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 * Copyright (c) 2011, 2021, 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
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package com.sun.javafx.webkit.prism;

import com.sun.prism.paint.Color;
import com.sun.prism.paint.RadialGradient;
import com.sun.prism.paint.Stop;
import com.sun.webkit.graphics.WCGradient;
import com.sun.webkit.graphics.WCPoint;
import com.sun.javafx.geom.transform.BaseTransform;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

final class WCRadialGradient extends WCGradient<RadialGradient> {

    static final Comparator<Stop> COMPARATOR = (s1, s2) -> {
        float o1 = s1.getOffset();
        float o2 = s2.getOffset();
        if (o1 < o2) {
            return -1;
        }
        if (o1 > o2) {
            return 1;
        }
        return 0;
    };

    private final boolean reverse;
    private final WCPoint p1;
    private final WCPoint p2;
    private final float r1over;
    private final float r1;
    private final float r2;
    private final List<Stop> stops = new ArrayList<Stop>();

    WCRadialGradient(WCPoint p1, float r1, WCPoint p2, float r2) {
        this.reverse = r1 < r2;
        this.p1 = this.reverse ? p2 : p1;
        this.p2 = this.reverse ? p1 : p2;
        this.r1 = this.reverse ? r2 : r1;
        this.r2 = this.reverse ? r1 : r2;
        this.r1over = (this.r1 > 0.0f)
                ? 1.0f / this.r1
                : 0.0f;
    }

    @Override
    protected void addStop(Color color, float offset) {
        if (this.reverse) {
            offset = 1.0f - offset;
        }
        offset = 1.0f - offset + offset * this.r2 * this.r1over;
        this.stops.add(new Stop(color, offset));
    }

    public RadialGradient getPlatformGradient() {
        Collections.sort(this.stops, COMPARATOR);
        float dx = this.p2.getX() - this.p1.getX();
        float dy = this.p2.getY() - this.p1.getY();
        return new RadialGradient(
                this.p1.getX(),
                this.p1.getY(),
                (float) (Math.atan2(dy, dx) * 180 / Math.PI),
                (float) Math.sqrt(dx * dx + dy * dy) * this.r1over,
                this.r1,
                BaseTransform.IDENTITY_TRANSFORM,
                isProportional(),
                getSpreadMethod() - 1, // convert webkit to prism
                this.stops);
    }

    @Override
    public String toString() {
        return toString(this, this.p1, this.p2, this.r1, this.stops);
    }

    static String toString(WCGradient g, WCPoint p1, WCPoint p2, Float radius, List<Stop> stops) {
        StringBuilder sb = new StringBuilder(g.getClass().getSimpleName());
        switch (g.getSpreadMethod()) {
            case PAD:
                sb.append("[spreadMethod=PAD");
                break;
            case REFLECT:
                sb.append("[spreadMethod=REFLECT");
                break;
            case REPEAT:
                sb.append("[spreadMethod=REPEAT");
                break;
        }
        sb.append(", proportional=").append(g.isProportional());
        if (radius != null) {
            sb.append(", radius=").append(radius);
        }
        sb.append(", x1=").append(p1.getX());
        sb.append(", y1=").append(p1.getY());
        sb.append(", x2=").append(p2.getX());
        sb.append(", y2=").append(p2.getY());
        sb.append(", stops=");
        for (int i = 0; i < stops.size(); i++) {
            sb.append(i == 0 ? "[" : ", ");
            sb.append(stops.get(i).getOffset()).append(":").append(stops.get(i).getColor());
        }
        return sb.append("]]").toString();
    }
}
