orderstacks/TheGameExtreme/view/TouchManipulationBitmap.cs

using System;
using System.Collections.Generic;
using SkiaSharp;
using TheGameExtreme.viewmodel;
using TouchTracking;
using Xamarin.Essentials;

namespace TheGameExtreme.view
{
    public class TouchManipulationBitmap
    {
        public SKPoint InitialPoint { get; set; }
        SKPaint textPaint;
        Dictionary<long, TouchManipulationInfo> touchDictionary = new Dictionary<long, TouchManipulationInfo>();
        public CardVM Value;
        public string display;
        private float width = 0.01f * (float)DeviceDisplay.MainDisplayInfo.Width;
        private float height = 0.01f * (float)DeviceDisplay.MainDisplayInfo.Width * 3f;

        public TouchManipulationBitmap(SKPaint textPaint, CardVM value)
        {
            this.textPaint = textPaint;
            Value = value;
            display = Value.ToString();

            if (!display.Contains(",") && !display.Contains(".") && !display.Contains("/"))
            {
                if (decimal.Parse(display) < 0 && decimal.Parse(display) > -10)
                {
                    display = "-0" + Math.Abs(decimal.Parse(display)).ToString();
                }
                else if (decimal.Parse(display) >= 0 && decimal.Parse(display) < 10)
                {
                    display = "0" + display;
                }
            }

            Matrix = SKMatrix.MakeIdentity();

            Mode = TouchManipulationMode.PanOnly;
        }

        public TouchManipulationMode Mode { set; get; }

        public SKMatrix Matrix { set; get; }

        public SKMatrix InitialMatrix { set; get; }

        public void Paint(SKCanvas canvas, SKColor color)
        {
            canvas.Save();

            SKMatrix matrix = Matrix;
            canvas.Concat(ref matrix);

            textPaint.Color = color;
            textPaint.StrokeWidth = 5;
            textPaint.Style = SKPaintStyle.Stroke;

            SKRect textBounds = new SKRect();
            textPaint.MeasureText(display, ref textBounds);

            SKRoundRect card = new SKRoundRect(textBounds, 1f, 1f);
            card.Inflate(width, height);

            canvas.DrawRoundRect(card, textPaint);
            canvas.DrawText(display, 0, 0, textPaint);

            canvas.Restore();

        }

        public void ChangeColor(SKColor color)
        {
            textPaint.Color = color;
        }

        public bool HitTest(SKPoint location)
        {
            // Invert the matrix
            SKMatrix inverseMatrix;

            if (Matrix.TryInvert(out inverseMatrix))
            {
                // Transform the point using the inverted matrix
                SKPoint transformedPoint = inverseMatrix.MapPoint(location);

                // Check if it's in the untransformed bitmap rectangle
                SKRect rect = new SKRect(-70, -110, textPaint.MeasureText(display) + 35, textPaint.TextSize);
                return rect.Contains(transformedPoint);
            }
            return false;
        }

        public void ProcessTouchEvent(long id, TouchActionType type, SKPoint location)
        {
            switch (type)
            {
                case TouchActionType.Pressed:
                    touchDictionary.Add(id, new TouchManipulationInfo
                    {
                        PreviousPoint = location,
                        NewPoint = location
                    });
                    break;

                case TouchActionType.Moved:
                    TouchManipulationInfo info = touchDictionary[id];
                    info.NewPoint = location;
                    Manipulate();
                    info.PreviousPoint = info.NewPoint;
                    break;

                case TouchActionType.Released:

                case TouchActionType.Cancelled:
                    touchDictionary.Remove(id);
                    break;
            }
        }

        void Manipulate()
        {
            TouchManipulationInfo[] infos = new TouchManipulationInfo[touchDictionary.Count];
            touchDictionary.Values.CopyTo(infos, 0);

            if (Mode == TouchManipulationMode.PanOnly)
            {
                Matrix = SKMatrix.MakeTranslation(infos[0].NewPoint.X, infos[0].NewPoint.Y);
            }
        }
    }
}