Scroll Bar Test

os.loadAPI("/agui")
local update
local on = 1
local bX = 0
local bY = 0

local function round(num)
  return math.floor(num+0.5)
end

local m = agui:new()
m:setBackgroundColor(colors.cyan)

local bar = m:create("button")
bar:setSize(1, 4)
bar:setPosition(51, 1)
bar:setBackgroundColor(colors.gray)
bar:setText("")
bar.button1Click(function(x, y)
  local px, py = bar:getPosition()
  bX = px - x
  bY = py - y
end)
bar.button1Drag(function(x, y)
  y = y + bY
  if y < 1 then
    y = 1
  end
  if y > 19-3 then
    y = 19-3
  end
  on = round((((y-(19-3))/((19-3))+1))*(32-18))
  bar:setPosition(51, y)
  update()
  m:draw()
end)

local items = {}
for i = 1, 19 do
  local it = m:create("label")
  it:setSize(50, 1)
  it:setPosition(1, i)
  it:setText("Derp")
  it:setBackgroundColor(colors.black)
  it:setTextColor(colors.white)
  table.insert(items, it)
end

function update()
  for i = on, on + 18 do
    local it = items[1 - on + i]
    it:setText("Number: " .. i)
  end
end

update()
m:draw()
m:listen()