Moved constants to a separate file, added a formal README

17 files changed, 207 insertions, 155 deletions

diff --git a/README.txt b/README.txt
new file mode 100644
index 0000000..fcb802f
--- /dev/null
+++ b/README.txt
@@ -0,0 +1 @@
+write this
diff --git a/src/jcgp/gui/GUI.java b/src/jcgp/gui/GUI.java
index 8735ccd..d99bfbc 100644
--- a/src/jcgp/gui/GUI.java
+++ b/src/jcgp/gui/GUI.java
@@ -46,63 +46,6 @@ import jcgp.gui.settings.SettingsPane;
  *
  */
 public class GUI extends Application {
-	
-	/* Colours */
-	/**
-	 * A string containing the hexadecimal colour used for representing neutrality.
-	 */
-	public static final String NEUTRAL_COLOUR = "#FFFFFF";
-	/**
-	 * A string containing the hexadecimal colour used for representing a hard highlight.
-	 * A "hard" select, for instance, happens when an output path is locked on the chromosome
-	 * pane.
-	 */
-	public static final String HARD_HIGHLIGHT_COLOUR = "#5496FF";
-	/**
-	 * A string containing the hexadecimal colour used for a medium highlight.
-	 * One example of such a selection is the colour applied to a node
-	 * when it is hovered over.
-	 */
-	public static final String MEDIUM_HIGHLIGHT_COLOUR = "#75BAFF";
-	/**
-	 * A string containing the hexadecimal colour used for a soft highlight.
-	 * When hovering over a node, its connections are soft-selected.
-	 */
-	public static final String SOFT_HIGHLIGHT_COLOUR = "#C7DFFF";
-	
-	/**
-	 * A string containing the hexadecimal colour used for representing a good selection.
-	 * Ideally a shade of green, used for instance when a manual connection is valid.
-	 */
-	public static final String GOOD_SELECTION_COLOUR = "#38C25B";
-	/**
-	 * A string containing the hexadecimal colour used for representing a neutral selection.
-	 * Ideally a shade of yellow, used for instance when a manual connection is already the
-	 * current connection.
-	 */
-	public static final String NEUTRAL_SELECTION_COLOUR = "#FFEF73";
-	/**
-	 * A string containing the hexadecimal colour used for representing a bad selection.
-	 * Ideally a shade of red, use for instance when a manual connection is not valid.
-	 */
-	public static final String BAD_SELECTION_COLOUR = "#FF5C5C";
-	
-	/* Sizes and distances */
-	/**
-	 * The width or height of the area that can be clicked on
-	 * to drag-resize a pane.
-	 */
-    public static final double RESIZE_MARGIN = 5.0;
-    /**
-	 * The minimum width of the settings pane, to prevent it
-	 * from being resized beyond visibility.
-	 */
-    public static final double SETTINGS_MIN_WIDTH = 200;
-    /**
-	 * The minimum width of the console pane, to prevent it
-	 * from being resized beyond visibility.
-	 */
-    public static final double CONSOLE_MIN_HEIGHT = 100;
     
 	/*
 	 * Actual GUI elements
diff --git a/src/jcgp/gui/console/ConsolePane.java b/src/jcgp/gui/console/ConsolePane.java
index 1e07b7d..de193a5 100644
--- a/src/jcgp/gui/console/ConsolePane.java
+++ b/src/jcgp/gui/console/ConsolePane.java
@@ -13,7 +13,7 @@ import javafx.scene.input.MouseButton;
 import javafx.scene.input.MouseEvent;
 import javafx.scene.layout.AnchorPane;
 import jcgp.backend.resources.Console;
-import jcgp.gui.GUI;
+import jcgp.gui.constants.Constants;
 
 /**
  * Console pane used by the GUI to display CGP output messages.
@@ -92,13 +92,13 @@ public class ConsolePane extends AnchorPane implements Console {
 												clearConsole));
 		
 		// anchor the text area so it resizes automatically
-		AnchorPane.setTopAnchor(textArea, GUI.RESIZE_MARGIN);
+		AnchorPane.setTopAnchor(textArea, Constants.RESIZE_MARGIN);
 		AnchorPane.setBottomAnchor(textArea, 0.0);
 		AnchorPane.setRightAnchor(textArea, 0.0);
 		AnchorPane.setLeftAnchor(textArea, 0.0);
 		
-		setMinHeight(GUI.CONSOLE_MIN_HEIGHT);
-		setPrefHeight(GUI.CONSOLE_MIN_HEIGHT);
+		setMinHeight(Constants.CONSOLE_MIN_HEIGHT);
+		setPrefHeight(Constants.CONSOLE_MIN_HEIGHT);
 		
