Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
/**
 * Copyright (C) 2009 - 2012 SC 4ViewSoft SRL
 *  
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *  
 *      http://www.apache.org/licenses/LICENSE-2.0
 *  
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

public class Main {
    /**
     * Computes a reasonable number of labels for a data range.
     * 
     * @param start start value
     * @param end final value
     * @param approxNumLabels desired number of labels
     * @return double[] array containing {start value, end value, increment}
     */
    private static double[] computeLabels(final double start, final double end, final int approxNumLabels,
            double minimumJump) {
        if (Math.abs(start - end) < 0.0000001f) {
            return new double[] { start, start, 0 };
        }
        double s = start;
        double e = end;
        boolean switched = false;
        if (s > e) {
            switched = true;
            double tmp = s;
            s = e;
            e = tmp;
        }
        double xStep = roundUp(Math.max(Math.abs(s - e) / approxNumLabels, minimumJump));
        // Compute x starting point so it is a multiple of xStep.
        double xStart = xStep * Math.ceil(s / xStep);
        double xEnd = xStep * Math.floor(e / xStep);
        if (switched) {
            return new double[] { xEnd, xStart, -1.0 * xStep };
        }
        return new double[] { xStart, xEnd, xStep };
    }

    /**
     * Given a number, round up to the nearest power of ten times 1, 2, or 5.
     * 
     * @param val the number, it must be strictly positive
     */
    private static double roundUp(final double val) {
        int exponent = (int) Math.floor(Math.log10(val));
        double rval = val * Math.pow(10, -exponent);
        if (rval > 5.0) {
            rval = 10.0;
        } else if (rval > 2.0) {
            rval = 5.0;
        } else if (rval > 1.0) {
            rval = 2.0;
        }
        rval *= Math.pow(10, exponent);
        return rval;
    }
}