logarithmicaxis.html

jfreechart1。0。2的api。

<FONT color="green">270</FONT>         * log axis processing.<a name="line.270"></a>
<FONT color="green">271</FONT>         *<a name="line.271"></a>
<FONT color="green">272</FONT>         * @param range  the new range.<a name="line.272"></a>
<FONT color="green">273</FONT>         */<a name="line.273"></a>
<FONT color="green">274</FONT>        public void setRange(Range range) {<a name="line.274"></a>
<FONT color="green">275</FONT>            super.setRange(range);      // call parent method<a name="line.275"></a>
<FONT color="green">276</FONT>            setupSmallLogFlag();        // setup flag based on bounds values<a name="line.276"></a>
<FONT color="green">277</FONT>        }<a name="line.277"></a>
<FONT color="green">278</FONT>    <a name="line.278"></a>
<FONT color="green">279</FONT>        /**<a name="line.279"></a>
<FONT color="green">280</FONT>         * Sets up flag for log axis processing.  Set true if negative values<a name="line.280"></a>
<FONT color="green">281</FONT>         * not allowed and the lower bound is between 0 and 10.<a name="line.281"></a>
<FONT color="green">282</FONT>         */<a name="line.282"></a>
<FONT color="green">283</FONT>        protected void setupSmallLogFlag() {<a name="line.283"></a>
<FONT color="green">284</FONT>            // set flag true if negative values not allowed and the<a name="line.284"></a>
<FONT color="green">285</FONT>            // lower bound is between 0 and 10:<a name="line.285"></a>
<FONT color="green">286</FONT>            double lowerVal = getRange().getLowerBound();<a name="line.286"></a>
<FONT color="green">287</FONT>            this.smallLogFlag<a name="line.287"></a>
<FONT color="green">288</FONT>                = (!this.allowNegativesFlag &amp;&amp; lowerVal &lt; 10.0 &amp;&amp; lowerVal &gt; 0.0);<a name="line.288"></a>
<FONT color="green">289</FONT>        }<a name="line.289"></a>
<FONT color="green">290</FONT>    <a name="line.290"></a>
<FONT color="green">291</FONT>        /**<a name="line.291"></a>
<FONT color="green">292</FONT>         * Sets up the number formatter object according to the<a name="line.292"></a>
<FONT color="green">293</FONT>         * 'expTickLabelsFlag' flag.<a name="line.293"></a>
<FONT color="green">294</FONT>         */<a name="line.294"></a>
<FONT color="green">295</FONT>        protected void setupNumberFmtObj() {<a name="line.295"></a>
<FONT color="green">296</FONT>            if (this.numberFormatterObj instanceof DecimalFormat) {<a name="line.296"></a>
<FONT color="green">297</FONT>                //setup for "1e#"-style tick labels or regular<a name="line.297"></a>
<FONT color="green">298</FONT>                // numeric tick labels, depending on flag:<a name="line.298"></a>
<FONT color="green">299</FONT>                ((DecimalFormat) this.numberFormatterObj).applyPattern(<a name="line.299"></a>
<FONT color="green">300</FONT>                    this.expTickLabelsFlag ? "0E0" : "0.###"<a name="line.300"></a>
<FONT color="green">301</FONT>                );<a name="line.301"></a>
<FONT color="green">302</FONT>            }<a name="line.302"></a>
<FONT color="green">303</FONT>        }<a name="line.303"></a>
<FONT color="green">304</FONT>    <a name="line.304"></a>
<FONT color="green">305</FONT>        /**<a name="line.305"></a>
<FONT color="green">306</FONT>         * Returns the log10 value, depending on if values between 0 and<a name="line.306"></a>
<FONT color="green">307</FONT>         * 1 are being plotted.  If negative values are not allowed and<a name="line.307"></a>
<FONT color="green">308</FONT>         * the lower bound is between 0 and 10 then a normal log is<a name="line.308"></a>
<FONT color="green">309</FONT>         * returned; otherwise the returned value is adjusted if the<a name="line.309"></a>
<FONT color="green">310</FONT>         * given value is less than 10.<a name="line.310"></a>
<FONT color="green">311</FONT>         *<a name="line.311"></a>
<FONT color="green">312</FONT>         * @param val the value.<a name="line.312"></a>
<FONT color="green">313</FONT>         *<a name="line.313"></a>
<FONT color="green">314</FONT>         * @return log&lt;sub&gt;10&lt;/sub&gt;(val).<a name="line.314"></a>
<FONT color="green">315</FONT>         */<a name="line.315"></a>
<FONT color="green">316</FONT>        protected double switchedLog10(double val) {<a name="line.316"></a>
