org.jaitools.imageutils.shape.PolygonIterator Maven / Gradle / Ivy
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Provides a single jar containing all JAITools modules which you can
use instead of including individual modules in your project. Note:
It does not include the Jiffle scripting language or Jiffle image
operator.
/*
* Copyright (c) 2011, Michael Bedward. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* - 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 distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.jaitools.imageutils.shape;
import java.awt.geom.AffineTransform;
import com.vividsolutions.jts.geom.CoordinateSequence;
import com.vividsolutions.jts.geom.LineString;
import com.vividsolutions.jts.geom.Polygon;
/**
* A path iterator for the LiteShape class, specialized to iterate over Polygon
* objects. This class was ported back and simplified from GeoTools, with permission from the author(s)
*
* @author Andrea Aime
* @author simone giannecchini
*/
public final class PolygonIterator extends AbstractLiteIterator {
/** Transform applied on the coordinates during iteration */
private AffineTransform at;
/** The rings describing the polygon geometry */
private LineString[] rings;
/** The current ring during iteration */
private int currentRing = 0;
/** Current line coordinate */
private int currentCoord = 0;
/** The array of coordinates that represents the line geometry */
private CoordinateSequence coords = null;
/** True when the iteration is terminated */
private boolean done = false;
/**
* Creates a new PolygonIterator object.
*
* @param p The polygon
* @param at The affine transform applied to coordinates during iteration
*/
public PolygonIterator(Polygon p, AffineTransform at) {
int numInteriorRings = p.getNumInteriorRing();
rings = new LineString[numInteriorRings + 1];
rings[0] = p.getExteriorRing();
for (int i = 0; i < numInteriorRings; i++) {
rings[i + 1] = p.getInteriorRingN(i);
}
if (at == null) {
at = new AffineTransform();
}
this.at = at;
coords = rings[0].getCoordinateSequence();
}
/**
* Returns the coordinates and type of the current path segment in the
* iteration. The return value is the path-segment type: SEG_MOVETO,
* SEG_LINETO, SEG_QUADTO, SEG_CUBICTO, or SEG_CLOSE. A double array of
* length 6 must be passed in and can be used to store the coordinates of
* the point(s). Each point is stored as a pair of double x,y coordinates.
* SEG_MOVETO and SEG_LINETO types returns one point, SEG_QUADTO returns
* two points, SEG_CUBICTO returns 3 points and SEG_CLOSE does not return
* any points.
*
* @param coords an array that holds the data returned from this method
*
* @return the path-segment type of the current path segment.
*
* @see #SEG_MOVETO
* @see #SEG_LINETO
* @see #SEG_QUADTO
* @see #SEG_CUBICTO
* @see #SEG_CLOSE
*/
public int currentSegment(double[] coords) {
// first make sure we're not at the last element, this prevents us from exceptions
// in the case where coords.size() == 0
if (currentCoord == this.coords.size()) {
return SEG_CLOSE;
} else if (currentCoord == 0) {
coords[0] = this.coords.getX(0);
coords[1] = this.coords.getY(0);
transform(coords, 0, coords, 0, 1);
return SEG_MOVETO;
} else {
coords[0] = this.coords.getX(currentCoord);
coords[1] = this.coords.getY(currentCoord);
transform(coords, 0, coords, 0, 1);
return SEG_LINETO;
}
}
protected void transform(double[] src, int index, double[] dest, int destIndex, int numPoints){
at.transform(src, index, dest, destIndex, numPoints);
}
/**
* Return the winding rule for determining the interior of the path.
*
* @return WIND_EVEN_ODD by default.
*/
public int getWindingRule() {
return WIND_EVEN_ODD;
}
/**
* Tests if the iteration is complete.
*
* @return true if all the segments have been read;
* false otherwise.
*/
public boolean isDone() {
return done;
}
/**
* Moves the iterator to the next segment of the path forwards along the
* primary direction of traversal as long as there are more points in that
* direction.
*/
public void next() {
if (currentCoord == coords.size()) {
if (currentRing < (rings.length - 1)) {
currentCoord = 0;
currentRing++;
coords = rings[currentRing].getCoordinateSequence();
} else {
done = true;
}
} else {
currentCoord++;
}
}
}