 		getChildren().add(textArea);
 	}
diff --git a/src/jcgp/gui/constants/Constants.java b/src/jcgp/gui/constants/Constants.java
new file mode 100644
index 0000000..350f8b1
--- /dev/null
+++ b/src/jcgp/gui/constants/Constants.java
@@ -0,0 +1,116 @@
+package jcgp.gui.constants;
+
+/**
+ * Holds the constants used in the GUI.
+ * 
+ * @author Eduardo Pedroni
+ *
+ */
+public abstract class Constants {
+
+	/* Colours */
+	/**
+	 * A string containing the hexadecimal colour used for representing neutrality.
+	 */
+	public static final String NEUTRAL_COLOUR = "#FFFFFF";
+	/**
+	 * A string containing the hexadecimal colour used for representing a hard highlight.
+	 * A "hard" select, for instance, happens when an output path is locked on the chromosome
+	 * pane.
+	 */
+	public static final String HARD_HIGHLIGHT_COLOUR = "#5496FF";
+	/**
+	 * A string containing the hexadecimal colour used for a medium highlight.
+	 * One example of such a selection is the colour applied to a node
+	 * when it is hovered over.
+	 */
+	public static final String MEDIUM_HIGHLIGHT_COLOUR = "#75BAFF";
+	/**
+	 * A string containing the hexadecimal colour used for a soft highlight.
+	 * When hovering over a node, its connections are soft-selected.
+	 */
+	public static final String SOFT_HIGHLIGHT_COLOUR = "#C7DFFF";
+	/**
+	 * A string containing the hexadecimal colour used for representing a good selection.
+	 * Ideally a shade of green, used for instance when a manual connection is valid.
+	 */
+	public static final String GOOD_SELECTION_COLOUR = "#38C25B";
+	/**
+	 * A string containing the hexadecimal colour used for representing a neutral selection.
+	 * Ideally a shade of yellow, used for instance when a manual connection is already the
+	 * current connection.
+	 */
+	public static final String NEUTRAL_SELECTION_COLOUR = "#FFEF73";
+	/**
+	 * A string containing the hexadecimal colour used for representing a bad selection.
+	 * Ideally a shade of red, use for instance when a manual connection is not valid.
+	 */
+	public static final String BAD_SELECTION_COLOUR = "#FF5C5C";
+	
+	
+	
+	/* Sizes and distances */
+	/**
+	 * The width or height of the area that can be clicked on
+	 * to drag-resize a pane.
+	 */
+    public static final double RESIZE_MARGIN = 5.0;
+    /**
+	 * The minimum width of the settings pane, to prevent it
+	 * from being resized beyond visibility.
+	 */
+    public static final double SETTINGS_MIN_WIDTH = 200;
+    /**
+	 * The minimum width of the console pane, to prevent it
+	 * from being resized beyond visibility.
+	 */
+    public static final double CONSOLE_MIN_HEIGHT = 100;
+    /**
+     * Radius used for the representation of nodes in the grid.
+     */
+    public static final double NODE_RADIUS = 35;
+	/**
+	 * Spacing between each node.
+	 */
+	public static final double SPACING = 15;
+	/**
+	 * The angle across which the node's sockets are evently distributed.
+	 */
+	public static final double THETA = Math.PI / 1.4;
+	/**
+	 * The radius of the connection sockets, calculated as a function of
+	 * NODE_RADIUS.
+	 * 
+	 */
+	public static final double SOCKET_RADIUS = Math.sqrt(NODE_RADIUS) / 1.8;
+	/**
+	 * Size of the text in each node.
+	 */
+	public static final double NODE_TEXT = NODE_RADIUS / 2.5;
+	
+	
+	/* CSS Styles
+	 * TODO extract to stylesheet?
+	 */
+	/**
+	 * The basic style of text boxes used in parameters.
+	 */
+	public static final String BASE_TEXT_STYLE = "-fx-border-color: #C9C9C9; -fx-border-radius: 2; -fx-padding: 0; ";
+	/**
+	 * The basic style of check boxes used in parameters.
+	 */
+	public static final String BASE_CHECKBOX_STYLE = "-fx-padding: 0; ";
+	/**
+	 * The style applied to invalid parameters, using BAD_SELECTION_COLOUR.
+	 */
+	public static final String INVALID_PARAMETER_STYLE = "-fx-background-color: " + BAD_SELECTION_COLOUR;
+	/**
+	 * The style applied to neutral parameters, using NEUTRAL_SELECTION_COLOUR.
+	 */
+	public static final String WARNING_PARAMETER_STYLE = "-fx-background-color: " + NEUTRAL_SELECTION_COLOUR;
+	/**
+	 * The style applied to valid parameters, using NEUTRAL_COLOUR.
+	 */
+	public static final String VALID_PARAMETER_STYLE = "-fx-background-color: " + NEUTRAL_COLOUR;	
+    
+}
diff --git a/src/jcgp/gui/dragresize/HorizontalDragResize.java b/src/jcgp/gui/dragresize/HorizontalDragResize.java
index b618b74..e88eafd 100644
--- a/src/jcgp/gui/dragresize/HorizontalDragResize.java
+++ b/src/jcgp/gui/dragresize/HorizontalDragResize.java
@@ -4,7 +4,7 @@ import javafx.event.EventHandler;
 import javafx.scene.Cursor;
 import javafx.scene.input.MouseEvent;
 import javafx.scene.layout.Region;
-import jcgp.gui.GUI;
+import jcgp.gui.constants.Constants;
 
 /**
  * This class adds horizontal drag resize functionality to any 
@@ -125,7 +125,7 @@ public class HorizontalDragResize {
 	 * @return true if the mouse position is in the draggable area.
 	 */
 	private boolean isInDraggableZone(MouseEvent event) {
-		return event.getX() < (GUI.RESIZE_MARGIN);
+		return event.getX() < (Constants.RESIZE_MARGIN);
 	}
 
 }
diff --git a/src/jcgp/gui/dragresize/VerticalDragResize.java b/src/jcgp/gui/dragresize/VerticalDragResize.java
index 06186c6..4f784e5 100644
--- a/src/jcgp/gui/dragresize/VerticalDragResize.java
+++ b/src/jcgp/gui/dragresize/VerticalDragResize.java
@@ -4,7 +4,7 @@ import javafx.event.EventHandler;
 import javafx.scene.Cursor;
 import javafx.scene.input.MouseEvent;
 import javafx.scene.layout.Region;
-import jcgp.gui.GUI;
+import jcgp.gui.constants.Constants;
 
 /**
  * This class adds vertical drag resize functionality to any 
@@ -126,7 +126,7 @@ public class VerticalDragResize {
 	 * @return true if the mouse position is in the draggable area.
 	 */
 	private boolean isInDraggableZone(MouseEvent event) {
-		return event.getY() < (GUI.RESIZE_MARGIN);
+		return event.getY() < (Constants.RESIZE_MARGIN);
 	}
 
 }
diff --git a/src/jcgp/gui/population/ChromosomePane.java b/src/jcgp/gui/population/ChromosomePane.java
index 1e04c37..3546011 100644
--- a/src/jcgp/gui/population/ChromosomePane.java
+++ b/src/jcgp/gui/population/ChromosomePane.java
@@ -11,6 +11,7 @@ import jcgp.backend.population.Input;
 import jcgp.backend.population.Node;
 import jcgp.backend.resources.Resources;
 import jcgp.gui.GUI;
+import jcgp.gui.constants.Constants;
 
