[*] Initial commit.

.gitignore

@@ -0,0 +1,48 @@
+# ---> Lua
+# Compiled Lua sources
+luac.out
+
+# luarocks build files
+*.src.rock
+*.zip
+*.tar.gz
+
+# Object files
+*.o
+*.os
+*.ko
+*.obj
+*.elf
+
+# Precompiled Headers
+*.gch
+*.pch
+
+# Libraries
+*.lib
+*.a
+*.la
+*.lo
+*.def
+*.exp
+
+# Shared objects (inc. Windows DLLs)
+*.dll
+*.so
+*.so.*
+*.dylib
+
+# Executables
+*.exe
+*.out
+*.app
+*.i*86
+*.x86_64
+*.hex
+
+# ldoc output directory
+doc/
+# crush library directory
+lib/
+
+

.lovedeps

@@ -0,0 +1,4 @@
+{
+    gear = "https://git.doublefourteen.io/lua/gear",
+    moonspeak = "https://git.doublefourteen.io/lua/moonspeak"
+}

LICENSE

@@ -0,0 +1,17 @@
+Copyright (c) 2022 The DoubleFourteen Code Forge
+
+This software is provided 'as-is', without any express or implied
+warranty. In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+1. The origin of this software must not be misrepresented; you must not
+   claim that you wrote the original software. If you use this software
+   in a product, an acknowledgment in the product documentation would be
+   appreciated but is not required.
+2. Altered source versions must be plainly marked as such, and must not be
+   misrepresented as being the original software.
+3. This notice may not be removed or altered from any source distribution.

README.ACKNOWLEDGEMENT

@@ -0,0 +1,29 @@
+Portions of Yui code are based on SUIT - Simple User Interface Toolkit for LÖVE,
+by Mathias Richter, available at:
+https://github.com/vrld/SUIT
+
+Under the following license:
+
+> Copyright (c) 2016 Matthias Richter
+>
+> Permission is hereby granted, free of charge, to any person obtaining a copy
+> of this software and associated documentation files (the "Software"), to deal
+> in the Software without restriction, including without limitation the rights
+> to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+> copies of the Software, and to permit persons to whom the Software is
+> furnished to do so, subject to the following conditions:
+>
+> The above copyright notice and this permission notice shall be included in
+> all copies or substantial portions of the Software.
+>
+> Except as contained in this notice, the name(s) of the above copyright holders
+> shall not be used in advertising or otherwise to promote the sale, use or
+> other dealings in this Software without prior written authorization.
+>
+> THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+> IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+> FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+> AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+> LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+> OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+> THE SOFTWARE.

README.md

@@ -0,0 +1,29 @@
+Yui - A Declarative UI library for LÖVE
+=======================================
+
+**Yui** - Yet another User Interface, is an attempt to ease the process of assembling trivial menu-like GUIs for your game using [LÖVE](https://love2d.org).
+
+## Why is that?
+
+Because I'm spending so much time tweaking and customizing existing libraries,
+I might as well make my own.
+
+## Dependencies
+
+**Yui** depends on:
+
+* [gear](https://git.doublefourteen.io/lua/gear) for general algorithms.
+* [moonspeak](https://git.doublefourteen.io/lua/moonspeak) for its localization functionality.
+
+## Acknowledgement
+
+Portions of this library's widget rendering code are taken from the
+Simple User Interface Toolkit (**SUIT**) for LÖVE by Matthias Richter.
+
+SUIT's source code is available at: [vrld/SUIT](https://github.com/vrld/SUIT).
+SUIT is licensed under the [MIT license](https://github.com/vrld/suit/blob/master/license.txt).
+
+Widgets offered by **yui** are also inspired by **SUIT**.
+
+See [ACKNOWLEDGEMENT](README.ACKNOWLEDGEMENT) for full SUIT license
+information and copyright notice.

button.lua

@@ -0,0 +1,59 @@
+local BASE = (...):gsub('button', '')
+
+local Widget = require BASE..'widget'
+local core = require BASE..'core'
+
+local shadowtext = require 'lib.gear.shadowtext'
+local T = require('lib.moonspeak').translate
+
+local Button = setmetatable({}, Widget)
+Button.__index = Button
+
+
+function Button.new(args)
+    local self = setmetatable(args, Button)
+
+    self.text = self.text or ""
+    self.align = self.align or 'center'
+    self.valign = self.valign or 'center'
+    self.color = self.color or core.theme.color
+    self.cornerRadius = self.cornerRadius or core.theme.cornerRadius
+    self.active = false
+    if not self.notranslate then
+        self.text = T(self.text)
+    end
+    return self
+end
+
+local function hit(button)
+    if not button.active then
+        button.active = true
+        button:onHit()
+
+        button.ui.timer:after(0.15, function() button.active = false end)
+    end
+end
+
+function Button:onPointerInput(px,py, clicked)
+    self:grabFocus()
+    if clicked then hit(self) end
+end
+
+function Button:onActionInput(action)
+    if action.confirm then hit(self) end
+end
+
+function Button:draw()
+    local x,y,w,h = self.x,self.y,self.w,self.h
+    local font = self.font or love.graphics.getFont()
+    local c = self:colorForState()
+
+    core.drawBox(x,y,w,h, c, self.cornerRadius)
+    love.graphics.setColor(c.fg)
+    love.graphics.setFont(font)
+
+    y = y + core.verticalOffsetForAlign(self.valign, font, h)
+    shadowtext.printf(self.text, x+2, y, w-4, self.align)
+end
+
+return Button

