Package com.singularsys.jepexamples.applets

Class FractalCanvas

java.lang.Object

java.awt.Component

java.awt.Container

javax.swing.JComponent

javax.swing.JPanel

com.singularsys.jepexamples.applets.FractalCanvas

All Implemented Interfaces:

java.awt.event.ComponentListener, java.awt.image.ImageObserver, java.awt.MenuContainer, java.io.Serializable, java.util.EventListener, javax.accessibility.Accessible

public class FractalCanvas
extends javax.swing.JPanel
implements java.awt.event.ComponentListener

This class performs the drawing of the fractal, using a number of threads/runnables to compute the image in chunks.

Each Runnable has is own local version of Jep, and its own copy of the expression. These are set during construction of the runnable.

 Jep localJep = new Jep(new LightWeightComponentSet(jep));
 ImportationVisitor iv = new ImportationVisitor(localJep);
 Node localExpression = iv.deepCopy(expression);
 Complex localC = new Complex(0, 0); // A single mutable value
 Complex localZ = new Complex(0, 0);
 localJep.addVariable("c", localC);
 localJep.addVariable("z", localZ);
 

These are copies are used in the main evaluation loop.

 localC.set(x, y);
 localZ.set(0, 0);
 int count = 0;
 while (count < iterations && localZ.abs2() < 4.0) {
        localZ.set((Complex) localJep.evaluate(localExpression));
        count++;
 }
 

Scheduling of threads is managed by a ThreadPoolExecutor with 10 threads

 ThreadPoolExecutor executor = new ThreadPoolExecutor(10, 100, 10, TimeUnit.SECONDS,
                new ArrayBlockingQueue<Runnable>(100));
 

When a new image is needed a set of Runnables is created and sent to the executor.

 try {
         for (int i = 0; i < nDivisions; ++i) {
            for (int j = 0; j < nDivisions; ++j) {
          Runnable blockRunner = new CalcBlockRunnable(i * wid, j * high, wid, high);
          Future<Integer> future = executor.submit(blockRunner, wid * high);
          synchronized (futures) {
              futures.add(future);
          }
      }
   }
 } catch (RejectedExecutionException ex) {
     System.out.println("Rejected execution " + ex.toString());
 } catch (JepException ex) {
     System.out.println(ex);
 }
 

Each of these has a Future value used to count the number of completed runnables and cancel the tasks if needed. An ArrayList of these futures is kept. If the screen needs to be redrawn before every task is finished then they are killed by first calling future.cancel(true) and then purging them with executor.purge().

An additional thread is used to collect statistics about completed tasks. A ConcurrentLinkedDeque<Integer> is used to send messages to this queue, and a Lock and Condition is used to wake this thread when there is a new message.

 ConcurrentLinkedDeque<Integer> reportQueue = new ConcurrentLinkedDeque<Integer>();
 Reporter reporter = new Reporter();
 Thread reportThead = new Thread(reporter, "ReportThread");
 reportThead.start();
 // Lock for reporter
 private Lock lock = new ReentrantLock();
 // Condition to signal when the reportQueue has data
 private Condition notEmpty = lock.newCondition();
 

Messages are sent to this queue using

 lock.lock();
 reportQueue.add(nItts);
 notEmpty.signal();
 lock.unlock();
 

And the report thread waits for messages

 lock.lock();
 while(true) {
     while(reportQueue.isEmpty()) {
           notEmpty.awaitUninterruptibly();
     }
     Integer itts =  reportQueue.pollFirst();
     ...
 }
 

The image is created using a MemoryImageSource backed by a shared pixel array.

 int[] pixels = new int[dimensions.width * dimensions.height];
 MemoryImageSource source = new MemoryImageSource(dimensions.width, dimensions.height, pixels, 0, dimensions.width);
 source.setAnimated(true);
 Image outImage = Toolkit.getDefaultToolkit().createImage(source);
 

The pixels are simply set by the runnable pixels[index] = Color.getRGB() and when an entire block is finished image consumers are informed using source.newPixels(rect.x,rect.y,rect.width,rect.height ). The paint method simply uses the Graphic.drawImage using Component imageUpdate() callback method to paint more of the image as it becomes available.

