[*] Rework theme customization.

This commit allows more flexible and consistent theme overriding
rules for each Widget. There are 3 levels of customization.

1. Global theme (yui.theme) this is the default theme for every Ui
2. Ui theme, this overrides the global theme and provides a default
   for every Widget of the Ui
3. Widget theme, this overrides the Ui theme for a single widget

This commit also allows themes to specify a font field.
This replaces the sparse color, font and cornerRadius field often
provided by each Widget.
Widgets and Uis may also partially override a theme by specifying
only a few fields.

button.lua

@@ -41,8 +41,6 @@ function Button:new(args)
     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)
@@ -70,10 +68,10 @@ 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()
+    local color, font, cornerRadius = core.themeForWidget(self)
+    local c = core.colorForWidgetState(self, color)
 
-    core.drawBox(x,y,w,h, c, self.cornerRadius)
+    core.drawBox(x,y,w,h, c, cornerRadius)
     love.graphics.setColor(c.fg)
     love.graphics.setFont(font)
 

checkbox.lua

@@ -27,7 +27,6 @@ Checkbox.__index = Checkbox
 -- @field text (string) text displayed inside the Checkbox
 -- @field[opt='center'] valign (string) vertical alignment 'top', 'bottom', 'center'
 -- @field[opt='center'] align (string) horizontal alignment, 'left', 'center', 'right'
--- @field cornerRadius (number) radius for rounded corner
 -- @field notranslate (boolean) don't translate text
 -- @table CheckboxAttributes
 
@@ -41,8 +40,6 @@ function Checkbox:new(args)
     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
@@ -64,11 +61,11 @@ 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()
+    local color, font, cornerRadius = core.themeForWidget(self)
+    local c = core.colorForWidgetState(self, color)
 
     -- Draw checkbox
-    core.drawBox(x+h/10,y+h/10,h*.8,h*.8, c, self.cornerRadius)
+    core.drawBox(x+h/10,y+h/10,h*.8,h*.8, c, cornerRadius)
     love.graphics.setColor(c.fg)
     if self.checked then
         love.graphics.setLineStyle('smooth')

choice.lua

@@ -27,7 +27,6 @@ Choice.__index = Choice
 -- @field nowrap (boolean) disable choices wrapping
 -- @field[opt='center'] valign (string) vertical alignment 'top', 'bottom', 'center'
 -- @field[opt='center'] align (string) horizontal alignment, 'left', 'center', 'right'
--- @field cornerRadius (number) radius for rounded corners
 -- @field notranslate (boolean) don't translate text
 -- @table ChoiceAttributes
 
@@ -39,8 +38,6 @@ function Choice:new(args)
 
     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 < 2
@@ -134,14 +131,14 @@ 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()
+    local color, font, cornerRadius = core.themeForWidget(self)
+    local c = core.colorForWidgetState(self, color)
 
-    core.drawBox(x,y,w,h, c, self.cornerRadius)
+    core.drawBox(x,y,w,h, c, cornerRadius)
 
     if self.ui.focused == self then
         -- draw < and > arrows, desaturate color if arrow is disabled
-        local cc = self.color.hovered
+        local cc = color.hovered
 
         love.graphics.setLineStyle('smooth')
         love.graphics.setLineWidth(3)

core.lua

@@ -1,7 +1,10 @@
-local BASE = (...):gsub('core$', '')
+--- Local drawing helpers
+--
+-- @module yui.core
+-- @copyright 2022, The DoubleFourteen Code Forge
+-- @author Lorenzo Cogotti, Andrea Pasquini
 
-local core = { theme = require(BASE..'theme') }
-core.__index = core
+local core = {}
 
 -- Helpers for drawing
 function core.verticalOffsetForAlign(valign, font, h)
@@ -10,10 +13,33 @@ function core.verticalOffsetForAlign(valign, font, h)
     elseif valign == 'bottom' then
         return h - font:getHeight()
     end
-    -- else: "middle"
+    -- else: 'middle'
     return (h - font:getHeight()) / 2
 end
 
+function core.themeForWidget(widget)
+    local uiTheme = widget.ui.theme
+    local theme = widget.theme or uiTheme
+
+    local color = theme.color or uiTheme.color
+    local font = theme.font or uiTheme.font or love.graphics.getFont()
+    local cornerRadius = theme.cornerRadius or uiTheme.cornerRadius
+
+    return color, font, cornerRadius
+end
+
+function core.colorForWidgetState(widget, color)
+    color = color or widget.theme.color or widget.ui.theme.color
+
+    if widget.active then
+        return color.active
+    elseif widget:isFocused() then
+        return color.hovered
+    else
+        return color.normal
+    end
+end
+
 function core.drawBox(x,y,w,h, color, cornerRadius)
     w = math.max(cornerRadius/2, w)
     if h < cornerRadius/2 then

init.lua

@@ -1,3 +1,14 @@
+--- Yui is Yet another User Interface library
+--
+-- @module yui
+-- @copyright 2022, The DoubleFourteen Code Forge
+-- @author Lorenzo Cogotti, Andrea Pasquini
+--
+-- This module exposes every module in Yui,
+-- except the local @{yui.core} module and the
+-- global @{yui.theme} (still accessible from @{yui.Ui}).
+-- Refer to each module documentation.
+
 local BASE = (...)..'.'
 
 return {
@@ -13,6 +24,4 @@ return {
     Spacer = require(BASE..'spacer'),
     Ui = require(BASE..'ui'),
     Widget = require(BASE..'widget'),
-
-    theme = require(BASE..'theme')
 }

input.lua

@@ -31,7 +31,6 @@ end
 -- and @{yui.Widget.WidgetCallbacks|callbacks}.
 --
 -- @field text (string) text displayed inside the Input
--- @field cornerRadius (number) radius for rounded corners
 -- @table InputAttributes
 
