annotations/Azaion.Annotator/Controls/AnnotationControl.cs

using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Shapes;
using Azaion.Annotator.DTO;

namespace Azaion.Annotator.Controls;

public class AnnotationControl : Border
{
    private readonly Action<object, MouseButtonEventArgs> _resizeStart;
    private const double RESIZE_RECT_SIZE = 10;

    private readonly Grid _grid;
    private readonly TextBlock _classNameLabel;

    private AnnotationClass _annotationClass = null!;
    public AnnotationClass AnnotationClass
    {
        get => _annotationClass;
        set
        {
            _grid.Background = value.ColorBrush;
            _classNameLabel.Text = value.Name;
            _annotationClass = value;
        }
    }
    
    private readonly Rectangle _selectionFrame;

    private bool _isSelected;
    public bool IsSelected
    {
        get => _isSelected;
        set
        {
            _selectionFrame.Visibility = value ? Visibility.Visible : Visibility.Collapsed;
            _isSelected = value;
        }
    }
    
    public AnnotationControl(AnnotationClass annotationClass, Action<object, MouseButtonEventArgs> resizeStart)
    {
        _resizeStart = resizeStart;
        _classNameLabel = new TextBlock
        {
            Text = annotationClass.Name,
            HorizontalAlignment = HorizontalAlignment.Center,
            VerticalAlignment = VerticalAlignment.Top,
            Margin = new Thickness(0, 15, 0, 0),
            FontSize = 14,
            Cursor = Cursors.Arrow
        };
        _selectionFrame = new Rectangle
        {
            HorizontalAlignment = HorizontalAlignment.Stretch,
            VerticalAlignment = VerticalAlignment.Stretch,
            Stroke = new SolidColorBrush(Colors.Black),
            StrokeThickness = 3,
            Visibility = Visibility.Collapsed
        };
        
        _grid = new Grid
        {
            HorizontalAlignment = HorizontalAlignment.Stretch,
            VerticalAlignment = VerticalAlignment.Stretch,
            Children =
            {
                _selectionFrame,
                _classNameLabel,
                AddRect("rLT", HorizontalAlignment.Left, VerticalAlignment.Top, Cursors.SizeNWSE),
                AddRect("rCT", HorizontalAlignment.Center, VerticalAlignment.Top, Cursors.SizeNS),
                AddRect("rRT", HorizontalAlignment.Right, VerticalAlignment.Top, Cursors.SizeNESW),
                AddRect("rLC", HorizontalAlignment.Left, VerticalAlignment.Center, Cursors.SizeWE),
                AddRect("rRC", HorizontalAlignment.Right, VerticalAlignment.Center, Cursors.SizeWE),
                AddRect("rLB", HorizontalAlignment.Left, VerticalAlignment.Bottom, Cursors.SizeNESW),
                AddRect("rCB", HorizontalAlignment.Center, VerticalAlignment.Bottom, Cursors.SizeNS),
                AddRect("rRB", HorizontalAlignment.Right, VerticalAlignment.Bottom, Cursors.SizeNWSE)
            },
            
            Background = new SolidColorBrush(annotationClass.Color) 
        };
        Child = _grid;
        Cursor = Cursors.SizeAll;
        AnnotationClass = annotationClass;
    }
    
    //small corners
    private Rectangle AddRect(string name, HorizontalAlignment ha, VerticalAlignment va, Cursor crs)
    {
        var rect = new Rectangle()   // small rectangles at the corners and sides
        {
            HorizontalAlignment = ha,
            VerticalAlignment = va,
            Width = RESIZE_RECT_SIZE,
            Height = RESIZE_RECT_SIZE,
            Stroke = new SolidColorBrush(Color.FromRgb(10, 10, 10)), // small rectangles color
            Fill = new SolidColorBrush(Color.FromArgb(1, 255, 255, 255)),
            Cursor = crs,
            Name = name,
        };
        rect.MouseDown += (sender, args) => _resizeStart(sender, args);
        return rect;
    }

    public AnnotationInfo Info => new(AnnotationClass.Id, Canvas.GetLeft(this), Canvas.GetTop(this), Width, Height);
}