 public void paint(Graphics g) {
     g.drawImage(outImage, 0, 0, this);
 }
 

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class javax.swing.JPanel

javax.swing.JPanel.AccessibleJPanel

Nested classes/interfaces inherited from class javax.swing.JComponent

javax.swing.JComponent.AccessibleJComponent

Nested classes/interfaces inherited from class java.awt.Container

java.awt.Container.AccessibleAWTContainer

Nested classes/interfaces inherited from class java.awt.Component

java.awt.Component.AccessibleAWTComponent, java.awt.Component.BaselineResizeBehavior, java.awt.Component.BltBufferStrategy, java.awt.Component.FlipBufferStrategy

Field Summary

Fields inherited from class javax.swing.JComponent

listenerList, TOOL_TIP_TEXT_KEY, ui, UNDEFINED_CONDITION, WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, WHEN_FOCUSED, WHEN_IN_FOCUSED_WINDOW

Fields inherited from class java.awt.Component

accessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT

Fields inherited from interface java.awt.image.ImageObserver

ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH

Constructor Summary

Constructors

Constructor	Description
FractalCanvas(java.lang.String initialExpression, Fractal parent)	Constructor.

Method Summary

Modifier and Type	Method	Description
void	componentHidden(java.awt.event.ComponentEvent e)
void	componentMoved(java.awt.event.ComponentEvent e)
void	componentResized(java.awt.event.ComponentEvent e)
void	componentShown(java.awt.event.ComponentEvent e)
void	paint(java.awt.Graphics g)
void	render()
boolean	setColorExpression(java.lang.String str)	Parses a new expression for colors
boolean	setExpressionString(java.lang.String newString)	Parses a new expression
void	setIterations(int iterations_in)	Sets number of iterations
void	shiftSelection(com.singularsys.jepexamples.applets.FractalCanvas.RegionListener regionListener)	Responds to mouse drag events translates the scene.
void	zoomIn(Complex mid)	Zoom in the sceen
void	zoomOut()	Zoom out the scene.

Methods inherited from class javax.swing.JPanel

getAccessibleContext, getUI, getUIClassID, paramString, setUI, updateUI

Methods inherited from class javax.swing.JComponent

addAncestorListener, addNotify, addVetoableChangeListener, computeVisibleRect, contains, createToolTip, disable, enable, firePropertyChange, firePropertyChange, firePropertyChange, fireVetoableChange, getActionForKeyStroke, getActionMap, getAlignmentX, getAlignmentY, getAncestorListeners, getAutoscrolls, getBaseline, getBaselineResizeBehavior, getBorder, getBounds, getClientProperty, getComponentGraphics, getComponentPopupMenu, getConditionForKeyStroke, getDebugGraphicsOptions, getDefaultLocale, getFontMetrics, getGraphics, getHeight, getInheritsPopupMenu, getInputMap, getInputMap, getInputVerifier, getInsets, getInsets, getListeners, getLocation, getMaximumSize, getMinimumSize, getNextFocusableComponent, getPopupLocation, getPreferredSize, getRegisteredKeyStrokes, getRootPane, getSize, getToolTipLocation, getToolTipText, getToolTipText, getTopLevelAncestor, getTransferHandler, getVerifyInputWhenFocusTarget, getVetoableChangeListeners, getVisibleRect, getWidth, getX, getY, grabFocus, hide, isDoubleBuffered, isLightweightComponent, isManagingFocus, isOpaque, isOptimizedDrawingEnabled, isPaintingForPrint, isPaintingOrigin, isPaintingTile, isRequestFocusEnabled, isValidateRoot, paintBorder, paintChildren, paintComponent, paintImmediately, paintImmediately, print, printAll, printBorder, printChildren, printComponent, processComponentKeyEvent, processKeyBinding, processKeyEvent, processMouseEvent, processMouseMotionEvent, putClientProperty, registerKeyboardAction, registerKeyboardAction, removeAncestorListener, removeNotify, removeVetoableChangeListener, repaint, repaint, requestDefaultFocus, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, resetKeyboardActions, reshape, revalidate, scrollRectToVisible, setActionMap, setAlignmentX, setAlignmentY, setAutoscrolls, setBackground, setBorder, setComponentPopupMenu, setDebugGraphicsOptions, setDefaultLocale, setDoubleBuffered, setEnabled, setFocusTraversalKeys, setFont, setForeground, setInheritsPopupMenu, setInputMap, setInputVerifier, setMaximumSize, setMinimumSize, setNextFocusableComponent, setOpaque, setPreferredSize, setRequestFocusEnabled, setToolTipText, setTransferHandler, setUI, setVerifyInputWhenFocusTarget, setVisible, unregisterKeyboardAction, update