checkbox.lua

@@ -0,0 +1,64 @@
+local BASE = (...):gsub('checkbox', '')
+
+local Widget = require BASE..'widget'
+local core = require BASE..'core'
+
+local shadowtext = require 'lib.gear.shadowtext'
+local T = require('lib.moonspeak').translate
+
+local Checkbox = setmetatable({}, Widget)
+Checkbox.__index = Checkbox
+
+
+function Checkbox.new(args)
+    local self = setmetatable(args, Checkbox)
+
+    self.text = self.text or ""
+    self.text = self.notranslate and self.text or T(self.text)
+    self.align = self.align or 'left'
+    self.valign = self.valign or 'center'
+    self.color = self.color or core.theme.color
+    self.cornerRadius = self.cornerRadius or core.theme.cornerRadius
+    self.checked = self.checked or false
+    return self
+end
+
+function Checkbox:onPointerInput(px,py, clicked)
+    self:grabFocus()
+    if clicked then
+        self.checked = not self.checked
+        self:onChange(self.checked)
+    end
+end
+
+function Checkbox:onActionInput(action)
+    if action.confirm then
+        self.checked = not self.checked
+        self:onChange(self.checked)
+    end
+end
+
+function Checkbox:draw()
+    local x,y,w,h = self.x,self.y,self.w,self.h
+    local c = self:colorForState()
+    local font = self.font or love.graphics.getFont()
+
+    -- Draw checkbox
+    core.drawBox(x+h/10,y+h/10,h*.8,h*.8, c, self.cornerRadius)
+    love.graphics.setColor(c.fg)
+    if self.checked then
+        love.graphics.setLineStyle('smooth')
+        love.graphics.setLineWidth(5)
+        love.graphics.setLineJoin('bevel')
+        love.graphics.line(x+h*.2,y+h*.55, x+h*.45,y+h*.75, x+h*.8,y+h*.2)
+    end
+
+    -- Most of the times checkboxes have no text, so test for performance
+    if self.text ~= "" then
+        love.graphics.setFont(font)
+        y = y + core.verticalOffsetForAlign(self.valign, font, self.h)
+        shadowtext.printf(self.text, x + h, y, w - h, self.align)
+    end
+end
+
+return Checkbox

choice.lua

@@ -0,0 +1,148 @@
+local BASE = (...):gsub('choice', '')
+
+local Widget = require BASE..'widget'
+local core = require BASE..'core'
+
+local shadowtext = require 'lib.gear.shadowtext'
+local T = require('lib.moonspeak').translate
+
+local Choice = setmetatable({}, Widget)
+Choice.__index = Choice
+
+
+function Choice.new(args)
+    local self = setmetatable(args, Choice)
+
+    self.align = self.align or 'center'
+    self.valign = self.valign or 'center'
+    self.cornerRadius = self.cornerRadius or core.theme.cornerRadius
+    self.color = self.color or core.theme.color
+    self.hovered = false
+    self.choices = self.choices or { "" }
+    self.nowrap = self.nowrap or #self.choices == 0
+    self.index = 1  -- by default
+
+    for i,choice in ipairs(self.choices) do
+        -- Expand shorthands
+        if type(choice) ~= 'table' then
+            choice = {
+                text = tostring(choice),
+                notranslate = type(choice) ~= 'string',
+                value = choice
+            }
+
+            self.choices[i] = choice
+        end
+        -- Mark default choice if needed
+        if choice.value == self.default then
+            self.index = i
+        end
+        -- Translate choice
+        if not (self.notranslate or choice.notranslate) then
+            choice.text = T(choice.text)
+        end
+    end
+    return self
+end
+
+function Choice:checkIndex()
+    if self.nowrap then
+        self.index = math.min(math.max(self.index, 1), #self.choices)
+    else
+        if self.index < 1 then
+            self.index = #self.choices
+        end
+        if self.index > #self.choices then
+            self.index = 1
+        end
+    end
+end
+
+function Choice:onActionInput(action)
+    local oldindex = self.index
+    local handled = false
+
+    -- Change choice
+    if action.left then
+        self.index = oldindex - 1
+        handled = true
+    end
+    if action.right then
+        self.index = oldindex + 1
+        handled = true
+    end
+    if not handled then
+        return false
+    end
+
+    -- Apply wrapping
+    self:checkIndex()
+
+    -- Fire event if necessary
+    if oldindex ~= self.index then
+        self:onChange(self.choices[self.index])
+    end
+    return true
+end
+
+function Choice:onPointerInput(px,py, clicked)
+    self:grabFocus()
+    if not clicked then
+        return
+    end
+
+    local mx = px - self.x
+    local oldindex = self.index
+
+    -- Test whether arrows are hit
+    -- NOTE: don't care about arrows being disabled, checkIndex() will fix that.
+    if mx <= self.h+2 then
+        self.index = self.index - 1
+    elseif mx >= self.w - self.h-2 then
+        self.index = self.index + 1
+    end
+
+    self:checkIndex()
+    if oldindex ~= self.index then
+        self:onChange(self.choices[self.index])
+    end
+end
+
+function Choice:draw()
+    local x,y,w,h = self.x,self.y,self.w,self.h
+    local font = self.font or love.graphics.getFont()
+    local c = self:colorForState()
+
+    core.drawBox(x,y,w,h, c, self.cornerRadius)
+
+    if self.ui.focused == self then
+        -- draw < and > arrows, desaturate color if arrow is disabled
+        local cc = self.color.hovered
+
+        love.graphics.setLineStyle('smooth')
+        love.graphics.setLineWidth(3)
+        love.graphics.setLineJoin('bevel')
+
+        local r, g, b = cc.fg[1], cc.fg[2], cc.fg[3]
+        local a = (self.nowrap and self.index == 1) and 0.4 or 1
+
+        love.graphics.setColor(r,g,b,a)
+        love.graphics.line(x+h*.8,y+h*.2, x+h*.5,y+h*.5, x+h*.8,y+h*.8)
+
+        a = (self.nowrap and self.index == #self.choices) and 0.4 or 1
+
+        love.graphics.setColor(r,g,b,a)
+        love.graphics.line(x+w-h*.8,y+h*.2, x+w-h*.5,y+h*.5, x+w-h*.8,y+h*.8)
+    end
+
+    -- draw text
+    local text = self.choices[self.index].text
+
+    y = y + core.verticalOffsetForAlign(self.valign, font, h)
+
+    love.graphics.setColor(c.fg)
+    love.graphics.setFont(font)
+    shadowtext.printf(text, x+h+2, y, w-2*(h + 2), self.align)
+end
+
+return Choice

