Repository: knowm/XChart (java)

Issue:
Reset Boom button is not displayed
@timmolter 
The first time you select the area, there is a match to the data, the Reset Boom button is displayed, and the map is redrawn; the area is selected again, the data is not matched, and the Reset button button disappears.
Looked at the source code, the selection area does not match the data, directly return false (causing the Reset button button will disappear), xData, yData, extraValues is the last data.

Source code, AxesChartSeriesNumericalNoErrorBars.filterXByValue() method:
```java
     If (remainingDataCount == length) {
       Return false;
     }
     If (remainingDataCount == 0) {
       Return false;
     }
```
Can it be changed to true here?
```java
     If (remainingDataCount == length) {
       Return false;
     }
     If (remainingDataCount == 0) {
       Return true;
     }
```



Pull request description:
Reset Zoom Button bug
Fixes #357 

The problem was when the zoom filters all data points. When no data remains AxisTickCalculator either hangs while trying to find tick places or throws an exception. I fixed both Number and Date tick calculators for such a case.

Added a new class TestForIssue349.java to fix issue #349. But my I could not reproduce the bug.



Patch:
diff --git a/xchart/src/main/java/org/knowm/xchart/internal/chartpart/AxisTickCalculator_Date.java b/xchart/src/main/java/org/knowm/xchart/internal/chartpart/AxisTickCalculator_Date.java
index 25f59b6c..ed18969b 100644
--- a/xchart/src/main/java/org/knowm/xchart/internal/chartpart/AxisTickCalculator_Date.java
+++ b/xchart/src/main/java/org/knowm/xchart/internal/chartpart/AxisTickCalculator_Date.java
@@ -113,6 +113,22 @@ class AxisTickCalculator_Date extends AxisTickCalculator_ {
       // System.out.println("Returning!");
       return;
     }
+    
+    // minValue & maxValue is not set
+    if (minValue > maxValue && minValue == Double.MAX_VALUE) {
+      String datePattern = timeSpans.get(0).getDatePattern();
+      if (styler.getDatePattern() != null) {
+        datePattern = styler.getDatePattern();
+      }
+
+      SimpleDateFormat simpleDateformat = new SimpleDateFormat(datePattern, styler.getLocale());
+      simpleDateformat.setTimeZone(styler.getTimezone());
+      axisFormat = simpleDateformat;
+
+      tickLabels.add(axisFormat.format(0.0));
+      tickLocations.add(workingSpace / 2.0);
+      return;
+    }
 
     // where the tick should begin in the working space in pixels
     double margin =
diff --git a/xchart/src/main/java/org/knowm/xchart/internal/chartpart/AxisTickCalculator_Number.java b/xchart/src/main/java/org/knowm/xchart/internal/chartpart/AxisTickCalculator_Number.java
index ee1939a7..c8df85e5 100644
--- a/xchart/src/main/java/org/knowm/xchart/internal/chartpart/AxisTickCalculator_Number.java
+++ b/xchart/src/main/java/org/knowm/xchart/internal/chartpart/AxisTickCalculator_Number.java
@@ -48,6 +48,13 @@ class AxisTickCalculator_Number extends AxisTickCalculator_ {
       return;
     }
 
+    // a check for no data
+    if (minValue > maxValue && minValue == Double.MAX_VALUE) {
+      tickLabels.add(numberFormatter.format(0.0));
+      tickLocations.add(workingSpace / 2.0);
+      return;
+    }
+
     // tick space - a percentage of the working space available for ticks
     double tickSpace = styler.getPlotContentSize() * workingSpace; // in plot space
 
diff --git a/xchart/src/main/java/org/knowm/xchart/internal/chartpart/components/ChartButton.java b/xchart/src/main/java/org/knowm/xchart/internal/chartpart/components/ChartButton.java
index f8ec6d93..fcaba6a4 100644
--- a/xchart/src/main/java/org/knowm/xchart/internal/chartpart/components/ChartButton.java
+++ b/xchart/src/main/java/org/knowm/xchart/internal/chartpart/components/ChartButton.java
@@ -352,4 +352,8 @@ public class ChartButton extends MouseAdapter implements ChartPart {
 
     this.yOffset = yOffset;
   }
+
+  public void setPosition(LegendPosition position) {
+    this.position = position;
+  }
 }
diff --git a/xchart/src/main/java/org/knowm/xchart/internal/series/AxesChartSeriesNumericalNoErrorBars.java b/xchart/src/main/java/org/knowm/xchart/internal/series/AxesChartSeriesNumericalNoErrorBars.java
index 2eebda43..fecf0f6f 100644
--- a/xchart/src/main/java/org/knowm/xchart/internal/series/AxesChartSeriesNumericalNoErrorBars.java
+++ b/xchart/src/main/java/org/knowm/xchart/internal/series/AxesChartSeriesNumericalNoErrorBars.java
@@ -109,12 +109,10 @@ public abstract class AxesChartSeriesNumericalNoErrorBars extends MarkerSeries {
       }
     }
 
