examples/org.eclipse.swt.examples/src/org/eclipse/swt/examples/graphics/CurvesSWTTab.java - platform/eclipse.platform.swt - Git at Google

 /*******************************************************************************
  * Copyright (c) 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  *     IBM Corporation - initial API and implementation
  *******************************************************************************/

 package org.eclipse.swt.examples.graphics;

 import org.eclipse.swt.*;
 import org.eclipse.swt.events.*;
 import org.eclipse.swt.graphics.*;
 import org.eclipse.swt.widgets.*;

 /**
  * This tab presents cubic and quadratic curves that can be drawn. As a
  * demonstration, cubic and quadratic curves are used to spell out "SWT".
  * The user may reposition the cubic and quadratic handles.
  */
 public class CurvesSWTTab extends GraphicsTab {
 	/** These rectangles represent the handles on the curves. */
 	private Rectangle sRect1, sRect2, wRect1, wRect2, tTopRect1, tTopRect2,
 			tBottomRect1, tBottomRect2;

 	/** These values represent the positions of the curves. */
 	private float sXPos, sYPos, wXPos, wYPos, topTXPos, topTYPos,
 			botTXPos, botTYPos;

 	/** These values represent the x and y displacement of each handle. */
 	private float sDiffX1, sDiffY1, sDiffX2, sDiffY2;
 	private float wDiffX1, wDiffY1, wDiffX2, wDiffY2;
 	private float tTopDiffX1, tTopDiffY1, tTopDiffX2, tTopDiffY2;
 	private float tBotDiffX1, tBotDiffY1, tBotDiffX2, tBotDiffY2;

 	/** These are flags that indicate whether or not a handle has been moved. */
 	private boolean sLeftPtMoved, sRightPtMoved, wPt1Moved, wPt2Moved,
 			tTopPt1Moved, tTopPt2Moved, tBotPt1Moved, tBotPt2Moved;

 	private MouseMoveListener mouseMoveListener;
 	private MouseListener mouseListener;
 	private Cursor cursor;

 	/** true if hovering over a handle, false otherwise */
 	private boolean hovering = false;

 	/** true if left mouse button is held down, false otherwise */
 	private boolean mouseDown = false;


 public CurvesSWTTab(GraphicsExample example) {
 	super(example);
 	sRect1 = new Rectangle(-75, 50, 5, 5);
 	sRect2 = new Rectangle(75, 100, 5, 5);
 	sDiffX1 = sDiffY1 = 0;
 	sDiffX2 = sDiffY2 = 0;
 	wRect1 = new Rectangle(80, 300, 5, 5);
 	wRect2 = new Rectangle(120, 300, 5, 5);
 	wDiffX1 = wDiffY1 = wDiffX2 = wDiffY2 = 0;
 	tTopRect1 = new Rectangle(33, -20, 5, 5);
 	tTopRect2 = new Rectangle(66, 20, 5, 5);
 	tTopDiffX1 = tTopDiffY1 = tTopDiffX2 = tTopDiffY2 = 0;
 	tBottomRect1 = new Rectangle(-33, 50, 5, 5);
 	tBottomRect2 = new Rectangle(33, 100, 5, 5);
 	tBotDiffX1 = tBotDiffY1 = tBotDiffX2 = tBotDiffY2 = 0;
 }

 public String getCategory() {
 	return GraphicsExample.getResourceString("Curves"); //$NON-NLS-1$
 }

 public String getText() {
 	return GraphicsExample.getResourceString("SWT"); //$NON-NLS-1$
 }

 public String getDescription() {
 	return GraphicsExample.getResourceString("CurvesSWTDescription"); //$NON-NLS-1$
 }

 public boolean getDoubleBuffered() {
 	return true;
 }

 public void dispose() {
 	if (mouseListener != null)
 		example.canvas.removeMouseListener(mouseListener);

 	if (mouseMoveListener != null)
 		example.canvas.removeMouseMoveListener(mouseMoveListener);

