fix overlapping x axis ticks

Gnuplot does not handle long x-axis ticks very good.
It should know how wide the labels are and could adapt
the increment size accordingly, but it doesn't.
Fixed by explicitly defining the increment for x-axis
labels.

pdb-plotting/src/main/java/org/lucares/recommind/logs/GnuplotFileGenerator.java

@@ -24,9 +24,10 @@ public class GnuplotFileGenerator {
 		final XAxisSettings xAxis = settings.getxAxisSettings();
 		if (xAxis.isxDataTime()) {
 			appendfln(result, "set xdata time");
+			appendln(result, XAxisTimeTicks.computeXTimeIncrements(settings));
+			appendfln(result, "set format x \"%s\"", xAxis.getFormatX());
 		}
 		appendfln(result, "set xtics nomirror rotate by %d", xAxis.getRotateXAxisLabel());
-		appendfln(result, "set format x \"%s\"", xAxis.getFormatX());
 		appendfln(result, "set xlabel \"%s\"", xAxis.getXlabel());
 		appendfln(result, "set xrange [\"%s\":\"%s\"]", xAxis.getFrom(), xAxis.getTo());
 
@@ -76,10 +77,10 @@ public class GnuplotFileGenerator {
 			appendln(result, "set tmargin 3"); // margin 3 -> 57px - marker (1)
 			appendln(result, "set bmargin 4"); // margin 4 -> 76
 
-			appendfln(result, "set tics font \",%d\"", YAxisTicks.TICKS_FONT_SIZE);
+			appendfln(result, "set tics font \",%d\"", GnuplotSettings.TICKS_FONT_SIZE);
 			appendln(result, YAxisTicks.computeYTicks(settings, dataSeries));
 		} else {
-			appendfln(result, "set tics font \",%d\"", YAxisTicks.TICKS_FONT_SIZE);
+			appendfln(result, "set tics font \",%d\"", GnuplotSettings.TICKS_FONT_SIZE);
 			appendln(result, YAxisTicks.computeYTicks(settings, dataSeries));
 		}
 

pdb-plotting/src/main/java/org/lucares/recommind/logs/GnuplotSettings.java

@@ -13,6 +13,7 @@ public class GnuplotSettings {
 	public final static int GNUPLOT_BOTTOM_MARGIN = 76; // The bottom margin configured for gnuplot
 	public final static int GNUPLOT_TOP_BOTTOM_MARGIN = GNUPLOT_TOP_MARGIN + GNUPLOT_BOTTOM_MARGIN;
 	public final static int GNUPLOT_LEFT_RIGHT_MARGIN = GNUPLOT_LEFT_MARGIN+GNUPLOT_RIGHT_MARGIN;
+	public static final int TICKS_FONT_SIZE = 12;
 
 	private String terminal = "png";
 	private int height = 1200;

pdb-plotting/src/main/java/org/lucares/recommind/logs/Plotter.java

@@ -185,6 +185,7 @@ public class Plotter {
     gnuplotSettings.getxAxisSettings().setRotateXAxisLabel(rotateX);
     gnuplotSettings.getxAxisSettings().setFrom(formattedMinDate);
     gnuplotSettings.getxAxisSettings().setTo(formattedMaxDate);
+    gnuplotSettings.getxAxisSettings().setDateTimeRange(dateTimeRange);
   }
 
   private static CsvSummary toCsvDeduplicated(final GroupResult groupResult, final Path tmpDir,

pdb-plotting/src/main/java/org/lucares/recommind/logs/XAxisSettings.java

@@ -1,76 +1,86 @@
 package org.lucares.recommind.logs;
 
+import org.lucares.pdb.api.DateTimeRange;
+
 public class XAxisSettings {
 
-	// set xdata time
+  // set xdata time
-	private boolean xDataTime = true;
+  private boolean xDataTime = true;
-	
-	// set format for x-axis
-	private String formatX = "%Y-%m-%d\\n%H:%M:%S";
 