 /**
  * This extension of {@code ScrollPane} contains a series of
@@ -69,9 +70,9 @@ public class ChromosomePane extends ScrollPane {
 				// make the connection lines
 				Line lines[] = new Line[resources.arity()];
 				for (int l = 0; l < lines.length; l++) {
-					angle = ((((double) (l + 1)) / ((double) (lines.length + 1))) * GUIGene.THETA) - (GUIGene.THETA / 2);
-					xPos = (-Math.cos(angle) * GUIGene.NODE_RADIUS) + (((c + 1) * (2 * GUIGene.NODE_RADIUS + GUIGene.SPACING)) + GUIGene.NODE_RADIUS);
-					yPos = (Math.sin(angle) * GUIGene.NODE_RADIUS) + ((r * (2 * GUIGene.NODE_RADIUS + GUIGene.SPACING)) + GUIGene.NODE_RADIUS);
+					angle = ((((double) (l + 1)) / ((double) (lines.length + 1))) * Constants.THETA) - (Constants.THETA / 2);
+					xPos = (-Math.cos(angle) * Constants.NODE_RADIUS) + (((c + 1) * (2 * Constants.NODE_RADIUS + Constants.SPACING)) + Constants.NODE_RADIUS);
+					yPos = (Math.sin(angle) * Constants.NODE_RADIUS) + ((r * (2 * Constants.NODE_RADIUS + Constants.SPACING)) + Constants.NODE_RADIUS);
 					
 					lines[l] = new Line(xPos, yPos, xPos, yPos);
 					lines[l].setMouseTransparent(true);
@@ -86,8 +87,8 @@ public class ChromosomePane extends ScrollPane {
 		// outputs
 		guiOutputs = new GUIOutput[resources.outputs()];
 		for (int i = 0; i < guiOutputs.length; i++) {
-			xPos = ((resources.columns() + 1) * (2 * GUIGene.NODE_RADIUS + GUIGene.SPACING));
-			yPos = (chromosome.getOutput(i).getIndex() * (2 * GUIGene.NODE_RADIUS + GUIGene.SPACING)) + GUIGene.NODE_RADIUS;
+			xPos = ((resources.columns() + 1) * (2 * Constants.NODE_RADIUS + Constants.SPACING));
+			yPos = (chromosome.getOutput(i).getIndex() * (2 * Constants.NODE_RADIUS + Constants.SPACING)) + Constants.NODE_RADIUS;
 			// make the line
 			Line line = new Line(xPos, yPos, xPos, yPos);
 			line.setMouseTransparent(true);
diff --git a/src/jcgp/gui/population/FunctionSelector.java b/src/jcgp/gui/population/FunctionSelector.java
index 0e6c6bb..ac7a2c2 100644
--- a/src/jcgp/gui/population/FunctionSelector.java
+++ b/src/jcgp/gui/population/FunctionSelector.java
@@ -5,7 +5,7 @@ import javafx.scene.control.Label;
 import javafx.scene.input.MouseEvent;
 import javafx.scene.layout.VBox;
 import jcgp.backend.function.FunctionSet;
-import jcgp.gui.GUI;
+import jcgp.gui.constants.Constants;
 
 /**
  * A menu class, exposes all of the allowed functions
@@ -46,7 +46,7 @@ public class FunctionSelector extends VBox {
 			l.addEventFilter(MouseEvent.MOUSE_ENTERED, new EventHandler<MouseEvent>() {
 				@Override
 				public void handle(MouseEvent event) {
-					((Label) event.getSource()).setStyle("-fx-background-color: " + GUI.SOFT_HIGHLIGHT_COLOUR + "; -fx-border-color: #B0B0B0; -fx-border-width: 0 0 1 0; -fx-padding: 2");
+					((Label) event.getSource()).setStyle("-fx-background-color: " + Constants.SOFT_HIGHLIGHT_COLOUR + "; -fx-border-color: #B0B0B0; -fx-border-width: 0 0 1 0; -fx-padding: 2");
 				}
 			});
 			l.addEventFilter(MouseEvent.MOUSE_EXITED, new EventHandler<MouseEvent>() {
diff --git a/src/jcgp/gui/population/GUIGene.java b/src/jcgp/gui/population/GUIGene.java
index 9980d53..bae7647 100644
--- a/src/jcgp/gui/population/GUIGene.java
+++ b/src/jcgp/gui/population/GUIGene.java
@@ -8,17 +8,10 @@ import javafx.scene.text.Font;
 import javafx.scene.text.Text;
 import javafx.scene.text.TextAlignment;
 import jcgp.backend.population.Connection;
+import jcgp.gui.constants.Constants;
 
 public abstract class GUIGene extends Group {
 
-	public static final double NODE_RADIUS = 35;
-	public static final double SPACING = 15;
-	
-	public static final double THETA = Math.PI / 1.4;
-	public static final double SOCKET_RADIUS = Math.sqrt(NODE_RADIUS) / 1.8;
-	
-	public static final double NODE_TEXT = NODE_RADIUS / 2.5;
-	
 	public enum GUIGeneState {
 		NEUTRAL,
 		HOVER,
@@ -32,7 +25,7 @@ public abstract class GUIGene extends Group {
 	}
 	
 	protected Text text = new Text();
-	protected Circle mainCircle = new Circle(NODE_RADIUS, Paint.valueOf("white"));
+	protected Circle mainCircle = new Circle(Constants.NODE_RADIUS, Paint.valueOf("white"));
 	
 	private GUIGeneState state = GUIGeneState.NEUTRAL;
 
