com.singularsys.jepexamples.applets
Class AbstractCanvas

java.lang.Object
  java.awt.Component
      java.awt.Canvas
          com.singularsys.jepexamples.applets.AbstractCanvas

All Implemented Interfaces:

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

Direct Known Subclasses:

FunctionCanvas, ParametrisedCanvas

public abstract class AbstractCanvas
extends java.awt.Canvas
implements java.awt.event.MouseListener, java.awt.event.ComponentListener, java.awt.event.MouseWheelListener, java.awt.event.MouseMotionListener, java.awt.event.KeyListener

An abstract base class providing scaling and double buffering support for Canvas components. Scaling is such that the position of the origin on the screen does not change. Has methods for clearing background, painting axis, grid, scales and elapse time.

Author:

Richard Morris

See Also:

Serialized Form

Nested Class Summary

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

java.awt.Canvas.AccessibleAWTCanvas

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

protected java.awt.Color	axisColor Color for axis
protected java.awt.Color	bgColor Color for background
protected double	cenX
protected double	cenY
protected int	defaultOffX
protected int	defaultOffY
protected double	defaultScaleX Default scale values, set in constructor used in reset
protected double	defaultScaleY Default scale values, set in constructor used in reset
protected java.awt.Dimension	dimensions Dimensions of the canvas
protected java.awt.Color	gridColor Color for grid
protected java.awt.Color	labelColor Color for labels
protected java.awt.Font	labelFont
protected java.awt.Point	lastpos
protected int	offX Offset of the graph in absolute coords
protected int	offY Offset of the graph in absolute coords
protected java.awt.PopupMenu	popup A popup menu
protected java.awt.Font	scaleFont
protected double	scaleX Scaling of the graph in x and y directions
protected double	scaleY Scaling of the graph in x and y directions
protected boolean	showGrid Whether to show calculation times
protected boolean	showScale Whether to show scales
protected boolean	showTime Whether to show calculation times
protected java.awt.image.BufferStrategy	strategy BufferStratergy to use

Fields inherited from class java.awt.Component

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

AbstractCanvas()
Constructor using 1 for scaling and 0 for offset.

AbstractCanvas(double sx, double sy, int offx, int offy)
Constructor specifying the default values for scaling and offset.

Method Summary

protected void	center()
protected int	clipX(int xAbsolute) Clip screen X values to lie within screen
protected int	clipY(int yAbsolute) Clip screen Y values to lie within screen
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)
abstract void	dump() Dump textual representation to System.out
int	getOffX()
int	getOffY()
java.awt.PopupMenu	getPopup() A pop-up menu which subclasses can add items to.
double	getScaleX()
double	getScaleY()
void	keyPressed(java.awt.event.KeyEvent e)
void	keyReleased(java.awt.event.KeyEvent e)
void	keyTyped(java.awt.event.KeyEvent e)
void	mouseClicked(java.awt.event.MouseEvent e)
void	mouseDragged(java.awt.event.MouseEvent e)
void	mouseEntered(java.awt.event.MouseEvent e)
void	mouseExited(java.awt.event.MouseEvent e)
void	mouseMoved(java.awt.event.MouseEvent e)
void	mousePressed(java.awt.event.MouseEvent e)
void	mouseReleased(java.awt.event.MouseEvent e)
void	mouseWheelMoved(java.awt.event.MouseWheelEvent e)
void	paint(java.awt.Graphics g) Provides double buffering support and calls paintCanvas.
protected void	paintAxes(java.awt.Graphics g) Paints the axes for the graph.
protected void	paintCanvas(java.awt.Graphics g) Paint the canvas.
protected abstract void	paintCurve(java.awt.Graphics g) Paint the curve
protected void	paintGrid(java.awt.Graphics g)
protected void	paintScale(java.awt.Graphics g)
protected void	paintTime(java.awt.Graphics g, long t1, long t2) Paints the elapse time
protected void	paintWhite(java.awt.Graphics g) Fills the background with white.
protected void	rescaled() Called when scale, or offset changed Default action is to call repaint
void	reset()
void	resetCanvas()
protected void	resized() Called when canvas sized changes Default action is to call repaint
void	setOffset(int offX, int offY)
void	setScale(double scX, double scY)
void	shiftCanvas(int xdiff, int ydiff)
void	update(java.awt.Graphics g) Just calls paint.
protected int	xAbsolute(double xRelative) Translates from scaled coordinates to screen coordinates.
protected double	xRelative(int xAbsolute) Translates from screen coordinates to scaled coordinates.
protected int	yAbsolute(double yRelative) Translates from scaled coordinates to screen coordinates.
protected double	yRelative(int yAbsolute) Translates from screen coordinates to scaled coordinates.
void	zoomCanvas(double amount) Zoom the canvas.

