1 | using System;
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2 | using System.Collections.Generic;
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3 | using System.Windows;
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4 | using Microsoft.Research.DynamicDataDisplay.Charts.Filters;
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5 |
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6 | namespace Microsoft.Research.DynamicDataDisplay.Filters
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7 | {
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8 | public sealed class FrequencyFilter : PointsFilterBase
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9 | {
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10 |
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11 | /// <summary>Visible region in screen coordinates</summary>
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12 | private Rect screenRect;
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13 |
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14 | #region IPointFilter Members
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15 |
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16 | public override void SetScreenRect(Rect screenRect)
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17 | {
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18 | this.screenRect = screenRect;
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19 | }
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20 |
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21 | // todo probably use LINQ here.
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22 | public override List<Point> Filter(List<Point> points)
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23 | {
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24 | if (points.Count == 0) return points;
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25 |
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26 | List<Point> resultPoints = points;
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27 | List<Point> currentChain = new List<Point>();
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28 |
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29 | if (points.Count > 2 * screenRect.Width)
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30 | {
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31 | resultPoints = new List<Point>();
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32 |
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33 | double currentX = Math.Floor(points[0].X);
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34 | foreach (Point p in points)
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35 | {
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36 | if (Math.Floor(p.X) == currentX)
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37 | {
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38 | currentChain.Add(p);
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39 | }
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40 | else
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41 | {
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42 | // Analyse current chain
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43 | if (currentChain.Count <= 2)
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44 | {
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45 | resultPoints.AddRange(currentChain);
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46 | }
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47 | else
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48 | {
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49 | Point first = MinByX(currentChain);
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50 | Point last = MaxByX(currentChain);
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51 | Point min = MinByY(currentChain);
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52 | Point max = MaxByY(currentChain);
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53 | resultPoints.Add(first);
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54 |
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55 | Point smaller = min.X < max.X ? min : max;
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56 | Point greater = min.X > max.X ? min : max;
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57 | if (smaller != resultPoints.GetLast())
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58 | {
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59 | resultPoints.Add(smaller);
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60 | }
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61 | if (greater != resultPoints.GetLast())
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62 | {
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63 | resultPoints.Add(greater);
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64 | }
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65 | if (last != resultPoints.GetLast())
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66 | {
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67 | resultPoints.Add(last);
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68 | }
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69 | }
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70 | currentChain.Clear();
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71 | currentChain.Add(p);
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72 | currentX = Math.Floor(p.X);
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73 | }
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74 | }
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75 | }
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76 |
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77 | resultPoints.AddRange(currentChain);
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78 |
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79 | return resultPoints;
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80 | }
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81 |
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82 | #endregion
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83 |
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84 | private static Point MinByX(IList<Point> points)
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85 | {
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86 | Point minPoint = points[0];
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87 | foreach (Point p in points)
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88 | {
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89 | if (p.X < minPoint.X)
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90 | {
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91 | minPoint = p;
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92 | }
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93 | }
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94 | return minPoint;
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95 | }
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96 |
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97 | private static Point MaxByX(IList<Point> points)
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98 | {
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99 | Point maxPoint = points[0];
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100 | foreach (Point p in points)
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101 | {
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102 | if (p.X > maxPoint.X)
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103 | {
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104 | maxPoint = p;
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105 | }
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106 | }
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107 | return maxPoint;
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108 | }
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109 |
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110 | private static Point MinByY(IList<Point> points)
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111 | {
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112 | Point minPoint = points[0];
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113 | foreach (Point p in points)
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114 | {
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115 | if (p.Y < minPoint.Y)
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116 | {
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117 | minPoint = p;
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118 | }
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119 | }
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120 | return minPoint;
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121 | }
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122 |
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123 | private static Point MaxByY(IList<Point> points)
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124 | {
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125 | Point maxPoint = points[0];
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126 | foreach (Point p in points)
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127 | {
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128 | if (p.Y > maxPoint.Y)
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129 | {
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130 | maxPoint = p;
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131 | }
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132 | }
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133 | return maxPoint;
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134 | }
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135 | }
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136 | }
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