<FONT color="green">317</FONT>            return this.smallLogFlag ? Math.log(val)<a name="line.317"></a>
<FONT color="green">318</FONT>                    / LOG10_VALUE : adjustedLog10(val);<a name="line.318"></a>
<FONT color="green">319</FONT>        }<a name="line.319"></a>
<FONT color="green">320</FONT>    <a name="line.320"></a>
<FONT color="green">321</FONT>        /**<a name="line.321"></a>
<FONT color="green">322</FONT>         * Returns an adjusted log10 value for graphing purposes.  The first<a name="line.322"></a>
<FONT color="green">323</FONT>         * adjustment is that negative values are changed to positive during<a name="line.323"></a>
<FONT color="green">324</FONT>         * the calculations, and then the answer is negated at the end.  The<a name="line.324"></a>
<FONT color="green">325</FONT>         * second is that, for values less than 10, an increasingly large<a name="line.325"></a>
<FONT color="green">326</FONT>         * (0 to 1) scaling factor is added such that at 0 the value is<a name="line.326"></a>
<FONT color="green">327</FONT>         * adjusted to 1, resulting in a returned result of 0.<a name="line.327"></a>
<FONT color="green">328</FONT>         *<a name="line.328"></a>
<FONT color="green">329</FONT>         * @param val  value for which log10 should be calculated.<a name="line.329"></a>
<FONT color="green">330</FONT>         *<a name="line.330"></a>
<FONT color="green">331</FONT>         * @return An adjusted log&lt;sub&gt;10&lt;/sub&gt;(val).<a name="line.331"></a>
<FONT color="green">332</FONT>         */<a name="line.332"></a>
<FONT color="green">333</FONT>        public double adjustedLog10(double val) {<a name="line.333"></a>
<FONT color="green">334</FONT>            boolean negFlag = (val &lt; 0.0);<a name="line.334"></a>
<FONT color="green">335</FONT>            if (negFlag) {<a name="line.335"></a>
<FONT color="green">336</FONT>                val = -val;          // if negative then set flag and make positive<a name="line.336"></a>
<FONT color="green">337</FONT>            }<a name="line.337"></a>
<FONT color="green">338</FONT>            if (val &lt; 10.0) {                // if &lt; 10 then<a name="line.338"></a>
<FONT color="green">339</FONT>                val += (10.0 - val) / 10;    //increase so 0 translates to 0<a name="line.339"></a>
<FONT color="green">340</FONT>            }<a name="line.340"></a>
<FONT color="green">341</FONT>            //return value; negate if original value was negative:<a name="line.341"></a>
<FONT color="green">342</FONT>            return negFlag ? -(Math.log(val) / LOG10_VALUE)<a name="line.342"></a>
<FONT color="green">343</FONT>                    : (Math.log(val) / LOG10_VALUE);<a name="line.343"></a>
<FONT color="green">344</FONT>        }<a name="line.344"></a>
<FONT color="green">345</FONT>    <a name="line.345"></a>
<FONT color="green">346</FONT>        /**<a name="line.346"></a>
<FONT color="green">347</FONT>         * Returns the largest (closest to positive infinity) double value that is<a name="line.347"></a>
<FONT color="green">348</FONT>         * not greater than the argument, is equal to a mathematical integer and<a name="line.348"></a>
<FONT color="green">349</FONT>         * satisfying the condition that log base 10 of the value is an integer<a name="line.349"></a>
<FONT color="green">350</FONT>         * (i.e., the value returned will be a power of 10: 1, 10, 100, 1000, etc.).<a name="line.350"></a>
<FONT color="green">351</FONT>         *<a name="line.351"></a>
<FONT color="green">352</FONT>         * @param lower a double value below which a floor will be calcualted.<a name="line.352"></a>
<FONT color="green">353</FONT>         *<a name="line.353"></a>
<FONT color="green">354</FONT>         * @return 10&lt;sup&gt;N&lt;/sup&gt; with N .. { 1 ... }<a name="line.354"></a>
<FONT color="green">355</FONT>         */<a name="line.355"></a>
<FONT color="green">356</FONT>        protected double computeLogFloor(double lower) {<a name="line.356"></a>
<FONT color="green">357</FONT>    <a name="line.357"></a>
<FONT color="green">358</FONT>            double logFloor;<a name="line.358"></a>
<FONT color="green">359</FONT>            if (this.allowNegativesFlag) {<a name="line.359"></a>
<FONT color="green">360</FONT>                //negative values are allowed<a name="line.360"></a>
<FONT color="green">361</FONT>                if (lower &gt; 10.0) {   //parameter value is &gt; 10<a name="line.361"></a>