@@ -44,8 +37,8 @@ public abstract class GUIGene extends Group {
 		text.setFont(Font.font("Arial", 12));
 		text.setTextOrigin(VPos.CENTER);
 		text.setTextAlignment(TextAlignment.CENTER);
-		text.setWrappingWidth(NODE_RADIUS * 2);
-		text.setX(-NODE_RADIUS);
+		text.setWrappingWidth(Constants.NODE_RADIUS * 2);
+		text.setX(-Constants.NODE_RADIUS);
 		text.setVisible(true);
 		
 		mainCircle.setStroke(Paint.valueOf("black"));
diff --git a/src/jcgp/gui/population/GUIInput.java b/src/jcgp/gui/population/GUIInput.java
index a48be51..8b55a58 100644
--- a/src/jcgp/gui/population/GUIInput.java
+++ b/src/jcgp/gui/population/GUIInput.java
@@ -7,7 +7,7 @@ import javafx.scene.paint.Paint;
 import javafx.scene.shape.Circle;
 import jcgp.backend.population.Connection;
 import jcgp.backend.population.Input;
-import jcgp.gui.GUI;
+import jcgp.gui.constants.Constants;
 
 public class GUIInput extends GUIGene {
 
@@ -19,12 +19,12 @@ public class GUIInput extends GUIGene {
 		this.parent = parentRef;
 		this.input = input;
 		
-		relocate(NODE_RADIUS,
-				(input.getIndex() * (2 * NODE_RADIUS + SPACING)) + NODE_RADIUS);
+		relocate(Constants.NODE_RADIUS,
+				(input.getIndex() * (2 * Constants.NODE_RADIUS + Constants.SPACING)) + Constants.NODE_RADIUS);
 		
 		updateText();
 
-		Circle outputSocket = new Circle(NODE_RADIUS, 0, SOCKET_RADIUS, Paint.valueOf("white"));
+		Circle outputSocket = new Circle(Constants.NODE_RADIUS, 0, Constants.SOCKET_RADIUS, Paint.valueOf("white"));
 		outputSocket.setId(String.valueOf(0));
 		outputSocket.setStroke(Paint.valueOf("black"));
 
@@ -126,38 +126,38 @@ public class GUIInput extends GUIGene {
 			if (locked > 0) {
 				setState(GUIGeneState.LOCKED_HOVER);
 			} else {
-				mainCircle.setFill(Paint.valueOf(GUI.SOFT_HIGHLIGHT_COLOUR));
+				mainCircle.setFill(Paint.valueOf(Constants.SOFT_HIGHLIGHT_COLOUR));
 			}
 			break;
 		case INVALID_TARGET:
-			mainCircle.setFill(Paint.valueOf(GUI.BAD_SELECTION_COLOUR));
+			mainCircle.setFill(Paint.valueOf(Constants.BAD_SELECTION_COLOUR));
 			break;
 		case LOCKED_HOVER:
-			mainCircle.setFill(Paint.valueOf(GUI.SOFT_HIGHLIGHT_COLOUR));
+			mainCircle.setFill(Paint.valueOf(Constants.SOFT_HIGHLIGHT_COLOUR));
 			break;
 		case HOVER:
-			mainCircle.setFill(Paint.valueOf(GUI.MEDIUM_HIGHLIGHT_COLOUR));
+			mainCircle.setFill(Paint.valueOf(Constants.MEDIUM_HIGHLIGHT_COLOUR));
 			break;
 		case INDIRECT_HOVER:
-			mainCircle.setFill(Paint.valueOf(GUI.SOFT_HIGHLIGHT_COLOUR));
+			mainCircle.setFill(Paint.valueOf(Constants.SOFT_HIGHLIGHT_COLOUR));
 			break;
 		case NEUTRAL:
 			if (locked > 0) {
 				setState(GUIGeneState.HOVER);
 			} else {
-				mainCircle.setFill(Paint.valueOf(GUI.NEUTRAL_COLOUR));
+				mainCircle.setFill(Paint.valueOf(Constants.NEUTRAL_COLOUR));
 			}
 			break;
 		case NO_CHANGE_TARGET:
 			parent.setTarget(true);
-			mainCircle.setFill(Paint.valueOf(GUI.NEUTRAL_SELECTION_COLOUR));
+			mainCircle.setFill(Paint.valueOf(Constants.NEUTRAL_SELECTION_COLOUR));
 			break;
 		case SOURCE:
-			mainCircle.setFill(Paint.valueOf(GUI.MEDIUM_HIGHLIGHT_COLOUR));
+			mainCircle.setFill(Paint.valueOf(Constants.MEDIUM_HIGHLIGHT_COLOUR));
 			break;
 		case VALID_TARGET:
 			parent.setTarget(true);
-			mainCircle.setFill(Paint.valueOf(GUI.GOOD_SELECTION_COLOUR));
+			mainCircle.setFill(Paint.valueOf(Constants.GOOD_SELECTION_COLOUR));
 			break;
 		default:
 			break;
diff --git a/src/jcgp/gui/population/GUINode.java b/src/jcgp/gui/population/GUINode.java
index 142d650..4d420ea 100644
--- a/src/jcgp/gui/population/GUINode.java
+++ b/src/jcgp/gui/population/GUINode.java
@@ -13,6 +13,7 @@ import jcgp.backend.population.Input;
 import jcgp.backend.population.Node;
 import jcgp.backend.resources.Resources;
 import jcgp.gui.GUI;
+import jcgp.gui.constants.Constants;
 
 public class GUINode extends GUIGene {
 
@@ -32,8 +33,8 @@ public class GUINode extends GUIGene {
 		this.resources = gui.getExperiment().getResources();
 		
 		// move the GUIGene to the right position
-		relocate(((node.getColumn() + 1) * (2 * NODE_RADIUS + SPACING)) + NODE_RADIUS,
-				(node.getRow() * (2 * NODE_RADIUS + SPACING)) + NODE_RADIUS);
+		relocate(((node.getColumn() + 1) * (2 * Constants.NODE_RADIUS + Constants.SPACING)) + Constants.NODE_RADIUS,
+				(node.getRow() * (2 * Constants.NODE_RADIUS + Constants.SPACING)) + Constants.NODE_RADIUS);
 
 		// set the line ends correctly
 		updateLines();
@@ -42,7 +43,7 @@ public class GUINode extends GUIGene {
 		connectionNumber.setStyle("-fx-background-color:rgb(255, 255, 255); -fx-border-color:rgba(0, 0, 0, 0.5); ");
 		connectionNumber.setVisible(false);
 
