1 files changed, 132 insertions, 0 deletions
diff --git a/src/jcgp/gui/dragresize/VerticalDragResize.java b/src/jcgp/gui/dragresize/VerticalDragResize.java
new file mode 100644
index 0000000..4f784e5
--- /dev/null
+++ b/src/jcgp/gui/dragresize/VerticalDragResize.java
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+package jcgp.gui.dragresize;
+
+import javafx.event.EventHandler;
+import javafx.scene.Cursor;
+import javafx.scene.input.MouseEvent;
+import javafx.scene.layout.Region;
+import jcgp.gui.constants.Constants;
+
+/**
+ * This class adds vertical drag resize functionality to any 
+ * arbitrary region provided. This is done by using the static
+ * method {@code makeDragResizable()}.
+ * <br><br>
+ * This is based on a class by Andrew Till found on:
+ * http://andrewtill.blogspot.co.uk/2012/12/dragging-to-resize-javafx-region.html
+ * 
+ */
+public class VerticalDragResize {
+	
+	private boolean dragging = false;
+	private final Region region;
+	
+	/**
+	 * For internal use only, creates an instance of the actual
+	 * resizer used.
+	 * 
+	 * @param region the region to make resizable.
+	 */
+	private VerticalDragResize(Region region) {
+		this.region = region;
+	}
+	
+	/**
+	 * Makes the specified region drag resizable.
+	 * This particular implementation only creates a resize 
+	 * click-and-drag area on the top side of the region. 
+	 * The resize area is defined by {@code GUI.RESIZE_MARGIN}.
+	 * 
+	 * @param region the region to make resizable.
+	 */
+	public static void makeDragResizable(final Region region) {
+		// make the instance, this actually performs the resizing
+		final VerticalDragResize dr = new VerticalDragResize(region);
+
+		// set mouse listeners
+		region.setOnMousePressed(new EventHandler<MouseEvent>() {
+			@Override
+			public void handle(MouseEvent event) {
+		        dr.mousePressed(event);
+			}
+		});
+		region.setOnMouseDragged(new EventHandler<MouseEvent>() {
+			@Override
+			public void handle(MouseEvent event) {
+				dr.mouseDragged(event);
+			}
+		});
+		region.setOnMouseMoved(new EventHandler<MouseEvent>() {
+			@Override
+			public void handle(MouseEvent event) {
+				dr.mouseMoved(event);
+			}
+		});
+		region.setOnMouseReleased(new EventHandler<MouseEvent>() {
+			@Override
+			public void handle(MouseEvent event) {
+				dr.mouseReleased();
+			}
+		});
+		
+	}
+	
+	/**
+	 * If the press happened in the resize area, raise the drag flag.
+	 * 
+	 * @param event the associated mouse event.
+	 */
+	private void mousePressed(MouseEvent event) {
+		if(isInDraggableZone(event)) {
+	        dragging = true;
+        }
+	}
+
+	/**
+	 * If drag flag is high, resize the region to match the mouse position.
+	 * 
+	 * @param event the associated mouse event.
+	 */
+	private void mouseDragged(MouseEvent event) {
+		if(dragging) {
+			double newHeight = region.getHeight() - event.getY();
+			if (newHeight >= region.getMinHeight()) {
+				region.setPrefHeight(newHeight);
+			} else {
+				region.setPrefHeight(region.getMinHeight());
+			}
+		}
+	}
+	
+	/**
+	 * Change the cursor if the mouse position overlaps with the resize area.
+	 * 
+	 * @param event the associated mouse event.
+	 */
+	private void mouseMoved(MouseEvent event) {
+		if(isInDraggableZone(event) || dragging) {
+			region.setCursor(Cursor.V_RESIZE);
+        }
+        else {
+        	region.setCursor(Cursor.DEFAULT);
+        }
+	}
+
+	/**
+	 * Finish resizing.
+	 */
+	private void mouseReleased() {
+		dragging = false;
+		region.setCursor(Cursor.DEFAULT);
+	}
+
+	/**
+	 * Assert whether the mouse cursor is in the draggable area defined by {@code GUI.RESIZE_MARGIN}.
+	 * 
+	 * @param event the associated mouse event.
+	 * @return true if the mouse position is in the draggable area.
+	 */
+	private boolean isInDraggableZone(MouseEvent event) {
+		return event.getY() < (Constants.RESIZE_MARGIN);
+	}
+
+}