 	if (cursor != null) {
 		cursor.dispose();
 		cursor = null;
 	}
 }

 	/**
 	 * This helper method determines whether or not the cursor is positioned
 	 * over a handle.
 	 *
 	 * @param e
 	 *            A MouseEvent
 	 * @return true if cursor is positioned over a handle; false otherwise
 	 */
 private boolean isHovering(MouseEvent e) {
 	Rectangle r1 = new Rectangle(sRect1.x + (int)sXPos - 1, sRect1.y + (int)sYPos - 1, sRect1.width+2, sRect1.height+2);
 	Rectangle r2 = new Rectangle(sRect2.x + (int)sXPos - 1, sRect2.y + (int)sYPos - 1, sRect2.width+2, sRect2.height+2);
 	Rectangle w1 = new Rectangle(wRect1.x + (int)wXPos - 1, wRect1.y + (int)wYPos - 1, wRect1.width+2, wRect1.height+2);
 	Rectangle w2 = new Rectangle(wRect2.x + (int)wXPos - 1, wRect2.y + (int)wYPos - 1, wRect2.width+2, wRect2.height+2);
 	Rectangle tTop1 = new Rectangle(tTopRect1.x + (int)topTXPos - 1, tTopRect1.y + (int)topTYPos - 1, tTopRect1.width+2, tTopRect1.height+2);
 	Rectangle tTop2 = new Rectangle(tTopRect2.x + (int)topTXPos - 1, tTopRect2.y + (int)topTYPos - 1, tTopRect2.width+2, tTopRect2.height+2);
 	Rectangle tBot1 = new Rectangle(tBottomRect1.x + (int)botTXPos - 1, tBottomRect1.y + (int)botTYPos - 1, tBottomRect1.width+2, tBottomRect1.height+2);
 	Rectangle tBot2 = new Rectangle(tBottomRect2.x + (int)botTXPos - 1, tBottomRect2.y + (int)botTYPos - 1, tBottomRect2.width+2, tBottomRect2.height+2);

 	return ( r1.contains(e.x, e.y) || r2.contains(e.x, e.y)
 		 || w1.contains(e.x, e.y) || w2.contains(e.x, e.y)
 		 || tTop1.contains(e.x, e.y) || tTop2.contains(e.x, e.y)
 		 || tBot1.contains(e.x, e.y) || tBot2.contains(e.x, e.y) );
 }
 /**
  * Creates the widgets used to control the drawing.
  */
 public void createControlPanel(Composite parent) {
 	if (cursor == null) {
 		cursor = new Cursor(parent.getDisplay(), SWT.CURSOR_HAND);
 	}

 	mouseMoveListener = new MouseMoveListener() {

 		public void mouseMove(MouseEvent e) {
 			if (hovering && mouseDown) {
 				example.canvas.setCursor(cursor);
 			} else if (isHovering(e)) {
 				example.canvas.setCursor(cursor);
 				hovering = true;
 			} else {
 				example.canvas.setCursor(null);
 				hovering = false;
 			}

 			if (sLeftPtMoved) {
 				sDiffX1 = sDiffX1 + e.x - (int)sXPos - sRect1.x;
 				sDiffY1 = sDiffY1 + e.y - (int)sYPos - sRect1.y;
 				sRect1.x = e.x - (int)sXPos;
 				sRect1.y = e.y - (int)sYPos;
 			} else if (sRightPtMoved) {
 				sDiffX2 = sDiffX2 + e.x - (int)sXPos - sRect2.x;
 				sDiffY2 = sDiffY2 + e.y - (int)sYPos - sRect2.y;
 				sRect2.x = e.x - (int)sXPos;
 				sRect2.y = e.y - (int)sYPos;
 			} else if (wPt1Moved) {
 				wDiffX1 = wDiffX1 + e.x - (int)wXPos - wRect1.x;
 				wDiffY1 = wDiffY1 + e.y - (int)wYPos - wRect1.y;
 				wRect1.x = e.x - (int)wXPos;
 				wRect1.y = e.y - (int)wYPos;
 			} else if (wPt2Moved) {
 				wDiffX2 = wDiffX2 + e.x - (int)wXPos - wRect2.x;
 				wDiffY2 = wDiffY2 + e.y - (int)wYPos - wRect2.y;
 				wRect2.x = e.x - (int)wXPos;
 				wRect2.y = e.y - (int)wYPos;
 			} else if (tTopPt1Moved) {
 				tTopDiffX1 = tTopDiffX1 + e.x - (int)topTXPos - tTopRect1.x;
 				tTopDiffY1 = tTopDiffY1 + e.y - (int)topTYPos - tTopRect1.y;
 				tTopRect1.x = e.x - (int)topTXPos;
 				tTopRect1.y = e.y - (int)topTYPos;
 			} else if (tTopPt2Moved) {
 				tTopDiffX2 = tTopDiffX2 + e.x - (int)topTXPos - tTopRect2.x;
 				tTopDiffY2 = tTopDiffY2 + e.y - (int)topTYPos - tTopRect2.y;
 				tTopRect2.x = e.x - (int)topTXPos;
 				tTopRect2.y = e.y - (int)topTYPos;
 			} else if (tBotPt1Moved) {
 				tBotDiffX1 = tBotDiffX1 + e.x - (int)botTXPos - tBottomRect1.x;
 				tBotDiffY1 = tBotDiffY1 + e.y - (int)botTYPos - tBottomRect1.y;
 				tBottomRect1.x = e.x - (int)botTXPos;
 				tBottomRect1.y = e.y - (int)botTYPos;
 			} else if (tBotPt2Moved) {
 				tBotDiffX2 = tBotDiffX2 + e.x - (int)botTXPos - tBottomRect2.x;
 				tBotDiffY2 = tBotDiffY2 + e.y - (int)botTYPos - tBottomRect2.y;
 				tBottomRect2.x = e.x - (int)botTXPos;
 				tBottomRect2.y = e.y - (int)botTYPos;
 			}
 			example.redraw();
 		}
 	};

 	mouseListener = new MouseListener() {

 		public void mouseDoubleClick(MouseEvent e) {}

 		/**
 		 * Sent when a mouse button is pressed.
 		 *
 		 * @param e an event containing information about the mouse button press
 		 */
 		public void mouseDown(MouseEvent e) {
 			Rectangle r1 = new Rectangle(sRect1.x + (int)sXPos - 1, sRect1.y + (int)sYPos - 1, sRect1.width+2, sRect1.height+2);
 			Rectangle r2 = new Rectangle(sRect2.x + (int)sXPos - 1, sRect2.y + (int)sYPos - 1, sRect2.width+2, sRect2.height+2);
 			Rectangle w1 = new Rectangle(wRect1.x + (int)wXPos - 1, wRect1.y + (int)wYPos - 1, wRect1.width+2, wRect1.height+2);
 			Rectangle w2 = new Rectangle(wRect2.x + (int)wXPos - 1, wRect2.y + (int)wYPos - 1, wRect2.width+2, wRect2.height+2);
 			Rectangle tTop1 = new Rectangle(tTopRect1.x + (int)topTXPos - 1, tTopRect1.y + (int)topTYPos - 1, tTopRect1.width+2, tTopRect1.height+2);
 			Rectangle tTop2 = new Rectangle(tTopRect2.x + (int)topTXPos - 1, tTopRect2.y + (int)topTYPos - 1, tTopRect2.width+2, tTopRect2.height+2);
 			Rectangle tBot1 = new Rectangle(tBottomRect1.x + (int)botTXPos - 1, tBottomRect1.y + (int)botTYPos - 1, tBottomRect1.width+2, tBottomRect1.height+2);
 			Rectangle tBot2 = new Rectangle(tBottomRect2.x + (int)botTXPos - 1, tBottomRect2.y + (int)botTYPos - 1, tBottomRect2.width+2, tBottomRect2.height+2);

 			if (r1.contains(e.x, e.y)) {
 				sLeftPtMoved = true;
 				mouseDown = true;
 			} else if (r2.contains(e.x, e.y)) {
 				sRightPtMoved = true;
 				mouseDown = true;
 			} else if (w1.contains(e.x, e.y)) {
 				wPt1Moved = true;
 				mouseDown = true;
 			} else if (w2.contains(e.x, e.y)) {
 				wPt2Moved = true;
 				mouseDown = true;
 			} else if (tTop1.contains(e.x, e.y)) {
 				tTopPt1Moved = true;
 				mouseDown = true;
 			} else if (tTop2.contains(e.x, e.y)) {
 				tTopPt2Moved = true;
 				mouseDown = true;
 			} else if (tBot1.contains(e.x, e.y)) {
 				tBotPt1Moved = true;
 				mouseDown = true;
 			} else if (tBot2.contains(e.x, e.y)) {
 				tBotPt2Moved = true;
 				mouseDown = true;
 			}
 		}

 		/**
 		 * Sent when a mouse button is released.
 		 *
 		 * @param e an event containing information about the mouse button release
 		 */
 		public void mouseUp(MouseEvent e) {
 			mouseDown = false;
 			if (isHovering(e)) {
 				example.canvas.setCursor(cursor);
 			} else {
 				example.canvas.setCursor(null);
 			}
 			if (sLeftPtMoved)
 				sLeftPtMoved = false;
 			if (sRightPtMoved)
 				sRightPtMoved = false;
 			if (wPt1Moved)
 				wPt1Moved = false;
 			if (wPt2Moved)
 				wPt2Moved = false;
 			if (tTopPt1Moved)
 				tTopPt1Moved = false;
 			if (tTopPt2Moved)
 				tTopPt2Moved = false;
 			if (tBotPt1Moved)
 				tBotPt1Moved = false;
 			if (tBotPt2Moved)
 				tBotPt2Moved = false;

 			example.redraw();
 		}
 	};
 	example.canvas.addMouseMoveListener(mouseMoveListener);
 	example.canvas.addMouseListener(mouseListener);
 }

 public void paint(GC gc, int width, int height) {
 	if (!example.checkAdvancedGraphics()) return;
 	Device device = gc.getDevice();

 	Font font = new Font(device, getPlatformFont(), 16, SWT.ITALIC);
 	gc.setFont(font);
 	gc.setLineWidth(2);

 	Transform transform;

 	// ----- letter s -----
 	sXPos = 4*width/16;
 	sYPos = (height-150)/2;

 	transform = new Transform(device);
 	transform.translate(sXPos, sYPos);
 	gc.setTransform(transform);
 	transform.dispose();

 	gc.setForeground(device.getSystemColor(SWT.COLOR_DARK_BLUE));
 	gc.drawString(GraphicsExample.getResourceString("Cubic"), 0, 175, true);

 	Path path = new Path(device);
 	path.cubicTo(-200 + sDiffX1, 50 + sDiffY1, 200 + sDiffX2, 100 + sDiffY2, 0, 150);
 	gc.drawPath(path);
 	path.dispose();

 	// draw the spline points
 	gc.setTransform(null);
 	gc.drawRectangle(sRect1.x + (int)sXPos, sRect1.y + (int)sYPos, sRect1.width, sRect1.height);
 	gc.drawRectangle(sRect2.x + (int)sXPos, sRect2.y + (int)sYPos, sRect2.width, sRect2.height);

 	// ----- letter w -----
 	wXPos = 6*width/16;
 	wYPos = (height-150)/2;

 	transform = new Transform(device);
 	transform.translate(wXPos, wYPos);
 	gc.setTransform(transform);
 	transform.dispose();

 	gc.setForeground(device.getSystemColor(SWT.COLOR_GRAY));
 	gc.drawString(GraphicsExample.getResourceString("Quadratic"), 0, -50, true);
 	gc.drawString(GraphicsExample.getResourceString("Quadratic"), 110, -50, true);

 	path = new Path(device);
 	path.quadTo(100 + wDiffX1, 300 + wDiffY1, 100, 0);
 	path.quadTo(100+wDiffX2, 300+wDiffY2, 200, 0);
 	gc.drawPath(path);
 	path.dispose();

 	gc.setTransform(null);
 	gc.drawRectangle(wRect1.x + (int)wXPos, wRect1.y + (int)wYPos, wRect1.width, wRect1.height);
 	gc.drawRectangle(wRect2.x + (int)wXPos, wRect2.y + (int)wYPos, wRect2.width, wRect2.height);


 	// ----- top of letter t -----
 	topTXPos = 11*width/16;
 	topTYPos = (height-150)/2;

 	transform = new Transform(device);
 	transform.translate(topTXPos, topTYPos);
 	gc.setTransform(transform);
 	transform.dispose();

 	gc.setForeground(device.getSystemColor(SWT.COLOR_YELLOW));
 	gc.drawString(GraphicsExample.getResourceString("Cubic"), 25, -50, true);

 	path = new Path(device);
 	path.cubicTo(33 + tTopDiffX1, -20 + tTopDiffY1, 66 + tTopDiffX2, 20 + tTopDiffY2, 100, 0);
 	gc.drawPath(path);
 	path.dispose();

 	gc.setTransform(null);
 	gc.drawRectangle(tTopRect1.x + (int)topTXPos, tTopRect1.y + (int)topTYPos, tTopRect1.width, tTopRect1.height);
 	gc.drawRectangle(tTopRect2.x + (int)topTXPos, tTopRect2.y + (int)topTYPos, tTopRect2.width, tTopRect2.height);


 	// ----- vertical bar of letter t -----
 	botTXPos = 12*width/16;
 	botTYPos = (height-150)/2;

 	transform = new Transform(device);
 	transform.translate(botTXPos, botTYPos);
 	gc.setTransform(transform);
 	transform.dispose();

 	gc.setForeground(device.getSystemColor(SWT.COLOR_RED));
 	gc.drawString(GraphicsExample.getResourceString("Cubic"), 0, 175, true);

 	path = new Path(device);
 	path.cubicTo(-33 + tBotDiffX1, 50 + tBotDiffY1, 33 + tBotDiffX2, 100 + tBotDiffY2, 0, 150);
 	gc.drawPath(path);
 	path.dispose();

 	gc.setTransform(null);
 	gc.drawRectangle(tBottomRect1.x + (int)botTXPos, tBottomRect1.y + (int)botTYPos, tBottomRect1.width, tBottomRect1.height);
 	gc.drawRectangle(tBottomRect2.x + (int)botTXPos, tBottomRect2.y + (int)botTYPos, tBottomRect2.width, tBottomRect2.height);

 	font.dispose();
 }

 /**
  * Returns the name of a valid font for the resident platform.
  */
 static String getPlatformFont() {
 	if(SWT.getPlatform() == "win32") {
 		return "Arial";
 	} else if (SWT.getPlatform() == "motif") {
 		return "Helvetica";
 	} else if (SWT.getPlatform() == "gtk") {
 		return "Baekmuk Batang";
 	} else if (SWT.getPlatform() == "carbon") {
 		return "Arial";
 	} else { // photon, etc ...
 		return "Verdana";
 	}
 }
 }
	/*******************************************************************************
	* Copyright (c) 2006 IBM Corporation and others.
	* All rights reserved. This program and the accompanying materials
	* are made available under the terms of the Eclipse Public License v1.0
	* which accompanies this distribution, and is available at
	* http://www.eclipse.org/legal/epl-v10.html
	*
	* Contributors:
	* IBM Corporation - initial API and implementation
	*******************************************************************************/

	package org.eclipse.swt.examples.graphics;

	import org.eclipse.swt.*;
	import org.eclipse.swt.events.*;
	import org.eclipse.swt.graphics.*;
	import org.eclipse.swt.widgets.*;

	/**
	* This tab presents cubic and quadratic curves that can be drawn. As a
	* demonstration, cubic and quadratic curves are used to spell out "SWT".
	* The user may reposition the cubic and quadratic handles.
	*/
	public class CurvesSWTTab extends GraphicsTab {
	/** These rectangles represent the handles on the curves. */
	private Rectangle sRect1, sRect2, wRect1, wRect2, tTopRect1, tTopRect2,
	tBottomRect1, tBottomRect2;

	/** These values represent the positions of the curves. */
	private float sXPos, sYPos, wXPos, wYPos, topTXPos, topTYPos,
	botTXPos, botTYPos;

	/** These values represent the x and y displacement of each handle. */
	private float sDiffX1, sDiffY1, sDiffX2, sDiffY2;
	private float wDiffX1, wDiffY1, wDiffX2, wDiffY2;
	private float tTopDiffX1, tTopDiffY1, tTopDiffX2, tTopDiffY2;
	private float tBotDiffX1, tBotDiffY1, tBotDiffX2, tBotDiffY2;

	/** These are flags that indicate whether or not a handle has been moved. */
	private boolean sLeftPtMoved, sRightPtMoved, wPt1Moved, wPt2Moved,
	tTopPt1Moved, tTopPt2Moved, tBotPt1Moved, tBotPt2Moved;

	private MouseMoveListener mouseMoveListener;
	private MouseListener mouseListener;
	private Cursor cursor;

	/** true if hovering over a handle, false otherwise */
	private boolean hovering = false;

	/** true if left mouse button is held down, false otherwise */
	private boolean mouseDown = false;


	public CurvesSWTTab(GraphicsExample example) {
	super(example);
	sRect1 = new Rectangle(-75, 50, 5, 5);
	sRect2 = new Rectangle(75, 100, 5, 5);
	sDiffX1 = sDiffY1 = 0;
	sDiffX2 = sDiffY2 = 0;
	wRect1 = new Rectangle(80, 300, 5, 5);
	wRect2 = new Rectangle(120, 300, 5, 5);
	wDiffX1 = wDiffY1 = wDiffX2 = wDiffY2 = 0;
	tTopRect1 = new Rectangle(33, -20, 5, 5);
	tTopRect2 = new Rectangle(66, 20, 5, 5);
	tTopDiffX1 = tTopDiffY1 = tTopDiffX2 = tTopDiffY2 = 0;
	tBottomRect1 = new Rectangle(-33, 50, 5, 5);
	tBottomRect2 = new Rectangle(33, 100, 5, 5);
	tBotDiffX1 = tBotDiffY1 = tBotDiffX2 = tBotDiffY2 = 0;
	}

	public String getCategory() {
	return GraphicsExample.getResourceString("Curves"); //$NON-NLS-1$
	}

	public String getText() {
	return GraphicsExample.getResourceString("SWT"); //$NON-NLS-1$
	}

	public String getDescription() {
	return GraphicsExample.getResourceString("CurvesSWTDescription"); //$NON-NLS-1$
	}

	public boolean getDoubleBuffered() {
	return true;
	}

	public void dispose() {
	if (mouseListener != null)
	example.canvas.removeMouseListener(mouseListener);

	if (mouseMoveListener != null)
	example.canvas.removeMouseMoveListener(mouseMoveListener);

