jj2000.disp

Class ImgKeyListener

java.lang.Object

java.awt.event.KeyAdapter

jj2000.disp.ImgKeyListener

All Implemented Interfaces:

KeyListener, EventListener

public class ImgKeyListener
extends KeyAdapter

This class implements the listener for keyboard events for the JJ2000 decoder that displays in a ImgScrollPane.

The following key sequences are defined:
- : scroll image up
- : scroll image down
- : scroll image left
- : scroll image right
- : scroll image up by a vertical block increment
- : scroll image down by a vertical block increment
- 'Q' or 'q': exit the application
- '-': zoom out by 2
- '=' or '+': zoom in by 2
- '1': display at a zoom of 1
- 'Ctrl-C': exit the application

The amount by which the arrows scroll the image is determined by the modifier keys. If the Ctrl key is held down, the block increment will be used, otherwise the unit increment will. If the Shift key is held down then the increment is multiplied by ACCEL_FACTOR. That is the Ctrl key selects between unit and block increments, while the Shift key selects between normal and accelerated mode.

Field Summary

Fields

Modifier and Type	Field and Description
static int	ACCEL_FACTOR The acceleration factor when the shift key is pressed: 10

Constructor Summary

Constructors

Constructor and Description
ImgKeyListener(ImgScrollPane isp, Decoder dec) Instantiate a new ImgKeyListener that will work on the specified ImgScrollPane.

Method Summary

Methods

Modifier and Type	Method and Description
void	keyPressed(KeyEvent evt) Hanldes the keyPressed events.
void	keyTyped(KeyEvent evt) Handles the key typed event.

Methods inherited from class java.awt.event.KeyAdapter

keyReleased

Methods inherited from class java.lang.Object

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

Field Detail

ACCEL_FACTOR

public static final int ACCEL_FACTOR

The acceleration factor when the shift key is pressed: 10

See Also:

Constant Field Values

Constructor Detail

ImgKeyListener

public ImgKeyListener(ImgScrollPane isp,
              Decoder dec)

Instantiate a new ImgKeyListener that will work on the specified ImgScrollPane.

Parameters:

isp - The image scroll pane on which the actions should operate.

dec - The decoder instance

Method Detail

keyPressed

public void keyPressed(KeyEvent evt)

Hanldes the keyPressed events. Normal keys are not treated here because some don't have a defined keycode (as incredible as it might seem!).

Specified by:

keyPressed in interface KeyListener

Overrides:

keyPressed in class KeyAdapter

Parameters:

evt - The key event to process.

keyTyped

public void keyTyped(KeyEvent evt)

Handles the key typed event. Normal (i.e. "text") keys are handled here.

Specified by:

keyTyped in interface KeyListener

Overrides:

keyTyped in class KeyAdapter

Parameters:

evt - The key event to process.