nplot/src/PiAxis.cs

/*
 * NPlot - A charting library for .NET
 * 
 * PiAxis.cs
 * Copyright (C) 2003-2006 Matt Howlett and others.
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 * 
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */

using System;
using System.Collections;
using System.Drawing;

namespace NPlot
{
    /// <summary>
    /// Axis with labels in multiples of Pi. Maybe needs a better name.
    /// Lots of functionality still to be added - currently only puts labels
    /// at whole increments of pi, want arbitrary increments, automatically
    /// determined and dependance on physical length.
    /// Volunteers?
    /// </summary>
    public class PiAxis : Axis
    {
        /// <summary>
        /// Copy constructor
        /// </summary>
        /// <param name="a">The Axis to clone.</param>
        /// <remarks>TODO: [review notes] I don't think this will work as desired.</remarks>
        public PiAxis(Axis a)
            : base(a)
        {
            Init();
        }

        /// <summary>
        /// Default constructor
        /// </summary>
        public PiAxis()
        {
            Init();
        }

        /// <summary>
        /// Constructor
        /// </summary>
        /// <param name="worldMin">Minimum world value</param>
        /// <param name="worldMax">Maximum world value</param>
        public PiAxis(double worldMin, double worldMax)
            : base(worldMin, worldMax)
        {
            Init();
        }

        /// <summary>
        /// Deep copy of PiAxis.
        /// </summary>
        /// <returns>A copy of the LinearAxis Class.</returns>
        public override object Clone()
        {
            PiAxis a = new PiAxis();
            // ensure that this isn't being called on a derived type. If it is, then oh no!
            if (GetType() != a.GetType())
            {
                throw new NPlotException("Error. Clone method is not defined in derived type.");
            }
            DoClone(this, a);
            return a;
        }

        /// <summary>
        /// Helper method for Clone.
        /// </summary>
        /// <param name="a">The original object to clone.</param>
        /// <param name="b">The cloned object.</param>
        protected static void DoClone(PiAxis b, PiAxis a)
        {
            Axis.DoClone(b, a);
        }

        /// <summary>
        /// Initialise PiAxis to default state.
        /// </summary>
        private void Init()
        {
        }

        /// <summary>
        /// Given Graphics surface, and physical extents of axis, draw ticks and
        /// associated labels.
        /// </summary>
        /// <param name="g">The GDI+ Graphics surface on which to draw.</param>
        /// <param name="physicalMin">The physical location of the world min point</param>
        /// <param name="physicalMax">The physical location of the world max point</param>
        /// <param name="boundingBox">out: smallest box that completely encompasses all of the ticks and tick labels.</param>
        /// <param name="labelOffset">out: a suitable offset from the axis to draw the axis label.</param>
        protected override void DrawTicks(
            Graphics g,
            Point physicalMin,
            Point physicalMax,
            out object labelOffset,
            out object boundingBox)
        {
            Point tLabelOffset;
            Rectangle tBoundingBox;

            labelOffset = getDefaultLabelOffset(physicalMin, physicalMax);
            boundingBox = null;

            int start = (int) Math.Ceiling(WorldMin/Math.PI);
            int end = (int) Math.Floor(WorldMax/Math.PI);

            // sanity checking.
            if (end - start < 0 || end - start > 30)
            {
                return;
            }

            for (int i = start; i <= end; ++i)
            {
                string label = i.ToString() + "Pi";

                if (i == 0)
                    label = "0";
                else if (i == 1)
                    label = "Pi";

                DrawTick(g, i*Math.PI, LargeTickSize,
                         label,
                         new Point(0, 0),
                         physicalMin, physicalMax,
                         out tLabelOffset, out tBoundingBox);

                UpdateOffsetAndBounds(
                    ref labelOffset, ref boundingBox,
                    tLabelOffset, tBoundingBox);
            }
        }

        /// <summary>
        /// Determines the positions, in world coordinates, of the large ticks.
        /// Label axes do not have small ticks.
        /// </summary>
        /// <param name="physicalMin">The physical position corresponding to the world minimum of the axis.</param>
        /// <param name="physicalMax">The physical position corresponding to the world maximum of the axis.</param>
        /// <param name="largeTickPositions">ArrayList containing the positions of the large ticks.</param>
        /// <param name="smallTickPositions">null</param>
        internal override void WorldTickPositions_FirstPass(
            Point physicalMin,
            Point physicalMax,
            out ArrayList largeTickPositions,
            out ArrayList smallTickPositions
            )
        {
            smallTickPositions = null;
            largeTickPositions = new ArrayList();

            int start = (int) Math.Ceiling(WorldMin/Math.PI);
            int end = (int) Math.Floor(WorldMax/Math.PI);

            // sanity checking.
            if (end - start < 0 || end - start > 30)
            {
                return;
            }

            for (int i = start; i < end; ++i)
            {
                largeTickPositions.Add(i*Math.PI);
            }
        }
    }
}