Java example source code file (AreaOp.java)
The AreaOp.java Java example source code
/*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code 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 General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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*/
package sun.awt.geom;
import java.util.Vector;
import java.util.Enumeration;
import java.util.Comparator;
import java.util.Arrays;
public abstract class AreaOp {
public static abstract class CAGOp extends AreaOp {
boolean inLeft;
boolean inRight;
boolean inResult;
public void newRow() {
inLeft = false;
inRight = false;
inResult = false;
}
public int classify(Edge e) {
if (e.getCurveTag() == CTAG_LEFT) {
inLeft = !inLeft;
} else {
inRight = !inRight;
}
boolean newClass = newClassification(inLeft, inRight);
if (inResult == newClass) {
return ETAG_IGNORE;
}
inResult = newClass;
return (newClass ? ETAG_ENTER : ETAG_EXIT);
}
public int getState() {
return (inResult ? RSTAG_INSIDE : RSTAG_OUTSIDE);
}
public abstract boolean newClassification(boolean inLeft,
boolean inRight);
}
public static class AddOp extends CAGOp {
public boolean newClassification(boolean inLeft, boolean inRight) {
return (inLeft || inRight);
}
}
public static class SubOp extends CAGOp {
public boolean newClassification(boolean inLeft, boolean inRight) {
return (inLeft && !inRight);
}
}
public static class IntOp extends CAGOp {
public boolean newClassification(boolean inLeft, boolean inRight) {
return (inLeft && inRight);
}
}
public static class XorOp extends CAGOp {
public boolean newClassification(boolean inLeft, boolean inRight) {
return (inLeft != inRight);
}
}
public static class NZWindOp extends AreaOp {
private int count;
public void newRow() {
count = 0;
}
public int classify(Edge e) {
// Note: the right curves should be an empty set with this op...
// assert(e.getCurveTag() == CTAG_LEFT);
int newCount = count;
int type = (newCount == 0 ? ETAG_ENTER : ETAG_IGNORE);
newCount += e.getCurve().getDirection();
count = newCount;
return (newCount == 0 ? ETAG_EXIT : type);
}
public int getState() {
return ((count == 0) ? RSTAG_OUTSIDE : RSTAG_INSIDE);
}
}
public static class EOWindOp extends AreaOp {
private boolean inside;
public void newRow() {
inside = false;
}
public int classify(Edge e) {
// Note: the right curves should be an empty set with this op...
// assert(e.getCurveTag() == CTAG_LEFT);
boolean newInside = !inside;
inside = newInside;
return (newInside ? ETAG_ENTER : ETAG_EXIT);
}
public int getState() {
return (inside ? RSTAG_INSIDE : RSTAG_OUTSIDE);
}
}
private AreaOp() {
}
/* Constants to tag the left and right curves in the edge list */
public static final int CTAG_LEFT = 0;
public static final int CTAG_RIGHT = 1;
/* Constants to classify edges */
public static final int ETAG_IGNORE = 0;
public static final int ETAG_ENTER = 1;
public static final int ETAG_EXIT = -1;
/* Constants used to classify result state */
public static final int RSTAG_INSIDE = 1;
public static final int RSTAG_OUTSIDE = -1;
public abstract void newRow();
public abstract int classify(Edge e);
public abstract int getState();
public Vector calculate(Vector left, Vector right) {
Vector edges = new Vector();
addEdges(edges, left, AreaOp.CTAG_LEFT);
addEdges(edges, right, AreaOp.CTAG_RIGHT);
edges = pruneEdges(edges);
if (false) {
System.out.println("result: ");
int numcurves = edges.size();
Curve[] curvelist = (Curve[]) edges.toArray(new Curve[numcurves]);
for (int i = 0; i < numcurves; i++) {
System.out.println("curvelist["+i+"] = "+curvelist[i]);
}
}
return edges;
}
private static void addEdges(Vector edges, Vector curves, int curvetag) {
Enumeration enum_ = curves.elements();
while (enum_.hasMoreElements()) {
Curve c = (Curve) enum_.nextElement();
if (c.getOrder() > 0) {
edges.add(new Edge(c, curvetag));
}
}
}
private static Comparator YXTopComparator = new Comparator() {
public int compare(Object o1, Object o2) {
Curve c1 = ((Edge) o1).getCurve();
Curve c2 = ((Edge) o2).getCurve();
double v1, v2;
if ((v1 = c1.getYTop()) == (v2 = c2.getYTop())) {
if ((v1 = c1.getXTop()) == (v2 = c2.getXTop())) {
return 0;
}
}
if (v1 < v2) {
return -1;
}
return 1;
}
};
private Vector pruneEdges(Vector edges) {
int numedges = edges.size();
if (numedges < 2) {
return edges;
}
Edge[] edgelist = (Edge[]) edges.toArray(new Edge[numedges]);
Arrays.sort(edgelist, YXTopComparator);
if (false) {
System.out.println("pruning: ");
for (int i = 0; i < numedges; i++) {
System.out.println("edgelist["+i+"] = "+edgelist[i]);
}
}
Edge e;
int left = 0;
int right = 0;
int cur = 0;
int next = 0;
double yrange[] = new double[2];
Vector subcurves = new Vector();
