koreader/frontend/ui/widget/container/widgetcontainer.lua

--[[--
WidgetContainer is a container for another Widget. Base class for all the widget containers.

It handles event propagation and paiting (with different alignments) for its children.
]]

local Geom = require("ui/geometry")
local Widget = require("ui/widget/widget")

if require("device"):isAndroid() then
    require("jit").off(true, true)
end

local WidgetContainer = Widget:new()

function WidgetContainer:init()
    if self.dimen then
        if self.initDimen then
            self:initDimen()
        else
            if not self.dimen.w then
                self.dimen.w = self[1]:getSize().w
            end
            if not self.dimen.h then
                self.dimen.h = self[1]:getSize().h
            end
        end
    end
end

function WidgetContainer:getSize()
    if self.dimen then
        -- fixed size
        return self.dimen
    elseif self[1] then
        -- return size of first child widget
        return self[1]:getSize()
    else
        return Geom:new{ w = 0, h = 0 }
    end
end

--[[--
Delete all child widgets
]]
function WidgetContainer:clear()
    while table.remove(self) do end
end

function WidgetContainer:paintTo(bb, x, y)
    -- default to pass request to first child widget
    if self[1] then
        x = x + (self.dimen.x or 0)
        y = y + (self.dimen.y or 0)
        if self.align == "top" then
            local contentSize = self[1]:getSize()
            self[1]:paintTo(bb,
                x + math.floor((self.dimen.w - contentSize.w)/2), y)
        elseif self.align == "bottom" then
            local contentSize = self[1]:getSize()
            self[1]:paintTo(bb,
                x + math.floor((self.dimen.w - contentSize.w)/2),
                y + (self.dimen.h - contentSize.h))
        elseif self.align == "center" then
            local contentSize = self[1]:getSize()
            self[1]:paintTo(bb,
                x + math.floor((self.dimen.w - contentSize.w)/2),
                y + math.floor((self.dimen.h - contentSize.h)/2))
        else
            return self[1]:paintTo(bb, x, y)
        end
    end
end

function WidgetContainer:propagateEvent(event)
    -- propagate to children
    for _, widget in ipairs(self) do
        if widget:handleEvent(event) then
            -- stop propagating when an event handler returns true
            return true
        end
    end
    return false
end

--[[--
WidgetContainer will pass event to its children by calling their handleEvent
methods. If no child responded to the event (by returning true), it will call its own
handleEvent method.

@tparam ui.event.Event event
@treturn bool true if event is consumed, othewise false. A consumed event will
not be sent to other widgets.
]]
function WidgetContainer:handleEvent(event)
    if not self:propagateEvent(event) then
        -- call our own standard event handler
        return Widget.handleEvent(self, event)
    else
        return true
    end
end

function WidgetContainer:free()
    for _, widget in ipairs(self) do
        if widget.free then widget:free() end
    end
end

return WidgetContainer