Methods inherited from class java.awt.Container

add, add, add, add, add, addContainerListener, addImpl, addPropertyChangeListener, addPropertyChangeListener, applyComponentOrientation, areFocusTraversalKeysSet, countComponents, deliverEvent, doLayout, findComponentAt, findComponentAt, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponents, getComponentZOrder, getContainerListeners, getFocusTraversalKeys, getFocusTraversalPolicy, getLayout, getMousePosition, insets, invalidate, isAncestorOf, isFocusCycleRoot, isFocusCycleRoot, isFocusTraversalPolicyProvider, isFocusTraversalPolicySet, layout, list, list, locate, minimumSize, paintComponents, preferredSize, printComponents, processContainerEvent, processEvent, remove, remove, removeAll, removeContainerListener, setComponentZOrder, setFocusCycleRoot, setFocusTraversalPolicy, setFocusTraversalPolicyProvider, setLayout, transferFocusDownCycle, validate, validateTree

Methods inherited from class java.awt.Component

action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, bounds, checkImage, checkImage, coalesceEvents, contains, createImage, createImage, createVolatileImage, createVolatileImage, disableEvents, dispatchEvent, enable, enableEvents, enableInputMethods, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getBackground, getBounds, getColorModel, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeysEnabled, getFont, getForeground, getGraphicsConfiguration, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getLocale, getLocation, getLocationOnScreen, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getToolkit, getTreeLock, gotFocus, handleEvent, hasFocus, imageUpdate, inside, isBackgroundSet, isCursorSet, isDisplayable, isEnabled, isFocusable, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isPreferredSizeSet, isShowing, isValid, isVisible, keyDown, keyUp, list, list, list, location, lostFocus, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paintAll, postEvent, prepareImage, prepareImage, processComponentEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, requestFocus, requestFocus, requestFocusInWindow, resize, resize, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setFocusable, setFocusTraversalKeysEnabled, setIgnoreRepaint, setLocale, setLocation, setLocation, setMixingCutoutShape, setName, setSize, setSize, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

FractalCanvas

public FractalCanvas(java.lang.String initialExpression,
                     Fractal parent)

Constructor.

Method Detail

setExpressionString

public boolean setExpressionString(java.lang.String newString)

Parses a new expression

Returns:

true on successful parse

setColorExpression

public boolean setColorExpression(java.lang.String str)

Parses a new expression for colors

Returns:

true on successful parse

setIterations

public void setIterations(int iterations_in)

Sets number of iterations

Parameters:

iterations_in -

paint

public void paint(java.awt.Graphics g)

Overrides:

paint in class javax.swing.JComponent

shiftSelection

public void shiftSelection(com.singularsys.jepexamples.applets.FractalCanvas.RegionListener regionListener)

Responds to mouse drag events translates the scene.

zoomIn

public void zoomIn(Complex mid)

Zoom in the sceen

Parameters:

mid - midpoint of the new scene

zoomOut

public void zoomOut()

Zoom out the scene.

componentResized

public void componentResized(java.awt.event.ComponentEvent e)

Specified by:

componentResized in interface java.awt.event.ComponentListener

componentMoved

public void componentMoved(java.awt.event.ComponentEvent e)

Specified by:

componentMoved in interface java.awt.event.ComponentListener

componentShown

public void componentShown(java.awt.event.ComponentEvent e)

Specified by:

componentShown in interface java.awt.event.ComponentListener

componentHidden

public void componentHidden(java.awt.event.ComponentEvent e)

Specified by:

componentHidden in interface java.awt.event.ComponentListener

render

public void render()