Implemented core logic

GifResizer/App.xaml.cs

@@ -1,6 +1,7 @@
 using System.Configuration;
 using System.Data;
 using System.Windows;
+using GifResizer.Service;
 using GifResizer.ViewModels;
 using GifResizer.Views;
 
@@ -15,7 +16,7 @@ public partial class App : Application
     {
         base.OnStartup(e);
         
-        var viewModel = new MainViewModel();
+        var viewModel = new MainViewModel(new ResizeService());
         var mainWindow = new MainWindow(viewModel);
         
         mainWindow.Show();

GifResizer/GifResizer.csproj

@@ -8,6 +8,10 @@
         <UseWPF>true</UseWPF>
     </PropertyGroup>
 
+    <ItemGroup>
+      <PackageReference Include="SixLabors.ImageSharp" Version="3.1.12" />
+    </ItemGroup>
+
 
 
 </Project>

GifResizer/Models/Gif.cs

@@ -1,6 +1,50 @@
-namespace GifResizer.Models;
+using System.Diagnostics;
+using System.IO;
+using GifResizer.Service;
+using SixLabors.ImageSharp;
+using SixLabors.ImageSharp.Processing;
 
-public class Gif
+namespace GifResizer.Models;
+
+public class Gif : IDisposable
 {
+
+    private readonly FileInfo _file;
+    private Image? _image;
     
+    public Gif(string path)
+    {
+        ArgumentNullException.ThrowIfNull(path);
+        if (path.Length == 0 || path.IsWhiteSpace() || !File.Exists(path)) 
+            throw new ArgumentException($"File '{path}' does not exist");
+        
+        _file = new FileInfo(path);
+    }
+
+    public void Load()
+    {
+        _image = Image.Load(_file.FullName);
+    }
+    
+    public void Resize(int width, int height)
+    {
+        if(_image == null) throw new InvalidOperationException("Image hasn't been loaded yet");
+        _image.Mutate(x => x.Resize(width, height));
+    }
+
+    public void Save(string outputPath)
+    {
+        if(_image == null) throw new InvalidOperationException("Image hasn't been loaded yet");
+        var directory = Path.GetDirectoryName(outputPath);
+        if (!string.IsNullOrEmpty(directory))
+        {
+            Directory.CreateDirectory(directory);
+        }
+        _image.Save(Path.Combine(outputPath));
+    }
+
+    public void Dispose()
+    {
+        _image?.Dispose();
+    }
 }

GifResizer/Service/ResizeService.cs

@@ -1,6 +1,20 @@
-namespace GifResizer.Service;
+using GifResizer.Models;
+
+namespace GifResizer.Service;
 
 public class ResizeService
 {
-    
+
+    public ResizeService()
+    {
+        
+    }
+
+    public void ResizeGif(string filePath, int width, int height)
+    {
+        using Gif gif = new Gif(filePath);
+        gif.Load();
+        gif.Resize(width, height);
+        gif.Save("D:/test-output.gif");
+    }
 }

GifResizer/ViewModels/MainViewModel.cs

@@ -1,17 +1,20 @@
 using System.ComponentModel;
 using System.IO;
 using System.Runtime.CompilerServices;
+using GifResizer.Models;
+using GifResizer.Service;
 
 namespace GifResizer.ViewModels;
 
 public class MainViewModel : INotifyPropertyChanged
 {
     
-
+    private readonly ResizeService _resizeService;
     public event PropertyChangedEventHandler? PropertyChanged;
     
-    public MainViewModel()
+    public MainViewModel(ResizeService service)
     {
+        _resizeService = service;
         FilePath = Directory.GetCurrentDirectory();
     }
 
@@ -21,6 +24,11 @@ public class MainViewModel : INotifyPropertyChanged
         get;
         set => SetField(ref field, value);
     }
+
+    public void ResizeGif(int width, int height)
+    {
+        _resizeService.ResizeGif(FilePath, width, height);
+    }
     
     private bool SetField<T>(ref T field, T value, [CallerMemberName] string? propertyName = null)
     {

GifResizer/Views/MainWindow.xaml

@@ -45,6 +45,12 @@
                 </StackPanel>
             </Border>
             
+            <StackPanel Orientation="Horizontal" HorizontalAlignment="Center">
+                <CheckBox Content="112x112" Margin="10"/>
+                <CheckBox Content="500x500" Margin="10"/>
+                <CheckBox Content="1000x1000" Margin="10"/>
+            </StackPanel>
+            
             <Button 
                 Content="Resize"
                 Padding="5"

GifResizer/Views/MainWindow.xaml.cs

@@ -17,24 +17,44 @@ public partial class MainWindow : Window
         InitializeComponent();
         _mainViewModel = viewModel;
         DataContext = _mainViewModel;
-        
     }
     
     private void BrowseButton_Click(object sender, RoutedEventArgs e)
     {
-        OpenFileDialog fileDialog = new OpenFileDialog
+        try
         {
-            Filter = "GIF files (*.gif)|*.gif|All files (*.*)|*.*",
-            Title = "Select a GIF file"
-        };
+            OpenFileDialog fileDialog = new OpenFileDialog
+            {
+                Title = "Select a GIF file",
+                Filter = "GIF files (*.gif)|*.gif|All files (*.*)|*.*"
+            };
         
-        if (fileDialog.ShowDialog() == true)
+            if (fileDialog.ShowDialog() == true)
+            {
+                _mainViewModel.FilePath = fileDialog.FileName;
+            }
+        } 
+        catch (Exception ex)
         {
-            _mainViewModel.FilePath = fileDialog.FileName;
+            DisplayErrorMessage("An error occured while selecting the GIF file: " + ex.Message);
         }
+
     }
     
     private void ResizeButton_Click(object sender, RoutedEventArgs e)
     {
+        try
+        {
+            _mainViewModel.ResizeGif(128,128);
+        }
+        catch (Exception ex)
+        {
+            DisplayErrorMessage("An error occured while resizing the GIF: " + ex.Message);
+        }
+    }
+    
+    private void DisplayErrorMessage(string message)
+    {
+        MessageBox.Show(message, "Error", MessageBoxButton.OK, MessageBoxImage.Error);
     }
 }