First Elm experiment

clickndraw.elm

import Mouse
import Window

relativeMouse : (Int, Int) -> (Int, Int) -> (Int, Int)
relativeMouse (dimx, dimy) (x, y) = let (cx, cy) = center (dimx, dimy)
                                    in (x - cx, cy - y)

center : (Int, Int) -> (Int, Int)
center (x, y) = ( x//2, y//2)

drawCirc : Pill -> Form
drawCirc {size, pos, col} = circle size |> filled col 
                                        |> move (toFloat <| fst pos, toFloat <| snd pos)
                                   
type Pill = {pos: (Int,Int),col:Color,size: Float}
defaultPill = {pos= (0,0), col=red, size=15}
type Game = {pills: [Pill], points: [(Float, Float)]}
game = {pills = [], points = []}


stepGame : Event -> Game -> Game
stepGame event game = 
  case event of 
      Click () ((w, h) as dim) mp -> let cpos = relativeMouse dim mp
                                         newPills = {defaultPill | pos<-cpos} :: game.pills
                                     in {game | pills <- newPills}
      Draw ((w, h) as dim) mp isDown -> let cpos = relativeMouse dim mp
                                            newPoints = (toFloat <| fst cpos,toFloat <| snd cpos)  :: game.points
                                        in (if isDown then {game | points<-newPoints} else game)
                                        

scene : (Int, Int) -> (Int, Int) -> Game -> Element
scene ((w, h) as dim) mp g = let cpos = relativeMouse dim mp
                                 pointer = {defaultPill | pos<-cpos, col<-green }
                                 pills = map drawCirc <| pointer :: g.pills
                                 forms = traced (solid purple) (path g.points) :: pills
                             in color lightGray <| container w h middle
                                                <| color white
                                                <| collage 400 400 forms


data Event = Draw (Int, Int) (Int, Int) Bool | Click () (Int, Int) (Int, Int)

event = merges [lift3 Draw Window.dimensions Mouse.position Mouse.isDown
                , lift3 Click Mouse.clicks Window.dimensions Mouse.position]


main = lift3 scene Window.dimensions Mouse.position <| foldp stepGame game event