columns.lua

@@ -0,0 +1,24 @@
+local BASE = (...):gsub('columns', '')
+
+local Layout = require BASE..'layout'
+
+local Columns = setmetatable({}, Layout)
+Columns.__index = Columns
+
+
+-- Advance position to next column,
+-- given current position, widget dimensions and padding.
+local function columnadvance(x,y, ww,wh, padding)
+    return x + ww + padding, y
+end
+
+function Columns.new(args)
+    local self = setmetatable(Layout.new(args), Columns)
+
+    self.advance = columnadvance
+    self.prev = 'left'
+    self.next = 'right'
+    return self
+end
+
+return Columns

core.lua

@@ -0,0 +1,27 @@
+local BASE = (...):gsub('core', '')
+
+local core = { theme = require(BASE..'theme') }
+core.__index = core
+
+-- Helpers for drawing
+function core.verticalOffsetForAlign(valign, font, h)
+    if valign == 'top' then
+        return 0
+    elseif valign == 'bottom' then
+        return h - font:getHeight()
+    end
+    -- else: "middle"
+    return (h - font:getHeight()) / 2
+end
+
+function core.drawBox(x,y,w,h, color, cornerRadius)
+    w = math.max(cornerRadius/2, w)
+    if h < cornerRadius/2 then
+        y,h = y - (cornerRadius - h), cornerRadius/2
+    end
+
+    love.graphics.setColor(color.bg)
+    love.graphics.rectangle('fill', x,y, w,h, cornerRadius)
+end
+
+return core

crush.lua

@@ -0,0 +1,284 @@
+--- crush - The uncomplicated dependency system for LÖVE.
+--
+-- Author: Lorenzo Cogotti
+-- Copyright: 2022 The DoubleFourteen Code Forge
+-- License: MIT (see LICENSE file for details)
+
+local io = require 'io'
+local os = require 'os'
+
+-- System specific functions
+--
+-- Portions of this code are based on work from the LuaRocks project.
+-- LuaRocks is free software and uses the MIT license.
+--
+-- LuaRocks website: https://luarocks.org
+-- LuaRocks sources: https://github.com/luarocks/luarocks
+
+local is_windows = package.config:sub(1,1) == "\\"
+
+local is_directory
+local Q
+local quiet
+local chdir
+local mkdir
+
+if is_windows then
+    -- ---------------
+    -- NOTE: untested!
+    -- ---------------
+
+    -- local
+    function is_directory(path)
+        local fh, _, code = io.open(path, 'r')
+
+        if code == 13 then  -- directories return "Permission denied"
+            fh, _, code = io.open(path.."\\", 'r')
+            if code == 2 then  -- directories return 2, files return 22
+                return true
+            end
+        end
+        if fh then
+            fh:close()
+        end
+        return false
+    end
+
+    local function split_path(s)
+        local drive = ""
+        local root = ""
+        local rest
+
+        local unquoted = s:match("^['\"](.*)['\"]$")
+        if unquoted then
+            s = unquoted
+        end
+        if s:match("^.:") then
+            drive = s:sub(1, 2)
+            s = s:sub(3)
+        end
+        if s:match("^[\\/]") then
+            root = s:sub(1, 1)
+            rest = s:sub(2)
+        else
+            rest = s
+        end
+        return drive, root, rest
+    end
+
+    -- local
+    function Q(s)
+        local drive, root, rest = split_path(s)
+        if root ~= "" then
+            s = s:gsub("/", "\\")
+        end
+        if s == "\\" then
+            return '\\' -- CHDIR needs special handling for root dir
+        end
+
+        -- URLs and anything else
+        s = s:gsub('\\(\\*)"', '\\%1%1"')
+        s = s:gsub('\\+$', '%0%0')
+        s = s:gsub('"', '\\"')
+        s = s:gsub('(\\*)%%', '%1%1"%%"')
+        return '"'..s..'"'
+    end
+
+    -- local
+    function quiet(cmd)
+        return cmd.."  2> NUL 1> NUL"
+    end
+
+    -- local
+    function chdir(newdir, cmd)
+        local drive = newdir:match("^([A-Za-z]:)")
+
+        cmd = "cd "..Q(newdir).." & "..cmd
+        if drive then
+            cmd = drive.." & "..cmd
+        end
+        return cmd
+    end
+
+    -- local
+    function mkdir(path)
+        local cmd = "mkdir "..Q(path).." 2> NUL 1> NUL"
+
+        os.execute(cmd)
+        if not is_directory(path) then
+            error("Couldn't create directory '"..path.."'.")
+        end
+    end
+else
+    -- local
+    function is_directory(path)
+        local fh, _, code = io.open(path.."/.", 'r')
+
+        if code == 2 then   -- "No such file or directory"
+            return false
+        end
+        if code == 20 then  -- "Not a directory", regardless of permissions
+            return false
+        end
+        if code == 13 then  -- "Permission denied", but is a directory
+            return true
+        end
+        if fh then
+            _, _, code = fh:read(1)
+            fh:close()
+            if code == 21 then  -- "Is a directory"
+                return true
+            end
+        end
+        return false
+    end
+
+    -- local
+    function Q(s)
+        return "'"..s:gsub("'", "'\\''").."'"
+    end
+
+    -- local
+    function quiet(cmd)
+        return cmd.." >/dev/null 2>&1"
+    end
+
+    -- local
+    function chdir(newdir, cmd)
+        return "cd "..Q(newdir).." && "..cmd
+    end
+
+    -- local
+    function mkdir(path)
+        local cmd = "mkdir "..Q(path).." >/dev/null 2>&1"
+
+        os.execute(cmd)
+        if not is_directory(path) then
+            error("Couldn't create directory '"..path.."'.")
+        end
+    end
+end
+
+-- Dependency fetch
+
+local function fetch(dep)
+    local dest = 'lib/'..dep.name
+
+    print(("Dependency %s -> %s (%s)"):format(dep.name, dest, dep.url))
+
+    local cmd, fullcmd
+
+    if is_directory(dest) then
+        -- Directory exists, pull operation
+        cmd = "git pull"
+        fullcmd = chdir(dest, quiet("git pull"))
+    else
+        -- Directory doesn't exist, clone operation
+        cmd = "git clone "..Q(dep.url).." "..Q(dep.name)
+        fullcmd = chdir("lib", quiet(cmd))
+    end
+
+    if not os.execute(fullcmd) then
+        error(name..": Dependency fetch failed ("..cmd..").")
+    end
+end
+
+-- .lovedeps file scan
+
+local function map_file(name)
+    local fh = io.open(name, 'r')
+    if fh == nil then
+        error(name..": can't read file.")
+    end
+
+    local contents = fh:read('*all')
+    fh:close()
+
+    return contents
+end
+
+local function scandeps(manifest, mode, deps)
+    mode = mode or 'nodups'
+    deps = deps or {}
+
+    local contents = map_file(manifest)
+    contents = "return "..contents
+
+    local fun, res = load(contents, manifest, 't', {})
+    if not fun then
+        error(res)
+    end
+
+    local ok, def = pcall(fun)
+    if not ok then
+        error(def)  -- def is now pcall()'s error message
+    end
+    if type(def) ~= 'table' then
+        error("[string \""..manifest.."\"]: Loading resulted in a '"..type(def).."', while 'table' was expected.")
+    end
+
+    for name,url in pairs(def) do
+        if type(url) == 'function' then
+            goto skip  -- ignore functions
+        end
+
+        if type(url) ~= 'string' then
+            error("[string \""..manifest.."\"]: "..name..": git repository URL must be a 'string'.")
+        end
+
+        for i in ipairs(deps) do
+            if name == deps[i].name then
+                if mode == 'skipdups' then
+                    goto skip
+                end
+
+                error("[string \""..manifest.."\"]: "..name..": Duplicate dependency.")
+            end
+        end
+
+        deps[#deps+1] = { name = name, url = url }
+
+        ::skip::
+    end
+
+    return deps
+end
+
+-- Entry point
+
+local function file_exists(name)
+    local fh = io.open(name, 'r')
+    if fh ~= nil then
+        fh:close()
+
+        return true
+    end
+
+    return false
+end
+
+local function run()
+    local deps = scandeps(".lovedeps")
+
+    mkdir("lib")
+
+    -- NOTE: deps array may grow while scanning
+    local i = 1
+    while i <= #deps do
+        local dep = deps[i]
+
+        -- Fetch dependency
+        fetch(dep)
+
+        -- Resolve dependency's dependencies
+        local depmanifest = "lib/"..dep.name.."/.lovedeps"
+
+        if file_exists(depmanifest) then
+            scandeps(depmanifest, 'skipdups', deps)
+        end
+
+        i = i + 1
+    end
+end
+
+run()

