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iText, a free Java-PDF library
/*
* $Id: 8911a20bce88eae6f29cc5945a999d9e7e00fc3d $
*
* This file is part of the iText (R) project.
* Copyright (c) 2014-2015 iText Group NV
* Authors: Bruno Lowagie, Paulo Soares, et al.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License version 3
* as published by the Free Software Foundation with the addition of the
* following permission added to Section 15 as permitted in Section 7(a):
* FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY
* ITEXT GROUP. ITEXT GROUP DISCLAIMS THE WARRANTY OF NON INFRINGEMENT
* OF THIRD PARTY RIGHTS
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU Affero General Public License for more details.
* You should have received a copy of the GNU Affero General Public License
* along with this program; if not, see http://www.gnu.org/licenses or write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA, 02110-1301 USA, or download the license from the following URL:
* http://itextpdf.com/terms-of-use/
*
* The interactive user interfaces in modified source and object code versions
* of this program must display Appropriate Legal Notices, as required under
* Section 5 of the GNU Affero General Public License.
*
* In accordance with Section 7(b) of the GNU Affero General Public License,
* a covered work must retain the producer line in every PDF that is created
* or manipulated using iText.
*
* You can be released from the requirements of the license by purchasing
* a commercial license. Buying such a license is mandatory as soon as you
* develop commercial activities involving the iText software without
* disclosing the source code of your own applications.
* These activities include: offering paid services to customers as an ASP,
* serving PDFs on the fly in a web application, shipping iText with a closed
* source product.
*
* For more information, please contact iText Software Corp. at this
* address: [email protected]
*
*
* This class is based on the C# open source freeware library Clipper:
* http://www.angusj.com/delphi/clipper.php
* The original classes were distributed under the Boost Software License:
*
* Freeware for both open source and commercial applications
* Copyright 2010-2014 Angus Johnson
* Boost Software License - Version 1.0 - August 17th, 2003
*
* Permission is hereby granted, free of charge, to any person or organization
* obtaining a copy of the software and accompanying documentation covered by
* this license (the "Software") to use, reproduce, display, distribute,
* execute, and transmit the Software, and to prepare derivative works of the
* Software, and to permit third-parties to whom the Software is furnished to
* do so, all subject to the following:
*
* The copyright notices in the Software and this entire statement, including
* the above license grant, this restriction and the following disclaimer,
* must be included in all copies of the Software, in whole or in part, and
* all derivative works of the Software, unless such copies or derivative
* works are solely in the form of machine-executable object code generated by
* a source language processor.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
* SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
* FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
package com.itextpdf.text.pdf.parser.clipper;
import com.itextpdf.text.pdf.parser.clipper.Point.LongPoint;
import java.util.ArrayList;
import java.util.List;
import java.util.logging.Logger;
public abstract class ClipperBase implements Clipper {
protected class LocalMinima {
long y;
Edge leftBound;
Edge rightBound;
LocalMinima next;
};
protected class Scanbeam {
long y;
Scanbeam next;
};
private static void initEdge( Edge e, Edge eNext, Edge ePrev, LongPoint pt ) {
e.next = eNext;
e.prev = ePrev;
e.setCurrent( new LongPoint( pt ) );
e.outIdx = Edge.UNASSIGNED;
}
private static void initEdge2( Edge e, PolyType polyType ) {
if (e.getCurrent().getY() >= e.next.getCurrent().getY()) {
