logarithmicaxis.java

java图形利器

     * Overridden version that calls original and then sets up flag for
     * log axis processing.
     *
     * @param range  the new range.
     */
    public void setRange(Range range) {
        super.setRange(range);      // call parent method
        setupSmallLogFlag();        // setup flag based on bounds values
    }

    /**
     * Sets up flag for log axis processing.  Set true if negative values
     * not allowed and the lower bound is between 0 and 10.
     */
    protected void setupSmallLogFlag() {
        // set flag true if negative values not allowed and the
        // lower bound is between 0 and 10:
        double lowerVal = getRange().getLowerBound();
        this.smallLogFlag = (!this.allowNegativesFlag && lowerVal < 10.0 
                && lowerVal > 0.0);
    }

    /**
     * Sets up the number formatter object according to the
     * 'expTickLabelsFlag' flag.
     */
    protected void setupNumberFmtObj() {
        if (this.numberFormatterObj instanceof DecimalFormat) {
            //setup for "1e#"-style tick labels or regular
            // numeric tick labels, depending on flag:
            ((DecimalFormat) this.numberFormatterObj).applyPattern(
                    this.expTickLabelsFlag ? "0E0" : "0.###");
        }
    }

    /**
     * Returns the log10 value, depending on if values between 0 and
     * 1 are being plotted.  If negative values are not allowed and
     * the lower bound is between 0 and 10 then a normal log is
     * returned; otherwise the returned value is adjusted if the
     * given value is less than 10.
     *
     * @param val the value.
     *
     * @return log<sub>10</sub>(val).
     * 
     * @see #switchedPow10(double) 
     */
    protected double switchedLog10(double val) {
        return this.smallLogFlag ? Math.log(val)
                / LOG10_VALUE : adjustedLog10(val);
    }

    /** 
     * Returns a power of 10, depending on if values between 0 and
     * 1 are being plotted.  If negative values are not allowed and
     * the lower bound is between 0 and 10 then a normal power is
     * returned; otherwise the returned value is adjusted if the
     * given value is less than 1.
     * 
     * @param val the value.
     * 
     * @return 10<sup>val</sup>.
     * 
     * @since 1.0.5
     * @see #switchedLog10(double) 
     */
    public double switchedPow10(double val) {
        return this.smallLogFlag ? Math.pow(10.0, val) : adjustedPow10(val);
    }

    /**
     * Returns an adjusted log10 value for graphing purposes.  The first
     * adjustment is that negative values are changed to positive during
     * the calculations, and then the answer is negated at the end.  The
     * second is that, for values less than 10, an increasingly large
     * (0 to 1) scaling factor is added such that at 0 the value is
     * adjusted to 1, resulting in a returned result of 0.
     *
     * @param val  value for which log10 should be calculated.
     *
     * @return An adjusted log<sub>10</sub>(val).
     * 
     * @see #adjustedPow10(double) 
     */
    public double adjustedLog10(double val) {
        boolean negFlag = (val < 0.0);
        if (negFlag) {
            val = -val;          // if negative then set flag and make positive
        }
        if (val < 10.0) {                // if < 10 then
            val += (10.0 - val) / 10.0;  //increase so 0 translates to 0
        }
        //return value; negate if original value was negative:
        double res = Math.log(val) / LOG10_VALUE;
        return negFlag ? (-res) : res;
    }

    /**
     * Returns an adjusted power of 10 value for graphing purposes.  The first
     * adjustment is that negative values are changed to positive during
     * the calculations, and then the answer is negated at the end.  The
     * second is that, for values less than 1, a progressive logarithmic
     * offset is subtracted such that at 0 the returned result is also 0.
     *
     * @param val  value for which power of 10 should be calculated.
     *
     * @return An adjusted 10<sup>val</sup>.
     * 
     * @since 1.0.5
     * @see #adjustedLog10(double)
     */
    public double adjustedPow10(double val) {
        boolean negFlag = (val < 0.0);
        if (negFlag) {
            val = -val; // if negative then set flag and make positive
        }
        double res;
        if (val < 1.0) {
            res = (Math.pow(10, val + 1.0) - 10.0) / 9.0; //invert adjustLog10
        }
        else {
            res = Math.pow(10, val);            
        }
        return negFlag ? (-res) : res;
    }

