inabox/inabox.wpf/Forms/ZoomPanel/ZoomPanel.xaml.cs

using java.security;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Markup;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace InABox.WPF;

/// <summary>
/// Interaction logic for ZoomPanel.xaml
/// </summary>
public partial class ZoomPanel : ContentControl, INotifyPropertyChanged
{
    public delegate void AreaChangedHandler(ZoomPanel panel);

    public event AreaChangedHandler? AreaChanged;

    private bool _showNavigationButtons = false;
    public bool ShowNavigationButtons
    {
        get => _showNavigationButtons;
        set
        {
            _showNavigationButtons = value;
            OnPropertyChanged();
        }
    }

    public double _minScale = 0.5;
    public double MinScale
    {
        get => _minScale;
        set
        {
            _minScale = value;
            if(_scale < _minScale)
            {
                Scale = _minScale;
            }
        }
    }


    public double _scale = 1;
    public double Scale
    {
        get => _scale;
        set
        {
            _scale = value;
            OnPropertyChanged();
            AreaChanged?.Invoke(this);
        }
    }

    private ScrollViewer Scroll => (ScrollViewer)GetTemplateChild("PART_Scroll");
    private Border ContentBorder => (Border)GetTemplateChild("PART_ContentBorder");

    public double ScrollX
    {
        get => Scroll.HorizontalOffset;
        set
        {
            Scroll.ScrollToHorizontalOffset(value);
            AreaChanged?.Invoke(this);
        }
    }

    public double ScrollY
    {
        get => Scroll.VerticalOffset;
        set
        {
            Scroll.ScrollToVerticalOffset(value);
            AreaChanged?.Invoke(this);
        }
    }

    public double WheelSpeed { get; set; } = 0.002;

    public double PanAmount { get; set; } = 50;

    static ZoomPanel()
    {
        DefaultStyleKeyProperty.OverrideMetadata(typeof(ZoomPanel), new FrameworkPropertyMetadata(typeof(ZoomPanel)));
    }

    public override void OnApplyTemplate()
    {
        base.OnApplyTemplate();

        ((Button)GetTemplateChild("PART_ZoomInButton")).Click += ZoomInButton_Click;
        ((Button)GetTemplateChild("PART_ZoomOutButton")).Click += ZoomOutButton_Click;
        ((Button)GetTemplateChild("PART_LeftButton")).Click += LeftButton_Click;
        ((Button)GetTemplateChild("PART_RightButton")).Click += RightButton_Click;
        ((Button)GetTemplateChild("PART_UpButton")).Click += UpButton_Click;
        ((Button)GetTemplateChild("PART_DownButton")).Click += DownButton_Click;
        ((Button)GetTemplateChild("PART_DownButton")).Click += DownButton_Click;
        ((Border)GetTemplateChild("PART_ContentBorder")).MouseWheel += ItemsControl_MouseWheel;
    }

    public event PropertyChangedEventHandler? PropertyChanged;

    protected void OnPropertyChanged([CallerMemberName] string propertyName = "")
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
    private void ZoomInButton_Click(object sender, RoutedEventArgs e)
    {
        Scale *= 1.1;
    }

    private void ZoomOutButton_Click(object sender, RoutedEventArgs e)
    {
        Scale /= 1.1;
    }

    private void Pan(double x, double y)
    {
        ScrollX += x;
        ScrollY += y;
        //Origin = new(Origin.X - x, Origin.Y - y);
    }

    private void DownButton_Click(object sender, RoutedEventArgs e)
    {
        Pan(0, PanAmount);
    }

    private void UpButton_Click(object sender, RoutedEventArgs e)
    {
        Pan(0, -PanAmount);
    }

    private void RightButton_Click(object sender, RoutedEventArgs e)
    {
        Pan(PanAmount, 0);
    }

    private void LeftButton_Click(object sender, RoutedEventArgs e)
    {
        Pan(-PanAmount, 0);
    }

    private void ItemsControl_MouseWheel(object sender, MouseWheelEventArgs e)
    {
        if ((Keyboard.Modifiers & ModifierKeys.Control) == ModifierKeys.Control)
        {
            var pos = e.GetPosition(ContentBorder);
            var contentMPos = new Point(pos.X / Scale, pos.Y / Scale);

            if (e.Delta > 0)
            {
                Scale *= 1 + e.Delta * WheelSpeed;
            }
            else
            {
                Scale /= 1 + (-e.Delta) * WheelSpeed;
            }

            Scale = Math.Max(MinScale, Scale);

            var scaledPos = new Point(contentMPos.X * Scale, contentMPos.Y * Scale);
            var offset = scaledPos - pos;
            Pan(offset.X, offset.Y);

            e.Handled = true;
        }
        else if ((Keyboard.Modifiers & ModifierKeys.Shift) == ModifierKeys.Shift)
        {
            Pan(-e.Delta, 0);

            e.Handled = true;
        }
    }
}