Slider

functions

Syntax	Description
UI.Slider.new (x, y, width, height, value, min_value, max_value, markers, direction)	Create a new slider `x` and `y` are the coordinates where the slider will be drawn: numbers `width` and `height` are the width and height of the slider: numbers `value` is the desired starting value: number `min_value` and `max_value` are the minimum and maximum values respectively, by which `value` is clamped: numbers `markers` are reference markers along the slider: table of floats or integers `direction` is the direction in which the slider moves, defaults to `up`: `up`, `down`, `left` or `right`
my_slider:set_value (number)	Set value : number
my_slider:set_value_delta (delta)	Set value using delta : number
my_slider:set_marker_position (id, position)	Set marker positions : number
my_slider:redraw ()	Redraw slider

variables

Syntax	Description
my_slider.x	Originating x-coordinate : number
my_slider.y	Originating y-coordinate : number
my_slider.width	Width : number
my_slider.height	Height : number
my_slider.value	Slider’s current value : number
my_slider.min_value	Slider’s minimum value : number
my_slider.max_value	Slider’s maximum value : number
my_slider.markers	Marker positions : table
my_slider.direction	Slider’s direction : string
my_slider.active	Slider’s active state : boolean

example

UI = require("ui")

slider = {}

-- create 4 sliders:
slider[1] = UI.Slider.new(5,10,5,50,30,0,127,{0},"down")
slider[2] = UI.Slider.new(15,10,50,5,97,0,127,{},"right")
slider[3] = UI.Slider.new(40,55,50,5,72,0,127,{72},"left")
slider[4] = UI.Slider.new(100,10,5,50,72,0,127,{0,32,64,96,127})
-- set fourth slider to inactive:
slider[4].active = false

-- label sliders
slider[1].label = "L"
slider[2].label = "R"
slider[3].label = "freq"
slider[4].label = "res"

function redraw()
  screen.clear()
  -- sliders need to be redrawn to display:
  for i = 1,4 do
    slider[i]:redraw()
  end
  screen.level(15)
  screen.move(slider[1].x,slider[1].y - 2) -- relative positioning using the originating x and y coordinates
  screen.text(slider[1].label)
  for i=2,4 do -- another way to position labels
    screen.move(slider[i].x,slider[i].y-2)
    screen.text(slider[i].label)
  end
  screen.move(42,28)
  screen.text("k2: pan")
  screen.move(42,37)
  screen.text("k3: lpf")
  screen.update()
end

function key(n,z)
  -- manipulating slider states + values:
  if n == 3 and z == 1 then
    slider[3].active = not slider[3].active
    slider[4].active = not slider[3].active
  elseif n == 2 then
    slider[1]:set_value(z == 1 and 97 or 30)
    slider[2]:set_value(z == 1 and 30 or 97)
  end
  redraw()
end

function enc(n,d)
  -- adjusting slider + marker values:
  if n == 3 then
    if slider[3].active then
      slider[3]:set_value_delta(d)
      slider[3]:set_marker_position(1,slider[3].value)
    else
      slider[4]:set_value_delta(d)
    end
    redraw()
  end
end

description

Draws a slider on the screen from the specified (x, y) pair. Width and height can extend beyond the screen’s bounds. Value is clamped to the slider’s min and max values and can be changed by direct assignment or incremental adjustment. Reference markers can be added, in the form of a table of floats or integers. Direction defaults to “up” if it is not specified.