 
@@ -41,8 +40,6 @@ function Input:new(args)
     self = setmetatable(args, self)
 
     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 }
@@ -155,7 +152,7 @@ function Input:draw()
     --   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 color, font, cornerRadius = core.themeForWidget(self)
     local th = font:getHeight()
     local tw = font:getWidth(self.text)
 
@@ -199,7 +196,7 @@ function Input:draw()
     end
 
     -- Perform actual draw
-    core.drawBox(x,y,w,h, self.color.normal, self.cornerRadius)
+    core.drawBox(x,y,w,h, color.normal, cornerRadius)
 
     -- Apply text margins
     x = math.min(x + 3, x + w)
@@ -212,7 +209,7 @@ function Input:draw()
     x = x - self.drawofs
 
     -- Text
-    love.graphics.setColor(self.color.normal.fg)
+    love.graphics.setColor(color.normal.fg)
     love.graphics.setFont(font)
     love.graphics.print(self.text, x, y + (h-th)/2)
 
@@ -220,7 +217,7 @@ function Input:draw()
         -- Candidate text
         local ctw = font:getWidth(self.candidate.text)
 
-        love.graphics.setColor(self.color.normal.fg)
+        love.graphics.setColor(color.normal.fg)
         love.graphics.print(self.candidate.text, x + tw, y + (h-th)/2)
 
         -- Candidate text rectangle box

label.lua

@@ -36,18 +36,16 @@ function Label:new(args)
     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
+    local color, font, _ = core.themeForWidget(self)
 
     y = y + core.verticalOffsetForAlign(self.valign, font, h)
 
-    love.graphics.setColor(c.fg)
+    love.graphics.setColor(color.normal.fg)
     love.graphics.setFont(font)
     shadowtext.printf(self.text, x+2, y, w-4, self.align)
 end

slider.lua

@@ -24,7 +24,6 @@ Slider.__index = Slider
 -- @field vertical (boolean) true for vertical slider, false or nil for horizontal slider
 -- @field value (number) default value
 -- @field step (number) number of slider's steps
--- @field cornerRadius (number) radius for rounded corners
 -- @table SliderAttributes
 
 
@@ -33,8 +32,6 @@ Slider.__index = Slider
 function Slider:new(args)
     self = setmetatable(args, self)
 
-    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
@@ -87,7 +84,8 @@ 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 color, _, cornerRadius = core.themeForWidget(self)
+    local c = core.colorForWidgetState(self, color)
     local fraction = (self.value - self.min) / (self.max - self.min)
 
     local xb, yb, wb, hb  -- size of the progress bar
@@ -99,8 +97,8 @@ function Slider:draw()
         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)
+    core.drawBox(x,y,w,h, c, cornerRadius)
+    core.drawBox(xb,yb,wb,hb, { bg = c.fg }, cornerRadius)
 
     if self:isFocused() then
         love.graphics.setColor(c.fg)

theme.lua

@@ -1,4 +1,4 @@
---- Global visual theme settings
+--- Visual theme settings
 --
 -- @module yui.theme
 -- @copyright 2022, The DoubleFourteen Code Forge
@@ -7,8 +7,9 @@
 --- Defines common visual attributes and colors applied to every @{yui.Widget|Widget}.
 --
 -- @field cornerRadius (number) radius for rounded corners
+-- @field font (love.graphics.Font) font used for text (defaults to love.graphics.getFont())
 -- @field color (@{ColorPalette}) default @{yui.Widget|Widget} color theme
--- @table theme
+-- @table Theme
 
 --- Defines which color corresponds to each @{yui.Widget|Widget} state.
 --
@@ -22,9 +23,12 @@
 -- @field bg (table) background color
 -- @field fg (table) foreground color (typically used for text)
 -- @table Color
+
 local theme = {
     cornerRadius = 4,
 
+    -- font = nil defaults to love.graphics.getFont()
+
     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}},

ui.lua

@@ -14,14 +14,16 @@ local Widget = require(BASE..'widget')
 local Layout = require(BASE..'layout')
 local Columns = require(BASE..'columns')
 local Rows = require(BASE..'rows')
-
+local theme = require(BASE..'theme')
 local gear = require 'lib.gear'
 
 local Timer = gear.Timer
 local isinstance = gear.meta.isinstance
 local pointinrect = gear.rect.pointinside
 
-local Ui = {}
+local Ui = {
+    theme = theme  -- fallback theme
+}
 Ui.__index = Ui
 
 
@@ -66,6 +68,7 @@ end
 --
 -- @field x (number) x position of the Ui
 -- @field y (number) y position of the Ui
+-- @field theme (@{yui.theme.Theme|Theme}) custom global Ui theme, defaults to @{yui.theme}
 -- @table UiAttributes
 
 

widget.lua

@@ -13,6 +13,7 @@
 --- Attributes accepted by all the Widget classes
 -- @field w (number) widget width
 -- @field h (number) widget height
+-- @field theme (@{yui.theme.Theme|Theme}) widget specific theme
 -- @field color (@{yui.theme.ColorPalette|ColorPalette}) widget color
 -- @table WidgetAttributes
 local rectunion = require('lib.gear.rect').union
@@ -105,17 +106,6 @@ function Widget:recalculateBounds()
     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
-
 -- NOP hooks for UI internal use
 function Widget:loseFocus() end
 function Widget:gainFocus() end