Fix Multiple Bugs in Crop Functionality (#284)

Summary
This Pull Request refactors crop management in the PicView Avalonia project, improving code clarity, maintainability, and functionality. It modifies CropLayoutManager, CropResizer, and CropControl.axaml.
Main Changes
CropLayoutManager.cs:
Simplified logic for calculating crop selection dimensions.
Improved logic for setting canvas boundaries.
CropResizer.cs:
Reduced redundant whitespace for consistency.
Added logic to prevent out-of-canvas bounds during resize operations.
Enforced square aspect ratio constraints more effectively.
CropControl.axaml:
Introduced the ClipToBounds property to ensure proper rendering behavior.

src/PicView.Avalonia/Crop/CropLayoutManager.cs

@@ -8,7 +8,7 @@ namespace PicView.Avalonia.Crop;
 public class CropLayoutManager(CropControl control)
 {
     private const int DefaultSelectionSize = 200;
-    
+
     public void InitializeLayout()
     {
         if (control.DataContext is not MainViewModel vm)
@@ -23,19 +23,15 @@ public class CropLayoutManager(CropControl control)
         }
 
         // Set initial width and height for the crop rectangle
-        var pixelWidth = vm.PicViewer.ImageWidth.CurrentValue / vm.PicViewer.AspectRatio.CurrentValue;
-        var pixelHeight = vm.PicViewer.ImageHeight.CurrentValue / vm.PicViewer.AspectRatio.CurrentValue;
+        var originalWidth = vm.PicViewer.ImageWidth.CurrentValue >= DefaultSelectionSize * 2
+            ? DefaultSelectionSize
+            : (uint)(vm.PicViewer.ImageWidth.CurrentValue / 2);
+        var originalHeight = vm.PicViewer.ImageHeight.CurrentValue >= DefaultSelectionSize * 2
+            ? DefaultSelectionSize
+            : (uint)(vm.PicViewer.ImageHeight.CurrentValue / 2);
 
-        if (pixelWidth >= DefaultSelectionSize * 2 || pixelHeight >= DefaultSelectionSize * 2)
-        {
-            vm.Crop.SetSelectionWidth(DefaultSelectionSize);
-            vm.Crop.SetSelectionHeight(DefaultSelectionSize);
-        }
-        else if (pixelWidth <= DefaultSelectionSize || pixelHeight <= DefaultSelectionSize)
-        {
-            vm.Crop.SetSelectionWidth((uint)(pixelWidth / 2));
-            vm.Crop.SetSelectionHeight((uint)(pixelHeight / 2));
-        }
+        vm.Crop.SetSelectionWidth(originalWidth);
+        vm.Crop.SetSelectionHeight(originalHeight);
 
         // Calculate centered position
         vm.Crop.SelectionX.Value = Convert.ToInt32((vm.PicViewer.ImageWidth.CurrentValue - vm.Crop.SelectionWidth.CurrentValue) / 2);
@@ -202,14 +198,6 @@ public class CropLayoutManager(CropControl control)
         Canvas.SetTop(control.RightMiddleButton, rightMiddleY);
 
         Canvas.SetLeft(control.SizeBorder, topLeftX + control.TopLeftButton.Bounds.Width + 2);
-
-        if (topLeftY != 0)
-        {
-            Canvas.SetTop(control.SizeBorder, topLeftY - control.TopLeftButton.Bounds.Height);
-        }
-        else
-        {
-            Canvas.SetTop(control.SizeBorder, topLeftY);
-        }
+        Canvas.SetTop(control.SizeBorder, Math.Max(0, topLeftY - control.TopLeftButton.Bounds.Height));
     }
 }