device/love.lua

@@ -0,0 +1,60 @@
+-- Simple Device driver for Yui, only depends on LÖVE 2D, listens to
+-- keyboard and mouse pointer.
+
+local Device = {}
+Device.__index = Device
+
+
+function Device.new()
+    return setmetatable({
+        px = nil, py = nil,
+        clicking = nil,
+
+        confirm = nil,
+        cancel = nil,
+        up = nil,
+        left = nil,
+        down = nil,
+        right = nil,
+    }, Device)
+end
+
+function Device:snapshot()
+    local snap = {}
+
+    -- Mouse pointer
+    local px,py = love.mouse.getPosition()
+    local clicking = love.mouse.isDown(1)
+
+    snap.px,snap.py = px,py
+    snap.pointing = clicking
+    snap.clicked = self.clicking and not clicking
+    snap.pointer = px ~= self.px or py ~= self.py or snap.clicked or snap.pointing
+
+    -- Keyboard input
+    local confirm = love.keyboard.isDown('return', 'space')
+    local cancel = love.keyboard.isDown('escape')
+    local up = love.keyboard.isDown('up', 'w')
+    local left = love.keyboard.isDown('left', 'a')
+    local down = love.keyboard.isDown('down', 's')
+    local right = love.keyboard.isDown('right', 'd')
+
+    snap.confirm = self.confirm and not confirm
+    snap.cancel = self.cancel and not cancel
+    snap.up = self.up and not up
+    snap.left = self.left and not left
+    snap.down = self.down and not down
+    snap.right = self.right and not right
+    snap.action = snap.confirm or snap.cancel or
+                  snap.up or snap.left or snap.down or snap.right
+
+    -- Update old state
+    self.px,self.py = px,py
+    self.clicking = clicking
+    self.confirm,self.cancel = confirm,cancel
+    self.left,self.up,self.right,self.down = left,up,right,down
+
+    return snap
+end
+
+return Device

init.lua

@@ -0,0 +1,18 @@
+local BASE = (...)..'.'
+
+return {
+    Button = require(BASE..'button'),
+    Checkbox = require(BASE..'checkbox'),
+    Choice = require(BASE..'choice'),
+    Columns = require(BASE..'columns'),
+    Input = require(BASE..'input'),
+    Label = require(BASE..'label'),
+    Layout = require(BASE..'layout'),
+    Rows = require(BASE..'rows'),
+    Slider = require(BASE..'slider'),
+    Spacer = require(BASE..'spacer'),
+    Ui = require(BASE..'ui'),
+    Widget = require(BASE..'widget'),
+
+    theme = require(BASE..'theme')
+}

