wc
Class CanvasWC

java.lang.Object
  java.awt.Component
      java.awt.Container
          javax.swing.JComponent
              javax.swing.JPanel
                  wc.CanvasWC

All Implemented Interfaces:

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

Direct Known Subclasses:

MohrCircleCanvas, MohrPrincipalStrsCanvas, MohrStateStrsCanvas, MohrThetaStrsCanvas

public abstract class CanvasWC

extends javax.swing.JPanel

implements java.awt.event.MouseListener, java.awt.event.MouseMotionListener

This CanvasWC class extends the JPanel class to provide control over displaying using a device-independent coordinate system called World Coordinates (WC), which is used by applications. Displaying is buffered to a BufferedImage object (offscreen image) to emulate double buffering rendering. The BufferedImage object contains a Graphics2D object as part of its rendering state. The Graphics2D object contains an AffineTransform object that defines how to convert coordinates from client space (world coordinates) to device-dependent (raster) coordinates in device space.

Clients need to extend this class, by creating subclasses, in order to use it.

The vertical Y axis of the CanvasWC object is set by default in downward direction, but clients may specify it in upward direction when the canvas is created.

===================

Version:

1.1 02/08/2000

Author:

Luiz Fernando Martha

See Also:

JPanel, Graphics2D, BufferedImage, MouseListener, MouseMotionListener, Serialized Form

Nested Class Summary

Nested classes inherited from class javax.swing.JPanel

javax.swing.JPanel.AccessibleJPanel

Nested classes inherited from class javax.swing.JComponent

javax.swing.JComponent.AccessibleJComponent

Nested classes inherited from class java.awt.Container

java.awt.Container.AccessibleAWTContainer

Nested classes inherited from class java.awt.Component

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

Field Summary

static int	BASE_CENTER Field constant used to define text alignment.
static int	BASE_LEFT Field constant used to define text alignment.
static int	BASE_RIGHT Field constant used to define text alignment.
static int	CENTER Field constant used to define text alignment.
static int	DOWNWARD_Y Field constant used to define the vertical Y axis of the canvas in downward direction.
static int	EAST Field constant used to define text alignment.
private java.awt.Point	ept_raster Private field that holds a mouse event point in raster (device) coordinates.
private java.awt.geom.Point2D.Double	ept_world Private field that holds a mouse event point in world coordinates.
private java.awt.Font	fnt Private field that holds current font that is used to display text.
private java.awt.font.FontRenderContext	frc Font renderer context: private field that is a container for the information needed to measure text that is displayed.
private java.awt.Graphics2D	g2off Graphics context object (Graphics2D) that contains an AffineTransform object that defines how to convert coordinates from client space (world coordinates) to device-dependent (raster) coordinates in device space.
private java.awt.Graphics	goff Graphics context object (Graphics) of the offscreen image used privately for double buffering.
(package private) java.awt.geom.AffineTransform	identity Private field that holds an auxiliary identity affine transformation matrix.
private java.awt.image.BufferedImage	ioff BufferedImage object that is used to implement double buffering rendering.
static int	NORTH Field constant used to define text alignment.
static int	NORTH_EAST Field constant used to define text alignment.
static int	NORTH_WEST Field constant used to define text alignment.
static int	OPAQUE Field constant used to define opaque text background opacity.
private java.awt.Point	pt_raster Private field that holds a auxiliary point in raster (device) coordinates.
private java.awt.geom.Point2D.Double	pt_world Private field that holds a auxiliary point in world coordinates.
protected java.awt.Dimension	raster_area Defines the canvas raster area.
static int	SOUTH Field constant used to define text alignment.
static int	SOUTH_EAST Field constant used to define text alignment.
static int	SOUTH_WEST Field constant used to define text alignment.
private int	text_alignment Private field that holds current text alignment parameter.
private java.awt.Rectangle	text_box Private field that holds text box for opaque displaying.
private int	text_opacity Private field that holds current text alignment parameter.
static int	TRANSPARENT Field constant used to define transparent text background opacity.
static int	UPWARD_Y Field constant used to define the vertical Y axis of the canvas in upward direction.
protected double	vdistortion Keeps the WC window vertical distortion factor.
static int	WEST Field constant used to define text alignment.
protected java.awt.geom.Rectangle2D.Double	world_area Defines the canvas world coordinate area.
protected java.awt.geom.Rectangle2D.Double	world_raw Defines the original canvas world coordinate area.
protected int	y_dir Keeps the vertical Y axis direction state.

