mirror of https://github.com/mhowlett/nplot.git
337 lines
12 KiB
C#
337 lines
12 KiB
C#
/*
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* NPlot - A charting library for .NET
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*
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* Utils.cs
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* Copyright (C) 2003-2006 Matt Howlett and others.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without modification,
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* are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
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* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
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* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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using System;
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using System.Collections;
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using System.Data;
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using System.Drawing;
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namespace NPlot
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{
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/// <summary>
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/// General purpose utility functions used internally.
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/// </summary>
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internal class Utils
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{
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/// <summary>
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/// Numbers less than this are considered insignificant. This number is
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/// bigger than double.Epsilon.
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/// </summary>
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public const double Epsilon = double.Epsilon*1000.0;
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/// <summary>
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/// Returns true if the absolute difference between parameters is less than Epsilon
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/// </summary>
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/// <param name="a">first number to compare</param>
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/// <param name="b">second number to compare</param>
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/// <returns>true if equal, false otherwise</returns>
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public static bool DoubleEqual(double a, double b)
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{
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if (Math.Abs(a - b) < Epsilon)
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{
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return true;
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}
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return false;
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}
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/// <summary>
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/// Swaps the value of two doubles.
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/// </summary>
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/// <param name="a">first value to swap.</param>
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/// <param name="b">second value to swap.</param>
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public static void Swap(ref double a, ref double b)
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{
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double c = a;
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a = b;
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b = c;
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}
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/// <summary>
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/// Calculate the distance between two points, a and b.
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/// </summary>
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/// <param name="a">First point</param>
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/// <param name="b">Second point</param>
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/// <returns>Distance between points a and b</returns>
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public static float Distance(PointF a, PointF b)
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{
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return (float) Math.Sqrt((a.X - b.X)*(a.X - b.X) + (a.Y - b.Y)*(a.Y - b.Y));
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}
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/// <summary>
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/// Calculate the distance between two points, a and b.
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/// </summary>
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/// <param name="a">First point</param>
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/// <param name="b">Second point</param>
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/// <returns>Distance between points a and b</returns>
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public static int Distance(Point a, Point b)
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{
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return (int) Math.Sqrt((a.X - b.X)*(a.X - b.X) + (a.Y - b.Y)*(a.Y - b.Y));
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}
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/// <summary>
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/// Converts an object of type DateTime or IConvertible to double representation.
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/// Mapping is 1:1. Note: the System.Convert.ToDouble method can not convert a boxed
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/// DateTime to double. This implementation can - but the "is" check probably makes
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/// it much slower.
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/// </summary>
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/// <remarks>Compare speed with System.Convert.ToDouble and revise code that calls this if significant speed difference.</remarks>
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/// <param name="o">The object to convert to double.</param>
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/// <returns>double value associated with the object.</returns>
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public static double ToDouble(object o)
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{
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if (o is DateTime)
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{
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return (((DateTime) o).Ticks);
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}
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else if (o is IConvertible)
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{
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return Convert.ToDouble(o);
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}
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throw new NPlotException("Invalid datatype");
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}
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/// <summary>
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/// Returns the minimum and maximum values in an IList. The members of the list
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/// can be of different types - any type for which the function Utils.ConvertToDouble
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/// knows how to convert into a double.
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/// </summary>
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/// <param name="a">The IList to search.</param>
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/// <param name="min">The minimum value.</param>
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/// <param name="max">The maximum value.</param>
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/// <returns>true if min max set, false otherwise (a == null or zero length).</returns>
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public static bool ArrayMinMax(IList a, out double min, out double max)
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{
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if (a == null || a.Count == 0)
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{
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min = 0.0;
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max = 0.0;
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return false;
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}
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min = ToDouble(a[0]);
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max = ToDouble(a[0]);
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foreach (object o in a)
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{
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double e = ToDouble(o);
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if ((min.Equals(double.NaN)) && (!e.Equals(double.NaN)))
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{
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// if min/max are double.NaN and the current value not, then
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// set them to the current value.
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min = e;
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max = e;
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}
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if (!double.IsNaN(e))
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{
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if (e < min)
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{
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min = e;
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}
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if (e > max)
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{
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max = e;
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}
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}
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}
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if (min.Equals(double.NaN))
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{
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// if min == double.NaN, then max is also double.NaN
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min = 0.0;
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max = 0.0;
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return false;
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}
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return true;
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}
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/// <summary>
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/// Returns the minimum and maximum values in a DataRowCollection.
