altoslib/altosuilib/altosui: More work towards using AltosFlightSeries for analysis

[fw/altos] / altoslib / AltosTimeSeries.java

diff --git a/altoslib/AltosTimeSeries.java b/altoslib/AltosTimeSeries.java
index 1d3d9a6c5185878fb6400412f400c23d2a831581..30b24d82bcf3503fe6f059e7ae022c512f700994 100644 (file)
--- a/altoslib/AltosTimeSeries.java
+++ b/altoslib/AltosTimeSeries.java
@@ -17,9 +17,9 @@ package org.altusmetrum.altoslib_11;
 import java.util.*;
 
 public class AltosTimeSeries implements Iterable<AltosTimeValue> {
-       public String           label;
-       public AltosUnits       units;
-       List<AltosTimeValue>    values;
+       public String                   label;
+       public AltosUnits               units;
+       ArrayList<AltosTimeValue>       values;
 
        public void add(AltosTimeValue tv) {
                values.add(tv);
@@ -33,6 +33,58 @@ public class AltosTimeSeries implements Iterable<AltosTimeValue> {
                return values.get(i);
        }
 
+       private double lerp(AltosTimeValue v0, AltosTimeValue v1, double t) {
+               /* degenerate case */
+               if (v0.time == v1.time)
+                       return (v0.value + v1.value) / 2;
+
+               return (v0.value * (v1.time - t) + v1.value * (t - v0.time)) / v1.time - v0.time;
+       }
+
+       private int after_index(double time) {
+               int     lo = 0;
+               int     hi = values.size() - 1;
+
+               while (lo <= hi) {
+                       int mid = (lo + hi) / 2;
+
+                       if (values.get(mid).time < time)
+                               lo = mid + 1;
+                       else
+                               hi = mid - 1;
+               }
+               return lo;
+       }
+
+       /* Compute a value for an arbitrary time */
+       public double value(double time) {
+               int after = after_index(time);
+               if (after == 0)
+                       return values.get(0).value;
+               if (after == values.size())
+                       return values.get(after - 1).value;
+
+               return lerp(values.get(after-1), values.get(after), time);
+       }
+
+       /* Find the value just before an arbitrary time */
+       public double value_before(double time) {
+               int after = after_index(time);
+
+               if (after == 0)
+                       return values.get(0).value;
+               return values.get(after-1).value;
+       }
+
+       /* Find the value just after an arbitrary time */
+       public double value_after(double time) {
+               int after = after_index(time);
+
+               if (after == values.size())
+                       return values.get(after-1).value;
+               return values.get(after).value;
+       }
+
        public int size() {
                return values.size();
        }
@@ -144,11 +196,16 @@ public class AltosTimeSeries implements Iterable<AltosTimeValue> {
 
                        int     left = find_left(i, half_width);
                        int     right = find_right(i, half_width);
+
                        for (int j = left; j <= right; j++) {
                                double  j_time = values.get(j).time;
 
                                if (left_time <= j_time && j_time <= right_time) {
-                                       double  coeff = filter_coeff(j_time - center_time, width);
+                                       double  j_left = j == left ? left_time : values.get(j-1).time;
+                                       double  j_right = j == right ? right_time : values.get(j+1).time;
+                                       double  interval = (j_right - j_left) / 2.0;
+                                       double  coeff = filter_coeff(j_time - center_time, width) * interval;
+
                                        total_coeff += coeff;
                                        total_value += coeff * values.get(j).value;
                                }