Fields inherited from class javax.swing.JPanel

Fields inherited from class javax.swing.JComponent

accessibleContext, 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.Container

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

CanvasWC()
Default constructor.

CanvasWC(int y_dir)
Constructor that sets up WC canvas according to a given orientation.

Method Summary

private void	adjustWorld() Adjusts the window in world coordinates (world_area) to have the same aspect ratio between height and width of the canvas (in its current state).
private void	buildOffscreen() Creates the BufferedImage object that is used to implement double buffering rendering.
void	drawString(java.lang.String text, double x, double y) Draw a given string on a given position.
double	getVDistortion() Gets the WC window vertical distortion factor.
void	mouseClicked(java.awt.event.MouseEvent e) Dummy method for the event of mouse clicked in canvas.
void	mouseDragged(java.awt.event.MouseEvent e) Handles the event of the user dragging the mouse while holding down the mouse button.
abstract void	mouseDraggedWC(java.awt.event.MouseEvent e, java.awt.geom.Point2D.Double pt) Mouse button dragged abstract method.
void	mouseEntered(java.awt.event.MouseEvent e) Dummy method for the event of mouse entered in canvas.
void	mouseExited(java.awt.event.MouseEvent e) Dummy method for the event of mouse exited from canvas.
void	mouseMoved(java.awt.event.MouseEvent e) Dummy method for the event of mouse motion in canvas.
void	mousePressed(java.awt.event.MouseEvent e) Handles the event of the user pressing down the mouse button.
abstract void	mousePressedWC(java.awt.event.MouseEvent e, java.awt.geom.Point2D.Double pt) Mouse button pressed abstract method.
void	mouseReleased(java.awt.event.MouseEvent e) Handles the event of the user releasing the mouse button.
abstract void	mouseReleasedWC(java.awt.event.MouseEvent e, java.awt.geom.Point2D.Double pt) Mouse button released abstract method.
void	paintComponent(java.awt.Graphics g) Update method of canvas.
void	panWorldX(double fac) Translates the world coordinate window of the target canvas in the horizontal direction based on a given pan factor.
void	panWorldY(double fac) Translates the world coordinate window of the target canvas in the vertical direction based on a given pan factor.
java.awt.geom.Point2D.Double	raster2world(int raster_x, int raster_y) Transforms the coordinates of a point given in device space (raster) to client space (world coordinates).
abstract void	redraw(java.awt.Graphics2D g) Redisplay abstract method.
void	scaleWorld(double fac) Scales the world coordinate window of the target canvas based on the given scaling factor.
void	setFont(java.awt.Font fnt) Set font to be used to display texts.
void	setTextAlignment(int text_alignment) Set alignment to be used to display texts.
void	setTextOpacity(int text_opacity) Set opacity to be used to display texts.
void	setVDistortion(double vdistortion) Sets the WC window vertical distortion factor.
void	setWorld(double xmin, double xmax, double ymin, double ymax) Sets the limits of the world coordinate window for the target canvas.
java.awt.Point	world2raster(double world_x, double world_y) Transforms the coordinates of a point given in client space (WC) to device-dependent (raster) coordinates.

