--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/artifacts/src/main/java/org/dive4elements/river/jfree/CollisionFreeXYTextAnnotation.java	Thu Apr 25 15:23:37 2013 +0200
@@ -0,0 +1,140 @@
+package org.dive4elements.river.jfree;
+
+import java.awt.Shape;
+import java.awt.geom.Rectangle2D;
+
+import org.jfree.chart.entity.EntityCollection;
+import org.jfree.chart.annotations.XYTextAnnotation;
+import org.jfree.chart.axis.ValueAxis;
+import org.jfree.chart.plot.PlotOrientation;
+import org.jfree.chart.plot.XYPlot;
+import org.jfree.chart.entity.XYAnnotationEntity;
+import org.jfree.chart.plot.PlotRenderingInfo;
+import org.jfree.chart.plot.Plot;
+
+import org.jfree.text.TextUtilities;
+
+import org.jfree.ui.RectangleEdge;
+
+/**
+ * Custom Annotations class that is drawn only if no collisions with other
+ * already drawn CustomAnnotations in current plot are found.
+ */
+public class CollisionFreeXYTextAnnotation extends XYTextAnnotation {
+
+    public CollisionFreeXYTextAnnotation(String text, double x, double y) {
+        super(text, x, y);
+    }
+
+
+    /**
+     * Draw the Annotation only if it does not collide with other
+     * already drawn Annotations- texts.
+     *
+     * @param g2            the graphics device.
+     * @param plot          the plot.
+     * @param dataArea      the data area.
+     * @param domainAxis    the domain axis.
+     * @param rangeAxis     the range axis.
+     * @param rendererIndex the render index.
+     * @param info          state information, escpecially collects info about
+     *                      already drawn shapes (and thus annotations), used
+     *                      for collision detection.
+     */
+    @Override
+    public void draw(
+        java.awt.Graphics2D g2,
+        XYPlot plot,
+        java.awt.geom.Rectangle2D dataArea,
+        ValueAxis domainAxis,
+        ValueAxis rangeAxis,
+        int rendererIndex,
+        PlotRenderingInfo info
+    ) {
+        // From superclass, adjusted access only.
+        PlotOrientation orientation = plot.getOrientation();
+        RectangleEdge domainEdge = Plot.resolveDomainAxisLocation(
+                plot.getDomainAxisLocation(), orientation);
+        RectangleEdge rangeEdge = Plot.resolveRangeAxisLocation(
+                plot.getRangeAxisLocation(), orientation);
+
+        float anchorX = (float) domainAxis.valueToJava2D(
+                this.getX(), dataArea, domainEdge);
+        float anchorY = (float) rangeAxis.valueToJava2D(
+                this.getY(), dataArea, rangeEdge);
+
+        if (orientation == PlotOrientation.HORIZONTAL) {
+            float tempAnchor = anchorX;
+            anchorX = anchorY;
+            anchorY = tempAnchor;
+        }
+
+        g2.setFont(getFont());
+        Shape hotspot = TextUtilities.calculateRotatedStringBounds(
+                getText(), g2, anchorX, anchorY, getTextAnchor(),
+                getRotationAngle(), getRotationAnchor());
+
+        // Deviation from superclass: prevent collision.
+        if (JFreeUtil.collides(hotspot, info.getOwner().getEntityCollection(),
+            XYAnnotationEntity.class)) {
+            return;
+        }
+
+        if (this.getBackgroundPaint() != null) {
+            g2.setPaint(this.getBackgroundPaint());
+            g2.fill(hotspot);
+        }
+        g2.setPaint(getPaint());
+        TextUtilities.drawRotatedString(getText(), g2, anchorX, anchorY,
+                getTextAnchor(), getRotationAngle(), getRotationAnchor());
+        if (this.isOutlineVisible()) {
+            g2.setStroke(this.getOutlineStroke());
+            g2.setPaint(this.getOutlinePaint());
+            g2.draw(hotspot);
+        }
+
+        //String toolTip = getToolTipText();
+        //String url = getURL();
+        String toolTip = "CollisionFreeXYTextAnnotation";
+        String url     = toolTip;
+
+        if (toolTip != null || url != null) {
+            addEntity(info, hotspot, rendererIndex, toolTip, url);
+        }
+        // XXX: DEAD CODE (as long as a hard value is assigned to toolTip
+        /*
+        else {
+            addEntity(info, hotspot, rendererIndex,
+                "CollisionFreeXYTextAnnotation",
+                "CollisionFreeXYTextAnnotation");
+        }
+        */
+    }
+
+    /**
+     * A utility method for adding an {@link CollisionFreeXYAnnotationEntity} to
+     * a {@link PlotRenderingInfo} instance.
+     *
+     * @param info  the plot rendering info (<code>null</code> permitted).
+     * @param hotspot  the hotspot area.
+     * @param rendererIndex  the renderer index.
+     * @param toolTipText  the tool tip text.
+     * @param urlText  the URL text.
+     */
+    protected void addEntity(PlotRenderingInfo info,
+                             Shape hotspot, int rendererIndex,
+                             String toolTipText, String urlText) {
+        if (info == null) {
+            return;
+        }
+        EntityCollection entities = info.getOwner().getEntityCollection();
+        if (entities == null) {
+            return;
+        }
+        CollisionFreeXYTextAnnotationEntity entity =
+            new CollisionFreeXYTextAnnotationEntity(hotspot,
+                rendererIndex, toolTipText, urlText);
+        entities.add(entity);
+    }
+}
+// vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :