Apply rendering hints to overlay drawing - fixes bug #187

README.md

@@ -60,8 +60,9 @@ History
 -------
 
 ##### Version 1.5.2 (not yet released)
-- update French translations (https://github.com/jfree/jfreechart/pull/186);
-- fix "Save_as" entries in localisation files (https://github.com/jfree/jfreechart/pull/184).
+- apply rendering hints to overlays (bug #187);
+- update French translations (PR #186);
+- fix "Save_as" entries in localisation files (PR #184).
 
 ##### Version 1.5.1 (29 October 2020)
 - add DeviationStepRenderer (PR #173)

src/main/java/org/jfree/chart/ChartPanel.java

@@ -1626,6 +1626,7 @@ else if (drawHeight > this.maximumDrawHeight) {
 
             // zap the buffer onto the panel...
             g2.drawImage(this.chartBuffer, insets.left, insets.top, (int) available.getWidth(), (int) available.getHeight(), this);
+            g2.addRenderingHints(this.chart.getRenderingHints()); // bug#187
 
         } else { // redrawing the chart every time...
             AffineTransform saved = g2.getTransform();

src/main/java/org/jfree/chart/panel/CrosshairOverlay.java

@@ -2,7 +2,7 @@
  * JFreeChart : a free chart library for the Java(tm) platform
  * ===========================================================
  *
- * (C) Copyright 2000-2017, by Object Refinery Limited and Contributors.
+ * (C) Copyright 2000-2020, by Object Refinery Limited and Contributors.
  *
  * Project Info:  http://www.jfree.org/jfreechart/index.html
  *
@@ -27,7 +27,7 @@
  * ---------------------
  * CrosshairOverlay.java
  * ---------------------
- * (C) Copyright 2011-2017, by Object Refinery Limited.
+ * (C) Copyright 2011-2020, by Object Refinery Limited.
  *
  * Original Author:  David Gilbert (for Object Refinery Limited);
  * Contributor(s):   John Matthews;
@@ -88,16 +88,16 @@ public class CrosshairOverlay extends AbstractOverlay implements Overlay,
     private List<Crosshair> yCrosshairs;
 
     /**
-     * Default constructor.
+     * Creates a new overlay that initially contains no crosshairs.
      */
     public CrosshairOverlay() {
         super();
-        this.xCrosshairs = new java.util.ArrayList<Crosshair>();
-        this.yCrosshairs = new java.util.ArrayList<Crosshair>();
+        this.xCrosshairs = new ArrayList<>();
+        this.yCrosshairs = new ArrayList<>();
     }
 
     /**
-     * Adds a crosshair against the domain axis and sends an
+     * Adds a crosshair against the domain axis (x-axis) and sends an
      * {@link OverlayChangeEvent} to all registered listeners.
      *
      * @param crosshair  the crosshair ({@code null} not permitted).
@@ -130,14 +130,14 @@ public void removeDomainCrosshair(Crosshair crosshair) {
 
     /**
      * Clears all the domain crosshairs from the overlay and sends an
-     * {@link OverlayChangeEvent} to all registered listeners.
+     * {@link OverlayChangeEvent} to all registered listeners (unless there
+     * were no crosshairs to begin with).
      */
     public void clearDomainCrosshairs() {
         if (this.xCrosshairs.isEmpty()) {
-            return;  // nothing to do
+            return;  // nothing to do - avoids firing change event
         }
-        List<Crosshair> crosshairs = getDomainCrosshairs();
-        for (Crosshair c : crosshairs) {
+        for (Crosshair c : getDomainCrosshairs()) {
             this.xCrosshairs.remove(c);
             c.removePropertyChangeListener(this);
         }
@@ -150,7 +150,7 @@ public void clearDomainCrosshairs() {
      * @return A list of crosshairs.
      */
     public List<Crosshair> getDomainCrosshairs() {
-        return new ArrayList<Crosshair>(this.xCrosshairs);
+        return new ArrayList<>(this.xCrosshairs);
     }
 
     /**
@@ -184,14 +184,14 @@ public void removeRangeCrosshair(Crosshair crosshair) {
 
     /**
      * Clears all the range crosshairs from the overlay and sends an
-     * {@link OverlayChangeEvent} to all registered listeners.
+     * {@link OverlayChangeEvent} to all registered listeners (unless there
+     * were no crosshairs to begin with).
      */
     public void clearRangeCrosshairs() {
         if (this.yCrosshairs.isEmpty()) {
-            return;  // nothing to do
+            return;  // nothing to do - avoids change notification
         }
-        List<Crosshair> crosshairs = getRangeCrosshairs();
-        for (Crosshair c : crosshairs) {
+        for (Crosshair c : getRangeCrosshairs()) {
             this.yCrosshairs.remove(c);
             c.removePropertyChangeListener(this);
         }
@@ -204,7 +204,7 @@ public void clearRangeCrosshairs() {
      * @return A list of crosshairs.
      */
     public List<Crosshair> getRangeCrosshairs() {
-        return new ArrayList<Crosshair>(this.yCrosshairs);
+        return new ArrayList<>(this.yCrosshairs);
     }
 
     /**
@@ -219,7 +219,10 @@ public void propertyChange(PropertyChangeEvent e) {
     }
 
     /**
-     * Paints the crosshairs in the layer.
+     * Renders the crosshairs in the overlay on top of the chart that has just
+     * been rendered in the specified {@code chartPanel}.  This method is
+     * called by the JFreeChart framework, you won't normally call it from
+     * user code.
      *
      * @param g2  the graphics target.
      * @param chartPanel  the chart panel.
@@ -233,32 +236,26 @@ public void paintOverlay(Graphics2D g2, ChartPanel chartPanel) {
         XYPlot plot = (XYPlot) chart.getPlot();
         ValueAxis xAxis = plot.getDomainAxis();
         RectangleEdge xAxisEdge = plot.getDomainAxisEdge();
-        Iterator<Crosshair> iterator = this.xCrosshairs.iterator();
-        while (iterator.hasNext()) {
-            Crosshair ch = iterator.next();
+        for (Crosshair ch : this.xCrosshairs) {
             if (ch.isVisible()) {
                 double x = ch.getValue();
                 double xx = xAxis.valueToJava2D(x, dataArea, xAxisEdge);
                 if (plot.getOrientation() == PlotOrientation.VERTICAL) {
                     drawVerticalCrosshair(g2, dataArea, xx, ch);
-                }
-                else {
+                } else {
                     drawHorizontalCrosshair(g2, dataArea, xx, ch);
                 }
             }
         }
         ValueAxis yAxis = plot.getRangeAxis();
         RectangleEdge yAxisEdge = plot.getRangeAxisEdge();
-        iterator = this.yCrosshairs.iterator();
-        while (iterator.hasNext()) {
-            Crosshair ch = iterator.next();
+        for (Crosshair ch : this.yCrosshairs) {
             if (ch.isVisible()) {
                 double y = ch.getValue();
                 double yy = yAxis.valueToJava2D(y, dataArea, yAxisEdge);
                 if (plot.getOrientation() == PlotOrientation.VERTICAL) {
                     drawHorizontalCrosshair(g2, dataArea, yy, ch);
-                }
-                else {
+                } else {
                     drawVerticalCrosshair(g2, dataArea, yy, ch);
                 }
             }