Methods inherited from class javax.swing.JPanel

getAccessibleContext, getUI, getUIClassID, paramString, setUI, updateUI

Methods inherited from class javax.swing.JComponent

addAncestorListener, addNotify, addPropertyChangeListener, addPropertyChangeListener, addVetoableChangeListener, computeVisibleRect, contains, createToolTip, disable, enable, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, fireVetoableChange, getActionForKeyStroke, getActionMap, getAlignmentX, getAlignmentY, getAncestorListeners, getAutoscrolls, getBorder, getBounds, getClientProperty, getComponentGraphics, getConditionForKeyStroke, getDebugGraphicsOptions, getDefaultLocale, getGraphics, getHeight, getInputMap, getInputMap, getInputVerifier, getInsets, getInsets, getListeners, getLocation, getMaximumSize, getMinimumSize, getNextFocusableComponent, getPreferredSize, getPropertyChangeListeners, getPropertyChangeListeners, getRegisteredKeyStrokes, getRootPane, getSize, getToolTipLocation, getToolTipText, getToolTipText, getTopLevelAncestor, getTransferHandler, getVerifyInputWhenFocusTarget, getVetoableChangeListeners, getVisibleRect, getWidth, getX, getY, grabFocus, isDoubleBuffered, isLightweightComponent, isManagingFocus, isMaximumSizeSet, isMinimumSizeSet, isOpaque, isOptimizedDrawingEnabled, isPaintingTile, isPreferredSizeSet, isRequestFocusEnabled, isValidateRoot, paint, paintBorder, paintChildren, paintImmediately, paintImmediately, print, printAll, printBorder, printChildren, printComponent, processComponentKeyEvent, processKeyBinding, processKeyEvent, processMouseMotionEvent, putClientProperty, registerKeyboardAction, registerKeyboardAction, removeAncestorListener, removeNotify, removePropertyChangeListener, removePropertyChangeListener, removeVetoableChangeListener, repaint, repaint, requestDefaultFocus, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, resetKeyboardActions, reshape, revalidate, scrollRectToVisible, setActionMap, setAlignmentX, setAlignmentY, setAutoscrolls, setBackground, setBorder, setDebugGraphicsOptions, setDefaultLocale, setDoubleBuffered, setEnabled, setForeground, 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, applyComponentOrientation, areFocusTraversalKeysSet, countComponents, deliverEvent, doLayout, findComponentAt, findComponentAt, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponents, getContainerListeners, getFocusTraversalKeys, getFocusTraversalPolicy, getLayout, insets, invalidate, isAncestorOf, isFocusCycleRoot, isFocusCycleRoot, isFocusTraversalPolicySet, layout, list, list, locate, minimumSize, paintComponents, preferredSize, printComponents, processContainerEvent, processEvent, remove, remove, removeAll, removeContainerListener, setFocusCycleRoot, setFocusTraversalKeys, setFocusTraversalPolicy, setLayout, transferFocusBackward, 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, getBackground, getBounds, getColorModel, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeysEnabled, getFont, getFontMetrics, getForeground, getGraphicsConfiguration, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getLocale, getLocation, getLocationOnScreen, getMouseListeners, getMouseMotionListeners, getMouseWheelListeners, getName, getParent, getPeer, getSize, getToolkit, getTreeLock, gotFocus, handleEvent, hasFocus, hide, imageUpdate, inside, isBackgroundSet, isCursorSet, isDisplayable, isEnabled, isFocusable, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, 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, processMouseEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, repaint, repaint, repaint, resize, resize, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setFocusable, setFocusTraversalKeysEnabled, setIgnoreRepaint, setLocale, setLocation, setLocation, setName, setSize, setSize, show, show, size, toString, transferFocus, transferFocusUpCycle

Methods inherited from class java.lang.Object

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

Field Detail

raster_area

protected java.awt.Dimension raster_area

Defines the canvas raster area. This area corresponds to the sizes of the canvas in pixels.

See Also:

Dimension

world_area

protected java.awt.geom.Rectangle2D.Double world_area

Defines the canvas world coordinate area. This area corresponds to the window in client space which is visible in the canvas. This window is adjusted to have the same aspect ratio between height and width of the canvas (in its current state). When the client specifies the windows, the adjustment maintains the center of given (raw) window in the same position. This adjustment may be affected by the canvas vertical distortion factor.

See Also:

Rectangle2D.Double, vdistortion, setWorld(double, double, double, double)

world_raw

protected java.awt.geom.Rectangle2D.Double world_raw

Defines the original canvas world coordinate area. This area corresponds to the window in world coordinates which was set by the client. That is, it corresponds to the world area prior to adjustment with respect to the canvas aspect ratio between height and width.

See Also:

setWorld(double, double, double, double), world_area

DOWNWARD_Y

public static final int DOWNWARD_Y

Field constant used to define the vertical Y axis of the canvas in downward direction.

See Also:

Constant Field Values

UPWARD_Y

public static final int UPWARD_Y

Field constant used to define the vertical Y axis of the canvas in upward direction.

