module internal ImageServices

    open System.Drawing
    open System.Drawing.Imaging
    open DeathSocket
    open ColourServices

    let createHorizontalLines width height rows =
        let interval = height / rows
        [| for point in 1 .. (rows - 1) ->
            [|Point (0, (interval * point))
              Point (width, (interval * point) )|]|]

    let createVerticalLines width height columns =
        let interval = width / columns
        [| for point in 1 .. (columns - 1) ->
            [| Point ((interval * point), 0)
               Point ((interval * point), height)|]|]

    (* Note on Use of Temp File in Functions which Add A Grid Overlay
    ===========================================================================
    The temp. file is used in the functions below are there to convert images
    with indexed pixels. Instead of listig them all, just assume any function
    with a "*Spec" type as a parameter will use this "temp" file. *)

    let drawBrushSpecGrid (spec: BrushSpec) =
        use original = Bitmap.FromFile spec.originalPath
        use temp = new Bitmap(original)
        use clone = temp.Clone(new Rectangle(0, 0, temp.Width, temp.Height), PixelFormat.Format32bppArgb)
        use graphics = Graphics.FromImage(clone)
        use pen = new Pen (spec.colour, width = spec.penWidth)
        graphics.DrawImage(original,new Rectangle(0, 0, clone.Width, clone.Height))
        let horizontalLines =
            createHorizontalLines (clone.Size.Width) (clone.Size.Height) (spec.rows)
        let verticalLines =
            createVerticalLines (clone.Size.Width) (clone.Size.Height) (spec.columns)
        for line in horizontalLines do graphics.DrawLines (pen, line)
        for line in verticalLines do graphics.DrawLines (pen, line)
        clone.Save (spec.savePath)

    let drawRGBAGrid (spec: RGBASpec) =
        use original = Bitmap.FromFile spec.originalPath
        use temp = new Bitmap(original)
        use clone = temp.Clone(new Rectangle(0, 0, temp.Width, temp.Height), PixelFormat.Format32bppArgb)
        use graphics = Graphics.FromImage(clone)
        use pen = new Pen ((makeBrushFromRGBASpec spec), width = spec.penWidth)
        graphics.DrawImage(original,new Rectangle(0, 0, clone.Width, clone.Height))
        let horizontalLines =
            createHorizontalLines (clone.Size.Width) (clone.Size.Height) (spec.rows)
        let verticalLines =
            createVerticalLines (clone.Size.Width) (clone.Size.Height) (spec.columns)
        for line in horizontalLines do graphics.DrawLines (pen, line)
        for line in verticalLines do graphics.DrawLines (pen, line)
        clone.Save (spec.savePath)