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nplot/src/ArrowItem.cs

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/*
* NPlot - A charting library for .NET
*
* ArrowItem.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.Drawing;
namespace NPlot
{
/// <summary>
/// An Arrow IDrawable, with a text label that is automatically
/// nicely positioned at the non-pointy end of the arrow. Future
/// feature idea: have constructor that takes a dataset, and have
/// the arrow know how to automatically set it's angle to avoid
/// the data.
/// </summary>
public class ArrowItem : IDrawable
{
private readonly Pen pen_ = new Pen(Color.Black);
private double angle_ = -45.0;
private Brush arrowBrush_ = new SolidBrush(Color.Black);
private Font font_;
private float headAngle_ = 40.0f;
private int headOffset_ = 2;
private float headSize_ = 10.0f;
private float physicalLength_ = 40.0f;
private Brush textBrush_ = new SolidBrush(Color.Black);
private string text_ = "";
private PointD to_;
/// <summary>
/// Default constructor :
/// text = ""
/// angle = 45 degrees anticlockwise from horizontal.
/// </summary>
/// <param name="position">The position the arrow points to.</param>
public ArrowItem(PointD position)
{
to_ = position;
Init();
}
/// <summary>
/// Constructor
/// </summary>
/// <param name="position">The position the arrow points to.</param>
/// <param name="angle">angle of arrow with respect to x axis.</param>
public ArrowItem(PointD position, double angle)
{
to_ = position;
angle_ = -angle;
Init();
}
/// <summary>
/// Constructor
/// </summary>
/// <param name="position">The position the arrow points to.</param>
/// <param name="angle">angle of arrow with respect to x axis.</param>
/// <param name="text">The text associated with the arrow.</param>
public ArrowItem(PointD position, double angle, string text)
{
to_ = position;
angle_ = -angle;
text_ = text;
Init();
}
/// <summary>
/// Text associated with the arrow.
/// </summary>
public string Text
{
get { return text_; }
set { text_ = value; }
}
/// <summary>
/// Angle of arrow anti-clockwise to right horizontal in degrees.
/// </summary>
/// <remarks>
/// The code relating to this property in the Draw method is
/// a bit weird. Internally, all rotations are clockwise [this is by
/// accient, I wasn't concentrating when I was doing it and was half
/// done before I realised]. The simplest way to make angle represent
/// anti-clockwise rotation (as it is normal to do) is to make the
/// get and set methods negate the provided value.
/// </remarks>
public double Angle
{
get { return -angle_; }
set { angle_ = -value; }
}
/// <summary>
/// Physical length of the arrow.
/// </summary>
public float PhysicalLength
{
get { return physicalLength_; }
set { physicalLength_ = value; }
}
/// <summary>
/// The point the arrow points to.
/// </summary>
public PointD To
{
get { return to_; }
set { to_ = value; }
}
/// <summary>
/// Size of the arrow head sides in pixels.
/// </summary>
public float HeadSize
{
get { return headSize_; }
set { headSize_ = value; }
}
/// <summary>
/// angle between sides of arrow head in degrees
/// </summary>
public float HeadAngle
{
get { return headAngle_; }
set { headAngle_ = value; }
}
/// <summary>
/// The brush used to draw the text associated with the arrow.
/// </summary>
public Brush TextBrush
{
get { return textBrush_; }
set { textBrush_ = value; }
}
/// <summary>
/// Set the text to be drawn with a solid brush of this color.
/// </summary>
public Color TextColor
{
set { textBrush_ = new SolidBrush(value); }
}
/// <summary>
/// The color of the pen used to draw the arrow.
/// </summary>
public Color ArrowColor
{
get { return pen_.Color; }
set
{
pen_.Color = value;
arrowBrush_ = new SolidBrush(value);
}
}
/// <summary>
/// The font used to draw the text associated with the arrow.
/// </summary>
public Font TextFont
{
get { return font_; }
set { font_ = value; }
}
/// <summary>
/// Offset the whole arrow back in the arrow direction this many pixels from the point it's pointing to.
/// </summary>
public int HeadOffset
{
get { return headOffset_; }
set { headOffset_ = value; }
}
/// <summary>
/// Draws the arrow on a plot surface.