+    // System.out.println("Filtering between " + String.format("%.2f %.2f", minValue, maxValue) + " all: " + length + " rem: " + remainingDataCount);
     if (remainingDataCount == length) {
       return false;
     }
-    if (remainingDataCount == 0) {
-      return false;
-    }
 
     xData = new double[remainingDataCount];
     yData = new double[remainingDataCount];


Test patch:
diff --git a/xchart-demo/src/main/java/org/knowm/xchart/standalone/issues/TestForIssue349.java b/xchart-demo/src/main/java/org/knowm/xchart/standalone/issues/TestForIssue349.java
new file mode 100644
index 00000000..a19e7013
--- /dev/null
+++ b/xchart-demo/src/main/java/org/knowm/xchart/standalone/issues/TestForIssue349.java
@@ -0,0 +1,77 @@
+package org.knowm.xchart.standalone.issues;
+
+import java.lang.reflect.InvocationTargetException;
+import java.util.Arrays;
+import java.util.List;
+
+import javax.swing.JFrame;
+import javax.swing.WindowConstants;
+
+import org.knowm.xchart.XChartPanel;
+import org.knowm.xchart.XYChart;
+import org.knowm.xchart.XYChartBuilder;
+import org.knowm.xchart.demo.charts.ExampleChart;
+import org.knowm.xchart.internal.chartpart.SelectionZoom;
+import org.knowm.xchart.style.Styler.LegendPosition;
+
+public class TestForIssue349 implements ExampleChart<XYChart> {
+
+  public static void main(String[] args) {
+
+    ExampleChart<XYChart> exampleChart = new TestForIssue349();
+    XYChart chart = exampleChart.getChart();
+    XChartPanel chartPanel = new XChartPanel(chart);
+    SelectionZoom sz = new SelectionZoom();
+    sz.getResetButton().setPosition(LegendPosition.InsideNW);
+    sz.init(chartPanel);
+
+    // Create and set up the window.
+    final JFrame frame = new JFrame("TestForIssue349");
+
+    // Schedule a job for the event-dispatching thread:
+    // creating and showing this application's GUI.
+    try {
+      javax.swing.SwingUtilities.invokeAndWait(
+          new Runnable() {
+
+            @Override
+            public void run() {
+
+              frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
+              frame.add(chartPanel);
+
+              // Display the window.
+              frame.pack();
+              frame.setVisible(true);
+            }
+          });
+    } catch (InterruptedException e) {
+      e.printStackTrace();
+    } catch (InvocationTargetException e) {
+      e.printStackTrace();
+    }
+  }
+
+  @Override
+  public XYChart getChart() {
+
+    // Create Chart
+    XYChart chart = new XYChartBuilder().width(800).height(600).build();
+
+    // Customize Chart
+    chart.getStyler().setChartTitleVisible(false);
+    chart.getStyler().setLegendVisible(false);
+
+    List<Integer> xData = Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
+    List<Double> yData = Arrays.asList(1.1, 2.2, 7.3, 8.4, 4.5, 6.6, 2.7, 6.8, 4.9, 3.10);
+
+    List<Double> xData2 = Arrays.asList(4.5, 6.5, 7.5);
+    List<Double> yData2 = Arrays.asList(3.4, 5.6, 3.7);
+
+    // Series
+    chart.addSeries("1", xData, yData);
+    chart.addSeries("2", xData2, yData2);
+
+    return chart;
+  }
+}
diff --git a/xchart-demo/src/main/java/org/knowm/xchart/standalone/issues/TestForSelectionZoom.java b/xchart-demo/src/main/java/org/knowm/xchart/standalone/issues/TestForSelectionZoom.java
index 3512bfed..61e8b308 100644
--- a/xchart-demo/src/main/java/org/knowm/xchart/standalone/issues/TestForSelectionZoom.java
+++ b/xchart-demo/src/main/java/org/knowm/xchart/standalone/issues/TestForSelectionZoom.java
@@ -9,6 +9,7 @@ import org.knowm.xchart.demo.ExampleChartTester;
 import org.knowm.xchart.demo.charts.ExampleChart;
 import org.knowm.xchart.internal.chartpart.Chart;
 import org.knowm.xchart.internal.chartpart.SelectionZoom;
+import org.knowm.xchart.style.Styler.LegendPosition;
 
 public class TestForSelectionZoom {
 
@@ -33,6 +34,7 @@ public class TestForSelectionZoom {
               XChartPanel chartPanel = new XChartPanel(chart);
               if (chart instanceof XYChart) {
                 SelectionZoom sz = new SelectionZoom();
+                sz.getResetButton().setPosition(LegendPosition.InsideNW);
                 sz.init(chartPanel);
               }
               tabbedPane.addTab(e.getKey(), chartPanel);