Methods inherited from class java.awt.Canvas

addNotify, createBufferStrategy, createBufferStrategy, getAccessibleContext, getBufferStrategy

Methods inherited from class java.awt.Component

action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, addPropertyChangeListener, addPropertyChangeListener, applyComponentOrientation, areFocusTraversalKeysSet, bounds, checkImage, checkImage, coalesceEvents, contains, contains, createImage, createImage, createVolatileImage, createVolatileImage, deliverEvent, disable, disableEvents, dispatchEvent, doLayout, enable, enable, enableEvents, enableInputMethods, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getAlignmentX, getAlignmentY, getBackground, getBaseline, getBaselineResizeBehavior, getBounds, getBounds, getColorModel, getComponentAt, getComponentAt, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeys, getFocusTraversalKeysEnabled, getFont, getFontMetrics, getForeground, getGraphics, getGraphicsConfiguration, getHeight, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getListeners, getLocale, getLocation, getLocation, getLocationOnScreen, getMaximumSize, getMinimumSize, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, getPeer, getPreferredSize, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getSize, getToolkit, getTreeLock, getWidth, getX, getY, gotFocus, handleEvent, hasFocus, hide, imageUpdate, inside, invalidate, isBackgroundSet, isCursorSet, isDisplayable, isDoubleBuffered, isEnabled, isFocusable, isFocusCycleRoot, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isOpaque, isPreferredSizeSet, isShowing, isValid, isVisible, keyDown, keyUp, layout, list, list, list, list, list, locate, location, lostFocus, minimumSize, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paintAll, paramString, postEvent, preferredSize, prepareImage, prepareImage, print, printAll, processComponentEvent, processEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processKeyEvent, processMouseEvent, processMouseMotionEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removeNotify, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, repaint, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, reshape, resize, resize, setBackground, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setEnabled, setFocusable, setFocusTraversalKeys, setFocusTraversalKeysEnabled, setFont, setForeground, setIgnoreRepaint, setLocale, setLocation, setLocation, setMaximumSize, setMinimumSize, setName, setPreferredSize, setSize, setSize, setVisible, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle, validate

Methods inherited from class java.lang.Object

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

Field Detail

bgColor

protected java.awt.Color bgColor

Color for background

labelColor

protected java.awt.Color labelColor

Color for labels

axisColor

protected java.awt.Color axisColor

Color for axis

gridColor

protected java.awt.Color gridColor

Color for grid

scaleFont

protected java.awt.Font scaleFont

labelFont

protected java.awt.Font labelFont

cenX

protected double cenX

cenY

protected double cenY

scaleX

protected double scaleX

Scaling of the graph in x and y directions

scaleY

protected double scaleY

Scaling of the graph in x and y directions

offX

protected int offX

Offset of the graph in absolute coords

offY

protected int offY

Offset of the graph in absolute coords

defaultScaleX

protected double defaultScaleX

Default scale values, set in constructor used in reset

defaultScaleY

protected double defaultScaleY

Default scale values, set in constructor used in reset

defaultOffX

protected int defaultOffX

defaultOffY

protected int defaultOffY

dimensions

protected java.awt.Dimension dimensions

Dimensions of the canvas

strategy

protected java.awt.image.BufferStrategy strategy

BufferStratergy to use

popup

protected java.awt.PopupMenu popup

A popup menu

showScale

protected boolean showScale

Whether to show scales

showGrid

protected boolean showGrid

Whether to show calculation times

showTime

protected boolean showTime

Whether to show calculation times

lastpos

protected java.awt.Point lastpos

Constructor Detail

AbstractCanvas

public AbstractCanvas()

Constructor using 1 for scaling and 0 for offset.

AbstractCanvas

public AbstractCanvas(double sx,
                      double sy,
                      int offx,
                      int offy)

Constructor specifying the default values for scaling and offset.