-		Circle output = new Circle(NODE_RADIUS, 0, SOCKET_RADIUS, Paint.valueOf("white"));
+		Circle output = new Circle(Constants.NODE_RADIUS, 0, Constants.SOCKET_RADIUS, Paint.valueOf("white"));
 		output.setStroke(Paint.valueOf("black"));
 
 		updateText();
@@ -50,11 +51,11 @@ public class GUINode extends GUIGene {
 		Circle[] sockets = new Circle[resources.arity()];
 		double angle, xPos, yPos;
 		for (int l = 0; l < sockets.length; l++) {
-			angle = (((l + 1) / ((double) (resources.arity() + 1))) * THETA) - (THETA / 2);
-			xPos = -Math.cos(angle) * NODE_RADIUS;
-			yPos = Math.sin(angle) * NODE_RADIUS;
+			angle = (((l + 1) / ((double) (resources.arity() + 1))) * Constants.THETA) - (Constants.THETA / 2);
+			xPos = -Math.cos(angle) * Constants.NODE_RADIUS;
+			yPos = Math.sin(angle) * Constants.NODE_RADIUS;
 
-			sockets[l] = new Circle(xPos, yPos, GUIGene.SOCKET_RADIUS, Paint.valueOf("white"));
+			sockets[l] = new Circle(xPos, yPos, Constants.SOCKET_RADIUS, Paint.valueOf("white"));
 			sockets[l].setId(String.valueOf(l));
 			sockets[l].setStroke(Paint.valueOf("black"));
 
@@ -253,19 +254,19 @@ public class GUINode extends GUIGene {
 			if (locked > 0) {
 				setState(GUIGeneState.LOCKED_HOVER);
 			} else {
-				mainCircle.setFill(Paint.valueOf(GUI.SOFT_HIGHLIGHT_COLOUR));
+				mainCircle.setFill(Paint.valueOf(Constants.SOFT_HIGHLIGHT_COLOUR));
 				showLines(true);
 			}
 			setConnectionStates(GUIGeneState.ACTIVE_HOVER);
 			break;
 		case LOCKED_HOVER:
-			mainCircle.setFill(Paint.valueOf(GUI.SOFT_HIGHLIGHT_COLOUR));
+			mainCircle.setFill(Paint.valueOf(Constants.SOFT_HIGHLIGHT_COLOUR));
 			break;
 		case INVALID_TARGET:
-			mainCircle.setFill(Paint.valueOf(GUI.BAD_SELECTION_COLOUR));
+			mainCircle.setFill(Paint.valueOf(Constants.BAD_SELECTION_COLOUR));
 			break;
 		case HOVER:
-			mainCircle.setFill(Paint.valueOf(GUI.MEDIUM_HIGHLIGHT_COLOUR));
+			mainCircle.setFill(Paint.valueOf(Constants.MEDIUM_HIGHLIGHT_COLOUR));
 			showLines(true);
 			if (locked <= 0) {
 				setConnectionStates(GUIGeneState.INDIRECT_HOVER);
@@ -274,13 +275,13 @@ public class GUINode extends GUIGene {
 			}
 			break;
 		case INDIRECT_HOVER:
-			mainCircle.setFill(Paint.valueOf(GUI.SOFT_HIGHLIGHT_COLOUR));
+			mainCircle.setFill(Paint.valueOf(Constants.SOFT_HIGHLIGHT_COLOUR));
 			break;
 		case NEUTRAL:
 			if (locked > 0) {
 				setState(GUIGeneState.HOVER);
 			} else {
-				mainCircle.setFill(Paint.valueOf(GUI.NEUTRAL_COLOUR));
+				mainCircle.setFill(Paint.valueOf(Constants.NEUTRAL_COLOUR));
 				showLines(false);
 				if (getState() == GUIGeneState.ACTIVE_HOVER) {
 					setConnectionStates(GUIGeneState.NEUTRAL);
@@ -289,14 +290,14 @@ public class GUINode extends GUIGene {
 			break;
 		case NO_CHANGE_TARGET:
 			parent.setTarget(true);
-			mainCircle.setFill(Paint.valueOf(GUI.NEUTRAL_SELECTION_COLOUR));
+			mainCircle.setFill(Paint.valueOf(Constants.NEUTRAL_SELECTION_COLOUR));
 			break;
 		case SOURCE:
-			mainCircle.setFill(Paint.valueOf(GUI.HARD_HIGHLIGHT_COLOUR));
+			mainCircle.setFill(Paint.valueOf(Constants.HARD_HIGHLIGHT_COLOUR));
 			break;
 		case VALID_TARGET:
 			parent.setTarget(true);
-			mainCircle.setFill(Paint.valueOf(GUI.GOOD_SELECTION_COLOUR));
+			mainCircle.setFill(Paint.valueOf(Constants.GOOD_SELECTION_COLOUR));
 			break;
 		default:
 			break;
@@ -355,12 +356,12 @@ public class GUINode extends GUIGene {
 		if (node.getConnection(index) instanceof Node) {
 			int row = ((Node) node.getConnection(index)).getRow(), 
 					column = ((Node) node.getConnection(index)).getColumn();
-			lines[index].setEndX(((column + 1) * (2 * NODE_RADIUS + SPACING)) + 2 * NODE_RADIUS);
-			lines[index].setEndY((row * (2 * NODE_RADIUS + SPACING)) + NODE_RADIUS);
+			lines[index].setEndX(((column + 1) * (2 * Constants.NODE_RADIUS + Constants.SPACING)) + 2 * Constants.NODE_RADIUS);
+			lines[index].setEndY((row * (2 * Constants.NODE_RADIUS + Constants.SPACING)) + Constants.NODE_RADIUS);
 		} else if (node.getConnection(index) instanceof Input) {
 			int inputIndex = ((Input) node.getConnection(index)).getIndex();
-			lines[index].setEndX(2 * NODE_RADIUS);
-			lines[index].setEndY(inputIndex * (2 * NODE_RADIUS + SPACING) + NODE_RADIUS);
+			lines[index].setEndX(2 * Constants.NODE_RADIUS);
+			lines[index].setEndY(inputIndex * (2 * Constants.NODE_RADIUS + Constants.SPACING) + Constants.NODE_RADIUS);
 		}
 	}
 
