AgraSandbox/AgraV2/EffectMedianFilter.cs

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Imaging;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace AgraV2
{
    internal class EffectMedianFilter : Effect
    {
        private readonly object balancelock = new object();
        private int _Radius;

        public int Radius { get => _Radius; set => _Radius = value; }

        public EffectMedianFilter(string name, Panel toolBox) : base(name, toolBox)
        {
            //This is just the default value
            Radius = 1;
        }
        public override void populatePannel()
        {
            Label label = new Label();
            label.Text = "Radius : ";

            NumericUpDown nup = new NumericUpDown();
            nup.Minimum = 1;
            nup.Maximum = 100;
            nup.Increment = 1;
            nup.ValueChanged += nup_ValueChanged;
            nup.Location = new Point(label.Location.X + label.Width,label.Location.Y);

            ToolBox.Controls.Add(label);
            ToolBox.Controls.Add(nup);
        }
        private void nup_ValueChanged(object sender, EventArgs e)
        {
            if (sender is NumericUpDown)
            {
                NumericUpDown nup = (NumericUpDown)sender;
                Radius = (int)nup.Value;
            }
        }
        public override Bitmap[] apply(Bitmap inputBmp)
        {
            if (inputBmp == null)
                return null;

            //This is important for when the user wants to re apply an effet
            ProcessingDuration = new List<double>();

            Bitmap[] result = new Bitmap[] { medianFilter(inputBmp) };
            return result;
        }
        public unsafe Bitmap medianFilter(Bitmap inputBmp)
        {
            Chrono.Restart();

            Size imgSize = new Size(inputBmp.Width,inputBmp.Height);
            Bitmap result = new Bitmap(imgSize.Width, imgSize.Height);
            BitmapData resultData = result.LockBits(new Rectangle(0, 0, imgSize.Width, imgSize.Height), ImageLockMode.ReadWrite, inputBmp.PixelFormat);
            BitmapData inputData = inputBmp.LockBits(new Rectangle(0, 0, imgSize.Width, imgSize.Height), ImageLockMode.ReadWrite, inputBmp.PixelFormat);

            int bytesPerPixel = Bitmap.GetPixelFormatSize(inputBmp.PixelFormat) / 8;
            int byteCount = resultData.Stride * inputBmp.Height;
            int offset = resultData.Stride - bytesPerPixel * imgSize.Width;

            lock (balancelock)
            {
                byte* resultStartPx = (byte*)resultData.Scan0.ToPointer();
                byte* resultCursor = resultStartPx;
                byte* originalStartPx = (byte*)inputData.Scan0.ToPointer();
                byte* originalCursor = originalStartPx;

                for (int y = 0; y < inputBmp.Height; y++)
                {
                    for (int x = 0; x < imgSize.Width; x++)
                    {
                        //We wont process border pixels
                        if (x > Radius && y > Radius && x < imgSize.Width - Radius && y < inputBmp.Height - Radius)
                        {
                            List<int> Blues = new List<int>();
                            List<int> Greens = new List<int>();
                            List<int> Reds = new List<int>();

                            List<Point> surroundingPixels = getSurroundingPixels(new Point(x, y), Radius, imgSize.Width, inputBmp.Height);

                            foreach (Point pixel in surroundingPixels)
                            {
                                int relativePosition = (pixel.X) * bytesPerPixel + (pixel.Y * (imgSize.Width * bytesPerPixel + offset));
                                byte* address = (byte*)(relativePosition + originalStartPx);
                                Blues.Add(address[0]);
                                Greens.Add(address[1]);
                                Reds.Add(address[2]);
                            }

                            Blues.Sort();
                            Greens.Sort();
                            Reds.Sort();
                            resultCursor[0] = (byte)Blues[Blues.Count / 2];
                            resultCursor[1] = (byte)Greens[Greens.Count / 2];
                            resultCursor[2] = (byte)Reds[Reds.Count / 2];

                        }
                        originalCursor += bytesPerPixel;
                        resultCursor += bytesPerPixel;
                    }
                    //Taking care of the offset
                    originalCursor += offset;
                    resultCursor += offset;
                }

            }
            result.UnlockBits(resultData);
            inputBmp.UnlockBits(inputData);

            Chrono.Stop();
            ProcessingDuration.Add(Chrono.ElapsedMilliseconds / 1000.0);

            return result;
        }
        public List<Point> getSurroundingPixels(Point centerPoint, int Radius, int imageWidth, int imageHeight)
        {
            List<Point> result = new List<Point>();
            int width = (Radius * 2 + 1);

            Point cursor = centerPoint;

            //we place the cursor on the top left of the matrix
            cursor = new Point(cursor.X - Radius, cursor.Y - Radius);

            for (int y = 0; y < width; y++)
            {
                //This scans top to bottom
                for (int x = 0; x < width; x++)
                {
                    //This scans left to right
                    result.Add(cursor);
                    cursor = new Point(cursor.X + 1, cursor.Y);
                }
                cursor = new Point(cursor.X - (Radius * 2 + 1), cursor.Y + 1);
            }
            return result;
        }
    }
}