    /**
     * Returns the largest (closest to positive infinity) double value that is
     * not greater than the argument, is equal to a mathematical integer and
     * satisfying the condition that log base 10 of the value is an integer
     * (i.e., the value returned will be a power of 10: 1, 10, 100, 1000, etc.).
     *
     * @param lower a double value below which a floor will be calcualted.
     *
     * @return 10<sup>N</sup> with N .. { 1 ... }
     */
    protected double computeLogFloor(double lower) {

        double logFloor;
        if (this.allowNegativesFlag) {
            //negative values are allowed
            if (lower > 10.0) {   //parameter value is > 10
                // The Math.log() function is based on e not 10.
                logFloor = Math.log(lower) / LOG10_VALUE;
                logFloor = Math.floor(logFloor);
                logFloor = Math.pow(10, logFloor);
            }
            else if (lower < -10.0) {   //parameter value is < -10
                //calculate log using positive value:
                logFloor = Math.log(-lower) / LOG10_VALUE;
                //calculate floor using negative value:
                logFloor = Math.floor(-logFloor);
                //calculate power using positive value; then negate
                logFloor = -Math.pow(10, -logFloor);
            }
            else {
                //parameter value is -10 > val < 10
                logFloor = Math.floor(lower);   //use as-is
            }
        }
        else {
            //negative values not allowed
            if (lower > 0.0) {   //parameter value is > 0
                // The Math.log() function is based on e not 10.
                logFloor = Math.log(lower) / LOG10_VALUE;
                logFloor = Math.floor(logFloor);
                logFloor = Math.pow(10, logFloor);
            }
            else {
                //parameter value is <= 0
                logFloor = Math.floor(lower);   //use as-is
            }
        }
        return logFloor;
    }

    /**
     * Returns the smallest (closest to negative infinity) double value that is
     * not less than the argument, is equal to a mathematical integer and
     * satisfying the condition that log base 10 of the value is an integer
     * (i.e., the value returned will be a power of 10: 1, 10, 100, 1000, etc.).
     *
     * @param upper a double value above which a ceiling will be calcualted.
     *
     * @return 10<sup>N</sup> with N .. { 1 ... }
     */
    protected double computeLogCeil(double upper) {

        double logCeil;
        if (this.allowNegativesFlag) {
            //negative values are allowed
            if (upper > 10.0) {
                //parameter value is > 10
                // The Math.log() function is based on e not 10.
                logCeil = Math.log(upper) / LOG10_VALUE;
                logCeil = Math.ceil(logCeil);
                logCeil = Math.pow(10, logCeil);
            }
            else if (upper < -10.0) {
                //parameter value is < -10
                //calculate log using positive value:
                logCeil = Math.log(-upper) / LOG10_VALUE;
                //calculate ceil using negative value:
                logCeil = Math.ceil(-logCeil);
                //calculate power using positive value; then negate
                logCeil = -Math.pow(10, -logCeil);
            }
            else {
               //parameter value is -10 > val < 10
               logCeil = Math.ceil(upper);     //use as-is
            }
        }
        else {
            //negative values not allowed
            if (upper > 0.0) {
                //parameter value is > 0
                // The Math.log() function is based on e not 10.
                logCeil = Math.log(upper) / LOG10_VALUE;
                logCeil = Math.ceil(logCeil);
                logCeil = Math.pow(10, logCeil);
            }
            else {
                //parameter value is <= 0
                logCeil = Math.ceil(upper);     //use as-is
            }
        }
        return logCeil;
    }

    /**
     * Rescales the axis to ensure that all data is visible.
     */
    public void autoAdjustRange() {

        Plot plot = getPlot();
        if (plot == null) {
            return;  // no plot, no data.
        }

        if (plot instanceof ValueAxisPlot) {
            ValueAxisPlot vap = (ValueAxisPlot) plot;

            double lower;
            Range r = vap.getDataRange(this);
            if (r == null) {
                   //no real data present
                r = getDefaultAutoRange();
                lower = r.getLowerBound();    //get lower bound value
            }
            else {
                //actual data is present
                lower = r.getLowerBound();    //get lower bound value
                if (this.strictValuesFlag
                        && !this.allowNegativesFlag && lower <= 0.0) {
                    //strict flag set, allow-negatives not set and values <= 0
                    throw new RuntimeException("Values less than or equal to "
                            + "zero not allowed with logarithmic axis");
                }
            }

            //apply lower margin by decreasing lower bound:
            final double lowerMargin;
            if (lower > 0.0 && (lowerMargin = getLowerMargin()) > 0.0) {
                   //lower bound and margin OK; get log10 of lower bound
                final double logLower = (Math.log(lower) / LOG10_VALUE);
                double logAbs;      //get absolute value of log10 value
                if ((logAbs = Math.abs(logLower)) < 1.0) {
                    logAbs = 1.0;     //if less than 1.0 then make it 1.0
                }              //subtract out margin and get exponential value:
                lower = Math.pow(10, (logLower - (logAbs * lowerMargin)));
            }