@@ -444,7 +445,7 @@ public class GUINode extends GUIGene {
 
 	@Override
 	public void setConnectionLine(GUIGene gene) {
-		lines[connectionIndex].setEndX(gene.getLayoutX() + NODE_RADIUS);
+		lines[connectionIndex].setEndX(gene.getLayoutX() + Constants.NODE_RADIUS);
 		lines[connectionIndex].setEndY(gene.getLayoutY());
 	}
 
diff --git a/src/jcgp/gui/population/GUIOutput.java b/src/jcgp/gui/population/GUIOutput.java
index a3f5a28..d715138 100644
--- a/src/jcgp/gui/population/GUIOutput.java
+++ b/src/jcgp/gui/population/GUIOutput.java
@@ -12,6 +12,7 @@ import jcgp.backend.population.Input;
 import jcgp.backend.population.Node;
 import jcgp.backend.population.Output;
 import jcgp.gui.GUI;
+import jcgp.gui.constants.Constants;
 
 public class GUIOutput extends GUIGene {
 
@@ -25,14 +26,14 @@ public class GUIOutput extends GUIGene {
 		this.output = output;
 		this.sourceLine = line;
 
-		relocate(((gui.getExperiment().getResources().columns() + 1) * (2 * NODE_RADIUS + SPACING)) + NODE_RADIUS,
-				(output.getIndex() * (2 * NODE_RADIUS + SPACING)) + NODE_RADIUS);
+		relocate(((gui.getExperiment().getResources().columns() + 1) * (2 * Constants.NODE_RADIUS + Constants.SPACING)) + Constants.NODE_RADIUS,
+				(output.getIndex() * (2 * Constants.NODE_RADIUS + Constants.SPACING)) + Constants.NODE_RADIUS);
 
 		// set the line ends correctly
 		updateLines();
 		updateText();
 
-		Circle socket = new Circle(-NODE_RADIUS, 0, SOCKET_RADIUS, Paint.valueOf("white"));
+		Circle socket = new Circle(-Constants.NODE_RADIUS, 0, Constants.SOCKET_RADIUS, Paint.valueOf("white"));
 		socket.setId(String.valueOf(0));
 		socket.setStroke(Paint.valueOf("black"));
 
@@ -193,32 +194,32 @@ public class GUIOutput extends GUIGene {
 		case ACTIVE_HOVER:
 			break;
 		case INVALID_TARGET:
-			mainCircle.setFill(Paint.valueOf(GUI.BAD_SELECTION_COLOUR));
+			mainCircle.setFill(Paint.valueOf(Constants.BAD_SELECTION_COLOUR));
 			break;
 		case HOVER:
-			mainCircle.setFill(Paint.valueOf(GUI.MEDIUM_HIGHLIGHT_COLOUR));
+			mainCircle.setFill(Paint.valueOf(Constants.MEDIUM_HIGHLIGHT_COLOUR));
 			sourceLine.setVisible(true);
 			if (!isLocked()) {
 				setConnectionStates(GUIGeneState.ACTIVE_HOVER);
 			}
 			break;
 		case INDIRECT_HOVER:
-			mainCircle.setFill(Paint.valueOf(GUI.SOFT_HIGHLIGHT_COLOUR));
+			mainCircle.setFill(Paint.valueOf(Constants.SOFT_HIGHLIGHT_COLOUR));
 			break;
 		case NEUTRAL:
-			mainCircle.setFill(Paint.valueOf(GUI.NEUTRAL_COLOUR));
+			mainCircle.setFill(Paint.valueOf(Constants.NEUTRAL_COLOUR));
 			sourceLine.setVisible(false);
 			break;
 		case NO_CHANGE_TARGET:
-			mainCircle.setFill(Paint.valueOf(GUI.NEUTRAL_SELECTION_COLOUR));
+			mainCircle.setFill(Paint.valueOf(Constants.NEUTRAL_SELECTION_COLOUR));
 			break;
 		case SOURCE:
-			mainCircle.setFill(Paint.valueOf(GUI.HARD_HIGHLIGHT_COLOUR));
+			mainCircle.setFill(Paint.valueOf(Constants.HARD_HIGHLIGHT_COLOUR));
 			setConnectionStates(GUIGeneState.NEUTRAL);
 			setConnectionStates(GUIGeneState.INDIRECT_HOVER);
 			break;
 		case VALID_TARGET:
-			mainCircle.setFill(Paint.valueOf(GUI.GOOD_SELECTION_COLOUR));
+			mainCircle.setFill(Paint.valueOf(Constants.GOOD_SELECTION_COLOUR));
 			break;
 		default:
 			break;
@@ -230,12 +231,12 @@ public class GUIOutput extends GUIGene {
 		if (output.getSource() instanceof Node) {
 			int row = ((Node) output.getSource()).getRow(), 
 					column = ((Node) output.getSource()).getColumn();
-			sourceLine.setEndX(((column + 1) * (2 * NODE_RADIUS + SPACING)) + 2 * NODE_RADIUS);
-			sourceLine.setEndY((row * (2 * NODE_RADIUS + SPACING)) + NODE_RADIUS);
+			sourceLine.setEndX(((column + 1) * (2 * Constants.NODE_RADIUS + Constants.SPACING)) + 2 * Constants.NODE_RADIUS);
+			sourceLine.setEndY((row * (2 * Constants.NODE_RADIUS + Constants.SPACING)) + Constants.NODE_RADIUS);
 		} else if (output.getSource() instanceof Input) {
 			int inputIndex = ((Input) output.getSource()).getIndex();
-			sourceLine.setEndX(2 * NODE_RADIUS);
-			sourceLine.setEndY(inputIndex * (2 * NODE_RADIUS + SPACING) + NODE_RADIUS);
+			sourceLine.setEndX(2 * Constants.NODE_RADIUS);
+			sourceLine.setEndY(inputIndex * (2 * Constants.NODE_RADIUS + Constants.SPACING) + Constants.NODE_RADIUS);
 		}
 	}
 
