org.piccolo2d.event.PPanEventHandler Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2011, Piccolo2D project, http://piccolo2d.org
* Copyright (c) 1998-2008, University of Maryland
* All rights reserved.
*
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* Redistributions of source code must retain the above copyright notice, this list of conditions
* and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright notice, this list of conditions
* and the following disclaimer in the documentation and/or other materials provided with the
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*
* None of the name of the University of Maryland, the name of the Piccolo2D project, or the names of its
* contributors may be used to endorse or promote products derived from this software without specific
* prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
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package org.piccolo2d.event;
import java.awt.event.InputEvent;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;
import org.piccolo2d.PCamera;
import org.piccolo2d.util.PBounds;
import org.piccolo2d.util.PDimension;
/**
* PPanEventHandler provides event handlers for basic panning of the
* canvas view with the left mouse. The interaction is that clicking and
* dragging the mouse translates the view so that the point on the surface stays
* under the mouse.
*
*
* @version 1.0
* @author Jesse Grosjean
*/
public class PPanEventHandler extends PDragSequenceEventHandler {
private static final int DEFAULT_MAX_AUTOPAN_SPEED = 750;
private static final int DEFAULT_MIN_AUTOPAN_SPEED = 250;
private boolean autopan;
private double minAutopanSpeed = DEFAULT_MIN_AUTOPAN_SPEED;
private double maxAutopanSpeed = DEFAULT_MAX_AUTOPAN_SPEED;
/**
* Constructs a Pan Event Handler that will by default perform auto-panning.
*/
public PPanEventHandler() {
super();
setEventFilter(new PInputEventFilter(InputEvent.BUTTON1_MASK));
setAutopan(true);
}
/**
* Updates the view in response to a user initiated drag event.
*
* @param event event responsible for the drag
*/
protected void drag(final PInputEvent event) {
super.drag(event);
pan(event);
}
/**
* Pans the camera in response to the pan event provided.
*
* @param event contains details about the drag used to translate the view
*/
protected void pan(final PInputEvent event) {
final PCamera c = event.getCamera();
final Point2D l = event.getPosition();
if (c.getViewBounds().contains(l)) {
final PDimension d = event.getDelta();
c.translateView(d.getWidth(), d.getHeight());
}
}
// ****************************************************************
// Auto Pan
// ****************************************************************
/**
* Determines if auto-panning will occur or not.
*
* @param autopan true if auto-panning functionality will be active
*/
public void setAutopan(final boolean autopan) {
this.autopan = autopan;
}
/**
* Returns whether the auto-panning functoinality is enabled.
*
* @return true if auto-panning is enabled
*/
public boolean getAutopan() {
return autopan;
}
/**
* Set the minAutoPan speed in pixels per second.
*
* @param minAutopanSpeed number of pixels to assign as the minimum the
* autopan feature can pan the view
*/
public void setMinAutopanSpeed(final double minAutopanSpeed) {
this.minAutopanSpeed = minAutopanSpeed;
}
/**
* Set the maxAutoPan speed in pixels per second.
*
* @param maxAutopanSpeed number of pixels to assign as the maximum the
* autopan feature can pan the view
*/
public void setMaxAutopanSpeed(final double maxAutopanSpeed) {
this.maxAutopanSpeed = maxAutopanSpeed;
}
/**
* Returns the minAutoPan speed in pixels per second.
*
* @since 1.3
* @return minimum distance the autopan feature can pan the view
*/
public double getMinAutoPanSpeed() {
return minAutopanSpeed;
}
/**
* Returns the maxAutoPan speed in pixels per second.
*
* @since 1.3
* @return max distance the autopan feature can pan the view by
*/
public double getMaxAutoPanSpeed() {
return maxAutopanSpeed;
}
/**
* Performs auto-panning if enabled, even when the mouse is not moving.
*
* @param event current drag relevant details about the drag activity
*/
protected void dragActivityStep(final PInputEvent event) {
if (!autopan) {
return;
}
final PCamera c = event.getCamera();
final PBounds b = c.getBoundsReference();
final Point2D l = event.getPositionRelativeTo(c);
final int outcode = b.outcode(l);
final PDimension delta = new PDimension();
if ((outcode & Rectangle2D.OUT_TOP) != 0) {
delta.height = validatePanningSpeed(-1.0 - 0.5 * Math.abs(l.getY() - b.getY()));
}
else if ((outcode & Rectangle2D.OUT_BOTTOM) != 0) {
delta.height = validatePanningSpeed(1.0 + 0.5 * Math.abs(l.getY() - (b.getY() + b.getHeight())));
}
if ((outcode & Rectangle2D.OUT_RIGHT) != 0) {
delta.width = validatePanningSpeed(1.0 + 0.5 * Math.abs(l.getX() - (b.getX() + b.getWidth())));
}
else if ((outcode & Rectangle2D.OUT_LEFT) != 0) {
delta.width = validatePanningSpeed(-1.0 - 0.5 * Math.abs(l.getX() - b.getX()));
}
c.localToView(delta);
if (delta.width != 0 || delta.height != 0) {
c.translateView(delta.width, delta.height);
}
}
/**
* Clips the panning speed to the minimum and maximum auto-pan speeds
* assigned. If delta is below the threshold, it will be increased. If
* above, it will be decreased.
*
* @param delta auto-pan delta to be clipped
* @return clipped delta value.
*/
protected double validatePanningSpeed(final double delta) {
final double stepsPerSecond = 1000d / getDragActivity().getStepRate();
final double minDelta = minAutopanSpeed / stepsPerSecond;
final double maxDelta = maxAutopanSpeed / stepsPerSecond;
final double absDelta = Math.abs(delta);
final double clippedDelta;
if (absDelta < minDelta) {
clippedDelta = minDelta;
}
else if (absDelta > maxDelta) {
clippedDelta = maxDelta;
}
else {
clippedDelta = delta;
}
if (delta < 0) {
return -clippedDelta;
}
else {
return clippedDelta;
}
}
}