input.lua

@@ -0,0 +1,184 @@
+local BASE = (...):gsub('input', '')
+
+local Widget = require BASE..'widget'
+local core = require BASE..'core'
+
+local utf8 = require 'utf8'
+
+-- Grabs keyboard on focus
+local Input = setmetatable({ grabkeyboard = true }, Widget)
+Input.__index = Input
+
+
+local function split(str, pos)
+    local ofs = utf8.offset(str, pos) or 0
+    return str:sub(1, ofs-1), str:sub(ofs)
+end
+
+function Input.new(args)
+    local self = setmetatable(args, Input)
+
+    self.text = self.text or ""
+    self.color = self.color or core.theme.color
+    self.cornerRadius = self.cornerRadius or core.theme.cornerRadius
+    self.cursor = math.max(1, math.min(utf8.len(self.text)+1,
+                                       self.cursor or utf8.len(self.text)+1))
+    self.candidate = { text = "", start = 0, length = 0 }
+
+    return self
+end
+
+function Input:onPointerInput(px,py, clicked)
+    if clicked then
+        self:grabFocus()
+
+        -- Schedule cursor reposition for next draw()
+        self.px = px
+        self.py = py
+    end
+end
+
+function Input:textedited(text, start, length)
+    self.candidate.text = text
+    self.candidate.start = start
+    self.candidate.length = length
+end
+
+function Input:textinput(text)
+    if text ~= "" then
+        local a,b = split(self.text, self.cursor)
+
+        self.text = table.concat {a, text, b}
+        self.cursor = self.cursor + utf8.len(text)
+    end
+end
+
+function Input:keypressed(key, code, isrepeat)
+    if isrepeat == nil then
+        -- LOVE sends 3 types of keypressed() events,
+        -- 1. with isrepeat = true
+        -- 2. with isrepeat = false
+        -- 3. with isrepeat = nil
+        --
+        -- We're only interested in the first 2.
+        return
+    end
+
+    if self.candidate.length == 0 then
+        if key == 'backspace' then
+            local a,b = split(self.text, self.cursor)
+
+            self.text = table.concat { split(a, utf8.len(a)), b }
+            self.cursor = math.max(1, self.cursor-1)
+
+        elseif key == 'delete' then
+            local a,b = split(self.text, self.cursor)
+            local _,b = split(b, 2)
+
+            self.text = table.concat { a, b }
+
+        elseif key == 'left' then
+            self.cursor = math.max(0, self.cursor-1)
+
+        elseif key == 'right' then
+            self.cursor = math.min(utf8.len(self.text)+1, self.cursor+1)
+        end
+    end
+end
+
+function Input:keyreleased(key)
+    if self.candidate.length == 0 then
+        if key == 'home' then
+            self.cursor = 1
+        elseif key == 'end' then
+            self.cursor = utf8.len(self.text)+1
+        elseif key == 'return' then
+            self:onChange(self.text)
+            self.cursor = 1
+        end
+    end
+end
+
+function Input:draw()
+    -- Cursor position is before the char (including EOS) i.e. in "hello":
+    --   position 1: |hello
+    --   position 2: h|ello
+    --   ...
+    --   position 6: hello|
+
+    local x,y,w,h = self.x,self.y,self.w,self.h
+    local font = self.font or love.graphics.getFont()
+    local th = font:getHeight()
+    local tw = font:getWidth(self.text)
+
+    -- Get size of text and cursor position
+    local cursor_pos = 0
+    if self.cursor > 1 then
+        local s = self.text:sub(1, utf8.offset(self.text, self.cursor)-1)
+        cursor_pos = font:getWidth(s)
+    end
+
+    -- Compute drawing offset
+    if self.px ~= nil then
+        -- Mouse movement
+        local mx = self.px - self.x
+
+        self.cursor = utf8.len(self.text) + 1
+        for c = 1,self.cursor do
+            local s = self.text:sub(0, utf8.offset(self.text, c)-1)
+            if font:getWidth(s) >= mx then
+                self.cursor = c-1
+                break
+            end
+        end
+
+        self.px,self.py = nil,nil
+    end
+
+    core.drawBox(x,y,w,h, self.color.normal, self.cornerRadius)
+
+    -- Apply text margins
+    w = math.max(w - 6, 0)
+    x = math.min(x + 3, x + w)
+
+    -- Set scissors
+    local sx, sy, sw, sh = love.graphics.getScissor()
+    love.graphics.setScissor(x-1,y,w+2,h)
+
+    -- Text
+    love.graphics.setColor(self.color.normal.fg)
+    love.graphics.setFont(font)
+    love.graphics.print(self.text, x, y + (h-th)/2)
+
+    if self.candidate.length > 0 then
+        -- Candidate text
+        local ctw = font:getWidth(self.candidate.text)
+
+        love.graphics.setColor(self.color.normal.fg)
+        love.graphics.print(self.candidate.text, x + tw, y + (h-th)/2)
+
+        -- Candidate text rectangle box
+        love.graphics.rectangle('line', x + tw, y + (h-th)/2, ctw, th)
+
+        self.candidate.text = ""
+        self.candidate.start = 0
+        self.candidate.length = 0
+    end
+
+    -- Cursor
+    if self:isFocused() and (love.timer.getTime() % 1) > .5 then
+        local ct = self.candidate
+        local ss = ct.text:sub(1, utf8.offset(ct.text, ct.start))
+        local ws = ct.start > 0 and font:getWidth(ss) or 0
+
+        love.graphics.setLineWidth(1)
+        love.graphics.setLineStyle('rough')
+        love.graphics.line(x + cursor_pos + ws, y + (h-th)/2,
+                           x + cursor_pos + ws, y + (h+th)/2)
+    end
+
+    -- Reset scissor
+    love.graphics.setScissor(sx,sy,sw,sh)
+end
+
+return Input

label.lua

@@ -0,0 +1,37 @@
+local BASE = (...):gsub('label', '')
+
+local Widget = require BASE..'widget'
+local core = require BASE..'core'
+
+local shadowtext = require 'lib.gear.shadowtext'
+local T = require('lib.moonspeak').translate
+
+-- Labels don't accept focus
+local Label = setmetatable({ nofocus = true }, Widget)
+Label.__index = Label
+
+
+function Label.new(args)
+    local self = setmetatable(args, Label)
+
+    self.text = self.text or ""
+    self.text = self.notranslate and self.text or T(self.text)
+    self.align = self.align or 'center'
+    self.valign = self.valign or 'center'
+    self.color = self.color or core.theme.color
+    return self
+end
+
+function Label:draw()
+    local x,y,w,h = self.x,self.y,self.w,self.h
+    local font = self.font or love.graphics.getFont()
+    local c = self.color.normal
+
+    y = y + core.verticalOffsetForAlign(self.valign, font, h)
+
+    love.graphics.setColor(c.fg)
+    love.graphics.setFont(font)
+    shadowtext.printf(self.text, x+2, y, w-4, self.align)
+end
+
+return Label