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/// </summary>
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/// <param name="rows">The row collection to search.</param>
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/// <param name="min">The minimum value.</param>
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/// <param name="max">The maximum value.</param>
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/// <param name="columnName">The name of the column in the row collection to search over.</param>
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/// <returns>true is min max set, false otherwise (a = null or zero length).</returns>
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public static bool RowArrayMinMax(DataRowCollection rows,
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out double min, out double max, string columnName)
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{
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// double[] is a reference type and can be null, if it is then I reckon the best
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// values for min and max are also null. double is a value type so can't be set
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// to null. So min an max return object, and we understand that if it is not null
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// it is a boxed double (same trick I use lots elsewhere in the lib). The
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// wonderful comment I didn't write at the top should explain everything.
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if (rows == null || rows.Count == 0)
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{
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min = 0.0;
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max = 0.0;
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return false;
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}
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min = ToDouble((rows[0])[columnName]);
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max = ToDouble((rows[0])[columnName]);
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foreach (DataRow r in rows)
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{
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double e = ToDouble(r[columnName]);
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if ((min.Equals(double.NaN)) && (!e.Equals(double.NaN)))
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{
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// if min/max are double.NaN and the current value not, then
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// set them to the current value.
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min = e;
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max = e;
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}
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if (!double.IsNaN(e))
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{
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if (e < min)
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{
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min = e;
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}
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if (e > max)
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{
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max = e;
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}
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}
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}
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if (min.Equals(double.NaN))
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{
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// if min == double.NaN, then max is also double.NaN
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min = 0.0;
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max = 0.0;
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return false;
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}
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return true;
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}
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/// <summary>
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/// Returns the minimum and maximum values in a DataView.
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/// </summary>
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/// <param name="data">The DataView to search.</param>
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/// <param name="min">The minimum value.</param>
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/// <param name="max">The maximum value.</param>
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/// <param name="columnName">The name of the column in the row collection to search over.</param>
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/// <returns>true is min max set, false otherwise (a = null or zero length).</returns>
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public static bool DataViewArrayMinMax(DataView data,
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out double min, out double max, string columnName)
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{
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// double[] is a reference type and can be null, if it is then I reckon the best
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// values for min and max are also null. double is a value type so can't be set
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// to null. So min an max return object, and we understand that if it is not null
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// it is a boxed double (same trick I use lots elsewhere in the lib). The
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// wonderful comment I didn't write at the top should explain everything.
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if (data == null || data.Count == 0)
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{
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min = 0.0;
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max = 0.0;
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return false;
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}
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min = ToDouble((data[0])[columnName]);
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max = ToDouble((data[0])[columnName]);
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for (int i = 0; i < data.Count; ++i)
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{
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double e = ToDouble(data[i][columnName]);
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if (e < min)
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{
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min = e;
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}
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if (e > max)
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{
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max = e;
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}
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}
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return true;
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}
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/// <summary>
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/// Returns unit vector along the line a->b.
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/// </summary>
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/// <param name="a">line start point.</param>
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/// <param name="b">line end point.</param>
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/// <returns>The unit vector along the specified line.</returns>
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public static PointF UnitVector(PointF a, PointF b)
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{
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PointF dir = new PointF(b.X - a.X, b.Y - a.Y);
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double dirNorm = Math.Sqrt(dir.X*dir.X + dir.Y*dir.Y);
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if (dirNorm > 0.0f)
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{
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dir = new PointF(
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(float) ((1.0f/dirNorm)*dir.X),
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(float) ((1.0f/dirNorm)*dir.Y)); // normalised axis direction vector
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}
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return dir;
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}
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/// <summary>
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/// Get a Font exactly the same as the passed in one, except for scale factor.
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/// </summary>
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/// <param name="initial">The font to scale.</param>
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/// <param name="scale">Scale by this factor.</param>
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/// <returns>The scaled font.</returns>
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public static Font ScaleFont(Font initial, double scale)
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{
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FontStyle fs = initial.Style;
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GraphicsUnit gu = initial.Unit;
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double sz = initial.Size;
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sz = sz*scale;
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string nm = initial.Name;
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return new Font(nm, (float) sz, fs, gu);
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}
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/// <summary>
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/// Creates a bitmap from another that is tiled size times in each direction.
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/// </summary>
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/// <param name="image">bitmap to tile</param>
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/// <param name="size">number of times to tile in each direction.</param>
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/// <returns>the tiled bitmap.</returns>
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public static System.Drawing.Bitmap TiledImage(System.Drawing.Bitmap image, Size size)
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{
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System.Drawing.Bitmap final = new System.Drawing.Bitmap(size.Width, size.Height);
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for (int i = 0; i < (size.Width/image.Width) + 1; ++i)
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{
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for (int j = 0; j < (size.Height/image.Height) + 1; ++j)
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{
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Graphics.FromImage(final).DrawImage(image, i*image.Width, j*image.Height);
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}
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}
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return final;
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}
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}
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} |