[*] Initial commit.

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