// Ulteriori informazioni su F# all'indirizzo http://fsharp.net

open System.Windows.Forms
open System.Drawing

#load "ColorPicker.fsx"
open ColorPicker

type PaintSimple() as x=
    inherit UserControl()

    let mutable pressed = false
    let mutable _line: Point list = []
    // ClientSize -> dimensioni dell'area effettivamente disegnabile, al netto
    // dei bordi
    let mutable _buffer: Bitmap = null

    let _allocateBuffer() =
         _buffer <- new Bitmap(x.ClientSize.Width, x.ClientSize.Height)
         use graphics = Graphics.FromImage(_buffer)
         graphics.FillRectangle(Brushes.White, 0, 0, _buffer.Width, _buffer.Height)

    do
        //x.DoubleBuffered <- true
        x.SetStyle(ControlStyles.OptimizedDoubleBuffer, true)
        _allocateBuffer()

    member x.Buffer = _buffer

    member x.Undo() =
        _line <- []
        x.Invalidate()

    override x.OnPaintBackground evt = ()

    override x.OnClientSizeChanged evt =
        base.OnClientSizeChanged evt

        _allocateBuffer()
        x.Invalidate()

    override x.OnKeyUp evt =
        match evt.KeyCode with
            //| Keys.Z when evt.Control -> x.Undo()
            | Keys.Z -> x.Undo()

    override x.OnMouseDown evt =
        base.OnMouseDown evt
        if _line <> [] then
            use graphics = Graphics.FromImage(_buffer)
            graphics.SmoothingMode <- Drawing2D.SmoothingMode.HighQuality
            if _line.Length > 1 then
                graphics.DrawLines(Pens.Black, (List.toArray _line))
            _line <- []

        pressed <- true

    override x.OnMouseUp evt =
        base.OnMouseUp evt
        //points <- (_color, _line)::points
        //_line <- []
        pressed <- false

    override x.OnMouseMove evt =
        base.OnMouseMove evt
        if pressed then
            //points <- evt.Location::points
            _line <- evt.Location::_line
            x.Invalidate()

    override x.OnPaint evt =
        let graphics = evt.Graphics

        graphics.SmoothingMode <- Drawing2D.SmoothingMode.HighQuality
        //if points.Length > 1 then
        graphics.DrawImage(_buffer, 0, 0)
        if _line.Length > 1 then
            graphics.DrawLines(Pens.Black, List.toArray _line)
        (*for list in points do
            match list with
            | (a, b) ->
                if b.Length > 1 then
                    graphics.DrawLines(new Pen(a), List.toArray b)*)

let form = new Form(Text="Paint bacato", TopMost=true)
//let paint = new PaintSimple(Width=500, Height=450)
let paint = new PaintSimple(Width=640,Height=480)
//colorPicker.BorderStyle <- BorderStyle.FixedSingle
paint.BorderStyle <- BorderStyle.FixedSingle

//form.Controls.Add(paint)
form.Controls.Add(paint)
form.Show()