FloodFill (WIP)

FloodFill.fs

open System
open System.Windows
open System.Windows.Controls
open System.Windows.Media.Imaging
open System.Windows.Media.Effects
open System.Diagnostics
open System.Collections.Generic

let fillBmp pixels color =
    Array.fill pixels 0 pixels.Length color

let distance x1 y1 x2 y2 =
//    Math.Sqrt ((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2))
    let a = (x1 - x2) * (x1 - x2)
    let b = (y1 - y2) * (y1 - y2)
    Math.Sqrt ((float a) + (float b))
    
let putPoint (pixels : int[]) width height px py =
    for y = 0 to height - 1 do
        for x = 0 to width - 1 do
            if (distance x y px py) < 10.0 then
                pixels.[x + y * width] <- 0xff

let floodFill (pixels : int[]) width height px py color =
    let region_map : byte[,] = Array2D.zeroCreate width height
    let regionid = 1uy
    region_map.[px, py] <- regionid

    let key = pixels.[px + py * width]

    let xdelt = [| -1; 1; 0; 0; |]
    let ydelt = [| 0; 0; -1; 1; |]

    let queue = new Queue<int * int>()
    queue.Enqueue(px, py)

    while queue.Count > 0 do
        let x, y = queue.Dequeue()

        for i = 0 to 3 do
            let cx = x + xdelt.[i]
            let cy = y + ydelt.[i]
            if 0 <= cx && cx < width && 0 <= cy && cy < height then
                if region_map.[cx, cy] <> regionid then
                    if pixels.[cx + cy * width] = key then
                        region_map.[cx, cy] <- regionid
                        queue.Enqueue(cx, cy)

    for y = 0 to height - 1 do
        for x = 0 to width - 1 do
            if region_map.[x, y] = regionid then
                pixels.[x + y * width] <- color
    ()
    

let w = new Window(Title = "title", Width = 1000., Height = 873. + 24.)

w.Loaded.Add(fun _ ->
    let img = new Image()
    let bmp = new BitmapImage(new Uri(@"..\..\25897778_p2.jpg", UriKind.Relative))
    img.Source <- bmp
//    img.Stretch <- Media.Stretch.None
//    Trace.WriteLine((sprintf "img:%f, %f" img.Width, img.Height))
    w.Content <- img

    let wbmp = new WriteableBitmap(bmp)
    let width = wbmp.PixelWidth
    let stride = wbmp.PixelWidth * wbmp.Format.BitsPerPixel / 8
    let pixels = Array.zeroCreate<int> (stride * wbmp.PixelHeight) // pixel format: ARGB
    wbmp.CopyPixels(pixels, stride, 0)

    img.MouseDown.Add(fun (e : Input.MouseButtonEventArgs) ->
        let x = e.GetPosition(null).X / img.ActualWidth * float(bmp.PixelWidth) |> int
        let y = e.GetPosition(null).Y / img.ActualHeight * float(bmp.PixelHeight) |> int
        Trace.WriteLine(sprintf "img.MouseDown %A" (e.GetPosition(null)))
        Trace.WriteLine(sprintf "x = %d y = %d" x y)

        if wbmp.Format.BitsPerPixel = 32 then
//            putPoint pixels bmp.PixelWidth bmp.PixelHeight x y
            floodFill pixels bmp.PixelWidth bmp.PixelHeight x y 0xff
//            for y = 0 to bmp.PixelHeight - 1 do
//                for x = 0 to wbmp.PixelWidth - 1 do
//                    pixels.[x + y * width] <- 0xff
        wbmp.WritePixels(new Int32Rect(0, 0, wbmp.PixelWidth, wbmp.PixelHeight), pixels, stride, 0)
        img.Source <- wbmp
        )
    )

[<EntryPoint>][<STAThread>]
let main _ = (Application()).Run w