<FONT color="green">362</FONT>                    // The Math.log() function is based on e not 10.<a name="line.362"></a>
<FONT color="green">363</FONT>                    logFloor = Math.log(lower) / LOG10_VALUE;<a name="line.363"></a>
<FONT color="green">364</FONT>                    logFloor = Math.floor(logFloor);<a name="line.364"></a>
<FONT color="green">365</FONT>                    logFloor = Math.pow(10, logFloor);<a name="line.365"></a>
<FONT color="green">366</FONT>                }<a name="line.366"></a>
<FONT color="green">367</FONT>                else if (lower &lt; -10.0) {   //parameter value is &lt; -10<a name="line.367"></a>
<FONT color="green">368</FONT>                    //calculate log using positive value:<a name="line.368"></a>
<FONT color="green">369</FONT>                    logFloor = Math.log(-lower) / LOG10_VALUE;<a name="line.369"></a>
<FONT color="green">370</FONT>                    //calculate floor using negative value:<a name="line.370"></a>
<FONT color="green">371</FONT>                    logFloor = Math.floor(-logFloor);<a name="line.371"></a>
<FONT color="green">372</FONT>                    //calculate power using positive value; then negate<a name="line.372"></a>
<FONT color="green">373</FONT>                    logFloor = -Math.pow(10, -logFloor);<a name="line.373"></a>
<FONT color="green">374</FONT>                }<a name="line.374"></a>
<FONT color="green">375</FONT>                else {<a name="line.375"></a>
<FONT color="green">376</FONT>                    //parameter value is -10 &gt; val &lt; 10<a name="line.376"></a>
<FONT color="green">377</FONT>                    logFloor = Math.floor(lower);   //use as-is<a name="line.377"></a>
<FONT color="green">378</FONT>                }<a name="line.378"></a>
<FONT color="green">379</FONT>            }<a name="line.379"></a>
<FONT color="green">380</FONT>            else {<a name="line.380"></a>
<FONT color="green">381</FONT>                //negative values not allowed<a name="line.381"></a>
<FONT color="green">382</FONT>                if (lower &gt; 0.0) {   //parameter value is &gt; 0<a name="line.382"></a>
<FONT color="green">383</FONT>                    // The Math.log() function is based on e not 10.<a name="line.383"></a>
<FONT color="green">384</FONT>                    logFloor = Math.log(lower) / LOG10_VALUE;<a name="line.384"></a>
<FONT color="green">385</FONT>                    logFloor = Math.floor(logFloor);<a name="line.385"></a>
<FONT color="green">386</FONT>                    logFloor = Math.pow(10, logFloor);<a name="line.386"></a>
<FONT color="green">387</FONT>                }<a name="line.387"></a>
<FONT color="green">388</FONT>                else {<a name="line.388"></a>
<FONT color="green">389</FONT>                    //parameter value is &lt;= 0<a name="line.389"></a>
<FONT color="green">390</FONT>                    logFloor = Math.floor(lower);   //use as-is<a name="line.390"></a>
<FONT color="green">391</FONT>                }<a name="line.391"></a>
<FONT color="green">392</FONT>            }<a name="line.392"></a>
<FONT color="green">393</FONT>            return logFloor;<a name="line.393"></a>
<FONT color="green">394</FONT>        }<a name="line.394"></a>
<FONT color="green">395</FONT>    <a name="line.395"></a>
<FONT color="green">396</FONT>        /**<a name="line.396"></a>
<FONT color="green">397</FONT>         * Returns the smallest (closest to negative infinity) double value that is<a name="line.397"></a>
<FONT color="green">398</FONT>         * not less than the argument, is equal to a mathematical integer and<a name="line.398"></a>
<FONT color="green">399</FONT>         * satisfying the condition that log base 10 of the value is an integer<a name="line.399"></a>
<FONT color="green">400</FONT>         * (i.e., the value returned will be a power of 10: 1, 10, 100, 1000, etc.).<a name="line.400"></a>
<FONT color="green">401</FONT>         *<a name="line.401"></a>
<FONT color="green">402</FONT>         * @param upper a double value above which a ceiling will be calcualted.<a name="line.402"></a>
<FONT color="green">403</FONT>         *<a name="line.403"></a>
<FONT color="green">404</FONT>         * @return 10&lt;sup&gt;N&lt;/sup&gt; with N .. { 1 ... }<a name="line.404"></a>
<FONT color="green">405</FONT>         */<a name="line.405"></a>