gamepad/keyboard support

[konsumer]

First, this library looks awesome. Great work!

A common issue I have with love GUI libs is no gamepad support. I'm making a game that only uses gamepad/keys, but things like button could work if I could say "this is the current menu selection" or "the user has navigated to this button using the joypad".

I looked at the code and tried to figure it out, from an external-to-imgui perspective. This example is meant to use up/down keys and space to select:

imgui = require 'imgui'

local uiState = require "imgui.Core.UIState"

-- this tracks the current key choice
local currentItem = 1

-- NOTE: I'm new to imgui so there is probably a better way...
function love.draw()
  uiState.hotItem = currentItem

  imgui.layout.setFlex(true)
  imgui.layout.setColumns(2)

  if imgui.button('A') then
    imgui.label('You are clicking on the A button!!')
  else
    imgui.label('')
  end
  
  if imgui.button('B') then
    imgui.label('You are clicking on the B button!!')
  else
    imgui.label('')
  end
  
  if imgui.button('C') then
    imgui.label('You are clicking on the C button!!')
  else
    imgui.label('')
  end
  imgui.draw()
end

function love.keypressed(key)
  if key == 'space' then
    uiState.activeItem=currentItem
  end
  if key == 'up' then
    currentItem = currentItem - 1
  end
  if key == 'down' then
    currentItem = currentItem + 1
  end
  if currentItem > imgui['_genID'] then
    currentItem = 1
  end
  if currentItem < 1 then
    currentItem = imgui['_genID']
  end
end

function love.keyreleased(key)
  if key == 'space' then
    uiState.activeItem=nil
  end
end

It seems to be tracking the current-selection ok, but I can't quite figure out how to say "this was chosen".

Do you have a suggestion of a better way to do it? Is there interest in making this more internal (I am using _genID which seems hacky, but I bet widgets could even track this on their own.)

Here is a ready-made demo, just rename to demo.love:
demo.zip