greenshot/Greenshot/Drawing/ArrowContainer.cs

/*
 * Greenshot - a free and open source screenshot tool
 * Copyright (C) 2007-2021 Thomas Braun, Jens Klingen, Robin Krom
 * 
 * For more information see: http://getgreenshot.org/
 * The Greenshot project is hosted on GitHub https://github.com/greenshot/greenshot
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 1 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
using System;
using System.Drawing;
using System.Drawing.Drawing2D;

using Greenshot.Drawing.Fields;
using GreenshotPlugin.Interfaces.Drawing;

namespace Greenshot.Drawing {
	/// <summary>
	/// Description of LineContainer.
	/// </summary>
	[Serializable()]
	public class ArrowContainer : LineContainer {
		public enum ArrowHeadCombination { NONE, START_POINT, END_POINT, BOTH };
		
		private static readonly AdjustableArrowCap ARROW_CAP = new AdjustableArrowCap(4, 6);

		public ArrowContainer(Surface parent) : base(parent) {
		}

		/// <summary>
		/// Do not use the base, just override so we have our own defaults
		/// </summary>
		protected override void InitializeFields() {
			AddField(GetType(), FieldType.LINE_THICKNESS, 2);
			AddField(GetType(), FieldType.ARROWHEADS, 2);
			AddField(GetType(), FieldType.LINE_COLOR, Color.Red);
			AddField(GetType(), FieldType.FILL_COLOR, Color.Transparent);
			AddField(GetType(), FieldType.SHADOW, true);
			AddField(GetType(), FieldType.ARROWHEADS, ArrowHeadCombination.END_POINT);
		}

		public override void Draw(Graphics graphics, RenderMode rm) {
			int lineThickness = GetFieldValueAsInt(FieldType.LINE_THICKNESS);
			bool shadow = GetFieldValueAsBool(FieldType.SHADOW);

			if (lineThickness > 0 ) {
				graphics.SmoothingMode = SmoothingMode.HighQuality;
				graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
				graphics.CompositingQuality = CompositingQuality.HighQuality;
				graphics.PixelOffsetMode = PixelOffsetMode.None;
				Color lineColor = GetFieldValueAsColor(FieldType.LINE_COLOR);
				ArrowHeadCombination heads = (ArrowHeadCombination)GetFieldValue(FieldType.ARROWHEADS);
				if (lineThickness > 0) {
					if (shadow) {
						//draw shadow first
						int basealpha = 100;
						int alpha = basealpha;
						int steps = 5;
						int currentStep = 1;
						while (currentStep <= steps)
                        {
                            using Pen shadowCapPen = new Pen(Color.FromArgb(alpha, 100, 100, 100), lineThickness);
                            SetArrowHeads(heads, shadowCapPen);

                            graphics.DrawLine(shadowCapPen,
                                Left + currentStep,
                                Top + currentStep,
                                Left + currentStep + Width,
                                Top + currentStep + Height);

                            currentStep++;
                            alpha -= basealpha / steps;
                        }

					}

                    using Pen pen = new Pen(lineColor, lineThickness);
                    SetArrowHeads(heads, pen);
                    graphics.DrawLine(pen, Left, Top, Left + Width, Top + Height);
                }
			}
		}
		
		private void SetArrowHeads(ArrowHeadCombination heads, Pen pen) {
			if ( heads == ArrowHeadCombination.BOTH || heads == ArrowHeadCombination.START_POINT ) {
				pen.CustomStartCap = ARROW_CAP;
			}
			if ( heads == ArrowHeadCombination.BOTH || heads == ArrowHeadCombination.END_POINT ) {
				pen.CustomEndCap = ARROW_CAP;
			}
		}
		
		public override Rectangle DrawingBounds {
			get {
				int lineThickness = GetFieldValueAsInt(FieldType.LINE_THICKNESS);
				if (lineThickness > 0)
                {
					using Pen pen = new Pen(Color.White)
					{
						Width = lineThickness
					};
					SetArrowHeads((ArrowHeadCombination)GetFieldValue(FieldType.ARROWHEADS), pen);
                    using GraphicsPath path = new GraphicsPath();
                    path.AddLine(Left, Top, Left + Width, Top + Height);
                    using Matrix matrix = new Matrix();
                    Rectangle drawingBounds = Rectangle.Round(path.GetBounds(matrix, pen));
                    drawingBounds.Inflate(2, 2);
                    return drawingBounds;
                }
				return Rectangle.Empty;
			}
		}
		
		public override bool ClickableAt(int x, int y) {
			int lineThickness = GetFieldValueAsInt(FieldType.LINE_THICKNESS) + 10;
			if (lineThickness > 0)
            {
				using Pen pen = new Pen(Color.White)
				{
					Width = lineThickness
				};
				SetArrowHeads((ArrowHeadCombination)GetFieldValue(FieldType.ARROWHEADS), pen);
                using GraphicsPath path = new GraphicsPath();
                path.AddLine(Left, Top, Left + Width, Top + Height);
                return path.IsOutlineVisible(x, y, pen);
            }
			return false;
		}
	}
}