finished new and improved auto-decimal fomatter

xchart-demo/src/main/java/com/xeiam/xchart/demo/charts/scatter/ScatterChart01.java

@@ -33,6 +33,7 @@ import com.xeiam.xchart.demo.charts.ExampleChart;
  * <li>ChartType.Scatter
  * <li>Series data as a Set
  * <li>Setting marker size
+ * <li>Formatting of negative numbers with large magnitude but small differences
  */
 public class ScatterChart01 implements ExampleChart {
 
@@ -52,7 +53,7 @@ public class ScatterChart01 implements ExampleChart {
     int size = 1000;
     for (int i = 0; i < size; i++) {
       xData.add(random.nextGaussian());
-      yData.add(random.nextGaussian());
+      yData.add(-100 + random.nextGaussian());
     }
 
     // Create Chart

xchart-demo/src/main/java/com/xeiam/xchart/demo/charts/scatter/ScatterChart02.java

@@ -33,6 +33,7 @@ import com.xeiam.xchart.demo.charts.ExampleChart;
  * <li>Scatter chart
  * <li>Logarithmic X-Axis
  * <li>Place legend at Inside-NW position
+ * <li>Formatting of number with large magnitude but small differences
  * 
  * @author timmolter
  */

xchart/src/main/java/com/xeiam/xchart/StyleManager.java

@@ -1097,9 +1097,9 @@ public class StyleManager {
    * 
    * @param pattern - the pattern describing the decimal format
    */
-  public void setDecimalPattern(String normalDecimalPattern) {
+  public void setDecimalPattern(String decimalPattern) {
 
-    this.decimalPattern = normalDecimalPattern;
+    this.decimalPattern = decimalPattern;
   }
 
   public String getDecimalPattern() {

xchart/src/main/java/com/xeiam/xchart/internal/chartpart/AxisTickBarChartCalculator.java

@@ -108,8 +108,6 @@ public class AxisTickBarChartCalculator extends AxisTickCalculator {
       NumberFormatter numberFormatter = null;
       DateFormatter dateFormatter = null;
 
-      String pattern = numberFormatter.getFormatPattern(minValue, maxValue);
-
       if (chartPainter.getAxisPair().getXAxis().getAxisType() == AxisType.Number) {
         numberFormatter = new NumberFormatter(styleManager);
       }
@@ -120,7 +118,7 @@ public class AxisTickBarChartCalculator extends AxisTickCalculator {
 
       for (Object category : categories) {
         if (chartPainter.getAxisPair().getXAxis().getAxisType() == AxisType.Number) {
-          tickLabels.add(numberFormatter.formatNumber((Double) category, pattern));
+          tickLabels.add(numberFormatter.formatNumber((Double) category, minValue, maxValue));
         }
         else if (chartPainter.getAxisPair().getXAxis().getAxisType() == AxisType.Date) {
           long span = (long) Math.abs(maxValue - minValue); // in data space
@@ -141,8 +139,6 @@ public class AxisTickBarChartCalculator extends AxisTickCalculator {
       NumberFormatter numberFormatter = null;
       DateFormatter dateFormatter = null;
 
-      String pattern = numberFormatter.getFormatPattern(minValue, maxValue);
-
       if (chartPainter.getAxisPair().getXAxis().getAxisType() == AxisType.Number) {
         numberFormatter = new NumberFormatter(styleManager);
       }
@@ -153,7 +149,7 @@ public class AxisTickBarChartCalculator extends AxisTickCalculator {
       for (double tickPosition = firstPosition; tickPosition <= maxValue; tickPosition = tickPosition + gridStep) {
 
         if (chartPainter.getAxisPair().getXAxis().getAxisType() == AxisType.Number) {
-          tickLabels.add(numberFormatter.formatNumber(tickPosition, pattern));
+          tickLabels.add(numberFormatter.formatNumber(tickPosition, minValue, maxValue));
         }
         else if (chartPainter.getAxisPair().getXAxis().getAxisType() == AxisType.Date) {
           long span = (long) Math.abs(maxValue - minValue); // in data space

xchart/src/main/java/com/xeiam/xchart/internal/chartpart/AxisTickLogarithmicCalculator.java

