kmpdfkit_demo/Demo/Examples/ComPDFKit.Tool/DrawTool/AnnotSelector.cs

using ComPDFKitViewer;
using ComPDFKitViewer.Layer;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Media;

namespace ComPDFKit.Tool.DrawTool
{
    internal class AnnotSelector:BaseLayer
    {
        public CPDFViewer PDFViewer { get; set; }
        public List<AnnotData> SelectAnnots { get; set; } = new List<AnnotData>();
        public Pen DrawPen { get; set; }
        public Brush DrawBrush { get; set; }
        private List<Point> ControlPoints { get; set; } = new List<Point>();
        private double RectPadding = 4;
        public AnnotSelector()
        {
            DrawPen = new Pen(new SolidColorBrush(Color.FromArgb(255, 71, 126, 222)), 2);
            DrawBrush = new SolidColorBrush(Color.FromArgb(40, 119, 180, 227));
        }
        public override void Draw()
        {
            DrawingContext drawDC = Open();
            DrawOutBound(drawDC);
            DrawIndividual(drawDC);
            DrawControlPoint(drawDC);
            Present();
        }

        public int GetSelectCount()
        {
            if(SelectAnnots!=null)
            {
                return SelectAnnots.Count;
            }
            return 0;
        }
        public bool AddItem(AnnotData item)
        {
            if (item == null)
            {
                return false;
            }
            List<int> pageIndexList = SelectAnnots.Select(x => x.PageIndex).Distinct().ToList();
            if(pageIndexList.Count > 1 )
            {
                SelectAnnots.Clear();
            }

            if( pageIndexList.Count==1 && pageIndexList[0]!=item.PageIndex)
            {
                SelectAnnots.Clear();
            }

            if (RemoveItem(item))
            {
                SelectAnnots.Add(item);
                return true;
            }
            return false;
        }
        public bool HasItem(AnnotData item)
        {
            if (item == null)
            {
                return false;
            }

            if(SelectAnnots!=null && SelectAnnots.Count > 0)
            {
                return SelectAnnots.Where(x => x.AnnotIndex == item.AnnotIndex && x.PageIndex == item.PageIndex).Count() > 0;
            }

            return false;
        }

        public bool RemoveItem(AnnotData item)
        {
            if (item == null || item.PageIndex < 0 || item.AnnotIndex < 0)
            {
                return false;
            }

            List<AnnotData> checkList = SelectAnnots.Where(x => x.AnnotIndex == item.AnnotIndex && x.PageIndex == item.PageIndex).ToList();
            if (checkList != null && checkList.Count > 0)
            {
                foreach (AnnotData removeItem in checkList)
                {
                    SelectAnnots.Remove(removeItem);
                }
            }
            return true;
        }

        public void ClearItem()
        { 
            SelectAnnots?.Clear(); 
        }
        public Rect GetOutBoundRect()
        {
            if (SelectAnnots.Count > 0)
            {
                double left = 0;
                double top = 0;
                double right = 0;
                double bottom = 0;

                for (int i=0;i< SelectAnnots.Count;i++)
                {
                   AnnotData checkItem= SelectAnnots[i];
                    if (i == 0) 
                    {
                        left=checkItem.PaintRect.Left;
                        top=checkItem.PaintRect.Top;
                        right=checkItem.PaintRect.Right;
                        bottom=checkItem.PaintRect.Bottom;
                        continue;
                    }

                    left = Math.Min(left, checkItem.PaintRect.Left);
                    top = Math.Min(top, checkItem.PaintRect.Top);
                    right = Math.Max(right, checkItem.PaintRect.Right);
                    bottom = Math.Max(bottom, checkItem.PaintRect.Bottom);
                }

                if(right<left ||  bottom<top)
                {
                    return Rect.Empty;
                }

                return new Rect(left, top, right-left, bottom-top);
            }
           
            return Rect.Empty;
        }

        public void DrawOutBound(DrawingContext drawDC) 
        {
            Rect boudRect = GetOutBoundRect();
            if (boudRect.IsEmpty || boudRect.Width == 0 || boudRect.Height == 0)
            { 
                return;
            }

            drawDC.DrawRectangle(Brushes.Transparent, DrawPen, boudRect);
        }

        public void DrawIndividual(DrawingContext drawDC)
        {
            if(SelectAnnots==null || SelectAnnots.Count==0)
            {
                return;
            }

            foreach(AnnotData checkItem in SelectAnnots)
            {
                drawDC.DrawRectangle(null, DrawPen, checkItem.PaintRect);
            }
        }

        public void DrawControlPoint(DrawingContext drawDC)
        {
            Rect boudRect = GetOutBoundRect();
            ControlPoints.Clear();
            double centerX = (boudRect.Left + boudRect.Right) / 2;
            double centerY = (boudRect.Top + boudRect.Bottom) / 2;

            ControlPoints.Add(new Point(boudRect.Left, boudRect.Top));
            ControlPoints.Add(new Point(boudRect.Left, centerY));
            ControlPoints.Add(new Point(boudRect.Left, boudRect.Bottom));
            ControlPoints.Add(new Point(centerX, boudRect.Bottom));
            ControlPoints.Add(new Point(boudRect.Right, boudRect.Bottom));
            ControlPoints.Add(new Point(boudRect.Right, centerY));
            ControlPoints.Add(new Point(boudRect.Right, boudRect.Top));
            ControlPoints.Add(new Point(centerX, boudRect.Top));

            foreach (Point point in ControlPoints)
            {
                drawDC.DrawRectangle(Brushes.White, DrawPen, new Rect(point.X- RectPadding,point.Y- RectPadding, RectPadding*2, RectPadding*2));
            }
        }

        public PointControlType GetHitControlIndex(Point point)
        {
            for (int i = 0; i < ControlPoints.Count; i++)
            {
                Point checkPoint = ControlPoints[i];
                Rect checkBound = new Rect(checkPoint.X - RectPadding, checkPoint.Y - RectPadding, RectPadding * 2, RectPadding * 2);
                if (checkBound.Contains(point))
                {
                    return (PointControlType)i;
                }
            }

            Rect outBound = GetOutBoundRect();
            if (outBound.Contains(point))
            {
                return PointControlType.Body;
            }

            return PointControlType.None;
        }
    }
}