e.setBot( new LongPoint( e.getCurrent() ) );
e.setTop( new LongPoint( e.next.getCurrent() ) );
}
else {
e.setTop( new LongPoint( e.getCurrent() ) );
e.setBot( new LongPoint( e.next.getCurrent() ) );
}
e.updateDeltaX();
e.polyTyp = polyType;
}
private static void rangeTest( LongPoint Pt ) {
if (Pt.getX() > LOW_RANGE || Pt.getY() > LOW_RANGE || -Pt.getX() > LOW_RANGE || -Pt.getY() > LOW_RANGE) {
if (Pt.getX() > HI_RANGE || Pt.getY() > HI_RANGE || -Pt.getX() > HI_RANGE || -Pt.getY() > HI_RANGE) {
throw new IllegalStateException( "Coordinate outside allowed range" );
}
}
}
private static Edge removeEdge( Edge e ) {
//removes e from double_linked_list (but without removing from memory)
e.prev.next = e.next;
e.next.prev = e.prev;
final Edge result = e.next;
e.prev = null; //flag as removed (see ClipperBase.Clear)
return result;
}
private final static long LOW_RANGE = 0x3FFFFFFF;
private final static long HI_RANGE = 0x3FFFFFFFFFFFFFFFL;
protected LocalMinima minimaList;
protected LocalMinima currentLM;
private final List> edges;
protected boolean hasOpenPaths;
protected final boolean preserveCollinear;
private final static Logger LOGGER = Logger.getLogger( Clipper.class.getName() );
protected ClipperBase( boolean preserveCollinear ) //constructor (nb: no external instantiation)
{
this.preserveCollinear = preserveCollinear;
minimaList = null;
currentLM = null;
hasOpenPaths = false;
edges = new ArrayList>();
}
public boolean addPath( Path pg, PolyType polyType, boolean Closed ) {
if (!Closed && polyType == PolyType.CLIP) {
throw new IllegalStateException( "AddPath: Open paths must be subject." );
}
int highI = pg.size() - 1;
if (Closed) {
while (highI > 0 && pg.get( highI ).equals( pg.get( 0 ) )) {
--highI;
}
}
while (highI > 0 && pg.get( highI ).equals( pg.get( highI - 1 ) )) {
--highI;
}
if (Closed && highI < 2 || !Closed && highI < 1) {
return false;
}
//create a new edge array ...
final List edges = new ArrayList( highI + 1 );
for (int i = 0; i <= highI; i++) {
edges.add( new Edge() );
}
boolean IsFlat = true;
//1. Basic (first) edge initialization ...
edges.get( 1 ).setCurrent( new LongPoint( pg.get( 1 ) ) );
rangeTest( pg.get( 0 ) );
rangeTest( pg.get( highI ) );
initEdge( edges.get( 0 ), edges.get( 1 ), edges.get( highI ), pg.get( 0 ) );
initEdge( edges.get( highI ), edges.get( 0 ), edges.get( highI - 1 ), pg.get( highI ) );
for (int i = highI - 1; i >= 1; --i) {
rangeTest( pg.get( i ) );
initEdge( edges.get( i ), edges.get( i + 1 ), edges.get( i - 1 ), pg.get( i ) );
}
Edge eStart = edges.get( 0 );
//2. Remove duplicate vertices, and (when closed) collinear edges ...
Edge e = eStart, eLoopStop = eStart;
for (;;) {
//nb: allows matching start and end points when not Closed ...
if (e.getCurrent().equals( e.next.getCurrent() ) && (Closed || !e.next.equals( eStart ))) {
if (e == e.next) {
break;
}
if (e == eStart) {
eStart = e.next;
}
e = removeEdge( e );
eLoopStop = e;
continue;
}
if (e.prev == e.next) {
break; //only two vertices
}
else if (Closed && Point.slopesEqual( e.prev.getCurrent(), e.getCurrent(), e.next.getCurrent() )
&& (!isPreserveCollinear() || !Point.isPt2BetweenPt1AndPt3( e.prev.getCurrent(), e.getCurrent(), e.next.getCurrent() ))) {
//Collinear edges are allowed for open paths but in closed paths
//the default is to merge adjacent collinear edges into a single edge.
//However, if the PreserveCollinear property is enabled, only overlapping
//collinear edges (ie spikes) will be removed from closed paths.
if (e == eStart) {
eStart = e.next;
}
e = removeEdge( e );
e = e.prev;
eLoopStop = e;
continue;
}
e = e.next;
if (e == eLoopStop || !Closed && e.next == eStart) {
break;
}
}
if (!Closed && e == e.next || Closed && e.prev == e.next) {
return false;
}
if (!Closed) {
hasOpenPaths = true;
eStart.prev.outIdx = Edge.SKIP;
}
//3. Do second stage of edge initialization ...
e = eStart;
do {
initEdge2( e, polyType );
e = e.next;
if (IsFlat && e.getCurrent().getY() != eStart.getCurrent().getY()) {
IsFlat = false;
}
}
while (e != eStart);
//4. Finally, add edge bounds to LocalMinima list ...