@@ -46,11 +46,9 @@ public class AxisTickLogarithmicCalculator extends AxisTickCalculator {
 
   private void calculate() {
 
-    String pattern = numberFormatter.getFormatPattern(minValue, maxValue);
-
     // a check if all axis data are the exact same values
     if (minValue == maxValue) {
-      tickLabels.add(numberFormatter.formatNumber(maxValue, pattern));
+      tickLabels.add(numberFormatter.formatNumber(maxValue, minValue, maxValue));
       tickLocations.add(workingSpace / 2.0);
       return;
     }
@@ -113,7 +111,7 @@ public class AxisTickLogarithmicCalculator extends AxisTickCalculator {
 
         // only add labels for the decades
         if (Math.abs(Math.log10(j) % 1) < 0.00000001) {
-          tickLabels.add(numberFormatter.formatNumber(j, pattern));
+          tickLabels.add(numberFormatter.formatLogNumber(j));
         }
         else {
           tickLabels.add(null);

xchart/src/main/java/com/xeiam/xchart/internal/chartpart/AxisTickNumericalCalculator.java

@@ -48,11 +48,9 @@ public class AxisTickNumericalCalculator extends AxisTickCalculator {
 
   private void calculate() {
 
-    String pattern = numberFormatter.getFormatPattern(minValue, maxValue);
-
     // a check if all axis data are the exact same values
     if (minValue == maxValue) {
-      tickLabels.add(numberFormatter.formatNumber(maxValue, pattern));
+      tickLabels.add(numberFormatter.formatNumber(maxValue, minValue, maxValue));
       tickLocations.add(workingSpace / 2.0);
       return;
     }
@@ -69,7 +67,7 @@ public class AxisTickNumericalCalculator extends AxisTickCalculator {
     // generate all tickLabels and tickLocations from the first to last position
     for (BigDecimal tickPosition = firstPosition; tickPosition.compareTo(BigDecimal.valueOf(maxValue + gridStep.doubleValue() * 0.2)) <= 0; tickPosition = tickPosition.add(gridStep)) {
 
-      tickLabels.add(numberFormatter.formatNumber(tickPosition.doubleValue(), pattern));
+      tickLabels.add(numberFormatter.formatNumber(tickPosition.doubleValue(), minValue, maxValue));
       // here we convert tickPosition finally to plot space, i.e. pixels
       double tickLabelPosition = margin + ((tickPosition.doubleValue() - minValue) / (maxValue - minValue) * tickSpace);
       tickLocations.add(tickLabelPosition);

xchart/src/main/java/com/xeiam/xchart/internal/chartpart/NumberFormatter.java

@@ -35,36 +35,43 @@ public class NumberFormatter {
     this.styleManager = styleManager;
   }
 
-  public String getFormatPattern(double min, double max) {
+  public String getFormatPattern(double value, double min, double max) {
 
+    System.out.println("value: " + value);
     System.out.println("min: " + min);
     System.out.println("max: " + max);
 
     double difference = max - min;
-    int placeOfDifference = (int) Math.floor(Math.log(difference) / Math.log(10)) + 1;
-    int placeOfSmallest = (int) Math.floor(Math.log(Math.min(Math.abs(min), Math.abs(max))) / Math.log(10)) + 1;
+    int placeOfDifference;
+    if (difference == 0.0) {
+      placeOfDifference = 0;
+    }
+    else {
+      placeOfDifference = (int) Math.floor(Math.log(difference) / Math.log(10));
+    }
+    int placeOfValue = (int) Math.floor(Math.log(value) / Math.log(10));
 