Vector chains = new Vector();
Vector links = new Vector();
// Active edges are between left (inclusive) and right (exclusive)
while (left < numedges) {
double y = yrange[0];
// Prune active edges that fall off the top of the active y range
for (cur = next = right - 1; cur >= left; cur--) {
e = edgelist[cur];
if (e.getCurve().getYBot() > y) {
if (next > cur) {
edgelist[next] = e;
}
next--;
}
}
left = next + 1;
// Grab a new "top of Y range" if the active edges are empty
if (left >= right) {
if (right >= numedges) {
break;
}
y = edgelist[right].getCurve().getYTop();
if (y > yrange[0]) {
finalizeSubCurves(subcurves, chains);
}
yrange[0] = y;
}
// Incorporate new active edges that enter the active y range
while (right < numedges) {
e = edgelist[right];
if (e.getCurve().getYTop() > y) {
break;
}
right++;
}
// Sort the current active edges by their X values and
// determine the maximum valid Y range where the X ordering
// is correct
yrange[1] = edgelist[left].getCurve().getYBot();
if (right < numedges) {
y = edgelist[right].getCurve().getYTop();
if (yrange[1] > y) {
yrange[1] = y;
}
}
if (false) {
System.out.println("current line: y = ["+
yrange[0]+", "+yrange[1]+"]");
for (cur = left; cur < right; cur++) {
System.out.println(" "+edgelist[cur]);
}
}
// Note: We could start at left+1, but we need to make
// sure that edgelist[left] has its equivalence set to 0.
int nexteq = 1;
for (cur = left; cur < right; cur++) {
e = edgelist[cur];
e.setEquivalence(0);
for (next = cur; next > left; next--) {
Edge prevedge = edgelist[next-1];
int ordering = e.compareTo(prevedge, yrange);
if (yrange[1] <= yrange[0]) {
throw new InternalError("backstepping to "+yrange[1]+
" from "+yrange[0]);
}
if (ordering >= 0) {
if (ordering == 0) {
// If the curves are equal, mark them to be
// deleted later if they cancel each other
// out so that we avoid having extraneous
// curve segments.
int eq = prevedge.getEquivalence();
if (eq == 0) {
eq = nexteq++;
prevedge.setEquivalence(eq);
}
e.setEquivalence(eq);
}
break;
}
edgelist[next] = prevedge;
}
edgelist[next] = e;
}
if (false) {
System.out.println("current sorted line: y = ["+
yrange[0]+", "+yrange[1]+"]");
for (cur = left; cur < right; cur++) {
System.out.println(" "+edgelist[cur]);
}
}
// Now prune the active edge list.
// For each edge in the list, determine its classification
// (entering shape, exiting shape, ignore - no change) and
// record the current Y range and its classification in the
// Edge object for use later in constructing the new outline.
newRow();
double ystart = yrange[0];
double yend = yrange[1];
for (cur = left; cur < right; cur++) {
e = edgelist[cur];
int etag;
int eq = e.getEquivalence();
if (eq != 0) {
// Find one of the segments in the "equal" range
// with the right transition state and prefer an
// edge that was either active up until ystart
// or the edge that extends the furthest downward
// (i.e. has the most potential for continuation)
int origstate = getState();
etag = (origstate == AreaOp.RSTAG_INSIDE
? AreaOp.ETAG_EXIT
: AreaOp.ETAG_ENTER);
Edge activematch = null;
Edge longestmatch = e;
double furthesty = yend;
do {
// Note: classify() must be called
// on every edge we consume here.
classify(e);
if (activematch == null &&
e.isActiveFor(ystart, etag))
{
activematch = e;
}
y = e.getCurve().getYBot();
if (y > furthesty) {
longestmatch = e;
furthesty = y;
}
} while (++cur < right &&
(e = edgelist[cur]).getEquivalence() == eq);
--cur;
if (getState() == origstate) {
etag = AreaOp.ETAG_IGNORE;
} else {
e = (activematch != null ? activematch : longestmatch);
}
} else {
etag = classify(e);
}
if (etag != AreaOp.ETAG_IGNORE) {
e.record(yend, etag);
links.add(new CurveLink(e.getCurve(), ystart, yend, etag));
}
}
// assert(getState() == AreaOp.RSTAG_OUTSIDE);
if (getState() != AreaOp.RSTAG_OUTSIDE) {
System.out.println("Still inside at end of active edge list!");
System.out.println("num curves = "+(right-left));
System.out.println("num links = "+links.size());
System.out.println("y top = "+yrange[0]);
if (right < numedges) {
System.out.println("y top of next curve = "+
edgelist[right].getCurve().getYTop());
} else {
System.out.println("no more curves");
}
for (cur = left; cur < right; cur++) {
e = edgelist[cur];
System.out.println(e);
int eq = e.getEquivalence();
if (eq != 0) {
System.out.println(" was equal to "+eq+"...");
}
}
}
if (false) {
System.out.println("new links:");
for (int i = 0; i < links.size(); i++) {
CurveLink link = (CurveLink) links.elementAt(i);
System.out.println(" "+link.getSubCurve());
}
}
resolveLinks(subcurves, chains, links);
links.clear();
// Finally capture the bottom of the valid Y range as the top
// of the next Y range.
