hu.kazocsaba.imageviewer.PixelModel Maven / Gradle / Ivy
package hu.kazocsaba.imageviewer;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
import javax.swing.event.EventListenerList;
/**
* Stores the x and y coordinate of a pixel. Either both coordinate is positive or zero, indicating a valid pixel,
* or both are -1, indicating no pixel is selected or should be shown.
* @author Kazó Csaba
*/
public class PixelModel {
private final EventListenerList listenerList = new EventListenerList();
private int x = -1, y = -1;
/**
* Adds a {@code ChangeListener} to the model.
* @param listener the listener to add
*/
public void addChangeListener(ChangeListener listener) {
listenerList.add(ChangeListener.class, listener);
}
/**
* Removes a {@code ChangeListener} from the model.
* @param listener the listener to remove
*/
public void removeChangeListener(ChangeListener listener) {
listenerList.remove(ChangeListener.class, listener);
}
/**
* Notifies the registered listeners that the model has changed.
*/
protected void fireChange() {
Object[] listeners = listenerList.getListenerList();
ChangeEvent event = new ChangeEvent(this);
for (int i = listeners.length - 2; i >= 0; i -= 2) {
if (listeners[i] == ChangeListener.class) {
((ChangeListener)listeners[i + 1]).stateChanged(event);
}
}
}
/**
* Changes the pixel stored in this model. If either coordinate is negative, the new value of the model will be
* (-1, -1).
* @param x the new x coordinate
* @param y the new y coordinate
*/
public void set(int x, int y) {
if (x<0 || y<0) {
x=-1;
y=-1;
}
if (this.x!=x || this.y!=y) {
this.x=x;
this.y=y;
fireChange();
}
}
/**
* Returns the current x coordinate.
* @return the x coordinate
*/
public int getX() {return x;}
/**
* Returns the current y coordinate.
* @return the y coordinate
*/
public int getY() {return y;}
/**
* Returns whether the pixel is marked as invalid by setting one of the coordinates to -1.
* @return {@code true} if the model does not have a valid pixel
*/
public boolean isInvalid() {
return x<0;
}
}