See Also:

Constant Field Values

y_dir

protected int y_dir

Keeps the vertical Y axis direction state. The possible values are DOWNWARD_Y (default) or UPWARD_Y. The Y axis direction is specified during creation, when the CanvasWC constructor is called.

ioff

private java.awt.image.BufferedImage ioff

BufferedImage object that is used to implement double buffering rendering. This object defines a Graphics2D graphics context object used to convert from world coordinates to raster coordinates.

goff

private java.awt.Graphics goff

Graphics context object (Graphics) of the offscreen image used privately for double buffering.

g2off

private java.awt.Graphics2D g2off

Graphics context object (Graphics2D) that contains an AffineTransform object that defines how to convert coordinates from client space (world coordinates) to device-dependent (raster) coordinates in device space.

vdistortion

protected double vdistortion

Keeps the WC window vertical distortion factor. This factor specifies the amount of distortion between the height and width of the world coordinate area. It is essentially a factor between the vertical and horizontal scales in client world coordinate space. A factor with value greater than one will cause a vertical stretching of the image.

See Also:

setVDistortion(double), world_area

pt_world

private java.awt.geom.Point2D.Double pt_world

Private field that holds a auxiliary point in world coordinates.

pt_raster

private java.awt.Point pt_raster

Private field that holds a auxiliary point in raster (device) coordinates.

ept_world

private java.awt.geom.Point2D.Double ept_world

Private field that holds a mouse event point in world coordinates.

ept_raster

private java.awt.Point ept_raster

Private field that holds a mouse event point in raster (device) coordinates.

TRANSPARENT

public static final int TRANSPARENT

Field constant used to define transparent text background opacity.

See Also:

Constant Field Values

OPAQUE

public static final int OPAQUE

Field constant used to define opaque text background opacity.

See Also:

Constant Field Values

text_opacity

private int text_opacity

Private field that holds current text alignment parameter.

text_box

private java.awt.Rectangle text_box

Private field that holds text box for opaque displaying.

NORTH_WEST

public static final int NORTH_WEST

Field constant used to define text alignment.

See Also:

Constant Field Values

NORTH

public static final int NORTH

Field constant used to define text alignment.

See Also:

Constant Field Values

NORTH_EAST

public static final int NORTH_EAST

Field constant used to define text alignment.

See Also:

Constant Field Values

SOUTH_WEST

public static final int SOUTH_WEST

Field constant used to define text alignment.

See Also:

Constant Field Values

SOUTH

public static final int SOUTH

Field constant used to define text alignment.

See Also:

Constant Field Values

SOUTH_EAST

public static final int SOUTH_EAST

Field constant used to define text alignment.

See Also:

Constant Field Values

WEST

public static final int WEST

Field constant used to define text alignment.

See Also:

Constant Field Values

CENTER

public static final int CENTER

Field constant used to define text alignment.

See Also:

Constant Field Values

EAST

public static final int EAST

Field constant used to define text alignment.

See Also:

Constant Field Values

BASE_LEFT

public static final int BASE_LEFT

Field constant used to define text alignment.

See Also:

Constant Field Values

BASE_CENTER

public static final int BASE_CENTER

Field constant used to define text alignment.

See Also:

Constant Field Values

BASE_RIGHT

public static final int BASE_RIGHT

Field constant used to define text alignment.

See Also:

Constant Field Values

text_alignment

private int text_alignment

Private field that holds current text alignment parameter.

fnt

private java.awt.Font fnt

Private field that holds current font that is used to display text.

frc

private java.awt.font.FontRenderContext frc

Font renderer context: private field that is a container for the information needed to measure text that is displayed.

identity

java.awt.geom.AffineTransform identity

Private field that holds an auxiliary identity affine transformation matrix.

Constructor Detail

CanvasWC

public CanvasWC()

Default constructor. Sets up vertical Y axis in downward direction.

CanvasWC

public CanvasWC(int y_dir)

Constructor that sets up WC canvas according to a given orientation.

Parameters:

y_dir - can either be DOWNWARD_Y or UPWARD_Y

See Also:

DOWNWARD_Y, UPWARD_Y

Method Detail

redraw

public abstract void redraw(java.awt.Graphics2D g)

Redisplay abstract method. Client's concrete class must implement it. This method is called every time the canvas is updated.

Parameters:

g - is the 2D graphics context that the client uses to display

mousePressedWC

public abstract void mousePressedWC(java.awt.event.MouseEvent e,
                                    java.awt.geom.Point2D.Double pt)

Mouse button pressed abstract method. Client's concrete class must implement it. This method is called when the user presses a mouse button in the canvas.

