/** * * The MIT License * * Copyright (c) 2011 the original author or authors. * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ package com.googlecode.charts4j; import static com.googlecode.charts4j.collect.Preconditions.checkArgument; import static com.googlecode.charts4j.collect.Preconditions.checkContentsNotNull; import static com.googlecode.charts4j.collect.Preconditions.checkNotNull; import java.util.Collections; import java.util.List; import com.googlecode.charts4j.collect.ImmutableList; import com.googlecode.charts4j.collect.Lists; import com.googlecode.charts4j.collect.PrimitiveArrays; /** * Perusing the <a href="http://groups.google.com/group/google-chart-api"> * Google Chart API Group</a> reveals that a lot of users and developers are * having difficulty scaling their data. A common question is "What do I do * about negative numbers?". Or "What if my data lies outside the simple or * extended encoding range?" The answer to these problems is that users must * scale their data so that they may be rendered in the chart. This class helps * users achieve that goal. * * @author Julien Chastang (julien.c.chastang at gmail dot com) * * @see Data * @see Plots * @see GCharts */ public final class DataUtil { /** * Constructor must never be called. */ private DataUtil() { throw new AssertionError(); } /** * Static factory method that will scale data between the min and max. If * max equals min or max is less than min, no scaling will occur. * * Note that the min value can be less than the minimum value of the data * and that the max value can be greater than the maximum value of the data. * This scenario is useful when you don't want your plot to span the entire * chart, but you would like the plots to be "squeezed in" a bit. * * @param min * The minimum value in the scaling range. * @param max * The maximum value in the scaling range. * @param data * The data * @return A Data object scaled between min and max. * * @see Data */ public static Data scaleWithinRange(final double min, final double max, final double[] data) { checkArgument(max - min > 0, "min >= max!"); return Data.newData(privateScale(data, min, max)); } /** * Static factory method that will scale data between the min and max. If * max equals min or max is less than min, no scaling will occur. * * Note that the min value can be less than the minimum value of the data * and that the max value can be greater than the maximum value of the data. * This scenario is useful when you don't want your plot to span the entire * chart, but you would like the plots to be "squeezed in" a bit. * * @param min * The minimum value in the scaling range. * @param max * The maximum value in the scaling range. * @param data * The data list to be scaled. The Number type is used as a * convenience but Numbers that fall outside the * {@link Double#MAX_VALUE} and {@link Double#MIN_VALUE} should * not be used. * @return A Data object scaled between min and max. * @see Data */ public static Data scaleWithinRange(final double min, final double max, final List<? extends Number> data) { return scaleWithinRange(min, max, toDoubleArray(Lists.copyOf(data))); } /** * Static factory method that will simply scale between the minimum and * maximum values in the data. * * @param data * Provide a data series that will be scaled by this method. * * @return A Data object scaled between minimum and maximum in the provided * data series. * @see Data */ public static Data scale(final double... data) { checkNotNull(data, "data is null or contents of data is null."); final double min = Collections.min(PrimitiveArrays.asList(data)); final double max = Collections.max(PrimitiveArrays.asList(data)); checkArgument(min < max, "Cannot scale this data. It is ill conditioned."); return Data.newData(privateScale(data, min, max)); } /** * Static factory method that will simply scale between the minimum and * maximum values in the data. * * @param data * Provide a data series that will be scaled by this method. * * @return A Data object scaled between minimum and maximum in the provided * data series. The Number type is used as a convenience but Numbers * that fall outside the {@link Double#MAX_VALUE} and * {@link Double#MIN_VALUE} should not be used. * @see Data */ public static Data scale(final List<? extends Number> data) { checkContentsNotNull(data, "data is null or contents of data is null."); return scale(toDoubleArray(Lists.copyOf(data))); } /** * This method is for scaling multiple data series at once. It is useful in * situations where you have multiple plots in one chart, and you want the * data consistently scaled by the same factor. The data are scaled between * the minimum and maximum data points found for all data. The returned * scaled {@link Data} list can be plotted with the guarantee that all the * plots will fit on the chart. * * @param data * the data. The first index is the data series index. The second * is the data series. * * @return the list of Data objects that can then be plotted. */ public static List<Data> scale(final double data[][]) { checkNotNull(data, "data cannot be null"); final List<Double> allData = Lists.newLinkedList(); for (double[] d : data) { for (double doub : d) { allData.add(doub); } } final double min = Collections.min(allData); final double max = Collections.max(allData); final List<Data> list = Lists.newLinkedList(); for (double[] d : data) { list.add(scaleWithinRange(min, max, d)); } return list; } /** * This method is for scaling multiple data series at once. It is useful in * situations where you have multiple plots in one chart, and you want the * data consistently scaled by the same factor. The data are scaled between * the minimum and maximum data points found for all data. The returned * scaled {@link Data} list can be plotted with the guarantee that all the * plots will fit on the chart. * * @param data * the data. * * @return the list of Data objects that can then be plotted. */ public static List<Data> scaleDataList(final List<? extends List<? extends Number>> data) { checkContentsNotNull(data, "data is null or contents of data is null."); final double[][] d = new double[data.size()][]; int j = 0; for (List<? extends Number> datum : data) { checkContentsNotNull(datum, "data is null or contents of data is null."); double[] plotData = new double[datum.size()]; int i = 0; for (Number n : datum) { plotData[i++] = n.doubleValue(); } d[j++] = plotData; } return scale(d); } /** * Convert a list of numbers to a double array. Numbers that fall outside * the {@link Double.MAX_VALUE} and {@link Double.MIN_VALUE} should not be * used. * * @param data * List of numbers * @return a double a array. */ static double[] toDoubleArray(final ImmutableList<? extends Number> data) { final double[] d = new double[data.size()]; for (int i = 0; i < d.length; i++) { d[i] = data.get(i).doubleValue(); } return d; } /** * Method that scales the data. * * @param doubleArray * Data to be scaled. Cannot be null. * @param min * Minimum range for scaled data. * @param max * Maximum range of scaled data. * @return scaled double array */ private static double[] privateScale(final double[] doubleArray, final double min, final double max) { checkNotNull(doubleArray, "doubleArray cannot be null"); checkArgument(max - min > 0, "min > max!"); final double[] scaledData = new double[doubleArray.length]; for (int j = 0; j < doubleArray.length; j++) { scaledData[j] = ((doubleArray[j] - min) / (max - min)) * Data.MAX_VALUE; } return scaledData; } }