@@ -287,7 +288,7 @@ public class GUIOutput extends GUIGene {
 
 	@Override
 	public void setConnectionLine(GUIGene gene) {
-		sourceLine.setEndX(gene.getLayoutX() + NODE_RADIUS);
+		sourceLine.setEndX(gene.getLayoutX() + Constants.NODE_RADIUS);
 		sourceLine.setEndY(gene.getLayoutY());	
 	}
 	
diff --git a/src/jcgp/gui/settings/SettingsPane.java b/src/jcgp/gui/settings/SettingsPane.java
index c59244b..bad42cd 100644
--- a/src/jcgp/gui/settings/SettingsPane.java
+++ b/src/jcgp/gui/settings/SettingsPane.java
@@ -26,6 +26,7 @@ import jcgp.backend.modules.problem.Problem;
 import jcgp.backend.modules.problem.TestCaseProblem;
 import jcgp.backend.parameters.Parameter;
 import jcgp.gui.GUI;
+import jcgp.gui.constants.Constants;
 import jcgp.gui.settings.parameters.GUIParameter;
 import jcgp.gui.settings.testcase.TestCaseTable;
 
@@ -79,10 +80,10 @@ public class SettingsPane extends AnchorPane {
 		
 		// make the overarching container
 		mainContainer = new VBox(8);
-		mainContainer.setPadding(new Insets(5, GUI.RESIZE_MARGIN, 0, 2));
+		mainContainer.setPadding(new Insets(5, Constants.RESIZE_MARGIN, 0, 2));
 		
-		setMinWidth(GUI.SETTINGS_MIN_WIDTH);
-		setPrefWidth(GUI.SETTINGS_MIN_WIDTH);
+		setMinWidth(Constants.SETTINGS_MIN_WIDTH);
+		setPrefWidth(Constants.SETTINGS_MIN_WIDTH);
 		
 		// initialise all sub-divisions
 		initialiseBaseParameters(jcgp);
@@ -105,7 +106,7 @@ public class SettingsPane extends AnchorPane {
 		AnchorPane.setTopAnchor(scroll, 0.0);
 		AnchorPane.setBottomAnchor(scroll, 0.0);
 		AnchorPane.setRightAnchor(scroll, 0.0);
-		AnchorPane.setLeftAnchor(scroll, GUI.RESIZE_MARGIN);
+		AnchorPane.setLeftAnchor(scroll, Constants.RESIZE_MARGIN);
 		
 		// add the scroll pane, all done!
 		getChildren().add(scroll);
diff --git a/src/jcgp/gui/settings/parameters/GUIBooleanParameter.java b/src/jcgp/gui/settings/parameters/GUIBooleanParameter.java
index a13a52b..a1f03fe 100644
--- a/src/jcgp/gui/settings/parameters/GUIBooleanParameter.java
+++ b/src/jcgp/gui/settings/parameters/GUIBooleanParameter.java
@@ -6,6 +6,7 @@ import javafx.scene.control.CheckBox;
 import javafx.scene.control.Control;
 import jcgp.backend.parameters.BooleanParameter;
 import jcgp.backend.parameters.ParameterStatus;
+import jcgp.gui.constants.Constants;
 import jcgp.gui.settings.SettingsPane;
 
 /**
@@ -59,16 +60,16 @@ public class GUIBooleanParameter extends GUIParameter<Boolean> {
 	protected void setValidityStyle() {
 		// update the Control's style and tooltip based on the status of the parameter
 		if (parameter.getStatus() == ParameterStatus.INVALID) {
-			checkBox.setStyle(BASE_CHECKBOX_STYLE + INVALID_PARAMETER_STYLE);
+			checkBox.setStyle(Constants.BASE_CHECKBOX_STYLE + Constants.INVALID_PARAMETER_STYLE);
 			checkBox.setTooltip(tooltip);
 			tooltip.setText(parameter.getStatus().getDetails());
 		} else if (parameter.getStatus() == ParameterStatus.WARNING 
 				|| parameter.getStatus() == ParameterStatus.WARNING_RESET) {
-			checkBox.setStyle(BASE_CHECKBOX_STYLE + WARNING_PARAMETER_STYLE);
+			checkBox.setStyle(Constants.BASE_CHECKBOX_STYLE + Constants.WARNING_PARAMETER_STYLE);
 			checkBox.setTooltip(tooltip);
 			tooltip.setText(parameter.getStatus().getDetails());
 		} else {
-			checkBox.setStyle(BASE_CHECKBOX_STYLE + VALID_PARAMETER_STYLE);
+			checkBox.setStyle(Constants.BASE_CHECKBOX_STYLE + Constants.VALID_PARAMETER_STYLE);
 			checkBox.setTooltip(null);
 		}
 	}
diff --git a/src/jcgp/gui/settings/parameters/GUIDoubleParameter.java b/src/jcgp/gui/settings/parameters/GUIDoubleParameter.java
index 9f4ea28..feee34c 100644
--- a/src/jcgp/gui/settings/parameters/GUIDoubleParameter.java
+++ b/src/jcgp/gui/settings/parameters/GUIDoubleParameter.java
@@ -9,6 +9,7 @@ import javafx.scene.control.Control;
 import javafx.scene.control.TextField;
 import jcgp.backend.parameters.DoubleParameter;
 import jcgp.backend.parameters.ParameterStatus;
+import jcgp.gui.constants.Constants;
 import jcgp.gui.settings.SettingsPane;
 
