✅ Implementation Complete: Add Pixel Precision for Helping Precision Placement

Successfully implemented a zoomed preview feature similar to PowerToys Color Picker that provides pixel-perfect point placement for image transformations and measurements.

📋 Summary

This PR adds a Pixel Precision Zoom control that automatically appears when users are placing or adjusting points for:

• Image transformation corner markers
• Distance, angle, rectangle, circle, and polygon measurements
• Any operation requiring precise point placement

The zoom preview shows a 6x magnified view of the image region under the cursor with a red crosshair and pixel coordinates, enabling pixel-perfect accuracy.

✨ Key Features

• ✅ 6x Magnification - Clear view of individual pixels
• ✅ Automatic Activation - Appears when measurement tools selected or transform mode active
• ✅ Always Visible by Cursor - Follows cursor continuously in precision modes
• ✅ Independent of Canvas Zoom - Not affected by canvas zoom level, maintains constant size
• ✅ Circular Shape - True circular clipping for professional magnifier appearance
• ✅ Smart Positioning - Positions near cursor without blocking the target
• ✅ Real-time Updates - Follows cursor movement smoothly
• ✅ Visual Indicators - Red crosshair and coordinate display
• ✅ Professional Design - Circular window with blue accent border matching app theme
• ✅ Universal Integration - Works with all measurement tools and transform corners
• ✅ Performant - Efficient rendering using WPF bitmap APIs

🔄 Recent Updates

Circular Clipping (Latest)

• True circular shape - Added EllipseGeometry clip to make control perfectly circular
• Professional appearance - Mimics traditional magnifying glass/loupe tools
• Clean edges - Content properly clipped to circular boundary

Canvas Independence

• Moved outside ShapeCanvas - Zoom control now positioned in MainGrid, not affected by canvas transforms
• Constant size - Preview maintains 150×150px size regardless of canvas zoom level
• Accurate positioning - Coordinates properly transformed from ShapeCanvas to MainGrid space

Visibility Improvements

• Zoom now appears when hovering with any measurement tool selected (not just when clicking)
• Zoom stays visible throughout precision operations
• Only hides when explicitly leaving precision modes
• Follows cursor continuously, ensuring it's always visible where needed

📁 Files Changed

New Files (4)

1. MagickCrop/Controls/PixelPrecisionZoom.xaml - UserControl XAML definition with circular clipping
2. MagickCrop/Controls/PixelPrecisionZoom.xaml.cs - Control logic and image magnification
3. PIXEL_PRECISION_ZOOM.md - Comprehensive feature documentation
4. PIXEL_PRECISION_VISUAL_GUIDE.md - ASCII art diagrams and visual layouts

Modified Files (2)

1. MagickCrop/MainWindow.xaml - Control placement in MainGrid (outside ShapeCanvas)
2. MagickCrop/MainWindow.xaml.cs - Zoom management and coordinate transformation

🔧 Implementation Details

Architecture

MainGrid (no transforms)
├── ShapeCanvas (has ScaleTransform + TranslateTransform)
│   └── Image, markers, measurements (scaled with canvas)
└── PixelPrecisionZoom (NOT scaled, always constant size)
    └── Grid with EllipseGeometry clip (perfect circle)
        ├── Circular Border (150x150px, blue #0066FF)
        ├── Viewbox with Zoom Canvas
        │   └── Image (magnified 6x)
        ├── Crosshair Overlay (red lines + center dot)
        └── Coordinate Display (X, Y pixel position)

Circular Clipping

The control uses EllipseGeometry for true circular clipping:

<Grid.Clip>
    <EllipseGeometry Center="75,75" RadiusX="75" RadiusY="75" />
</Grid.Clip>

This creates a perfect 150px diameter circle that clips all content.

Coordinate Transformation

The zoom control receives mouse positions in ShapeCanvas coordinates but needs to position itself in MainGrid coordinates:

Point mainGridPosition = ShapeCanvas.TransformToAncestor(MainGrid).Transform(mousePosition);

This ensures the zoom preview appears at the correct screen location even when the canvas is zoomed or panned.

🎯 Benefits

Before This Feature

❌ Hard to align corners precisely with document edges
❌ Difficult to target small features or specific pixels
❌ No visual feedback during point placement
❌ Trial and error for pixel-perfect placement

After This Feature

✅ See exactly which pixel you're targeting
✅ 6x magnified view shows fine details clearly
✅ Red crosshair indicates exact target position
✅ Pixel coordinates provide numeric reference
✅ Real-time preview follows cursor continuously
✅ Always visible when precision is needed
✅ Maintains constant size regardless of canvas zoom
✅ Professional circular magnifier appearance

This feature brings MagickCrop's precision capabilities to a professional level, making it easier than ever to achieve pixel-perfect accuracy in image transformations and measurements! 🎯✨

<issue_title>Add pixel precision for helping the precision placement</issue_title>
><issue_description>Similar to other precision utilities like color picker (PowerToys) or cropping tools, have a zoomed preview which gives the user more accurate placement of the points when setting the corners of a transformation.</issue_description>
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> ## Comments on the Issue (you are @copilot in this section)
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• Fixes Add pixel precision for helping the precision placement #39

• Fixes Add pixel precision for helping the precision placement #39

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