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

local WidgetContainer = require("ui/widget/container/widgetcontainer")
local Geom = require("ui/geometry")
local Blitbuffer = require("ffi/blitbuffer")

--[[
an UnderlineContainer is a WidgetContainer that is able to paint
a line under its child node
--]]

local UnderlineContainer = WidgetContainer:new{
    linesize = 2,
    padding = 1,
    -- TODO: shouldn't this default to black instead?
    color = Blitbuffer.COLOR_WHITE,
    vertical_align = "top",
}

function UnderlineContainer:getSize()
    return self:getContentSize()
end

function UnderlineContainer:getContentSize()
    local contentSize = self[1]:getSize()
    return Geom:new{
        w = contentSize.w,
        h = contentSize.h + self.linesize + self.padding
    }
end

function UnderlineContainer:paintTo(bb, x, y)
    local container_size = self:getSize()
    local content_size = self:getContentSize()
    local p_y = y
    if self.vertical_align == "center" then
        p_y = math.floor((container_size.h - content_size.h) / 2) + y
    elseif self.vertical_align == "bottom" then
        p_y = (container_size.h - content_size.h) + y
    end
    self[1]:paintTo(bb, x, p_y)
    bb:paintRect(x, y + container_size.h - self.linesize,
        container_size.w, self.linesize, self.color)
end

return UnderlineContainer