/// </summary>
/// <param name="g">graphics surface on which to draw</param>
/// <param name="xAxis">The X-Axis to draw against.</param>
/// <param name="yAxis">The Y-Axis to draw against.</param>
public void Draw(Graphics g, PhysicalAxis xAxis, PhysicalAxis yAxis)
{
if (To.X > xAxis.Axis.WorldMax || To.X < xAxis.Axis.WorldMin)
return;
if (To.Y > yAxis.Axis.WorldMax || To.Y < yAxis.Axis.WorldMin)
return;
double angle = angle_;
if (angle_ < 0.0)
{
int mul = -(int) (angle_/360.0) + 2;
angle = angle_ + 360.0*mul;
}
double normAngle = angle%360.0; // angle in range 0 -> 360.
Point toPoint = new Point(
(int) xAxis.WorldToPhysical(to_.X, true).X,
(int) yAxis.WorldToPhysical(to_.Y, true).Y);
float xDir = (float) Math.Cos(normAngle*2.0*Math.PI/360.0);
float yDir = (float) Math.Sin(normAngle*2.0*Math.PI/360.0);
toPoint.X += (int) (xDir*headOffset_);
toPoint.Y += (int) (yDir*headOffset_);
float xOff = physicalLength_*xDir;
float yOff = physicalLength_*yDir;
Point fromPoint = new Point(
(int) (toPoint.X + xOff),
(int) (toPoint.Y + yOff));
g.DrawLine(pen_, toPoint, fromPoint);
Point[] head = new Point[3];
head[0] = toPoint;
xOff = headSize_*(float) Math.Cos((normAngle - headAngle_/2.0f)*2.0*Math.PI/360.0);
yOff = headSize_*(float) Math.Sin((normAngle - headAngle_/2.0f)*2.0*Math.PI/360.0);
head[1] = new Point(
(int) (toPoint.X + xOff),
(int) (toPoint.Y + yOff));
float xOff2 = headSize_*(float) Math.Cos((normAngle + headAngle_/2.0f)*2.0*Math.PI/360.0);
float yOff2 = headSize_*(float) Math.Sin((normAngle + headAngle_/2.0f)*2.0*Math.PI/360.0);
head[2] = new Point(
(int) (toPoint.X + xOff2),
(int) (toPoint.Y + yOff2));
g.FillPolygon(arrowBrush_, head);
SizeF textSize = g.MeasureString(text_, font_);
SizeF halfSize = new SizeF(textSize.Width/2.0f, textSize.Height/2.0f);
float quadrantSlideLength = halfSize.Width + halfSize.Height;
float quadrantF = (float) normAngle/90.0f; // integer part gives quadrant.
int quadrant = (int) quadrantF; // quadrant in.
float prop = quadrantF - quadrant; // proportion of way through this qadrant.
float dist = prop*quadrantSlideLength; // distance along quarter of bounds rectangle.
// now find the offset from the middle of the text box that the
// rear end of the arrow should end at (reverse this to get position
// of text box with respect to rear end of arrow).
//
// There is almost certainly an elgant way of doing this involving
// trig functions to get all the signs right, but I'm about ready to
// drop off to sleep at the moment, so this blatent method will have
// to do.
PointF offsetFromMiddle = new PointF(0.0f, 0.0f);
switch (quadrant)
{
case 0:
if (dist > halfSize.Height)
{
dist -= halfSize.Height;
offsetFromMiddle = new PointF(-halfSize.Width + dist, halfSize.Height);
}
else
{
offsetFromMiddle = new PointF(-halfSize.Width, - dist);
}
break;
case 1:
if (dist > halfSize.Width)
{
dist -= halfSize.Width;
offsetFromMiddle = new PointF(halfSize.Width, halfSize.Height - dist);
}
else
{
offsetFromMiddle = new PointF(dist, halfSize.Height);
}
break;
case 2:
if (dist > halfSize.Height)
{
dist -= halfSize.Height;
offsetFromMiddle = new PointF(halfSize.Width - dist, -halfSize.Height);
}
else
{
offsetFromMiddle = new PointF(halfSize.Width, -dist);
}
break;
case 3:
if (dist > halfSize.Width)
{
dist -= halfSize.Width;
offsetFromMiddle = new PointF(-halfSize.Width, -halfSize.Height + dist);
}
else
{
offsetFromMiddle = new PointF(-dist, -halfSize.Height);
}
break;
default:
throw new NPlotException("Programmer error.");
}
g.DrawString(
text_, font_, textBrush_,
(int) (fromPoint.X - halfSize.Width - offsetFromMiddle.X),
(int) (fromPoint.Y - halfSize.Height + offsetFromMiddle.Y));
}
private void Init()
{
FontFamily fontFamily = new FontFamily("Arial");
font_ = new Font(fontFamily, 10, FontStyle.Regular, GraphicsUnit.Pixel);
}
}
}
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