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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.*;
import java.awt.event.MouseEvent;
/**
* A mouse constrained by a line. Constrained points (in local coordinates)
* lie on a line through a specified origin point and parallel to a specified
* vector.
*
* Given a mouse event with pixel (x,y) coordinates, a mouse-on-line computes
* a constrained point. When the mouse pixel coordinates equal those used to
* construct the mouse-on-line, the constrained point equals the specified
* origin point.
* @author Dave Hale, Colorado School of Mines
* @version 2005.07.05
*/
public class MouseOnLine extends MouseConstrained {
/**
* Constructs a mouse constrained by a line. The line of constraint
* contains the specified origin point and is parallel to the specified
* vector.
* @param event the mouse event.
* @param origin the origin point, in local coordinates.
* @param vector the vector parallel to the line of constraint.
* @param localToPixel the transform from local to pixel coordinates.
*/
public MouseOnLine(
MouseEvent event, Point3 origin, Vector3 vector, Matrix44 localToPixel)
{
super(localToPixel);
//_xmouse = event.getX();
_ymouse = event.getY();
_origin = new Point3(origin);
_vector = vector.normalize();
// The mode of operation is either nearest or push-pull, depending on
// how parallel the initial mouse segment is to the line of constraint.
Segment mouseSegment = getMouseSegment(event);
Point3 mouseNear = mouseSegment.getA();
Point3 mouseFar = mouseSegment.getB();
Vector3 mouseVector = mouseFar.minus(mouseNear).normalize();
double d = mouseVector.dot(_vector);
if (d<0.0) {
d = -d;
_vector.negateEquals();
}
_mode = (d<0.867)?Mode.NEAREST:Mode.PUSH_PULL;
_length = mouseSegment.length();
_delta = origin.minus(getPointOnLine(event));
}
/**
* Gets the point in local coordinates for the specified event.
* @param event the mouse event.
* @return the point, in local coordinates.
*/
public Point3 getPoint(MouseEvent event) {
return getPointOnLine(event).plusEquals(_delta);
}
///////////////////////////////////////////////////////////////////////////
// private
private enum Mode {
NEAREST,
PUSH_PULL
}
//private double _xmouse; // initial mouse pixel x coordinate
private double _ymouse; // initial mouse pixel y coordinate
private Point3 _origin; // the specified origin point
private Vector3 _vector; // vector parallel to line
private Vector3 _delta; // specified point minus initial intersection point
private double _length; // length of initial mouse segment
private Mode _mode; // either nearest or push-pull
private Point3 getPointOnLine(MouseEvent event) {
Point3 point = null;
// If mode is nearest, ...
if (_mode==Mode.NEAREST) {
// Ray 1 from near point A through far point B of mouse segment.
Segment segment = getMouseSegment(event);
Point3 p1 = segment.getA();
Vector3 v1 = segment.getB().minus(p1);
// Ray 2 from specified origin is parallel to specified vector.
Point3 p2 = _origin;
Vector3 v2 = _vector;
// Point on ray 2 that is nearest to ray 1.
Vector3 a = p2.minus(p1);
Vector3 b = v1;
Vector3 c = v1.cross(v2);
double cc = c.lengthSquared();
double t = a.cross(b).dot(c)/cc;
point = p2.plus(v2.times(t));
}
// else, if mode is push-pull, ...
else if (_mode==Mode.PUSH_PULL) {
// Use mouse y coordinate only to determine distance along line.
Component component = (Component)event.getSource();
double height = component.getHeight();
double ymouse = event.getY();
double scale = 0.05*(_ymouse-ymouse)/height;
point = _origin.plus(_vector.times(scale*_length));
}
return point;
}
}