Prevent repeated y-axis values by controlling granularity

MPChartExample/src/com/xxmassdeveloper/mpchartexample/LineChartActivity2.java

@@ -114,6 +114,7 @@ public class LineChartActivity2 extends DemoBase implements OnSeekBarChangeListe
         leftAxis.setAxisMaxValue(200f);
         leftAxis.setAxisMinValue(0f);
         leftAxis.setDrawGridLines(true);
+        leftAxis.setGranularityEnabled(true);
 
         YAxis rightAxis = mChart.getAxisRight();
         rightAxis.setTypeface(tf);
@@ -122,6 +123,7 @@ public class LineChartActivity2 extends DemoBase implements OnSeekBarChangeListe
         rightAxis.setAxisMinValue(-200);
         rightAxis.setDrawGridLines(false);
         rightAxis.setDrawZeroLine(false);
+        rightAxis.setGranularityEnabled(false);
     }
 
     @Override

MPChartLib/src/com/github/mikephil/charting/components/YAxis.java

@@ -123,6 +123,19 @@ public class YAxis extends AxisBase {
      */
     private AxisDependency mAxisDependency;
 
+    /**
+     * When true, axis labels are controlled by the `granularity` property.
+     * When false, axis values could possibly be repeated.
+     * This could happen if two adjacent axis values are rounded to same value.
+     * If using granularity this could be avoided by having fewer axis values visible.
+     */
+    protected boolean mGranularityEnabled = true;
+
+    /**
+     * the minimum interval between axis values
+     */
+    protected float mGranularity = 1.0f;
+
     /**
      * Enum that specifies the axis a DataSet should be plotted against, either LEFT or RIGHT.
      *
@@ -148,6 +161,36 @@ public class YAxis extends AxisBase {
         return mAxisDependency;
     }
 
+    /**
+     * @return true if granularity is enabled
+     */
+    public boolean isGranularityEnabled() {
+        return mGranularityEnabled;
+    }
+
+    /**
+     * Enabled/disable granularity control on axis value intervals
+     * @param enabled
+     */
+    public void setGranularityEnabled(boolean enabled) {
+        mGranularityEnabled = true;
+    }
+
+    /**
+     * @return the minimum interval between axis values
+     */
+    public float getGranularity() {
+        return mGranularity;
+    }
+
+    /**
+     * set the minimum interval between axis values
+     * @param granularity
+     */
+    public void setGranularity(float granularity) {
+        mGranularity = granularity;
+    }
+
     /**
      * returns the position of the y-labels
      */

MPChartLib/src/com/github/mikephil/charting/renderer/YAxisRenderer.java

@@ -85,8 +85,16 @@ public class YAxisRenderer extends AxisRenderer {
             return;
         }
 
+        // Find out how much spacing (in y value space) between axis values
         double rawInterval = range / labelCount;
         double interval = Utils.roundToNextSignificant(rawInterval);
+
+        // If granularity is enabled, then do not allow the interval to go below specified granularity.
+        // This is used to avoid repeated values when rounding values for display.
+        if (mYAxis.isGranularityEnabled())
+            interval = interval < mYAxis.getGranularity() ? mYAxis.getGranularity() : interval;
+
+        // Normalize interval
         double intervalMagnitude = Math.pow(10, (int) Math.log10(interval));
         int intervalSigDigit = (int) (interval / intervalMagnitude);
         if (intervalSigDigit > 5) {