WritableBitmap

It’s just for my memo.

using System;
using System.Windows;
using System.Windows.Media.Imaging;
using Microsoft.Win32;

namespace WritableBitmap
{
    /// <summary>
    /// MainWindow.xaml の相互作用ロジック
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        WriteableBitmap srcWritableBitmap;
        WriteableBitmap destWritableBitmap;

        private void button1_Click(object sender, RoutedEventArgs e)
        {
            LoadImage();
            Process();
        }

        float[,] filter = {
                          { 1 / 25f, 1 / 25f, 1 / 25f, 1 / 25f, 1 / 25f },
                          { 1 / 25f, 1 / 25f, 1 / 25f, 1 / 25f, 1 / 25f },
                          { 1 / 25f, 1 / 25f, 1 / 25f, 1 / 25f, 1 / 25f },
                          { 1 / 25f, 1 / 25f, 1 / 25f, 1 / 25f, 1 / 25f },
                          { 1 / 25f, 1 / 25f, 1 / 25f, 1 / 25f, 1 / 25f }
                          };

        private void Process()
        {
            int width = srcWritableBitmap.PixelWidth;
            int height = srcWritableBitmap.PixelHeight;
            int bytesPerPixel = srcWritableBitmap.Format.BitsPerPixel / 8;

            int srcPtr = (int)srcWritableBitmap.BackBuffer;
            int destPtr = (int)destWritableBitmap.BackBuffer;

            for (int y = 2; y < height-2; y++)
                for (int x = 2; x < width-2; x++)
                    for (int col = 0; col < bytesPerPixel; col++)
                    {
                        int destIndex = destPtr + width * bytesPerPixel * y + bytesPerPixel * x + col;

                        if (y < height/3 || y > (height/3)*2)
                        {
                            float v = 0f;

                            for (int yy = -2; yy <= 2; yy++)
                                for (int xx = -2; xx <= 2; xx++)
                                {
                                    int srcIndex = srcPtr + width * bytesPerPixel * (y + yy) + bytesPerPixel * (x + xx) + col;

                                    float filterValue = filter[yy + 2, xx + 2];

                                    unsafe
                                    {
                                        v = v + (*((byte*)srcIndex) * filterValue);
                                    }
                                }
                            v = Math.Abs(v);
                            v = (v > 255) ? 255 : v;
                            unsafe
                            {
                                *((byte*)destIndex) = (byte)v;
                            }
                        }
                        else
                        {
                            int srcIndex = srcPtr + width * bytesPerPixel * y + bytesPerPixel * x + col;
                            unsafe
                            {
                                *((byte*)destIndex) = *((byte*)srcIndex);
                            }
                        }
                    }
            resultImage.Source = destWritableBitmap;
        }

        private void LoadImage()
        {
            OpenFileDialog dlg = new OpenFileDialog();
            dlg.Filter = “Bitmap files|*.bmp;*.png;*.jpeg;*.jpg;*.gif;*.tiff;*.tif;*.wdp|” +
                         “BMP files (*.bmp)|*.bmp|” +
                         “PNG files (*.png)|*.png|” +
                         “JPEG files (*.jpeg, *.jpg)|*.jpeg;*.jpg|” +
                         “GIF files (*.gif)|*.gif|” +
                         “TIFF files (*.tiff, *.tif)|*.tiff;*.tif|” +
                         “Windows Media Player files (*.wdp)|*.wdp|” +
                         “All files (*.*)|*.*”;

            if ((bool)dlg.ShowDialog())
            {
                srcImage.Source = null;
                srcWritableBitmap = null;
                BitmapFrame frame = null;

                try
                {
                    frame = BitmapFrame.Create(new Uri(dlg.FileName), BitmapCreateOptions.None,
                                                                      BitmapCacheOption.None);
                }
                catch (Exception exc)
                {
                    MessageBox.Show(exc.Message, Title);
                    return;
                }

                srcWritableBitmap = new WriteableBitmap(frame);

                if (srcWritableBitmap.Format.BitsPerPixel != 8 &&
                    srcWritableBitmap.Format.BitsPerPixel != 24 &&
                    srcWritableBitmap.Format.BitsPerPixel != 32)
                {
                    MessageBox.Show(“Bitmap must have 8 or 24 bits or 32 bits per pixel”, Title);
                    srcWritableBitmap = null;
                    return;
                }
                srcImage.Source = srcWritableBitmap;
                destWritableBitmap = srcWritableBitmap.Clone();
            }
        }
    }
}