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/****************************************************************************
Copyright 2004, Colorado School of Mines and others.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
****************************************************************************/
package edu.mines.jtk.sgl;
import java.awt.event.MouseEvent;
/**
* A context for dragging. {@link Dragable} nodes use a drag context to
* implement dragging with a mouse.
*
* A drag context is constructed from a pick result, which has a picked
* point in local coordinates, as well as transforms to world and pixel
* coordinates. Those local-to-world and and local-to-pixel transforms
* are assumed to be constant while the the mouse is being dragged. This
* assumption implies that the view must not change while dragging.
*
* A drag context has a current mouse event and a current point, with
* local, world, and pixel coordinates. A mouse motion listener (not
* part of this context) is responsible for updating this context as
* the mouse is dragged. Updates modify the current mouse event and the
* current point maintained by this context.
* @author Dave Hale, Colorado School of Mines
* @version 2005.07.07
*/
public class DragContext {
/**
* Constructs a drag context for the specified pick result.
* @param pr the pick result.
*/
public DragContext(PickResult pr) {
_event = pr.getMouseEvent();
_canvas = pr.getViewCanvas();
_view = pr.getView();
_world = pr.getWorld();
_pointLocal = pr.getPointLocal();
_pointWorld = pr.getPointWorld();
_pointPixel = pr.getPointPixel();
_localToWorld = pr.getLocalToWorld();
_localToPixel = pr.getLocalToPixel();
_worldToPixel = pr.getWorldToPixel();
_pixelToLocal = _localToPixel.inverse();
_pixelToWorld = _worldToPixel.inverse();
}
/**
* Updates this drag context for the specified mouse event. Updates the
* current mouse event and the current point's local, world, and pixel
* coordinates. Mouse motion listeners call this method as the mouse is
* dragged.
* @param event the mouse event.
*/
public void update(MouseEvent event) {
_event = event;
_pointPixel.x = event.getX();
_pointPixel.y = event.getY();
_pointLocal = _pixelToLocal.times(_pointPixel);
_pointWorld = _pixelToWorld.times(_pointPixel);
}
/**
* Gets the canvas for which this context was constructed.
* @return the view canvas.
*/
public ViewCanvas getViewCanvas() {
return _canvas;
}
/**
* Gets the view for which this context was constructed.
* @return the view.
*/
public View getView() {
return _view;
}
/**
* Gets the world for which this context was constructed.
* @return the world.
*/
public World getWorld() {
return _world;
}
/**
* Gets the current mouse event.
* @return the mouse event.
*/
public MouseEvent getMouseEvent() {
return _event;
}
/**
* Gets the current point in local coordinates.
* @return the current point in local coordinates.
*/
public Point3 getPointLocal() {
return new Point3(_pointLocal);
}
/**
* Gets the current point in world coordinates.
* @return the current point in world coordinates.
*/
public Point3 getPointWorld() {
return new Point3(_pointWorld);
}
/**
* Gets the current point in pixel coordinates.
* @return the current point in pixel coordinates.
*/
public Point3 getPointPixel() {
return new Point3(_pointPixel);
}
/**
* Gets the pixel z (depth) coordinate of the current point. This depth
* depth coordinate increases from 0.0 at the near clipping plane to 1.0
* at the far clipping plane.
* @return the pixel z coordinate.
*/
public double getPixelZ() {
return _pointPixel.z;
}
/**
* Gets the local-to-world coordinate transform matrix.
* @return the local-to-world coordinate transform matrix.
*/
public Matrix44 getLocalToWorld() {
return new Matrix44(_localToWorld);
}
/**
* Gets the local-to-pixel coordinate transform matrix.
* @return the local-to-pixel coordinate transform matrix.
*/
public Matrix44 getLocalToPixel() {
return new Matrix44(_localToPixel);
}
/**
* Gets the world-to-pixel coordinate transform matrix.
* @return the world-to-pixel coordinate transform matrix.
*/
public Matrix44 getWorldToPixel() {
return new Matrix44(_worldToPixel);
}
///////////////////////////////////////////////////////////////////////////
// private
private MouseEvent _event;
private ViewCanvas _canvas;
private View _view;
private World _world;
private Point3 _pointLocal;
private Point3 _pointWorld;
private Point3 _pointPixel;
private Matrix44 _localToWorld;
private Matrix44 _localToPixel;
private Matrix44 _worldToPixel;
private Matrix44 _pixelToLocal;
private Matrix44 _pixelToWorld;
}