ShapeStroke.java

/*
Copyright 2006 Jerry Huxtable

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
 */

package com.jhlabs.awt;

import java.awt.Shape;
import java.awt.Stroke;
import java.awt.geom.AffineTransform;
import java.awt.geom.FlatteningPathIterator;
import java.awt.geom.GeneralPath;
import java.awt.geom.PathIterator;
import java.awt.geom.Rectangle2D;

/**
 * Stroke that draw a shape.
 * 
 * Slightly adapted to OTP from original source.
 * 
 * @see <a
 *      href="http://www.jhlabs.com/java/java2d/strokes/">http://www.jhlabs.com/java/java2d/strokes/</a>
 * 
 */
public class ShapeStroke implements Stroke {
    private Shape theShape;

    private float advance;

    private float phase;

    private AffineTransform t = new AffineTransform();

    private static final float FLATNESS = 1;

    public ShapeStroke(Shape shape, float width, float advance, float phase) {
        this.advance = advance;
        this.phase = phase;
        Rectangle2D bounds = shape.getBounds2D();
        double scale = width / bounds.getHeight();
        t.setToScale(scale, scale);
        t.translate(-bounds.getCenterX(), -bounds.getCenterY());
        this.theShape = t.createTransformedShape(shape);
    }

    public Shape createStrokedShape(Shape shape) {
        GeneralPath result = new GeneralPath();
        PathIterator it = new FlatteningPathIterator(shape.getPathIterator(null), FLATNESS);
        float points[] = new float[6];
        float moveX = 0, moveY = 0;
        float lastX = 0, lastY = 0;
        float thisX = 0, thisY = 0;
        int type = 0;
        float next = phase;

        while (!it.isDone()) {
            type = it.currentSegment(points);
            switch (type) {
            case PathIterator.SEG_MOVETO:
                moveX = lastX = points[0];
                moveY = lastY = points[1];
                result.moveTo(moveX, moveY);
                next = 0;
                break;

            case PathIterator.SEG_CLOSE:
                points[0] = moveX;
                points[1] = moveY;
                // Fall into....

            case PathIterator.SEG_LINETO:
                thisX = points[0];
                thisY = points[1];
                float dx = thisX - lastX;
                float dy = thisY - lastY;
                float distance = (float) Math.sqrt(dx * dx + dy * dy);
                if (distance >= next) {
                    float r = 1.0f / distance;
                    float angle = (float) Math.atan2(dy, dx);
                    while (distance >= next) {
                        float x = lastX + next * dx * r;
                        float y = lastY + next * dy * r;
                        t.setToTranslation(x, y);
                        t.rotate(angle);
                        result.append(t.createTransformedShape(theShape), false);
                        next += advance;
                    }
                }
                next -= distance;
                lastX = thisX;
                lastY = thisY;
                break;
            }
            it.next();
        }

        return result;
    }
}