src/PicView.Avalonia/Crop/CropResizer.cs

@@ -15,13 +15,13 @@ public static class CropResizer
     {
         var currentPos = e.GetPosition(control.RootCanvas);
         var delta = currentPos - resizeStart;
-        
+
         // Initialize with original values
         var newX = originalRect.X;
         var newY = originalRect.Y;
         var newWidth = originalRect.Width;
         var newHeight = originalRect.Height;
-        
+
         // Calculate new dimensions based on resize mode
         switch (mode)
         {
@@ -31,49 +31,49 @@ public static class CropResizer
                 newWidth -= delta.X;
                 newHeight -= delta.Y;
                 break;
-                
+
             case CropResizeMode.TopRight:
                 newY += delta.Y;
                 newWidth += delta.X;
                 newHeight -= delta.Y;
                 break;
-                
+
             case CropResizeMode.BottomLeft:
                 newX += delta.X;
                 newWidth -= delta.X;
                 newHeight += delta.Y;
                 break;
-                
+
             case CropResizeMode.BottomRight:
                 newWidth += delta.X;
                 newHeight += delta.Y;
                 break;
-                
+
             case CropResizeMode.Left:
                 newX += delta.X;
                 newWidth -= delta.X;
                 break;
-                
+
             case CropResizeMode.Right:
                 newWidth += delta.X;
                 break;
-                
+
             case CropResizeMode.Top:
                 newY += delta.Y;
                 newHeight -= delta.Y;
                 break;
-                
+
             case CropResizeMode.Bottom:
                 newHeight += delta.Y;
                 break;
         }
-        
+
         // Handle aspect ratio constraints (maintain square when Shift is pressed)
         if (MainKeyboardShortcuts.ShiftDown && IsCornerMode(mode))
         {
             // Use the larger dimension to determine square size
             var size = Math.Max(newWidth, newHeight);
-            
+
             // Adjust position based on resize mode to maintain the correct anchor point
             switch (mode)
             {
@@ -81,23 +81,23 @@ public static class CropResizer
                     newX = originalRect.X + originalRect.Width - size;
                     newY = originalRect.Y + originalRect.Height - size;
                     break;
-                    
+
                 case CropResizeMode.TopRight:
                     newY = originalRect.Y + originalRect.Height - size;
                     break;
-                    
+
                 case CropResizeMode.BottomLeft:
                     newX = originalRect.X + originalRect.Width - size;
                     break;
             }
-            
+
             newWidth = size;
             newHeight = size;
         }
-        
+
         // Apply bounds constraints
         ApplyBoundsConstraints(ref newX, ref newY, ref newWidth, ref newHeight, vm.ImageWidth.CurrentValue, vm.ImageHeight.CurrentValue);
-        
+
         // Update the view model
         try
         {
@@ -110,18 +110,18 @@ public static class CropResizer
         {
             DebugHelper.LogDebug(nameof(CropResizer), nameof(Resize), exception);
         }
-        
+
         // Update the rectangle position on canvas
         Canvas.SetLeft(control.MainRectangle, newX);
         Canvas.SetTop(control.MainRectangle, newY);
     }
-    
-    private static bool IsCornerMode(CropResizeMode mode) => mode is 
-        CropResizeMode.TopLeft or 
-        CropResizeMode.TopRight or 
-        CropResizeMode.BottomLeft or 
+
+    private static bool IsCornerMode(CropResizeMode mode) => mode is
+        CropResizeMode.TopLeft or
+        CropResizeMode.TopRight or
+        CropResizeMode.BottomLeft or
         CropResizeMode.BottomRight;
-        
+
     private static void ApplyBoundsConstraints(ref double x, ref double y, ref double width, ref double height, double maxWidth, double maxHeight)
     {
         // Ensure we don't go beyond canvas bounds
@@ -130,23 +130,33 @@ public static class CropResizer
             width += x;
             x = 0;
         }
-        
+
         if (y < 0)
         {
             height += y;
             y = 0;
         }
-        
+
+        if (x >= maxWidth)
+        {
+            x = maxWidth - 1;
+        }
+
+        if (y >= maxHeight)
+        {
+            y = maxHeight - 1;
+        }
+
         // Ensure minimum dimensions
         width = Math.Max(width, 1);
         height = Math.Max(height, 1);
-        
+
         // Ensure we don't exceed the canvas bounds
         if (x + width > maxWidth)
         {
             width = maxWidth - x;
         }
-        
+
         if (y + height > maxHeight)
         {
             height = maxHeight - y;

src/PicView.Avalonia/Views/UC/CropControl.axaml

@@ -3,7 +3,8 @@
     x:DataType="viewModels:MainViewModel"
     xmlns="https://github.com/avaloniaui"
     xmlns:viewModels="clr-namespace:PicView.Avalonia.ViewModels"
-    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    ClipToBounds="False">
     <UserControl.Resources>
         <SolidColorBrush Color="{DynamicResource MainTextColor}" x:Key="Brush0" />
     </UserControl.Resources>