=1,#words do
local word_count = #words
for i = 1, word_count do
local word = words[i]
--print("word: [" .. word.text .. "]")

-- get font to use based on word tags
local font_for_word = get_font(word, settings.fonts)

-- create node and get metrics
word.node, word.metrics = create_node(word, settings.parent, font_for_word)

-- assign layer
local layer = get_layer(word, settings.layers)
if layer then
gui.set_layer(word.node, layer)
-- get the previous word, so we can combine
local previous_word
if settings.combine_words then
previous_word = line_words[#line_words]
if not compare_words(previous_word, word) then
previous_word = nil
end
end

-- get metrics first, without creating the node (if possible)
local word_metrics, combined_metrics, node = measure_node(word, font_for_word, previous_word)
local should_create_node = true

-- does the word fit on the line or does it overflow?
local overflow = (settings.width and (line_width + word.metrics.width) > settings.width)
local overflow = (settings.width and ((combined_metrics
and (line_width - previous_word.metrics.total_width + combined_metrics.width)
or (line_width + word_metrics.width)
) > settings.width))

if overflow and not word.nobr then
-- overflow, position the words that fit on the line
position.x = settings.position.x
Expand All @@ -341,16 +360,36 @@ function M.create(text, font, settings)
-- update text metrics
text_metrics.width = math.max(text_metrics.width, line_width)
text_metrics.height = text_metrics.height + (line_height * settings.line_spacing)
line_width = word.metrics.total_width
line_height = word.metrics.height
line_width = word_metrics.total_width
line_height = word_metrics.height
else
-- the word fits on the line, add it and update text metrics
line_width = line_width + word.metrics.total_width
line_height = math.max(line_height, word.metrics.height)
line_words[#line_words + 1] = word
if combined_metrics then
line_width = line_width - previous_word.metrics.total_width + combined_metrics.total_width
line_height = math.max(line_height, combined_metrics.height)
combine_node(previous_word, word, combined_metrics)
should_create_node = false
else
line_width = line_width + word_metrics.total_width
line_height = math.max(line_height, word_metrics.height)
line_words[#line_words + 1] = word
end
text_metrics.width = math.max(text_metrics.width, line_width)
end

if should_create_node then
word.node, word.metrics = create_node(word, settings.parent, font_for_word, node, word_metrics)

-- assign layer
local layer = get_layer(word, settings.layers)
if layer then
gui.set_layer(word.node, layer)
end
else
-- queue this word for deletion
word.delete = true
end

-- handle line break
if word.linebreak then
-- position all words on the line up until the linebreak
Expand All @@ -360,7 +399,7 @@ function M.create(text, font, settings)

-- update text metrics
text_metrics.height = text_metrics.height + (line_height * settings.line_spacing)
line_height = word.metrics.height
line_height = word_metrics.height
line_width = 0
end
end
Expand All @@ -373,8 +412,17 @@ function M.create(text, font, settings)
text_metrics.height = text_metrics.height + line_height
end

while #TEXT_NODE_CACHE > 0 do
gui.delete_node(table.remove(TEXT_NODE_CACHE))
-- compact words table
local j = 1
for i = 1, word_count do
local word = words[i]
if not word.delete then
words[j] = word
j = j + 1
end
end
for i = j, word_count do
words[i] = nil
end

return words, text_metrics
Expand Down Expand Up @@ -466,8 +514,10 @@ function M.characters(word)
local font = gui.get_font(word.node)
local layer = gui.get_layer(word.node)

local word_length = utf8.len(word.text)

-- exit early if word is a single character or empty
if utf8.len(word.text) <= 1 then
if word_length <= 1 then
local char = deepcopy(word)
char.node, char.metrics = create_node(char, parent, font)
gui.set_position(char.node, gui.get_position(word.node))
Expand All @@ -477,25 +527,19 @@ function M.characters(word)

-- split word into characters
local chars = {}
local chars_width = 0
for i = 1, utf8.len(word.text) do
local position = gui.get_position(word.node)
local position_x = position.x

for i = 1, word_length do
local char = deepcopy(word)
chars[#chars + 1] = char
char.text = utf8.sub(word.text, i, i)
char.node, char.metrics = create_node(char, parent, font)
gui.set_layer(char.node, layer)
chars_width = chars_width + char.metrics.width
end

-- position each character
-- take into account that the sum of the width of the individual
-- characters differ from the width of the entire word
local position = gui.get_position(word.node)
local spacing = (word.metrics.width - chars_width) / (#chars - 1)
for i=1,#chars do
local char = chars[i]
local sub_metrics = get_text_metrics(word, font, utf8.sub(word.text, 1, i))
position.x = position_x + sub_metrics.width - char.metrics.width
gui.set_position(char.node, position)
position.x = position.x + char.metrics.width + spacing
end

return chars
Expand Down

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