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/*
* Copyright (c) 2015, 2017, Oracle and/or its affiliates. All rights reserved.
* 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
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package sun.java2d.marlin;
final class DCollinearSimplifier implements DPathConsumer2D {
private static final int STATE_PREV_LINE = 0;
private static final int STATE_PREV_POINT = 1;
private static final int STATE_EMPTY = 2;
// slope precision threshold
private static final double EPS = 1e-3d; // aaime proposed 1e-3d
// members:
private DPathConsumer2D delegate;
private int state;
private double px1, py1;
private double pdx, pdy;
private double px2, py2;
DCollinearSimplifier() {
}
public DCollinearSimplifier init(final DPathConsumer2D delegate) {
this.delegate = delegate;
this.state = STATE_EMPTY;
return this; // fluent API
}
@Override
public void pathDone() {
emitStashedLine();
delegate.pathDone();
state = STATE_EMPTY;
}
@Override
public void closePath() {
emitStashedLine();
delegate.closePath();
state = STATE_EMPTY;
}
@Override
public long getNativeConsumer() {
return 0;
}
@Override
public void quadTo(final double x1, final double y1,
final double xe, final double ye)
{
emitStashedLine();
delegate.quadTo(x1, y1, xe, ye);
// final end point:
state = STATE_PREV_POINT;
px1 = xe;
py1 = ye;
}
@Override
public void curveTo(final double x1, final double y1,
final double x2, final double y2,
final double xe, final double ye)
{
emitStashedLine();
delegate.curveTo(x1, y1, x2, y2, xe, ye);
// final end point:
state = STATE_PREV_POINT;
px1 = xe;
py1 = ye;
}
@Override
public void moveTo(final double xe, final double ye) {
emitStashedLine();
delegate.moveTo(xe, ye);
state = STATE_PREV_POINT;
px1 = xe;
py1 = ye;
}
@Override
public void lineTo(final double xe, final double ye) {
// most probable case first:
if (state == STATE_PREV_LINE) {
// test for collinearity
final double dx = (xe - px2);
final double dy = (ye - py2);
// perf: avoid slope computation (fdiv) replaced by 3 fmul
if ((dy == 0.0d && pdy == 0.0d && (pdx * dx) >= 0.0d)
// uncertainty on slope:
// || (Math.abs(pdx * dy - pdy * dx) < EPS * Math.abs(pdy * dy))) {
// try 0
|| ((pdy * dy) != 0.0d && (pdx * dy - pdy * dx) == 0.0d)) {
// same horizontal orientation or same slope:
// TODO: store cumulated error on slope ?
// merge segments
px2 = xe;
py2 = ye;
} else {
// emit previous segment
delegate.lineTo(px2, py2);
px1 = px2;
py1 = py2;
pdx = dx;
pdy = dy;
px2 = xe;
py2 = ye;
}
} else if (state == STATE_PREV_POINT) {
state = STATE_PREV_LINE;
pdx = (xe - px1);
pdy = (ye - py1);
px2 = xe;
py2 = ye;
} else if (state == STATE_EMPTY) {
delegate.lineTo(xe, ye);
state = STATE_PREV_POINT;
px1 = xe;
py1 = ye;
}
}
private void emitStashedLine() {
if (state == STATE_PREV_LINE) {
delegate.lineTo(px2, py2);
}
}
}
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