Parameters:

e - is mouse event object

pt - is the mouse position in client's floating point world coordinates

mouseDraggedWC

public abstract void mouseDraggedWC(java.awt.event.MouseEvent e,
                                    java.awt.geom.Point2D.Double pt)

Mouse button dragged abstract method. Client's concrete class must implement it. This method is called when user drags the mouse in the canvas with a button pressed.

Parameters:

e - is mouse event object

pt - is the mouse position in client's floating point world coordinates

mouseReleasedWC

public abstract void mouseReleasedWC(java.awt.event.MouseEvent e,
                                     java.awt.geom.Point2D.Double pt)

Mouse button released abstract method. Client's concrete class must implement it. This method is called when user the mouse button at the end of a mouse pressed-dragged-released interaction.

Parameters:

e - is mouse event object

pt - is the mouse position in client's floating point world coordinates

buildOffscreen

private void buildOffscreen()

Creates the BufferedImage object that is used to implement double buffering rendering. This object defines a Graphics2D graphics context object used to convert from world coordinates to raster coordinates.

adjustWorld

private void adjustWorld()

Adjusts the window in world coordinates (world_area) to have the same aspect ratio between height and width of the canvas (in its current state). The adjustment maintains the center of given (raw) window in the same position. This adjustment may be affected by the canvas vertical distortion factor (vdistortion).

setWorld

public void setWorld(double xmin,
                     double xmax,
                     double ymin,
                     double ymax)

Sets the limits of the world coordinate window for the target canvas. The limits are adjusted to be consistent with the canvas viewport aspect ratio and with the canvas vertical distortion factor. The adjustment is such that the center of the given window is maintained.

The canvas is not automatically repainted by this method.

Parameters:

xmin - is the left limit of target window

xmax - is the right limit of target window

ymin - is the bottom limit of target window if vertical Y axis is upward, otherwise it is the top limit

ymax - is the top limit of target window if vertical Y axis is upward, otherwise it is the bottom limit

See Also:

world_area, setVDistortion(double)

panWorldX

public void panWorldX(double fac)

Translates the world coordinate window of the target canvas in the horizontal direction based on a given pan factor. This factor is a percentage of the current window horizontal size. A negative factor indicates a window translation to the right (the client model will move left), and a positive factor indicates a window translation to the left (the client model will move right).

The canvas is not automatically repainted by this method.

Parameters:

fac - is the pan factor

See Also:

world_area, setWorld(double, double, double, double)

panWorldY

public void panWorldY(double fac)

Translates the world coordinate window of the target canvas in the vertical direction based on a given pan factor. This factor is a percentage of the current window horizontal size. If the vertical Y axis is upward, a negative factor indicates a upward window translation (the client model will move downward), and a positive factor indicates a downward window translation (the client model will move upward). If the vertical Y axis is downward, the reverse will occur.

The canvas is not automatically repainted by this method.

Parameters:

fac - is the pan factor

See Also:

world_area, setWorld(double, double, double, double)

scaleWorld

public void scaleWorld(double fac)

Scales the world coordinate window of the target canvas based on the given scaling factor. This factor is a percentage of decrease (positive factor) or increase (negative factor) of the window sizes. The result of this inversion (positive ==> decrease, negative ==> increase) is that the size of the client's enviroment decreases with a negative factor and increases with a positive factor.

The canvas is not automatically repainted by this method.

Parameters:

fac - is the scaling factor

See Also:

world_area, setWorld(double, double, double, double)

setVDistortion

public void setVDistortion(double vdistortion)

Sets the WC window vertical distortion factor. This factor specifies the amount of distortion between the height and width of the world coordinate area. It is essentially a factor between the vertical and horizontal scales in client world coordinate space. A factor with value greater than one will cause a vertical stretching of the image.

The canvas is not automatically repainted by this method.

Parameters:

vdistortion - is the vertical distortion factor

See Also:

vdistortion, setWorld(double, double, double, double)

getVDistortion

public double getVDistortion()

Gets the WC window vertical distortion factor.