	if (cursor != null) {
	cursor.dispose();
	cursor = null;
	}
	}

	/**
	* This helper method determines whether or not the cursor is positioned
	* over a handle.
	*
	* @param e
	* A MouseEvent
	* @return true if cursor is positioned over a handle; false otherwise
	*/
	private boolean isHovering(MouseEvent e) {
	Rectangle r1 = new Rectangle(sRect1.x + (int)sXPos - 1, sRect1.y + (int)sYPos - 1, sRect1.width+2, sRect1.height+2);
	Rectangle r2 = new Rectangle(sRect2.x + (int)sXPos - 1, sRect2.y + (int)sYPos - 1, sRect2.width+2, sRect2.height+2);
	Rectangle w1 = new Rectangle(wRect1.x + (int)wXPos - 1, wRect1.y + (int)wYPos - 1, wRect1.width+2, wRect1.height+2);
	Rectangle w2 = new Rectangle(wRect2.x + (int)wXPos - 1, wRect2.y + (int)wYPos - 1, wRect2.width+2, wRect2.height+2);
	Rectangle tTop1 = new Rectangle(tTopRect1.x + (int)topTXPos - 1, tTopRect1.y + (int)topTYPos - 1, tTopRect1.width+2, tTopRect1.height+2);
	Rectangle tTop2 = new Rectangle(tTopRect2.x + (int)topTXPos - 1, tTopRect2.y + (int)topTYPos - 1, tTopRect2.width+2, tTopRect2.height+2);
	Rectangle tBot1 = new Rectangle(tBottomRect1.x + (int)botTXPos - 1, tBottomRect1.y + (int)botTYPos - 1, tBottomRect1.width+2, tBottomRect1.height+2);
	Rectangle tBot2 = new Rectangle(tBottomRect2.x + (int)botTXPos - 1, tBottomRect2.y + (int)botTYPos - 1, tBottomRect2.width+2, tBottomRect2.height+2);

	return ( r1.contains(e.x, e.y) \|\| r2.contains(e.x, e.y)
	\|\| w1.contains(e.x, e.y) \|\| w2.contains(e.x, e.y)
	\|\| tTop1.contains(e.x, e.y) \|\| tTop2.contains(e.x, e.y)
	\|\| tBot1.contains(e.x, e.y) \|\| tBot2.contains(e.x, e.y) );
	}
	/**
	* Creates the widgets used to control the drawing.
	*/
	public void createControlPanel(Composite parent) {
	if (cursor == null) {
	cursor = new Cursor(parent.getDisplay(), SWT.CURSOR_HAND);
	}

	mouseMoveListener = new MouseMoveListener() {

	public void mouseMove(MouseEvent e) {
	if (hovering && mouseDown) {
	example.canvas.setCursor(cursor);
	} else if (isHovering(e)) {
	example.canvas.setCursor(cursor);
	hovering = true;
	} else {
	example.canvas.setCursor(null);
	hovering = false;
	}

	if (sLeftPtMoved) {
	sDiffX1 = sDiffX1 + e.x - (int)sXPos - sRect1.x;
	sDiffY1 = sDiffY1 + e.y - (int)sYPos - sRect1.y;
	sRect1.x = e.x - (int)sXPos;
	sRect1.y = e.y - (int)sYPos;
	} else if (sRightPtMoved) {
	sDiffX2 = sDiffX2 + e.x - (int)sXPos - sRect2.x;
	sDiffY2 = sDiffY2 + e.y - (int)sYPos - sRect2.y;
	sRect2.x = e.x - (int)sXPos;
	sRect2.y = e.y - (int)sYPos;
	} else if (wPt1Moved) {
	wDiffX1 = wDiffX1 + e.x - (int)wXPos - wRect1.x;
	wDiffY1 = wDiffY1 + e.y - (int)wYPos - wRect1.y;
	wRect1.x = e.x - (int)wXPos;
	wRect1.y = e.y - (int)wYPos;
	} else if (wPt2Moved) {
	wDiffX2 = wDiffX2 + e.x - (int)wXPos - wRect2.x;
	wDiffY2 = wDiffY2 + e.y - (int)wYPos - wRect2.y;
	wRect2.x = e.x - (int)wXPos;
	wRect2.y = e.y - (int)wYPos;
	} else if (tTopPt1Moved) {
	tTopDiffX1 = tTopDiffX1 + e.x - (int)topTXPos - tTopRect1.x;
	tTopDiffY1 = tTopDiffY1 + e.y - (int)topTYPos - tTopRect1.y;
	tTopRect1.x = e.x - (int)topTXPos;
	tTopRect1.y = e.y - (int)topTYPos;
	} else if (tTopPt2Moved) {
	tTopDiffX2 = tTopDiffX2 + e.x - (int)topTXPos - tTopRect2.x;
	tTopDiffY2 = tTopDiffY2 + e.y - (int)topTYPos - tTopRect2.y;
	tTopRect2.x = e.x - (int)topTXPos;
	tTopRect2.y = e.y - (int)topTYPos;
	} else if (tBotPt1Moved) {
	tBotDiffX1 = tBotDiffX1 + e.x - (int)botTXPos - tBottomRect1.x;
	tBotDiffY1 = tBotDiffY1 + e.y - (int)botTYPos - tBottomRect1.y;
	tBottomRect1.x = e.x - (int)botTXPos;
	tBottomRect1.y = e.y - (int)botTYPos;
	} else if (tBotPt2Moved) {
	tBotDiffX2 = tBotDiffX2 + e.x - (int)botTXPos - tBottomRect2.x;
	tBotDiffY2 = tBotDiffY2 + e.y - (int)botTYPos - tBottomRect2.y;
	tBottomRect2.x = e.x - (int)botTXPos;
	tBottomRect2.y = e.y - (int)botTYPos;
	}
	example.redraw();
	}
	};