 /**
@@ -40,7 +41,7 @@ public class GUIDoubleParameter extends GUIParameter<Number> {
 		decimalFormat = new DecimalFormat();
 		decimalFormat.setMaximumFractionDigits(10);
 		textField = new TextField(decimalFormat.format(parameter.get().doubleValue()));
-		textField.setStyle(VALID_PARAMETER_STYLE);
+		textField.setStyle(Constants.VALID_PARAMETER_STYLE);
 		textField.setAlignment(Pos.CENTER_RIGHT);
 		textField.prefWidthProperty().bind(widthProperty().divide(2));
 		return textField;
@@ -87,15 +88,15 @@ public class GUIDoubleParameter extends GUIParameter<Number> {
 	protected void setValidityStyle() {
 		// update the Control's style and tooltip based on the status of the parameter
 		if (parameter.getStatus() == ParameterStatus.INVALID) {
-			textField.setStyle(BASE_TEXT_STYLE + INVALID_PARAMETER_STYLE);
+			textField.setStyle(Constants.BASE_TEXT_STYLE + Constants.INVALID_PARAMETER_STYLE);
 			textField.setTooltip(tooltip);
 			tooltip.setText(parameter.getStatus().getDetails());
 		} else if (parameter.getStatus() == ParameterStatus.WARNING || parameter.getStatus() ==  ParameterStatus.WARNING_RESET) {
-			textField.setStyle(BASE_TEXT_STYLE + WARNING_PARAMETER_STYLE);
+			textField.setStyle(Constants.BASE_TEXT_STYLE + Constants.WARNING_PARAMETER_STYLE);
 			textField.setTooltip(tooltip);
 			tooltip.setText(parameter.getStatus().getDetails());
 		} else {
-			textField.setStyle(BASE_TEXT_STYLE + VALID_PARAMETER_STYLE);
+			textField.setStyle(Constants.BASE_TEXT_STYLE + Constants.VALID_PARAMETER_STYLE);
 			textField.setTooltip(null);
 		}
 	}
diff --git a/src/jcgp/gui/settings/parameters/GUIIntegerParameter.java b/src/jcgp/gui/settings/parameters/GUIIntegerParameter.java
index d36c1b3..bcfbe50 100644
--- a/src/jcgp/gui/settings/parameters/GUIIntegerParameter.java
+++ b/src/jcgp/gui/settings/parameters/GUIIntegerParameter.java
@@ -7,6 +7,7 @@ import javafx.scene.control.Control;
 import javafx.scene.control.TextField;
 import jcgp.backend.parameters.IntegerParameter;
 import jcgp.backend.parameters.ParameterStatus;
+import jcgp.gui.constants.Constants;
 import jcgp.gui.settings.SettingsPane;
 
 /**
@@ -35,7 +36,7 @@ public class GUIIntegerParameter extends GUIParameter<Number> {
 	protected Control makeControl() {
 		// this uses a text field
 		textField = new TextField(String.valueOf(parameter.get()));
-		textField.setStyle(VALID_PARAMETER_STYLE);
+		textField.setStyle(Constants.VALID_PARAMETER_STYLE);
 		textField.setAlignment(Pos.CENTER_RIGHT);
 		textField.prefWidthProperty().bind(widthProperty().divide(2));
 		
@@ -83,16 +84,16 @@ public class GUIIntegerParameter extends GUIParameter<Number> {
 	protected void setValidityStyle() {
 		// update the Control's style and tooltip based on the status of the parameter
 		if (parameter.getStatus() == ParameterStatus.INVALID) {
-			textField.setStyle(BASE_TEXT_STYLE + INVALID_PARAMETER_STYLE);
+			textField.setStyle(Constants.BASE_TEXT_STYLE + Constants.INVALID_PARAMETER_STYLE);
 			textField.setTooltip(tooltip);
 			tooltip.setText(parameter.getStatus().getDetails());
 		} else if (parameter.getStatus() == ParameterStatus.WARNING 
 				|| parameter.getStatus() ==  ParameterStatus.WARNING_RESET) {
-			textField.setStyle(BASE_TEXT_STYLE + WARNING_PARAMETER_STYLE);
+			textField.setStyle(Constants.BASE_TEXT_STYLE + Constants.WARNING_PARAMETER_STYLE);
 			textField.setTooltip(tooltip);
 			tooltip.setText(parameter.getStatus().getDetails());
 		} else {
-			textField.setStyle(BASE_TEXT_STYLE + VALID_PARAMETER_STYLE);
+			textField.setStyle(Constants.BASE_TEXT_STYLE + Constants.VALID_PARAMETER_STYLE);
 			textField.setTooltip(null);
 		}
 	}
diff --git a/src/jcgp/gui/settings/parameters/GUIParameter.java b/src/jcgp/gui/settings/parameters/GUIParameter.java
index 9188aec..59aecf6 100644
--- a/src/jcgp/gui/settings/parameters/GUIParameter.java
+++ b/src/jcgp/gui/settings/parameters/GUIParameter.java
@@ -15,7 +15,6 @@ import jcgp.backend.parameters.DoubleParameter;
 import jcgp.backend.parameters.IntegerParameter;
 import jcgp.backend.parameters.Parameter;
 import jcgp.backend.parameters.ParameterStatus;
-import jcgp.gui.GUI;
 import jcgp.gui.settings.SettingsPane;
 
 /**
@@ -39,13 +38,6 @@ import jcgp.gui.settings.SettingsPane;
  */
 public abstract class GUIParameter<T> extends HBox {
 	
-	public static final String BASE_TEXT_STYLE = "-fx-border-color: #C9C9C9; -fx-border-radius: 2; -fx-padding: 0; ";
-	public static final String BASE_CHECKBOX_STYLE = "-fx-padding: 0; ";
-	
-	public static final String INVALID_PARAMETER_STYLE = "-fx-background-color: " + GUI.BAD_SELECTION_COLOUR;
-	public static final String WARNING_PARAMETER_STYLE = "-fx-background-color: " + GUI.NEUTRAL_SELECTION_COLOUR;
-	public static final String VALID_PARAMETER_STYLE = "-fx-background-color: " + GUI.NEUTRAL_COLOUR;	
-	
 	private Label name;
 	private Control valueControl;