-	// set xlabel
+  // set format for x-axis
-	private String xlabel = "Time";
+  private String formatX = "%Y-%m-%d\\n%H:%M:%S";
 
-	// set xtics rotation in degree
+  // set xlabel
-	private int rotateXAxisLabel = 0;
+  private String xlabel = "Time";
 
-	private String from;
+  // set xtics rotation in degree
-	private String to;
+  private int rotateXAxisLabel = 0;
 
-	public boolean isxDataTime() {
+  private String from;
-		return xDataTime;
+  private String to;
-	}
 
-	public void setxDataTime(boolean xDataTime) {
+  private DateTimeRange dateTimeRange;
-		this.xDataTime = xDataTime;
-	}
 
-	public String getFormatX() {
+  public boolean isxDataTime() {
-		return formatX;
+    return xDataTime;
-	}
+  }
 
-	public void setFormatX(String formatX) {
+  public void setxDataTime(boolean xDataTime) {
-		this.formatX = formatX;
+    this.xDataTime = xDataTime;
-	}
+  }
 
-	public String getXlabel() {
+  public String getFormatX() {
-		return xlabel;
+    return formatX;
-	}
+  }
 
-	public void setXlabel(String xlabel) {
+  public void setFormatX(String formatX) {
-		this.xlabel = xlabel;
+    this.formatX = formatX;
-	}
+  }
 
-	public int getRotateXAxisLabel() {
+  public String getXlabel() {
-		return rotateXAxisLabel;
+    return xlabel;
-	}
+  }
 
-	public void setRotateXAxisLabel(int rotateXAxisLabel) {
+  public void setXlabel(String xlabel) {
-		this.rotateXAxisLabel = rotateXAxisLabel;
+    this.xlabel = xlabel;
-	}
+  }
 
-	public String getFrom() {
+  public int getRotateXAxisLabel() {
-		return from;
+    return rotateXAxisLabel;
-	}
+  }
 
-	public void setFrom(String from) {
+  public void setRotateXAxisLabel(int rotateXAxisLabel) {
-		this.from = from;
+    this.rotateXAxisLabel = rotateXAxisLabel;
-	}
+  }
 
-	public String getTo() {
+  public String getFrom() {
-		return to;
+    return from;
-	}
+  }
 
-	public void setTo(String to) {
+  public void setFrom(String from) {
-		this.to = to;
+    this.from = from;
-	}
+  }
 
-	@Override
+  public String getTo() {
-	public String toString() {
+    return to;
-		return "XAxisSettings [xDataTime=" + xDataTime + ", formatX=" + formatX
+  }
-				+ ", xlabel=" + xlabel + ", rotateXAxisLabel="
+
-				+ rotateXAxisLabel + ", from=" + from + ", to=" + to + "]";
+  public void setTo(String to) {
-	}
+    this.to = to;
+  }
+
+  public void setDateTimeRange(DateTimeRange dateTimeRange) {
+    this.dateTimeRange = dateTimeRange;
+  }
+
+  public DateTimeRange getDateTimeRange() {
+    return dateTimeRange;
+  }
+
+  @Override
+  public String toString() {
+    return "XAxisSettings [xDataTime=" + xDataTime + ", formatX=" + formatX + ", xlabel=" + xlabel
+        + ", rotateXAxisLabel=" + rotateXAxisLabel + ", from=" + from + ", to=" + to + ", dateTimeRange="+dateTimeRange+"]";
+  }
 
