WPF学習中「２枚の画像を左右に並べて表示」

mkdir プロジェクト名
cd プロジェクト名
dotnet new wpf
code .

<Window x:Class="Sample55CopyPixels.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:Sample55CopyPixels"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Grid>
        <StackPanel>
            <Image Name="Image1">
            </Image>
        </StackPanel>
    </Grid>
</Window>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

using System.IO;

namespace Sample55CopyPixels
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();

            // 左側画像の読み込み
            var leftPath = @"C:\Users\asagao\Pictures\202108070814.png";
            var lb = new BitmapImage();
            using (var fs = new FileStream(leftPath, FileMode.Open, FileAccess.Read))
            {
                lb.BeginInit();
                lb.CacheOption = BitmapCacheOption.OnLoad;
                lb.StreamSource = fs;
                lb.EndInit();
            }
            lb.Freeze();

            // 左側画像をbyte配列にコピー
            int lb_stride = lb.PixelWidth * 4;
            byte[] lb_datas = new byte[lb_stride * lb.PixelHeight];
            lb.CopyPixels(new Int32Rect(0, 0, lb.PixelWidth, lb.PixelHeight), lb_datas, lb_stride, 0);

            // 右側画像の読み込み
            var rightPath = @"C:\Users\asagao\Pictures\202108070821.png";
            var rb = new BitmapImage();
            using (var fs = new FileStream(rightPath, FileMode.Open, FileAccess.Read))
            {
                rb.BeginInit();
                rb.CacheOption = BitmapCacheOption.OnLoad;
                rb.StreamSource = fs;
                rb.EndInit();
            }
            rb.Freeze();
            
            // 右側画像をbyte配列にコピー
            int rb_stride = rb.PixelWidth * 4;
            byte[] rb_datas = new byte[rb_stride * rb.PixelHeight];
            rb.CopyPixels(new Int32Rect(0, 0, rb.PixelWidth, rb.PixelHeight), rb_datas, rb_stride, 0);

            // 表示画像の作成
            int height = lb.PixelHeight;
            int width = (int)((height/9)*16);
            var wb = new WriteableBitmap(
                width,
                height,
                lb.DpiX,
                lb.DpiY,
                lb.Format,
                null);
            
            // 貼り付け先のx座標を計算
            int x = (int)((width - (lb.PixelWidth + rb.PixelWidth))/2);
            
            // 画像をコピー
            wb.WritePixels(
                new Int32Rect(x, 0, lb.PixelWidth, lb.PixelHeight),
                lb_datas,
                lb_stride,
                0);
            wb.WritePixels(
                new Int32Rect(x+lb.PixelWidth, 0, rb.PixelWidth, rb.PixelHeight),
                rb_datas,
                rb_stride,
                0);
            wb.Freeze();



            // イメージコントロールのソースにビットマップイメージを割り当て
            Image1.Source = wb;
        }
    }
}