//Totally flat paths must be handled differently when adding them
//to LocalMinima list to avoid endless loops etc ...
if (IsFlat) {
if (Closed) {
return false;
}
e.prev.outIdx = Edge.SKIP;
final LocalMinima locMin = new LocalMinima();
locMin.next = null;
locMin.y = e.getBot().getY();
locMin.leftBound = null;
locMin.rightBound = e;
locMin.rightBound.side = Edge.Side.RIGHT;
locMin.rightBound.windDelta = 0;
for ( ; ; )
{
if (e.getBot().getX() != e.prev.getTop().getX()) e.reverseHorizontal();
if (e.next.outIdx == Edge.SKIP) break;
e.nextInLML = e.next;
e = e.next;
}
insertLocalMinima( locMin );
this.edges.add( edges );
return true;
}
this.edges.add( edges );
boolean leftBoundIsForward;
Edge EMin = null;
//workaround to avoid an endless loop in the while loop below when
//open paths have matching start and end points ...
if (e.prev.getBot().equals( e.prev.getTop() )) {
e = e.next;
}
for (;;) {
e = e.findNextLocMin();
if (e == EMin) {
break;
}
else if (EMin == null) {
EMin = e;
}
//E and E.Prev now share a local minima (left aligned if horizontal).
//Compare their slopes to find which starts which bound ...
final LocalMinima locMin = new LocalMinima();
locMin.next = null;
locMin.y = e.getBot().getY();
if (e.deltaX < e.prev.deltaX) {
locMin.leftBound = e.prev;
locMin.rightBound = e;
leftBoundIsForward = false; //Q.nextInLML = Q.prev
}
else {
locMin.leftBound = e;
locMin.rightBound = e.prev;
leftBoundIsForward = true; //Q.nextInLML = Q.next
}
locMin.leftBound.side = Edge.Side.LEFT;
locMin.rightBound.side = Edge.Side.RIGHT;
if (!Closed) {
locMin.leftBound.windDelta = 0;
}
else if (locMin.leftBound.next == locMin.rightBound) {
locMin.leftBound.windDelta = -1;
}
else {
locMin.leftBound.windDelta = 1;
}
locMin.rightBound.windDelta = -locMin.leftBound.windDelta;
e = processBound( locMin.leftBound, leftBoundIsForward );
if (e.outIdx == Edge.SKIP) {
e = processBound( e, leftBoundIsForward );
}
Edge E2 = processBound( locMin.rightBound, !leftBoundIsForward );
if (E2.outIdx == Edge.SKIP) {
E2 = processBound( E2, !leftBoundIsForward );
}
if (locMin.leftBound.outIdx == Edge.SKIP) {
locMin.leftBound = null;
}
else if (locMin.rightBound.outIdx == Edge.SKIP) {
locMin.rightBound = null;
}
insertLocalMinima( locMin );
if (!leftBoundIsForward) {
e = E2;
}
}
return true;
}
public boolean addPaths( Paths ppg, PolyType polyType, boolean closed ) {
boolean result = false;
for (int i = 0; i < ppg.size(); ++i) {
if (addPath( ppg.get( i ), polyType, closed )) {
result = true;
}
}
return result;
}
public void clear() {
disposeLocalMinimaList();
edges.clear();
hasOpenPaths = false;
}
private void disposeLocalMinimaList() {
while (minimaList != null) {
final LocalMinima tmpLm = minimaList.next;
minimaList = null;
minimaList = tmpLm;
}
currentLM = null;
}
private void insertLocalMinima( LocalMinima newLm ) {
if (minimaList == null) {
minimaList = newLm;
}
else if (newLm.y >= minimaList.y) {
newLm.next = minimaList;
minimaList = newLm;
}
else {
LocalMinima tmpLm = minimaList;
while (tmpLm.next != null && newLm.y < tmpLm.next.y) {
tmpLm = tmpLm.next;
}
newLm.next = tmpLm.next;
tmpLm.next = newLm;
}
}
public boolean isPreserveCollinear() {
return preserveCollinear;
}
protected void popLocalMinima() {
LOGGER.entering( ClipperBase.class.getName(), "popLocalMinima" );
if (currentLM == null) {
return;
}
currentLM = currentLM.next;
}
private Edge processBound( Edge e, boolean LeftBoundIsForward ) {
Edge EStart, result = e;
Edge Horz;
if (result.outIdx == Edge.SKIP) {
//check if there are edges beyond the skip edge in the bound and if so
//create another LocMin and calling ProcessBound once more ...