Parameters:

sx -

sy -

offx -

offy -

Method Detail

center

protected void center()

dump

public abstract void dump()

Dump textual representation to System.out

rescaled

protected void rescaled()

Called when scale, or offset changed Default action is to call repaint

resized

protected void resized()

Called when canvas sized changes Default action is to call repaint

clipX

protected int clipX(int xAbsolute)

Clip screen X values to lie within screen

clipY

protected int clipY(int yAbsolute)

Clip screen Y values to lie within screen

xAbsolute

protected int xAbsolute(double xRelative)

Translates from scaled coordinates to screen coordinates.

yAbsolute

protected int yAbsolute(double yRelative)

Translates from scaled coordinates to screen coordinates.

xRelative

protected double xRelative(int xAbsolute)

Translates from screen coordinates to scaled coordinates.

yRelative

protected double yRelative(int yAbsolute)

Translates from screen coordinates to scaled coordinates.

getScaleX

public double getScaleX()

getScaleY

public double getScaleY()

setScale

public void setScale(double scX,
                     double scY)

getOffX

public int getOffX()

getOffY

public int getOffY()

setOffset

public void setOffset(int offX,
                      int offY)

reset

public void reset()

resetCanvas

public void resetCanvas()

zoomCanvas

public void zoomCanvas(double amount)

Zoom the canvas. The x, y scales are multiplied by 1+amount/10.

Parameters:

amount -

shiftCanvas

public void shiftCanvas(int xdiff,
                        int ydiff)

getPopup

public java.awt.PopupMenu getPopup()

A pop-up menu which subclasses can add items to.

Returns:

the menu

update

public void update(java.awt.Graphics g)

Just calls paint. Eliminates background flicker problems with Canvas.update.

Overrides:

update in class java.awt.Canvas

paint

public void paint(java.awt.Graphics g)

Provides double buffering support and calls paintCanvas. Subclasses should not override this method unless they want a different buffering strategy. Instead they should implement paintCanvas.

Overrides:

paint in class java.awt.Canvas

See Also:

paintCanvas(Graphics)

paintCanvas

protected void paintCanvas(java.awt.Graphics g)

Paint the canvas. Calls paintWhite(g); paintAxes(g); paintScale(g); paintGrid(g); paintCurve(g); and paintTime(g,t1,t2);

Parameters:

g - the graphics object

paintCurve

protected abstract void paintCurve(java.awt.Graphics g)

Paint the curve

Parameters:

g -

paintTime

protected void paintTime(java.awt.Graphics g,
                         long t1,
                         long t2)

Paints the elapse time

Parameters:

g -

t1 - start time in nano-secs.

t2 - end time in nano-secs.

paintWhite

protected void paintWhite(java.awt.Graphics g)

Fills the background with white.

paintAxes

protected void paintAxes(java.awt.Graphics g)

Paints the axes for the graph.

paintScale

protected void paintScale(java.awt.Graphics g)

paintGrid

protected void paintGrid(java.awt.Graphics g)

componentHidden

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

Specified by:

componentHidden 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

componentResized

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

Specified by:

componentResized in interface java.awt.event.ComponentListener

mouseWheelMoved

public void mouseWheelMoved(java.awt.event.MouseWheelEvent e)

Specified by:

mouseWheelMoved in interface java.awt.event.MouseWheelListener

mousePressed

public void mousePressed(java.awt.event.MouseEvent e)

Specified by:

mousePressed in interface java.awt.event.MouseListener

mouseReleased

public void mouseReleased(java.awt.event.MouseEvent e)

Specified by:

mouseReleased in interface java.awt.event.MouseListener

mouseDragged

public void mouseDragged(java.awt.event.MouseEvent e)

Specified by:

mouseDragged in interface java.awt.event.MouseMotionListener

mouseMoved

public void mouseMoved(java.awt.event.MouseEvent e)

Specified by:

mouseMoved in interface java.awt.event.MouseMotionListener

mouseClicked

public void mouseClicked(java.awt.event.MouseEvent e)

Specified by:

mouseClicked in interface java.awt.event.MouseListener

mouseEntered

public void mouseEntered(java.awt.event.MouseEvent e)

Specified by:

mouseEntered in interface java.awt.event.MouseListener

mouseExited

public void mouseExited(java.awt.event.MouseEvent e)

Specified by:

mouseExited in interface java.awt.event.MouseListener

keyPressed

public void keyPressed(java.awt.event.KeyEvent e)

Specified by:

keyPressed in interface java.awt.event.KeyListener

keyReleased

public void keyReleased(java.awt.event.KeyEvent e)

Specified by:

keyReleased in interface java.awt.event.KeyListener

keyTyped

public void keyTyped(java.awt.event.KeyEvent e)

Specified by:

keyTyped in interface java.awt.event.KeyListener