layout.lua

@@ -0,0 +1,251 @@
+local BASE = (...):gsub('layout', '')
+
+local Widget = require BASE..'widget'
+local core = require BASE..'core'
+
+local utils = require 'lib.gear'
+
+local isinstance = gear.meta.isinstance
+local rectunion = gear.rect.union
+local pointinrect = gear.rect.pointinside
+
+local Layout = setmetatable({}, Widget)
+Layout.__index = Layout
+
+
+-- Calculate initial widget size.
+local function calcsize(sizes, widget)
+    local w, h = widget.w, widget.h
+    if w == nil then
+        assert(#sizes > 0, "Default width is undefined!")
+        w = sizes[#sizes].w
+    end
+    if h == nil then
+        assert(#sizes > 0, "Default height is undefined!")
+        h = sizes[#sizes].h
+    end
+
+    if w == 'max' then
+        w = 0
+        for _,v in ipairs(sizes) do
+            if v.w > w then
+                w = v.w
+            end
+        end
+    elseif w == 'median' then
+        w = 0
+        for _,v in ipairs(sizes) do
+            w = w + v.w
+        end
+        w = math.ceil(w / #sizes)
+    elseif w == 'min' then
+        w = math.huge
+        for _,v in ipairs(sizes) do
+            if v.w < w then
+                w = v.w
+            end
+        end
+    else
+        assert(type(w) == 'number')
+    end
+
+    if h == 'max' then
+        h = 0
+        for _,v in ipairs(sizes) do
+            if v.h > h then
+                h = v.h
+            end
+        end
+    elseif h == 'median' then
+        h = 0
+        for _,v in ipairs(sizes) do
+            h = h + v.h
+        end
+        h = math.ceil(h / #sizes)
+    elseif h == 'min' then
+        h = math.huge
+        for _,v in ipairs(sizes) do
+            if v.h < h then
+                h = v.h
+            end
+        end
+    else
+        assert(type(h) == 'number')
+    end
+
+    sizes[#sizes+1] = { w = w, h = h }
+
+    widget.w, widget.h = w, h
+    return w, h
+end
+
+-- Lay down container widgets according to Layout type.
+function Layout:layoutWidgets()
+    local nx,ny = self.x,self.y
+    local sizes = {}
+    local stack = self.stack
+    local pad = self.padding
+
+    -- Container bounds, empty
+    local rx,ry,rw,rh = nx,ny,-1,-1
+
+    -- Layout container children
+    for _,widget in ipairs(self) do
+        widget.x, widget.y = nx, ny
+        widget.ui = self.ui
+        widget.parent = self
+
+        if isinstance(widget, Layout) then
+            widget:layoutWidgets()
+        end
+
+        local w,h = calcsize(sizes, widget)
+        rx,ry,rw,rh = rectunion(rx,ry,rw,rh, nx,ny,w,h)
+
+        nx,ny = self.advance(nx,ny, w,h, pad)
+
+        stack[#stack+1] = widget
+    end
+
+    self.x = rx
+    self.y = ry
+    self.w = math.max(rw, 0)
+    self.h = math.max(rh, 0)
+end
+
+function Layout:onPointerInput(px,py, clicked, down)
+    local stack = self.stack
+
+    -- Propagate pointer event from topmost widget to bottom
+    for i = #stack,1,-1 do
+        local widget = stack[i]
+        local x,y,w,h = widget.x,widget.y,widget.w,widget.h
+
+        if pointinrect(px,py, x,y,w,h) then
+            widget:handlePointer(px,py, clicked, down)
+            break
+        end
+    end
+end
+
+-- Find layout's child containing the provided widget.
+local function childof(layout, widget)
+    local parent = widget.parent
+    while parent ~= layout do
+        widget = parent
+        parent = widget.parent
+    end
+    return widget
+end
+local function findfirst(widget)
+    while isinstance(widget, Layout) do
+        -- Find first element accepting focus
+        for i = 1,#widget do
+            if not widget[i].nofocus then
+                widget = widget[i]
+                break
+            end
+        end
+    end
+    return widget
+end
+local function findnext(layout, widget)
+    local child = childof(layout, widget)
+
+    for i,w in ipairs(layout) do
+        if w == child then
+            -- Search to the right, wraparound to the left
+            for j = i+1,#layout do
+                if not layout[j].nofocus then
+                    return findfirst(layout[j])
+                end
+            end
+            for j = 1,i-1 do
+                if not layout[j].nofocus then
+                    return findfirst(layout[j])
+                end
+            end
+        end
+    end
+    return widget
+end
+local function findprev(layout, widget)
+    local child = childof(layout, widget)
+
+    for i,w in ipairs(layout) do
+        if w == child then
+            -- Search to the left, wraparound to the right
+            for j = i-1,1,-1 do
+                if not layout[j].nofocus then
+                    return findfirst(layout[j])
+                end
+            end
+            for j = #layout,i+1,-1 do
+                if not layout[j].nofocus then
+                    return findfirst(layout[j])
+                end
+            end
+        end
+    end
+    return widget
+end
+
+function Layout:firstFocusableWidget()
+    return findfirst(self)
+end
+function Layout:nextFocusableWidget()
+    return findnext(self, self.ui.focused)
+end
+function Layout:previousFocusableWidget()
+    return findprev(self, self.ui.focused)
+end
+
+function Layout:onActionInput(action)
+    local handled = false
+
+    if action[self.next] then
+        local n = self:nextFocusableWidget()
+
+        n:grabFocus()
+        handled = true
+    end
+    if action[self.prev] then
+        local p = self:previousFocusableWidget()
+
+        p:grabFocus()
+        handled = true
+    end
+    return handled
+end
+
+function Layout:update(dt)
+    for _,widget in ipairs(self.stack) do
+        widget:update(dt)
+    end
+end
+
+function Layout:draw()
+    -- Draw all children according to their order (topmost last)
+    for _,widget in ipairs(self.stack) do
+        widget:draw()
+    end
+end
+
+function Layout.new(args)
+    local self = setmetatable(args, Layout)
+
+    self.padding = self.padding or 0
+    self.stack = {}
+
+    -- A Layout ignores focus if empty or containing only nofocus widgets
+    self.nofocus = true
+    for _,w in ipairs(self) do
+        if not w.nofocus then
+            self.nofocus = false
+            break
+        end
+    end
+    return self
+end
+
+return Layout