     System.out.println("difference: " + difference);
     System.out.println("placeOfDifference: " + placeOfDifference);
-    System.out.println("placeOfSmallest: " + placeOfSmallest);
+    System.out.println("placeOfValue: " + placeOfValue);
 
     if (placeOfDifference <= 4 && placeOfDifference >= -4) {
       System.out.println("getNormalDecimalPattern");
-      return getNormalDecimalPattern(placeOfSmallest, placeOfDifference);
+      return getNormalDecimalPattern(placeOfValue, placeOfDifference);
     }
     else {
       System.out.println("getScientificDecimalPattern");
-      return getScientificDecimalPattern(placeOfSmallest, placeOfDifference);
+      return getScientificDecimalPattern(placeOfValue, placeOfDifference);
     }
   }
 
-  private String getNormalDecimalPattern(int placeOfMin, int placeOfDifference) {
+  private String getNormalDecimalPattern(int placeOfValue, int placeOfDifference) {
 
     int maxNumPlaces = 15;
     StringBuilder sb = new StringBuilder();
     for (int i = maxNumPlaces - 1; i >= -1 * maxNumPlaces; i--) {
 
-      if (i < placeOfMin && i >= placeOfDifference - 2) {
+      if (i < placeOfValue && i >= placeOfDifference) {
         sb.append("0");
       }
       else {
@@ -81,10 +88,10 @@ public class NumberFormatter {
     return sb.toString();
   }
 
-  private String getScientificDecimalPattern(int placeOfMin, int placeOfDifference) {
+  private String getScientificDecimalPattern(int placeOfValue, int placeOfDifference) {
 
     StringBuilder sb = new StringBuilder();
-    for (int i = placeOfMin; i >= 0; i--) {
+    for (int i = placeOfValue; i >= 0; i--) {
       sb.append("0");
       if (i == placeOfDifference) {
         sb.append(".");
@@ -101,12 +108,48 @@ public class NumberFormatter {
    * @param value
    * @return
    */
-  public String formatNumber(double value, String pattern) {
+  public String formatNumber(double value, double min, double max) {
+
+    NumberFormat numberFormat = NumberFormat.getNumberInstance(styleManager.getLocale());
+
+    String decimalPattern;
+
+    if (styleManager.getDatePattern() == null) {
+
+      decimalPattern = getFormatPattern(value, min, max);
+    }
+    else {
+      decimalPattern = styleManager.getDecimalPattern();
+    }
+
+    DecimalFormat normalFormat = (DecimalFormat) numberFormat;
+    normalFormat.applyPattern(decimalPattern);
+    return normalFormat.format(value);
+
+  }
+
+  /**
+   * Format a log number value for log Axes which show only decade tick labels. if the override patterns are null, it uses defaults
+   * 
+   * @param value
+   * @return
+   */
+  public String formatLogNumber(double value) {
 
     NumberFormat numberFormat = NumberFormat.getNumberInstance(styleManager.getLocale());
 
+    String decimalPattern;
+
+    if (styleManager.getDatePattern() == null) {
+
+      decimalPattern = "0E0";
+    }
+    else {
+      decimalPattern = styleManager.getDatePattern();
+    }
+
     DecimalFormat normalFormat = (DecimalFormat) numberFormat;
-    normalFormat.applyPattern(styleManager.getDecimalPattern() == null ? pattern : styleManager.getDecimalPattern());
+    normalFormat.applyPattern(decimalPattern);
     return normalFormat.format(value);
 
   }

xchart/src/test/java/com/xeiam/xchart/NumberFormatterTest2.java

-/**
- * Copyright 2011 - 2014 Xeiam LLC.
- *
- * 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.
- */
-package com.xeiam.xchart;
-
-import static org.hamcrest.CoreMatchers.equalTo;
-import static org.hamcrest.MatcherAssert.assertThat;
-
-import org.junit.Test;
-
-import com.xeiam.xchart.internal.chartpart.NumberFormatter;
-
-/**
- * @author timmolter
- */
-public class NumberFormatterTest2 {
-
-  @Test
-  public void testNumberFormatting() {
-
-    StyleManager styleManager = new StyleManager();
-    NumberFormatter numberFormatter = new NumberFormatter(styleManager);
-
-    String pattern = numberFormatter.getFormatPattern(1000000, 1000010);
-    System.out.println(pattern);
-    assertThat(pattern, equalTo("00000.00E0"));
-  }
-
-}