Slider Library

slider.lua

--[[
Copyright (c) 2018, Josef Patoprsty

Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated documentation
files (the "Software"), to deal in the Software without
restriction, including without limitation the rights to use,
copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following
conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.
--]]

local slider = {}

function slider.new(init)
  init = init or {}
  local self = {}

  self.update = slider.update
  self.draw = slider.draw
  self.mouseInside = slider.mouseInside
  self._onChange = init.onChange or slider._onChange
  self.setOnChange = slider.setOnChange

  self._value = init.value or 0.5
  self.setValue = slider.setValue
  self.getValue = slider.getValue

  self._range = init.range or {0,1}
  self.setRange = slider.setRange
  self.getRange = slider.getRange
  self.setRangeValue = slider.setRangeValue
  self.getRangeValue = slider.getRangeValue

  self._text = init.text or slider.defaultText
  self.setText = slider.setText
  self.getText = slider.getText

  self._barPadding = 4
  self._bgColor = init.bgColor or {63,63,63}
  self._barColor = init.color or {246,197,42}
  self._textColor = init.textColor or {0,0,0}
  self._textInverseColor = init.textInverseColor

  self._x = init.x or 32
  self.setX = slider.setX
  self.getX = slider.getX
  self._y = init.y or 32
  self.setY = slider.setY
  self.getY = slider.getY
  self._width = init.width or 256
  self.setWidth = slider.setWidth
  self.getWidth = slider.getWidth
  self._height = init.height or 48
  self.setHeight = slider.setHeight
  self.getHeight = slider.getHeight

  self._ready = false

  return self
end

function slider:defaultText()
  return "value: " .. math.floor(self._value*100)/100
end

function slider:update(dt)
  if self:mouseInside() then
    if not love.mouse.isDown(1) then
      if self._depressed then
        self._depressed = false
        if self._onChange then
          self._onChange(self._value,self:getRangeValue(),true)
        end
      end
      self._ready = true
    elseif self._ready then
      self._depressed = true
      local mx = love.mouse.getX()
      self._value = (mx - self._x)/self._width
      if self._onChange then
        self._onChange(self._value,self:getRangeValue(),false)
      end
    end
  else
    if self._depressed then
      self._depressed = false
      if self._onChange then
        self._onChange(self._value,self:getRangeValue(),true)
      end
    end
    self._ready = false
  end
end

function slider:setOnChange(val)
  assert(type(val)=="function")
  self._onChange = val
end

function slider:draw()
  local old_color = {love.graphics.getColor()}
  love.graphics.setColor(self._bgColor)
  love.graphics.rectangle("fill",self._x,self._y,self._width,self._height)
  local tvoff = (self._height-love.graphics.getFont():getHeight())/2
  local text = type(self._text)=="function" and self._text(self) or tostring(self._text)
  if self._textInverseColor then
    love.graphics.setColor(self._textInverseColor)
  end
  love.graphics.printf(text,self._x,self._y+tvoff,self._width,"center")
  love.graphics.setColor(self._barColor)
  local barwidth = (self._width-self._barPadding*2)*self._value

  love.graphics.rectangle("fill",
    self._x+self._barPadding,
    self._y+self._barPadding,
    barwidth,
    self._height-self._barPadding*2)

  love.graphics.setScissor(self._x,self._y,barwidth+self._barPadding,self._height)
  love.graphics.setColor(self._textColor)
  love.graphics.printf(text,self._x,self._y+tvoff,self._width,"center")
  love.graphics.setScissor()
  love.graphics.setColor(old_color)
end

function slider:mouseInside()
  local mx,my = love.mouse.getPosition()
  return mx >= self._x and mx < self._x + self._width and
    my >= self._y and my < self._y + self._height
end

function slider:setValue(val)
  self._value = val
end

function slider:getValue()
  return self._value
end

function slider:setRange(min,max)
  self._range = {min,max}
end

function slider:getRange(min,max)
  return self._range[1],self._range[2]
end

function slider:setRangeValue(val)
  self._value = (val - self._range[1]) / (self._range[2]-self._range[1])
end

function slider:getRangeValue()
  return self._range[1] + (self._range[2]-self._range[1])*self._value
end

function slider:setX(val)
  self._x = val
end

function slider:getX()
  return self._x
end

function slider:setY(val)
  self._y = val
end

function slider:getY()
  return self._y
end

function slider:setWidth(val)
  self._width = val
end

function slider:getWidth()
  return self._width
end

function slider:setHeight(val)
  self._height = val
end

function slider:getHeight()
  return self._height
end

return slider