e = result;
if (LeftBoundIsForward) {
while (e.getTop().getY() == e.next.getBot().getY()) {
e = e.next;
}
while (e != result && e.deltaX == Edge.HORIZONTAL) {
e = e.prev;
}
}
else {
while (e.getTop().getY() == e.prev.getBot().getY()) {
e = e.prev;
}
while (e != result && e.deltaX == Edge.HORIZONTAL) {
e = e.next;
}
}
if (e == result) {
if (LeftBoundIsForward) {
result = e.next;
}
else {
result = e.prev;
}
}
else {
//there are more edges in the bound beyond result starting with E
if (LeftBoundIsForward) {
e = result.next;
}
else {
e = result.prev;
}
final LocalMinima locMin = new LocalMinima();
locMin.next = null;
locMin.y = e.getBot().getY();
locMin.leftBound = null;
locMin.rightBound = e;
e.windDelta = 0;
result = processBound( e, LeftBoundIsForward );
insertLocalMinima( locMin );
}
return result;
}
if (e.deltaX == Edge.HORIZONTAL) {
//We need to be careful with open paths because this may not be a
//true local minima (ie E may be following a skip edge).
//Also, consecutive horz. edges may start heading left before going right.
if (LeftBoundIsForward) {
EStart = e.prev;
}
else {
EStart = e.next;
}
if (EStart.deltaX == Edge.HORIZONTAL) //ie an adjoining horizontal skip edge
{
if (EStart.getBot().getX() != e.getBot().getX() && EStart.getTop().getX() != e.getBot().getX())
e.reverseHorizontal();
}
else if (EStart.getBot().getX() != e.getBot().getX())
e.reverseHorizontal();
}
EStart = e;
if (LeftBoundIsForward) {
while (result.getTop().getY() == result.next.getBot().getY() && result.next.outIdx != Edge.SKIP) {
result = result.next;
}
if (result.deltaX == Edge.HORIZONTAL && result.next.outIdx != Edge.SKIP) {
//nb: at the top of a bound, horizontals are added to the bound
//only when the preceding edge attaches to the horizontal's left vertex
//unless a Skip edge is encountered when that becomes the top divide
Horz = result;
while (Horz.prev.deltaX == Edge.HORIZONTAL) {
Horz = Horz.prev;
}
if (Horz.prev.getTop().getX() > result.next.getTop().getX()) result = Horz.prev;
}
while (e != result) {
e.nextInLML = e.next;
if (e.deltaX == Edge.HORIZONTAL && e != EStart && e.getBot().getX() != e.prev.getTop().getX()) {
e.reverseHorizontal();
}
e = e.next;
}
if (e.deltaX == Edge.HORIZONTAL && e != EStart && e.getBot().getX() != e.prev.getTop().getX()) {
e.reverseHorizontal();
}
result = result.next; //move to the edge just beyond current bound
}
else {
while (result.getTop().getY() == result.prev.getBot().getY() && result.prev.outIdx != Edge.SKIP) {
result = result.prev;
}
if (result.deltaX == Edge.HORIZONTAL && result.prev.outIdx != Edge.SKIP) {
Horz = result;
while (Horz.next.deltaX == Edge.HORIZONTAL) {
Horz = Horz.next;
}
if (Horz.next.getTop().getX() == result.prev.getTop().getX() ||
Horz.next.getTop().getX() > result.prev.getTop().getX()) result = Horz.next;
}
while (e != result) {
e.nextInLML = e.prev;
if (e.deltaX == Edge.HORIZONTAL && e != EStart && e.getBot().getX() != e.next.getTop().getX()) {
e.reverseHorizontal();
}
e = e.prev;
}
if (e.deltaX == Edge.HORIZONTAL && e != EStart && e.getBot().getX() != e.next.getTop().getX()) {
e.reverseHorizontal();
}
result = result.prev; //move to the edge just beyond current bound
}
return result;
}
protected void reset() {
currentLM = minimaList;
if (currentLM == null) {
return; //ie nothing to process
}
//reset all edges ...
LocalMinima lm = minimaList;
while (lm != null) {
Edge e = lm.leftBound;
if (e != null) {
e.setCurrent( new LongPoint( e.getBot() ) );
e.side = Edge.Side.LEFT;
e.outIdx = Edge.UNASSIGNED;
}
e = lm.rightBound;
if (e != null) {
e.setCurrent( new LongPoint( e.getBot() ) );
e.side = Edge.Side.RIGHT;
e.outIdx = Edge.UNASSIGNED;
}
lm = lm.next;
}
}
}