OpenCVSharp「メディアンフィルタ」を試す。

namespace medianBlurSample;

using OpenCvSharp;
using OpenCvSharp.Extensions;
public partial class Form1 : Form
{
    Mat? view = null;

    static Mat filter(Mat src, int ksize)
    {
        Mat result = src.Clone();
        Cv2.MedianBlur(src, result, ksize);
        return result;
    }
    public Form1()
    {
        InitializeComponent();

        Text = "メディアンフィルタ";
        Size = new System.Drawing.Size(850, 800);

        var fnt = new Font("MS UI Gothic", 12);
        var vb = new Bitmap(800, 600);
        using (var g = Graphics.FromImage(vb)) {
            g.FillRectangle(Brushes.White, 0, 0, vb.Width, vb.Height);
            g.DrawString("こちらにD&D Or Ctrl+Cコピー Ctrl+V貼り付け", fnt,  Brushes.Green, 0.0f, 0.0f);
        }
        
        var ud = new SplitContainer {
            Dock = DockStyle.Fill,
            Orientation = Orientation.Horizontal,   // 上下
            Panel1MinSize = 120,
        };
        var picboxV = new PictureBox {
            SizeMode = PictureBoxSizeMode.Zoom,
            Dock = DockStyle.Fill,
            
            AllowDrop = true,
            Image = vb,
        };
        var execBtn = new RadioButton {
            Text = "フィルターOFF",
            Appearance = Appearance.Button,
            AutoCheck = false,
            Size = new System.Drawing.Size(120, 50),
        };
        var flowPanel = new FlowLayoutPanel { Dock = DockStyle.Fill, };
        
        var kernelOptions = new Dictionary<string, int>{
            {"3x3", 3},{"5x5", 5},{"7x7", 7},{"9x9", 9},{"1x1", 1},};
        var kernelOptionsCmd = new ComboBox {
            DataSource = kernelOptions.Keys.ToArray<string>(),
        };

        picboxV.DragEnter += (sender, e) => {
            if (e.Data == null) return;
            if(!e.Data.GetDataPresent(DataFormats.FileDrop)) return;
            e.Effect = DragDropEffects.Copy;
        };
        picboxV.DragDrop += (sender, e) => {
            if (e.Data == null) return;
            var fd = e.Data.GetData(DataFormats.FileDrop);
            if (fd == null) return;
            string? path = ((string[])fd)[0];
            if (view is not null) view.Dispose();
            view = Cv2.ImRead(path);
            if (picboxV.Image is not null) picboxV.Image.Dispose();
            picboxV.Image = BitmapConverter.ToBitmap(view);
            execBtn.Checked = false;
        };
        execBtn.Click += async (sender, e) => {
            if (view is null) return;
            if (execBtn.Checked == true) {
                if (picboxV.Image is not null) picboxV.Image.Dispose();
                picboxV.Image = BitmapConverter.ToBitmap(view);

                execBtn.Text = "フィルターOff";
                execBtn.Checked = false;
            } else {
                var key = (string)kernelOptionsCmd.SelectedValue;
                if (!kernelOptions.ContainsKey(key)) return;
                int ksize = kernelOptions[key];
                await Task.Run(()=>{
                    using (var result = filter(view, ksize)) {
                        if (picboxV.Image is not null) picboxV.Image.Dispose();
                        picboxV.Image = BitmapConverter.ToBitmap(result);
                    }
                });

                execBtn.Text = "フィルターOn";
                execBtn.Checked = true;
            }            
        };
        KeyPreview = true;
        KeyDown += (sender, e) => {
            if (e.KeyData == (Keys.Control | Keys.C)) {
                // コピー                
                if (picboxV.Image is null) return;
                var ms = new MemoryStream();
                picboxV.Image.Save(ms, System.Drawing.Imaging.ImageFormat.Png);
                Clipboard.SetData("PNG", ms);            
            } else if (e.KeyData == (Keys.Control | Keys.V)) {
                // 貼り付け
                var obj = Clipboard.GetData("PNG");
                if (obj == null) return;
                var ms = (MemoryStream)obj;
                if (ms is null) return;
                if (view is not null) view.Dispose();
                using(var b = new Bitmap(ms)) {
                    view = BitmapConverter.ToMat(b);
                }
                if (picboxV.Image is not null) picboxV.Image.Dispose();
                picboxV.Image = BitmapConverter.ToBitmap(view);
                execBtn.Checked = false;
            }
        };

        ud.Panel1.Controls.Add(picboxV);
        flowPanel.Controls.AddRange(new Control[]{execBtn, kernelOptionsCmd});
        ud.Panel2.Controls.Add(flowPanel);
        Controls.Add(ud);
    }
}