	mouseListener = new MouseListener() {

	public void mouseDoubleClick(MouseEvent e) {}

	/**
	* Sent when a mouse button is pressed.
	*
	* @param e an event containing information about the mouse button press
	*/
	public void mouseDown(MouseEvent e) {
	Rectangle r1 = new Rectangle(sRect1.x + (int)sXPos - 1, sRect1.y + (int)sYPos - 1, sRect1.width+2, sRect1.height+2);
	Rectangle r2 = new Rectangle(sRect2.x + (int)sXPos - 1, sRect2.y + (int)sYPos - 1, sRect2.width+2, sRect2.height+2);
	Rectangle w1 = new Rectangle(wRect1.x + (int)wXPos - 1, wRect1.y + (int)wYPos - 1, wRect1.width+2, wRect1.height+2);
	Rectangle w2 = new Rectangle(wRect2.x + (int)wXPos - 1, wRect2.y + (int)wYPos - 1, wRect2.width+2, wRect2.height+2);
	Rectangle tTop1 = new Rectangle(tTopRect1.x + (int)topTXPos - 1, tTopRect1.y + (int)topTYPos - 1, tTopRect1.width+2, tTopRect1.height+2);
	Rectangle tTop2 = new Rectangle(tTopRect2.x + (int)topTXPos - 1, tTopRect2.y + (int)topTYPos - 1, tTopRect2.width+2, tTopRect2.height+2);
	Rectangle tBot1 = new Rectangle(tBottomRect1.x + (int)botTXPos - 1, tBottomRect1.y + (int)botTYPos - 1, tBottomRect1.width+2, tBottomRect1.height+2);
	Rectangle tBot2 = new Rectangle(tBottomRect2.x + (int)botTXPos - 1, tBottomRect2.y + (int)botTYPos - 1, tBottomRect2.width+2, tBottomRect2.height+2);

	if (r1.contains(e.x, e.y)) {
	sLeftPtMoved = true;
	mouseDown = true;
	} else if (r2.contains(e.x, e.y)) {
	sRightPtMoved = true;
	mouseDown = true;
	} else if (w1.contains(e.x, e.y)) {
	wPt1Moved = true;
	mouseDown = true;
	} else if (w2.contains(e.x, e.y)) {
	wPt2Moved = true;
	mouseDown = true;
	} else if (tTop1.contains(e.x, e.y)) {
	tTopPt1Moved = true;
	mouseDown = true;
	} else if (tTop2.contains(e.x, e.y)) {
	tTopPt2Moved = true;
	mouseDown = true;
	} else if (tBot1.contains(e.x, e.y)) {
	tBotPt1Moved = true;
	mouseDown = true;
	} else if (tBot2.contains(e.x, e.y)) {
	tBotPt2Moved = true;
	mouseDown = true;
	}
	}

	/**
	* Sent when a mouse button is released.
	*
	* @param e an event containing information about the mouse button release
	*/
	public void mouseUp(MouseEvent e) {
	mouseDown = false;
	if (isHovering(e)) {
	example.canvas.setCursor(cursor);
	} else {
	example.canvas.setCursor(null);
	}
	if (sLeftPtMoved)
	sLeftPtMoved = false;
	if (sRightPtMoved)
	sRightPtMoved = false;
	if (wPt1Moved)
	wPt1Moved = false;
	if (wPt2Moved)
	wPt2Moved = false;
	if (tTopPt1Moved)
	tTopPt1Moved = false;
	if (tTopPt2Moved)
	tTopPt2Moved = false;
	if (tBotPt1Moved)
	tBotPt1Moved = false;
	if (tBotPt2Moved)
	tBotPt2Moved = false;

	example.redraw();
	}
	};
	example.canvas.addMouseMoveListener(mouseMoveListener);
	example.canvas.addMouseListener(mouseListener);
	}

	public void paint(GC gc, int width, int height) {
	if (!example.checkAdvancedGraphics()) return;
	Device device = gc.getDevice();

	Font font = new Font(device, getPlatformFont(), 16, SWT.ITALIC);
	gc.setFont(font);
	gc.setLineWidth(2);