rows.lua

@@ -0,0 +1,24 @@
+local BASE = (...):gsub('rows')
+
+local Layout = require BASE..'layout'
+
+local Rows = setmetatable({}, Layout)
+Rows.__index = Rows
+
+
+-- Advance position to next row,
+-- given current position, widget dimensions and padding.
+local function rowadvance(x,y, ww,wh, padding)
+    return x, y + wh + padding
+end
+
+function Rows.new(args)
+    local self = setmetatable(Layout.new(args), Rows)
+
+    self.advance = rowadvance
+    self.prev = 'up'
+    self.next = 'down'
+    return self
+end
+
+return Rows

slider.lua

@@ -0,0 +1,92 @@
+local BASE = (...):gsub('slider', '')
+
+local Widget = require BASE..'widget'
+local core = require BASE..'core'
+
+local Slider = setmetatable({}, Widget)
+Slider.__index = Slider
+
+
+function Slider.new(args)
+    local self = setmetatable(args, Slider)
+
+    self.color = self.color or core.theme.color
+    self.cornerRadius = self.cornerRadius or core.theme.cornerRadius
+    self.vertical = self.vertical or false
+    self.min = self.min or 0
+    self.max = self.max or 1
+    self.value = self.value or self.min
+    self.step = self.step or (self.max - self.min) / 10
+    return self
+end
+
+function Slider:onPointerInput(px,py, clicked, down)
+    self:grabFocus()
+    if not down then
+        return
+    end
+
+    local x,y,w,h = self.x,self.y,self.w,self.h
+
+    local fraction
+    if self.vertical then
+        fraction = math.min(1, math.max(0, (y+h - py) / h))
+    else
+        fraction = math.min(1, math.max(0, (px - x) / w))
+    end
+
+    local v = fraction*(self.max - self.min) + self.min
+    if v ~= self.value then
+        self.value = v
+        self:onChange(v)
+    end
+end
+
+function Slider:onActionInput(action)
+    local up = self.vertical and 'up' or 'right'
+    local down = self.vertical and 'down' or 'left'
+
+    local handled = false
+    if action[up] then
+        self.value = math.min(self.max, self.value + self.step)
+        handled = true
+    elseif action[down] then
+        self.value = math.max(self.min, self.value - self.step)
+        handled = true
+    end
+    if handled then
+        self:onChange(self.value)
+    end
+
+    return handled
+end
+
+function Slider:draw()
+    local x,y,w,h = self.x,self.y,self.w,self.h
+    local r = math.min(w,h) / 2.1
+    local c = self:colorForState()
+    local fraction = (self.value - self.min) / (self.max - self.min)
+
+    local xb, yb, wb, hb  -- size of the progress bar
+    if self.vertical then
+        x, w = x + w*.25, w*.5
+        xb, yb, wb, hb = x, y+h*(1-fraction), w, h*fraction
+    else
+        y, h = y + h*.25, h*.5
+        xb, yb, wb, hb = x,y, w*fraction, h
+    end
+
+    core.drawBox(x,y,w,h, c, self.cornerRadius)
+    core.drawBox(xb,yb,wb,hb, {bg=c.fg}, self.cornerRadius)
+
+    if self:isFocused() then
+        love.graphics.setColor(c.fg)
+        if self.vertical then
+            love.graphics.circle('fill', x+wb/2, yb, r)
+        else
+            love.graphics.circle('fill', x+wb, yb+hb/2, r)
+        end
+    end
+end
+
+return Slider

spacer.lua

@@ -0,0 +1,14 @@
+local BASE = (...):gsub('spacer', '')
+
+local Widget = require BASE..'widget'
+
+-- Spacers don't accept focus
+local Spacer = setmetatable({ nofocus = true }, Widget)
+Spacer.__index = Spacer
+
+
+function Spacer.new(args)
+    return setmetatable(args, Spacer)
+end
+
+return Spacer

theme.lua

@@ -0,0 +1,11 @@
+local theme = {
+    cornerRadius = 4,
+
+    color = {
+        normal   = {bg = { 0.25, 0.25, 0.25}, fg = {0.73, 0.73, 0.73}},
+        hovered  = {bg = { 0.19, 0.6, 0.73}, fg = {1, 1, 1}},
+        active   = {bg = { 1, 0.6, 0}, fg = {1, 1, 1}}
+    }
+}
+
+return theme