Returns:

vertical distortion factor

See Also:

vdistortion, setVDistortion(double)

world2raster

public java.awt.Point world2raster(double world_x,
                                   double world_y)

Transforms the coordinates of a point given in client space (WC) to device-dependent (raster) coordinates. The canvas device space has its origin in the upper-left corner of the canvas. The CanvasWC object contains an AffineTransform object that defines how to convert coordinates from client space (world coordinates) to device-dependent (raster) coordinates in device space. Note that, to avoid creating new point objects, the method returns a reference to a private object and not a copy of a new point. If needed, clients must clone the returned object.

Parameters:

world_x - is the x coordinate of given point in client space

world_y - is the y coordinate of given point in client space

Returns:

point in raster (device) coordinates

See Also:

setWorld(double, double, double, double), raster2world(int, int)

raster2world

public java.awt.geom.Point2D.Double raster2world(int raster_x,
                                                 int raster_y)

Transforms the coordinates of a point given in device space (raster) to client space (world coordinates). The canvas device space has its origin in the upper-left corner of the canvas. The CanvasWC object contains an AffineTransform object that defines how to convert coordinates from device-dependent (raster) coordinates in device space to client space (world coordinates). Note that, to avoid creating new point objects, the method returns a reference to a private object and not a copy of a new point. If needed, clients must clone the returned object.

Parameters:

raster_x - is the x coordinate of the given point in device space

raster_y - is the y coordinate of the given point in device space

Returns:

point in world (client) coordinates

See Also:

setWorld(double, double, double, double), world2raster(double, double)

mousePressed

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

Handles the event of the user pressing down the mouse button. Calls client method mousePressedWC

Specified by:

mousePressed in interface java.awt.event.MouseListener

Parameters:

e - is mouse event object

See Also:

mousePressedWC(java.awt.event.MouseEvent, java.awt.geom.Point2D.Double)

mouseDragged

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

Handles the event of the user dragging the mouse while holding down the mouse button. Calls client method mouseDraggedWC

Specified by:

mouseDragged in interface java.awt.event.MouseMotionListener

Parameters:

e - is mouse event object

See Also:

mouseDraggedWC(java.awt.event.MouseEvent, java.awt.geom.Point2D.Double)

mouseReleased

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

Handles the event of the user releasing the mouse button. Calls client method mouseReleasedWC

Specified by:

mouseReleased in interface java.awt.event.MouseListener

Parameters:

e - is mouse event object

See Also:

mouseReleasedWC(java.awt.event.MouseEvent, java.awt.geom.Point2D.Double)

mouseMoved

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

Dummy method for the event of mouse motion in canvas.

Specified by:

mouseMoved in interface java.awt.event.MouseMotionListener

Parameters:

e - is mouse event object

mouseClicked

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

Dummy method for the event of mouse clicked in canvas.

Specified by:

mouseClicked in interface java.awt.event.MouseListener

Parameters:

e - is mouse event object

mouseExited

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

Dummy method for the event of mouse exited from canvas.

Specified by:

mouseExited in interface java.awt.event.MouseListener

Parameters:

e - is mouse event object

mouseEntered

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

Dummy method for the event of mouse entered in canvas.

Specified by:

mouseEntered in interface java.awt.event.MouseListener

Parameters:

e - is mouse event object

paintComponent

public void paintComponent(java.awt.Graphics g)

Update method of canvas.
In case the sizes of the canvas have changed, it (re)builds a BufferedImage object (offscreen image) to implement double buffering rendering. In this case, the world coordinate window defined by the client (if defined) is adjusted according to the new canvas sizes.
Then, it clears the canvas using the currently defined background color and calls the client's redraw method, passing the Graphics2D graphics context object of the offscreen image, so that the client may display on it.
Finally, it fills the canvas with the image that was displayed by the canvas on the offscreen image.

Parameters:

g - is the target graphics context

See Also:

setWorld(double, double, double, double), redraw(java.awt.Graphics2D)

setFont

public void setFont(java.awt.Font fnt)

Set font to be used to display texts.

setTextOpacity

public void setTextOpacity(int text_opacity)

Set opacity to be used to display texts.

setTextAlignment

public void setTextAlignment(int text_alignment)

Set alignment to be used to display texts.

drawString

public void drawString(java.lang.String text,
                       double x,
                       double y)

Draw a given string on a given position. (Parts of this method were stolen from TWFText.java)