Refine background removal ROI and mask logic, UI flow

- Use the entire image as the region of interest for background removal instead of a central crop.
- Invert the mask before applying it as alpha to correct background/foreground handling.
- Store the result image path in RemoveBackgroundDialog only after user confirmation.
- Add explicit PrimaryButtonClick handling for result commitment.
- Refactor dialog loading logic for clearer error handling and UI state management.

Author: TheJoeFin

Simple Icon File Maker/Simple Icon File Maker/Helpers/BackgroundRemoverHelper.cs

@@ -47,23 +47,11 @@ public static async Task<string> RemoveBackgroundAsync(string imagePath)
 
         using ImageObjectExtractor extractor = await ImageObjectExtractor.CreateWithSoftwareBitmapAsync(sourceBitmap);
 
-        // Use a rectangle covering the central ~90% of the image so the model
-        // identifies the dominant object rather than a single small element.
-        int marginX = sourceBitmap.PixelWidth / 20;
-        int marginY = sourceBitmap.PixelHeight / 20;
-
-        RectInt32 rect = new()
-        {
-            X = marginX,
-            Y = marginY,
-            Width = sourceBitmap.PixelWidth - 2 * marginX,
-            Height = sourceBitmap.PixelHeight - 2 * marginY
-        };
-
+        // Hint with the entire image rect as the region of interest
         ImageObjectExtractorHint hint = new(
-            includeRects: [rect],
-            includePoints: null,
-            excludePoints: null);
+            includeRects: [new RectInt32(0, 0, sourceBitmap.PixelWidth, sourceBitmap.PixelHeight)],
+            includePoints: [],
+            excludePoints: []);
 
         SoftwareBitmap mask = extractor.GetSoftwareBitmapObjectMask(hint);
 
@@ -102,7 +90,7 @@ private static SoftwareBitmap ApplyMaskAsAlpha(SoftwareBitmap original, Software
         for (int i = 0; i < maskPixels.Length; i++)
         {
             int px = i * 4;
-            int m = maskPixels[i];
+            int m = 255 - maskPixels[i];
             resultPixels[px + 0] = (byte)(originalPixels[px + 0] * m / 255);
             resultPixels[px + 1] = (byte)(originalPixels[px + 1] * m / 255);
             resultPixels[px + 2] = (byte)(originalPixels[px + 2] * m / 255);

Simple Icon File Maker/Simple Icon File Maker/Views/RemoveBackgroundDialog.xaml.cs

@@ -10,36 +10,42 @@ public sealed partial class RemoveBackgroundDialog : ContentDialog
     public string? ResultImagePath { get; private set; }
 
     private readonly string _imagePath;
+    private string? _pendingResultPath;
 
     public RemoveBackgroundDialog(string imagePath)
     {
         InitializeComponent();
         _imagePath = imagePath;
+        PrimaryButtonClick += OnPrimaryButtonClick;
+    }
+
+    private void OnPrimaryButtonClick(ContentDialog sender, ContentDialogButtonClickEventArgs args)
+    {
+        ResultImagePath = _pendingResultPath;
     }
 
     private async void ContentDialog_Loaded(object sender, RoutedEventArgs e)
     {
-        try
+        BeforeImage.Source = new BitmapImage(new Uri(_imagePath));
+
+        bool isAvailable = await BackgroundRemoverHelper.IsAvailableAsync();
+        if (!isAvailable)
         {
-            BeforeImage.Source = new BitmapImage(new Uri(_imagePath));
-
-            bool available = await BackgroundRemoverHelper.IsAvailableAsync();
-            if (!available)
-            {
-                StatusInfoBar.Title = "Not Available";
-                StatusInfoBar.Message = "The AI background removal model is not available on this device. This feature requires a Copilot+ PC with the latest Windows updates.";
-                StatusInfoBar.Severity = InfoBarSeverity.Warning;
-                StatusInfoBar.IsOpen = true;
-                ProcessingRing.IsActive = false;
-                return;
-            }
+            StatusInfoBar.Title = "Not Available";
+            StatusInfoBar.Message = "The AI background removal model is not available on this device. This feature requires a Copilot+ PC with the latest Windows updates.";
+            StatusInfoBar.Severity = InfoBarSeverity.Warning;
+            StatusInfoBar.IsOpen = true;
+            ProcessingRing.IsActive = false;
+            return;
+        }
 
+        try
+        {
             string resultPath = await BackgroundRemoverHelper.RemoveBackgroundAsync(_imagePath);
-            ResultImagePath = resultPath;
+            _pendingResultPath = resultPath;
 
             AfterImage.Source = new BitmapImage(new Uri(resultPath));
 
-            ProcessingRing.IsActive = false;
             IsPrimaryButtonEnabled = true;
         }
         catch (Exception ex)
@@ -48,6 +54,9 @@ private async void ContentDialog_Loaded(object sender, RoutedEventArgs e)
             StatusInfoBar.Message = $"Failed to remove background: {ex.Message}";
             StatusInfoBar.Severity = InfoBarSeverity.Error;
             StatusInfoBar.IsOpen = true;
+        }
+        finally
+        {
             ProcessingRing.IsActive = false;
         }
     }