-	
 }

pdb-plotting/src/main/java/org/lucares/recommind/logs/XAxisTimeTicks.java

@@ -0,0 +1,76 @@
+package org.lucares.recommind.logs;
+
+import java.util.concurrent.TimeUnit;
+
+import org.lucares.collections.LongList;
+import org.lucares.pdb.api.DateTimeRange;
+
+public class XAxisTimeTicks {
+   
+  
+  public static String computeXTimeIncrements(GnuplotSettings settings) {
+
+    DateTimeRange dateTimeRange = settings.getxAxisSettings().getDateTimeRange();
+    final long startEpochMilli = dateTimeRange.getStartEpochMilli();
+    final long endEpochMilli = dateTimeRange.getEndEpochMilli();
+    final long rangeInMs = endEpochMilli - startEpochMilli + 1;
+    
+    int widthInPx = settings.getWidth() - GnuplotSettings.GNUPLOT_LEFT_RIGHT_MARGIN;
+    
+    final long maxLabels = widthInPx / (GnuplotSettings.TICKS_FONT_SIZE * 8);
+
+    final long tickIncrement = roundToTickIncrement(rangeInMs / maxLabels);
+    
+    return "set xtics "+ tickIncrement/1000.0;
+  }
+  
+  private static long roundToTickIncrement(long milliseconds) {
+    LongList increments = LongList.of(
+        100,
+        200,
+        500,
+        TimeUnit.SECONDS.toMillis(1),
+        TimeUnit.SECONDS.toMillis(2),
+        TimeUnit.SECONDS.toMillis(5),
+        TimeUnit.SECONDS.toMillis(10),
+        TimeUnit.SECONDS.toMillis(15),
+        TimeUnit.SECONDS.toMillis(30),
+        TimeUnit.MINUTES.toMillis(1),
+        TimeUnit.MINUTES.toMillis(2),
+        TimeUnit.MINUTES.toMillis(5),
+        TimeUnit.MINUTES.toMillis(10),
+        TimeUnit.MINUTES.toMillis(15),
+        TimeUnit.MINUTES.toMillis(30),
+        TimeUnit.HOURS.toMillis(1),
+        TimeUnit.HOURS.toMillis(2),
+        TimeUnit.HOURS.toMillis(3),
+        TimeUnit.HOURS.toMillis(6),
+        TimeUnit.HOURS.toMillis(12),
+        TimeUnit.HOURS.toMillis(18),
+        TimeUnit.DAYS.toMillis(1),
+        TimeUnit.DAYS.toMillis(2),
+        TimeUnit.DAYS.toMillis(3),
+        TimeUnit.DAYS.toMillis(4),
+        TimeUnit.DAYS.toMillis(5),
+        TimeUnit.DAYS.toMillis(6),
+        TimeUnit.DAYS.toMillis(7),
+        TimeUnit.DAYS.toMillis(14),
+        TimeUnit.DAYS.toMillis(30),
+        TimeUnit.DAYS.toMillis(90),
+        TimeUnit.DAYS.toMillis(180),
+        TimeUnit.DAYS.toMillis(365),
+        TimeUnit.DAYS.toMillis(365*2),
+        TimeUnit.DAYS.toMillis(365*5),
+        TimeUnit.DAYS.toMillis(365*10),
+        TimeUnit.DAYS.toMillis(365*20)
+        );
+    
+    for ( int i = 0; i < increments.size(); i++) {
+      if (increments.get(i) > milliseconds) {
+        return increments.get(i);
+      }
+    }
+    
+    return TimeUnit.DAYS.toMillis(365*10);
+  }
+}

pdb-plotting/src/main/java/org/lucares/recommind/logs/YAxisTicks.java

@@ -13,7 +13,6 @@ import java.util.concurrent.TimeUnit;
 
 class YAxisTicks {
   
-  static final int TICKS_FONT_SIZE = 12;
   
   public static String computeYTicks(final GnuplotSettings settings, final Collection<DataSeries> dataSeries) {
     String result = "";
@@ -91,7 +90,7 @@ private static String computeLinearYTicks(final long height, final long yRangeMi
 
     final long plotHeight = height - GnuplotSettings.GNUPLOT_TOP_BOTTOM_MARGIN; // sum of top/bottom margin, see
                                                                                 // marker (1)
-    final long maxLabels = plotHeight / (TICKS_FONT_SIZE * 5);
+    final long maxLabels = plotHeight / (GnuplotSettings.TICKS_FONT_SIZE * 5);
 
     final long range = yRangeMax - yRangeMin;
     final long msPerLabel = roundToLinearLabelSteps(range / maxLabels);