yrange[0] = yend;
}
finalizeSubCurves(subcurves, chains);
Vector ret = new Vector();
Enumeration enum_ = subcurves.elements();
while (enum_.hasMoreElements()) {
CurveLink link = (CurveLink) enum_.nextElement();
ret.add(link.getMoveto());
CurveLink nextlink = link;
while ((nextlink = nextlink.getNext()) != null) {
if (!link.absorb(nextlink)) {
ret.add(link.getSubCurve());
link = nextlink;
}
}
ret.add(link.getSubCurve());
}
return ret;
}
public static void finalizeSubCurves(Vector subcurves, Vector chains) {
int numchains = chains.size();
if (numchains == 0) {
return;
}
if ((numchains & 1) != 0) {
throw new InternalError("Odd number of chains!");
}
ChainEnd[] endlist = new ChainEnd[numchains];
chains.toArray(endlist);
for (int i = 1; i < numchains; i += 2) {
ChainEnd open = endlist[i - 1];
ChainEnd close = endlist[i];
CurveLink subcurve = open.linkTo(close);
if (subcurve != null) {
subcurves.add(subcurve);
}
}
chains.clear();
}
private static CurveLink[] EmptyLinkList = new CurveLink[2];
private static ChainEnd[] EmptyChainList = new ChainEnd[2];
public static void resolveLinks(Vector subcurves,
Vector chains,
Vector links)
{
int numlinks = links.size();
CurveLink[] linklist;
if (numlinks == 0) {
linklist = EmptyLinkList;
} else {
if ((numlinks & 1) != 0) {
throw new InternalError("Odd number of new curves!");
}
linklist = new CurveLink[numlinks+2];
links.toArray(linklist);
}
int numchains = chains.size();
ChainEnd[] endlist;
if (numchains == 0) {
endlist = EmptyChainList;
} else {
if ((numchains & 1) != 0) {
throw new InternalError("Odd number of chains!");
}
endlist = new ChainEnd[numchains+2];
chains.toArray(endlist);
}
int curchain = 0;
int curlink = 0;
chains.clear();
ChainEnd chain = endlist[0];
ChainEnd nextchain = endlist[1];
CurveLink link = linklist[0];
CurveLink nextlink = linklist[1];
while (chain != null || link != null) {
/*
* Strategy 1:
* Connect chains or links if they are the only things left...
*/
boolean connectchains = (link == null);
boolean connectlinks = (chain == null);
if (!connectchains && !connectlinks) {
// assert(link != null && chain != null);
/*
* Strategy 2:
* Connect chains or links if they close off an open area...
*/
connectchains = ((curchain & 1) == 0 &&
chain.getX() == nextchain.getX());
connectlinks = ((curlink & 1) == 0 &&
link.getX() == nextlink.getX());
if (!connectchains && !connectlinks) {
/*
* Strategy 3:
* Connect chains or links if their successor is
* between them and their potential connectee...
*/
double cx = chain.getX();
double lx = link.getX();
connectchains =
(nextchain != null && cx < lx &&
obstructs(nextchain.getX(), lx, curchain));
connectlinks =
(nextlink != null && lx < cx &&
obstructs(nextlink.getX(), cx, curlink));
}
}
if (connectchains) {
CurveLink subcurve = chain.linkTo(nextchain);
if (subcurve != null) {
subcurves.add(subcurve);
}
curchain += 2;
chain = endlist[curchain];
nextchain = endlist[curchain+1];
}
if (connectlinks) {
ChainEnd openend = new ChainEnd(link, null);
ChainEnd closeend = new ChainEnd(nextlink, openend);
openend.setOtherEnd(closeend);
chains.add(openend);
chains.add(closeend);
curlink += 2;
link = linklist[curlink];
nextlink = linklist[curlink+1];
}
if (!connectchains && !connectlinks) {
// assert(link != null);
// assert(chain != null);
// assert(chain.getEtag() == link.getEtag());
chain.addLink(link);
chains.add(chain);
curchain++;
chain = nextchain;
nextchain = endlist[curchain+1];
curlink++;
link = nextlink;
nextlink = linklist[curlink+1];
}
}
if ((chains.size() & 1) != 0) {
System.out.println("Odd number of chains!");
}
}
/*
* Does the position of the next edge at v1 "obstruct" the
* connectivity between current edge and the potential
* partner edge which is positioned at v2?
*
* Phase tells us whether we are testing for a transition
* into or out of the interior part of the resulting area.
*
* Require 4-connected continuity if this edge and the partner
* edge are both "entering into" type edges
* Allow 8-connected continuity for "exiting from" type edges
*/
public static boolean obstructs(double v1, double v2, int phase) {
return (((phase & 1) == 0) ? (v1 <= v2) : (v1 < v2));
}
}
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