ui.lua

@@ -0,0 +1,176 @@
+local BASE = (...):gsub('ui', '')
+
+local Widget = require BASE..'widget'
+local Layout = require BASE..'layout'
+
+local gear = require 'lib.gear'
+
+local Timer = gear.Timer
+local isinstance = gear.meta.isinstance
+local pointinrect = gear.rect.pointinside
+
+local Ui = {}
+Ui.__index = Ui
+
+
+-- Scan UI for the LAST widgets with 'cancelfocus' or 'firstfocus' flags
+local function resolveautofocus(widget)
+    local firstfocus, cancelfocus
+
+    if isinstance(widget, Layout) then
+        for _,w in ipairs(widget) do
+            local firstf, cancelf
+
+            if not w.nofocus then
+                if isinstance(w, Layout) then
+                    firstf, cancelf = resolveautofocus(w)
+                else
+                    if w.firstfocus then
+                        firstf = w
+                    end
+                    if w.cancelfocus then
+                        cancelf = w
+                    end
+                end
+            end
+
+            firstfocus = firstf or firstfocus
+            cancelfocus = cancelf or cancelfocus
+        end
+
+    elseif not widget.nofocus then
+        if widget.firstfocus then
+            firstfocus = widget
+        end
+        if widget.cancelfocus then
+            cancelfocus = widget
+        end
+    end
+
+    return firstfocus, cancelfocus
+end
+
+local function propagateaction(ui, action)
+    local focused = ui.focused
+    if focused.grabkeyboard then
+        -- A widget stealing input
+        -- explicitly consumes any action.
+        return true
+    end
+    while focused ~= nil do
+        if focused:onActionInput(action) then
+            return true  -- action consumed
+        end
+
+        focused = focused.parent
+    end
+
+    return false
+end
+
+function Ui.new(args)
+    local self = setmetatable(args, Ui)
+    assert(#self == 1, "Ui.new() must have exactly one root widget.")
+
+    self.device = self.device or require('device.love').new()
+    self.x = self.x or 0
+    self.y = self.y or 0
+    self.pointerActive = true
+    self.timer = Timer.new()
+
+    local root = self[1]
+    if not isinstance(root, Widget) then
+        error("Ui.new() bad root Widget type: "..type(root)..".")
+    end
+
+    root.x,root.y = self.x,self.y
+    root.ui = self
+    if isinstance(root, Layout) then
+        root:layoutWidgets()
+    else
+        assert(type(root.w) == 'number', "Ui.new() root Widget must have a numeric width.")
+        assert(type(root.h) == 'number', "Ui.new() root Widget must have a numeric height.")
+        assert(not root.nofocus, "Ui.new() single root Widget can't be nofocus.")
+    end
+
+    self.w,self.h = root.w,root.h
+
+    local firstfocus, cancelfocus = resolveautofocus(root)
+    if firstfocus == nil then
+        firstfocus = isinstance(root, Layout) and
+                     root:firstFocusableWidget() or
+                     root
+    end
+
+    self.cancelfocus = cancelfocus
+    firstfocus:grabFocus()
+
+    return self
+end
+
+-- Event propagators for widgets listening to keyboard input
+function Ui:keypressed(key, scancode, isrepeat)
+    local focused = self.focused
+
+    if focused ~= nil and focused.grabkeyboard then
+        focused:keypressed(key, scancode, isrepeat)
+    end
+end
+function Ui:keyreleased(key, scancode)
+    local focused = self.focused
+
+    if focused ~= nil and focused.grabkeyboard then
+        focused:keyreleased(key, scancode)
+    end
+end
+function Ui:textinput(text)
+    local focused = self.focused
+
+    if focused ~= nil and focused.grabkeyboard then
+        focused:textinput(text)
+    end
+end
+function Ui:textedited(text, start, length)
+    local focused = self.focused
+
+    if focused ~= nil and focused.grabkeyboard then
+        focused:textedited(text, start, length)
+    end
+end
+
+function Ui:update(dt)
+    local root = self[1]
+    local x,y,w,h = root.x,root.y,root.w,root.h
+    local snap = self.device:snapshot()
+
+    self.timer:update(dt)
+
+    -- Propagate pointer events in focus order
+    if self.pointerActive then
+        if snap.pointer and pointinrect(snap.px,snap.py, x,y,w,h) then
+            root:onPointerInput(snap.px,snap.py, snap.clicked, snap.pointing)
+        end
+    end
+
+    -- Propagate actions from focused widget up
+    if snap.action and not propagateaction(self, snap) then
+        -- Take global actions if nobody consumed the event
+        if snap.cancel and self.cancelfocus then
+            -- Focus on the last widget with 'cancelfocus'
+            self.cancelfocus:grabFocus()
+        end
+    end
+
+    -- Perform regular lifetime updates
+    root:update(dt)
+end
+
+function Ui:draw()
+    local root = self[1]
+
+    love.graphics.push('all')
+        root:draw()
+    love.graphics.pop()
+end
+
+return Ui

widget.lua

@@ -0,0 +1,117 @@
+local rectunion = require('lib.gear.rect').union
+
+local Widget = {
+    __call = function(cls, args)
+        return cls.new(args)
+    end
+}
+Widget.__index = Widget
+
+
+local function raise(widget)
+    local parent = widget.parent
+
+    -- A parent of a widget is necessarily a Layout
+    while parent ~= nil do
+        local stack = parent.stack
+
+        -- Move widget at the end of the stack, so it is rendered last.
+        for i,w in ipairs(stack) do
+            if w == widget then
+                table.remove(stack, i)
+                stack[#stack+1] = widget
+                break
+            end
+        end
+
+        -- Focus widget's container, if any
+        widget = parent
+        parent = widget.parent
+    end
+end
+
+function Widget:grabFocus()
+    local ui = self.ui
+    local focused = ui.focused
+
+    if focused == self then
+        return
+    end
+    if focused ~= nil then
+        -- Notify leave
+        focused.hovered = false
+        if focused.grabkeyboard then
+            if love.system.getOS() == 'Android' or love.system.getOS() == 'iOS' then
+                love.keyboard.setTextInput(false)
+            end
+            love.keyboard.setKeyRepeat(false)
+        end
+
+        focused:onLeave()
+    end
+
+    local wasHovered = self.hovered
+
+    self.hovered = true
+    if self.grabkeyboard then
+        love.keyboard.setTextInput(true, self.x,self.y,self.w,self.h)
+        love.keyboard.setKeyRepeat(true)
+    end
+    if not wasHovered then
+        -- First time hovered, notify enter
+        self:onEnter()
+    end
+
+    -- Raise widget
+    ui.focused = self
+    raise(self)
+end
+
+function Widget:isFocused()
+    return self.ui.focused == self
+end
+
+function Widget.recalculateBounds()
+    local widget = self.parent
+    while widget ~= nil do
+        local rx,ry,rw,rh = widget.x,widget.y,-1,-1
+
+        for _,w in ipairs(widget) do
+            rx,ry,rw,rh = rectunion(rx,ry,rw,rh, w.x,w.y,w.w,w.h)
+        end
+
+        widget.x = rx
+        widget.y = ry
+        widget.w = rw
+        widget.h = rh
+
+        widget = widget.parent
+    end
+end
+
+-- Helper for drawing
+function Widget:colorForState()
+    if self.active then
+        return self.color.active
+    elseif self:isFocused() then
+        return self.color.hovered
+    else
+        return self.color.normal
+    end
+end
+
+-- Common NOP event handlers
+function Widget:onHit() end
+function Widget:onEnter() end
+function Widget:onLeave() end
+function Widget:onChange() end
+
+-- NOP input event handlers
+function Widget:onActionInput(action) end
+function Widget:onPointerInput(x,y, clicked) end
+
+-- NOP UI event handlers
+function Widget:update(dt) end
+function Widget:draw() end
+
+return Widget