	Transform transform;

	// ----- letter s -----
	sXPos = 4*width/16;
	sYPos = (height-150)/2;

	transform = new Transform(device);
	transform.translate(sXPos, sYPos);
	gc.setTransform(transform);
	transform.dispose();

	gc.setForeground(device.getSystemColor(SWT.COLOR_DARK_BLUE));
	gc.drawString(GraphicsExample.getResourceString("Cubic"), 0, 175, true);

	Path path = new Path(device);
	path.cubicTo(-200 + sDiffX1, 50 + sDiffY1, 200 + sDiffX2, 100 + sDiffY2, 0, 150);
	gc.drawPath(path);
	path.dispose();

	// draw the spline points
	gc.setTransform(null);
	gc.drawRectangle(sRect1.x + (int)sXPos, sRect1.y + (int)sYPos, sRect1.width, sRect1.height);
	gc.drawRectangle(sRect2.x + (int)sXPos, sRect2.y + (int)sYPos, sRect2.width, sRect2.height);

	// ----- letter w -----
	wXPos = 6*width/16;
	wYPos = (height-150)/2;

	transform = new Transform(device);
	transform.translate(wXPos, wYPos);
	gc.setTransform(transform);
	transform.dispose();

	gc.setForeground(device.getSystemColor(SWT.COLOR_GRAY));
	gc.drawString(GraphicsExample.getResourceString("Quadratic"), 0, -50, true);
	gc.drawString(GraphicsExample.getResourceString("Quadratic"), 110, -50, true);

	path = new Path(device);
	path.quadTo(100 + wDiffX1, 300 + wDiffY1, 100, 0);
	path.quadTo(100+wDiffX2, 300+wDiffY2, 200, 0);
	gc.drawPath(path);
	path.dispose();

	gc.setTransform(null);
	gc.drawRectangle(wRect1.x + (int)wXPos, wRect1.y + (int)wYPos, wRect1.width, wRect1.height);
	gc.drawRectangle(wRect2.x + (int)wXPos, wRect2.y + (int)wYPos, wRect2.width, wRect2.height);


	// ----- top of letter t -----
	topTXPos = 11*width/16;
	topTYPos = (height-150)/2;

	transform = new Transform(device);
	transform.translate(topTXPos, topTYPos);
	gc.setTransform(transform);
	transform.dispose();

	gc.setForeground(device.getSystemColor(SWT.COLOR_YELLOW));
	gc.drawString(GraphicsExample.getResourceString("Cubic"), 25, -50, true);

	path = new Path(device);
	path.cubicTo(33 + tTopDiffX1, -20 + tTopDiffY1, 66 + tTopDiffX2, 20 + tTopDiffY2, 100, 0);
	gc.drawPath(path);
	path.dispose();

	gc.setTransform(null);
	gc.drawRectangle(tTopRect1.x + (int)topTXPos, tTopRect1.y + (int)topTYPos, tTopRect1.width, tTopRect1.height);
	gc.drawRectangle(tTopRect2.x + (int)topTXPos, tTopRect2.y + (int)topTYPos, tTopRect2.width, tTopRect2.height);


	// ----- vertical bar of letter t -----
	botTXPos = 12*width/16;
	botTYPos = (height-150)/2;

	transform = new Transform(device);
	transform.translate(botTXPos, botTYPos);
	gc.setTransform(transform);
	transform.dispose();

	gc.setForeground(device.getSystemColor(SWT.COLOR_RED));
	gc.drawString(GraphicsExample.getResourceString("Cubic"), 0, 175, true);

	path = new Path(device);
	path.cubicTo(-33 + tBotDiffX1, 50 + tBotDiffY1, 33 + tBotDiffX2, 100 + tBotDiffY2, 0, 150);
	gc.drawPath(path);
	path.dispose();

	gc.setTransform(null);
	gc.drawRectangle(tBottomRect1.x + (int)botTXPos, tBottomRect1.y + (int)botTYPos, tBottomRect1.width, tBottomRect1.height);
	gc.drawRectangle(tBottomRect2.x + (int)botTXPos, tBottomRect2.y + (int)botTYPos, tBottomRect2.width, tBottomRect2.height);

	font.dispose();
	}

	/**
	* Returns the name of a valid font for the resident platform.
	*/
	static String getPlatformFont() {
	if(SWT.getPlatform() == "win32") {
	return "Arial";
	} else if (SWT.getPlatform() == "motif") {
	return "Helvetica";
	} else if (SWT.getPlatform() == "gtk") {
	return "Baekmuk Batang";
	} else if (SWT.getPlatform() == "carbon") {
	return "Arial";
	} else { // photon, etc ...
	return "Verdana";
	}
	}
	}