/*
* Copyright 2003-2010 Tufts University Licensed under the
* Educational Community 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.osedu.org/licenses/ECL-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 tufts.vue.shape;
import java.awt.geom.Rectangle2D;
import java.awt.geom.PathIterator;
import java.util.Vector;
final class Order1 extends Curve {
private double x0;
private double y0;
private double x1;
private double y1;
private double xmin;
private double xmax;
public Order1(double x0, double y0,
double x1, double y1,
int direction)
{
super(direction);
this.x0 = x0;
this.y0 = y0;
this.x1 = x1;
this.y1 = y1;
if (x0 < x1) {
this.xmin = x0;
this.xmax = x1;
} else {
this.xmin = x1;
this.xmax = x0;
}
}
public int getOrder() {
return 1;
}
public double getXTop() {
return x0;
}
public double getYTop() {
return y0;
}
public double getXBot() {
return x1;
}
public double getYBot() {
return y1;
}
public double getXMin() {
return xmin;
}
public double getXMax() {
return xmax;
}
public double getX0() {
return (direction == INCREASING) ? x0 : x1;
}
public double getY0() {
return (direction == INCREASING) ? y0 : y1;
}
public double getX1() {
return (direction == DECREASING) ? x0 : x1;
}
public double getY1() {
return (direction == DECREASING) ? y0 : y1;
}
public double XforY(double y) {
if (x0 == x1 || y == y0) {
return x0;
}
if (y == y1) {
return x1;
}
// assert(y0 != y1); /* No horizontal lines... */
return (x0 + (y - y0) * (x1 - x0) / (y1 - y0));
}
public double TforY(double y) {
return (y - y0) / (y1 - y0);
}
public double XforT(double t) {
return x0 + t * (x1 - x0);
}
public double YforT(double t) {
return y0 + t * (y1 - y0);
}
public double dXforT(double t, int deriv) {
switch (deriv) {
case 0:
return x0 + t * (x1 - x0);
case 1:
return (x1 - x0);
default:
return 0;
}
}
public double dYforT(double t, int deriv) {
switch (deriv) {
case 0:
return y0 + t * (y1 - y0);
case 1:
return (y1 - y0);
default:
return 0;
}
}
public double nextVertical(double t0, double t1) {
return t1;
}
public boolean accumulateCrossings(Crossings c) {
double xlo = c.getXLo();
double ylo = c.getYLo();
double xhi = c.getXHi();
double yhi = c.getYHi();
if (xmin >= xhi) {
return false;
}
double xstart, ystart, xend, yend;
if (y0 < ylo) {
if (y1 <= ylo) {
return false;
}
ystart = ylo;
xstart = XforY(ylo);
} else {
if (y0 >= yhi) {
return false;
}
ystart = y0;
xstart = x0;
}
if (y1 > yhi) {
yend = yhi;
xend = XforY(yhi);
} else {
yend = y1;
xend = x1;
}
if (xstart >= xhi && xend >= xhi) {
return false;
}
if (xstart > xlo || xend > xlo) {
return true;
}
c.record(ystart, yend, direction);
return false;
}
public void enlarge(Rectangle2D r) {
r.add(x0, y0);
r.add(x1, y1);
}
public Curve getSubCurve(double ystart, double yend, int dir) {
if (ystart == y0 && yend == y1) {
return getWithDirection(dir);
}
if (x0 == x1) {
return new Order1(x0, ystart, x1, yend, dir);
}
double num = x0 - x1;
double denom = y0 - y1;
double xstart = (x0 + (ystart - y0) * num / denom);
double xend = (x0 + (yend - y0) * num / denom);
return new Order1(xstart, ystart, xend, yend, dir);
}
public Curve getReversedCurve() {
return new Order1(x0, y0, x1, y1, -direction);
}
public int compareTo(Curve other, double yrange[]) {
if (!(other instanceof Order1)) {
return super.compareTo(other, yrange);
}
Order1 c1 = (Order1) other;
if (yrange[1] <= yrange[0]) {
throw new InternalError("yrange already screwed up...");
}
yrange[1] = Math.min(Math.min(yrange[1], y1), c1.y1);
if (yrange[1] <= yrange[0]) {
throw new InternalError("backstepping from "+yrange[0]+" to "+yrange[1]);
}
if (xmax <= c1.xmin) {
return (xmin == c1.xmax) ? 0 : -1;
}
if (xmin >= c1.xmax) {
return 1;
}
/*
* If "this" is curve A and "other" is curve B, then...
* xA(y) = x0A + (y - y0A) (x1A - x0A) / (y1A - y0A)
* xB(y) = x0B + (y - y0B) (x1B - x0B) / (y1B - y0B)
* xA(y) == xB(y)
* x0A + (y - y0A) (x1A - x0A) / (y1A - y0A)
* == x0B + (y - y0B) (x1B - x0B) / (y1B - y0B)
* 0 == x0A (y1A - y0A) (y1B - y0B) + (y - y0A) (x1A - x0A) (y1B - y0B)
* - x0B (y1A - y0A) (y1B - y0B) - (y - y0B) (x1B - x0B) (y1A - y0A)
* 0 == (x0A - x0B) (y1A - y0A) (y1B - y0B)
* + (y - y0A) (x1A - x0A) (y1B - y0B)
* - (y - y0B) (x1B - x0B) (y1A - y0A)
* If (dxA == x1A - x0A), etc...
* 0 == (x0A - x0B) * dyA * dyB
* + (y - y0A) * dxA * dyB
* - (y - y0B) * dxB * dyA
* 0 == (x0A - x0B) * dyA * dyB
* + y * dxA * dyB - y0A * dxA * dyB
* - y * dxB * dyA + y0B * dxB * dyA
* 0 == (x0A - x0B) * dyA * dyB
* + y * dxA * dyB - y * dxB * dyA
* - y0A * dxA * dyB + y0B * dxB * dyA
* 0 == (x0A - x0B) * dyA * dyB
* + y * (dxA * dyB - dxB * dyA)
* - y0A * dxA * dyB + y0B * dxB * dyA
* y == ((x0A - x0B) * dyA * dyB
* - y0A * dxA * dyB + y0B * dxB * dyA)
* / (-(dxA * dyB - dxB * dyA))
* y == ((x0A - x0B) * dyA * dyB
* - y0A * dxA * dyB + y0B * dxB * dyA)
* / (dxB * dyA - dxA * dyB)
*/
double dxa = x1 - x0;
double dya = y1 - y0;
double dxb = c1.x1 - c1.x0;
double dyb = c1.y1 - c1.y0;
double denom = dxb * dya - dxa * dyb;
double y;
if (denom != 0) {
double num = ((x0 - c1.x0) * dya * dyb
- y0 * dxa * dyb
+ c1.y0 * dxb * dya);
y = num / denom;
if (y <= yrange[0]) {
// intersection is above us
// Use bottom-most common y for comparison
y = Math.min(y1, c1.y1);
} else {
// intersection is below the top of our range
if (y < yrange[1]) {
// If intersection is in our range, adjust valid range
yrange[1] = y;
}
// Use top-most common y for comparison
y = Math.max(y0, c1.y0);
}
} else {
// lines are parallel, choose any common y for comparison
// Note - prefer an endpoint for speed of calculating the X
// (see shortcuts in Order1.XforY())
y = Math.max(y0, c1.y0);
}
return orderof(XforY(y), c1.XforY(y));
}
public int getSegment(double coords[]) {
if (direction == INCREASING) {
coords[0] = x1;
coords[1] = y1;
} else {
coords[0] = x0;
coords[1] = y0;
}
return PathIterator.SEG_LINETO;
}
}