Java tutorial
/* * Copyright 2006-2015 The MZmine 3 Development Team * * This file is part of MZmine 3. * * MZmine 3 is free software; you can redistribute it and/or modify it under the terms of the GNU * General Public License as published by the Free Software Foundation; either version 2 of the * License, or (at your option) any later version. * * MZmine 3 is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without * even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License along with MZmine 3; if not, * write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 * USA */ package io.github.mzmine.util.jfreechart; import org.jfree.chart.fx.ChartViewer; import org.jfree.chart.labels.XYItemLabelGenerator; import org.jfree.chart.plot.XYPlot; import org.jfree.data.xy.XYDataset; import com.google.common.collect.Range; /** * This implementation of XYItemLabelGenerator assumes that the data points in each series are * sorted in the X-axis order. It places the item labels only on local maxima, or on left-most data * points in case multiple data points have the same maximal Y value. * */ public class IntelligentItemLabelGenerator implements XYItemLabelGenerator { private final ChartViewer chartNode; private final XYItemLabelGenerator underlyingGenerator; private final int reservedPixels; /** * * @param chartNode * @param plot * @param reservedPoints Number of screen pixels to reserve for each label, so that the labels do * not overlap * @param underlyingGenerator */ public IntelligentItemLabelGenerator(ChartViewer chartNode, int reservedPixels, XYItemLabelGenerator underlyingGenerator) { this.chartNode = chartNode; this.reservedPixels = reservedPixels; this.underlyingGenerator = underlyingGenerator; } /** * @see org.jfree.chart.labels.XYItemLabelGenerator#generateLabel(org.jfree.data.xy.XYDataset, * int, int) */ public String generateLabel(XYDataset currentDataset, int currentSeries, int currentItem) { XYPlot plot = chartNode.getChart().getXYPlot(); // X and Y values of the current data point final double currentXValue = currentDataset.getXValue(currentSeries, currentItem); final double currentYValue = currentDataset.getYValue(currentSeries, currentItem); // Calculate X axis span of 1 screen pixel final double xLength = plot.getDomainAxis().getRange().getLength(); final double pixelX = xLength / chartNode.getWidth(); // Calculate the distance from the current point where labels might // overlap final double dangerZoneX = (reservedPixels / 2) * pixelX; // Range on X axis that we're going to check for higher data points. If // a higher data point is found, we don't place a label on this one. final Range<Double> dangerZoneRange = Range.closed(currentXValue - dangerZoneX, currentXValue + dangerZoneX); // Iterate through data sets for (int datasetIndex = 0; datasetIndex < plot.getDatasetCount(); datasetIndex++) { XYDataset dataset = plot.getDataset(datasetIndex); // Some data sets could have been removed if (dataset == null) continue; final int seriesCount = dataset.getSeriesCount(); // Iterate through series for (int seriesIndex = 0; seriesIndex < seriesCount; seriesIndex++) { final int itemCount = dataset.getItemCount(seriesIndex); // Find the index of a data point that is closest to // currentXValue int closestValueIndex; if (dataset == currentDataset && seriesIndex == currentSeries) { closestValueIndex = currentItem; } else { closestValueIndex = findClosestXIndex(dataset, seriesIndex, currentXValue, 0, itemCount - 1); } // Search to the left of the closest data point for (int i = closestValueIndex; (i >= 0) && (dangerZoneRange.contains(dataset.getX(seriesIndex, i).doubleValue())); i--) { if (dataset.getYValue(seriesIndex, i) > currentYValue) return null; // In the case there are equal values, only place the label // on the leftmost value if (dataset.getYValue(seriesIndex, i) == currentYValue && (dataset.getXValue(seriesIndex, i) < currentXValue)) return null; } // Search to the right of the closest data point for (int i = closestValueIndex + 1; (i < itemCount) && (dangerZoneRange.contains(dataset.getX(seriesIndex, i).doubleValue())); i++) { if (dataset.getYValue(seriesIndex, i) > currentYValue) return null; } } } // If no higher data point was found, create the label String label = underlyingGenerator.generateLabel(currentDataset, currentSeries, currentItem); return label; } /** * Finds the data point in given dataset/series that is closest to the given xValue. Uses * recursion and binary search , minIndex and maxIndex provide the boundaries of the currently * examined region. */ private int findClosestXIndex(XYDataset dataset, int series, double xValue, int minIndex, int maxIndex) { if (minIndex == maxIndex) return minIndex; if (minIndex == maxIndex - 1) { double minIndexValue = dataset.getXValue(series, minIndex); double maxIndexValue = dataset.getXValue(series, maxIndex); if (Math.abs(minIndexValue - xValue) < Math.abs(maxIndexValue - xValue)) return minIndex; else return maxIndex; } int middleIndex = (maxIndex + minIndex) / 2; double middleValue = dataset.getXValue(series, middleIndex); if (middleValue == xValue) return middleIndex; else if (middleValue > xValue) return findClosestXIndex(dataset, series, xValue, minIndex, middleIndex); else return findClosestXIndex(dataset, series, xValue, middleIndex, maxIndex); } }