fix for issue #582

xchart-demo/src/main/java/org/knowm/xchart/standalone/issues/TestForIssue582.java

@@ -0,0 +1,54 @@
+package org.knowm.xchart.standalone.issues;
+
+import org.knowm.xchart.SwingWrapper;
+import org.knowm.xchart.XYChart;
+import org.knowm.xchart.XYChartBuilder;
+
+import java.text.DecimalFormatSymbols;
+import java.text.ParseException;
+import java.util.Locale;
+
+public class TestForIssue582 {
+
+    public static void main(String[] args) throws ParseException {
+
+        XYChart chart = getXYChart();
+        new SwingWrapper(chart).displayChart();
+    }
+
+    public static XYChart getXYChart() {
+        XYChart chart = new XYChartBuilder()
+                .width(720)
+                .height(480)
+                .title("Deadlock Example")
+                .xAxisTitle("Count")
+                .yAxisTitle("Value")
+                .build();
+
+        // If the decimal places in the pattern is fewer than the largest data value, the deadlock occurs.
+//        chart.getStyler().setDecimalPattern("#0.0000");
+//        chart.getStyler().setDecimalPattern("#,###.00");
+
+//        chart.getStyler().setDecimalPattern("$ #0.00");
+//        chart.getStyler().setDecimalPattern("$ #0.000");
+
+        chart.getStyler().setLocale(Locale.ITALIAN);
+        chart.getStyler().setDecimalPattern("#0.000");
+
+        double[] xValues = new double[]{1, 2, 3, 4, 5, 6, 7, 8};
+
+        // The only value here is 0.001 which is one decimal place below the pattern.
+      double[] yValues =  new double[] { 0.0, 0.0, 0.0, 0.0, 0.001, 0.0, 0.0, 0.0};
+//      double[] yValues =  new double[] { 0.0, 0.0, 0.0, 0.0, -0.001, 0.0, 0.0, 0.0};
+//      double[] yValues =  new double[] { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0};
+//      double[] yValues =  new double[] { 0.0001, 0.0, 0.0, 0.0, -0.001, 0.0, 0.0, 0.0};
+//      double[] yValues =  new double[] { -0.0002, -0.0002, -0.0002, -0.0002, -0.001, -0.0002, -0.0002, -0.0002};
+//        double[] yValues = new double[]{0.0002, 0.0002, 0.0002, 0.0002, 0.0001, 0.0002, 0.0002, 0.0002};
+//        double[] yValues =  new double[] { 20.0002, 20.0002, 20.0002, 20.0002, 20.001, 20.0002, 20.0002, 20.0002};
+
+        chart.addSeries("main", xValues, yValues);
+
+
+        return chart;
+    }
+}

xchart/src/main/java/org/knowm/xchart/XYChart.java

@@ -39,7 +39,7 @@ public XYChart(int width, int height) {
    *
    * @param width
    * @param height
-   * @param theme - pass in a instance of Theme class, probably a custom Theme.
+   * @param theme - pass in an instance of Theme class, probably a custom Theme.
    */
   public XYChart(int width, int height, Theme theme) {
 

xchart/src/main/java/org/knowm/xchart/internal/chartpart/AxisTickCalculator_.java

@@ -8,7 +8,7 @@
 import java.math.BigDecimal;
 import java.math.MathContext;
 import java.math.RoundingMode;
-import java.text.Format;
+import java.text.*;
 import java.util.*;
 import java.util.List;
 import java.util.stream.Collectors;
@@ -161,6 +161,8 @@ public Format getAxisFormat() {
 
   protected void calculate() {
 
+       // System.out.println("calculate");
+
     // a check if all axis data are the exact same values
     if (minValue == maxValue) {
       tickLabels.add(getAxisFormat().format(BigDecimal.valueOf(maxValue).doubleValue()));
@@ -186,7 +188,14 @@ protected void calculate() {
       return;
     }
 
-    // where the tick should begin in the working space in pixels
+      // this prevents an infinite loop when the axis number formatter "rounds" all axis ticks to the same value i.e. "#0.00" for 0.0, 0.0001, 0.0002
+      // issue #582
+      if(isNumberFormatChoppingDecimals(maxValue, minValue)){
+          System.out.println("returning");
+          return;
+      }
+
+      // where the tick should begin in the working space in pixels
     double margin =
         Utils.getTickStartOffset(
             workingSpace,
@@ -216,7 +225,7 @@ protected void calculate() {
 
     do {
 
-      // System.out.println("calculating ticks...");
+//       System.out.println("calculating ticks...");
       tickLabels.clear();
       tickLocations.clear();
 
@@ -342,6 +351,7 @@ protected void calculate() {
       }
     } while (!areAllTickLabelsUnique(tickLabels)
         || !willLabelsFitInTickSpaceHint(tickLabels, gridStepInChartSpace));
+
   }
 
   private boolean areValuesEquallySpaced(List<Double> values) {
@@ -452,4 +462,19 @@ private static double getAxisMaxValue(
       return 0;
     return dataMaxValue;
   }
+
+    private boolean isNumberFormatChoppingDecimals(double axisMax, double axisMin){
+
+//        System.out.println("axisMax = " + axisMax);
+//        System.out.println("axisMin = " + axisMin);
+        String formattedMaxValue = getAxisFormat().format(axisMax);
+//        System.out.println("formattedMaxValue = " + formattedMaxValue);
+        String formattedMinValue = getAxisFormat().format(axisMin);
+//        System.out.println("formattedMinValue = " + formattedMinValue);
+        // if formatted number lost its decimals due to formatter
+        if(formattedMaxValue.equals(formattedMinValue)){
+            return true;
+        }
+            return false;
+    }
 }