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The OpenTripPlanner multimodal journey planning system
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/*
  This file is based on code copied from project Java Image Processing, JH Labs,
  see the LICENSE file for further information.
*/
package com.jhlabs.awt;

import java.awt.Font;
import java.awt.Shape;
import java.awt.Stroke;
import java.awt.font.FontRenderContext;
import java.awt.font.GlyphVector;
import java.awt.geom.AffineTransform;
import java.awt.geom.FlatteningPathIterator;
import java.awt.geom.GeneralPath;
import java.awt.geom.PathIterator;
import java.awt.geom.Point2D;

import org.apache.commons.math3.util.FastMath;

/**
 * Stroke that paint a text.
 * 
 * Slightly adapted to OTP from original source.
 * 
 * @see http://www.jhlabs.com/java/java2d/strokes/
 * 
 */
public class TextStroke implements Stroke {
    private String text;

    private Font font;

    private boolean stretchToFit = false;

    private boolean repeat = false;

    private AffineTransform t = new AffineTransform();

    private static final float FLATNESS = 1;

    public TextStroke(String text, Font font) {
        this(text, font, true, false);
    }

    public TextStroke(String text, Font font, boolean stretchToFit, boolean repeat) {
        this.text = text;
        this.font = font;
        this.stretchToFit = stretchToFit;
        this.repeat = repeat;
    }

    public Shape createStrokedShape(Shape shape) {
        FontRenderContext frc = new FontRenderContext(null, true, true);
        GlyphVector glyphVector = font.createGlyphVector(frc, text);

        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 = 0;
        int currentChar = 0;
        int length = glyphVector.getNumGlyphs();

        if (length == 0)
            return result;

        float factor = stretchToFit ? measurePathLength(shape)
                / (float) glyphVector.getLogicalBounds().getWidth() : 1.0f;
        float height = (float) glyphVector.getLogicalBounds().getHeight();
        float nextAdvance = 0;

        while (currentChar < length && !it.isDone()) {
            type = it.currentSegment(points);
            switch (type) {
            case PathIterator.SEG_MOVETO:
                moveX = lastX = points[0];
                moveY = lastY = points[1];
                result.moveTo(moveX, moveY);
                nextAdvance = glyphVector.getGlyphMetrics(currentChar).getAdvance() * 0.5f;
                next = nextAdvance;
                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) FastMath.sqrt(dx * dx + dy * dy);
                if (distance >= next) {
                    float r = 1.0f / distance;
                    float angle = (float) FastMath.atan2(dy, dx);
                    while (currentChar < length && distance >= next) {
                        Shape glyph = glyphVector.getGlyphOutline(currentChar);
                        Point2D p = glyphVector.getGlyphPosition(currentChar);
                        float px = (float) p.getX();
                        float py = (float) p.getY();
                        float x = lastX + next * dx * r;
                        float y = lastY + next * dy * r;
                        float advance = nextAdvance;
                        nextAdvance = currentChar < length - 1 ? glyphVector.getGlyphMetrics(
                                currentChar + 1).getAdvance() * 0.5f : 0;
                        t.setToTranslation(x, y);
                        t.rotate(angle);
                        t.translate(-px - advance, -py + height * factor / 2.0f);
                        result.append(t.createTransformedShape(glyph), false);
                        next += (advance + nextAdvance) * factor;
                        currentChar++;
                        if (repeat)
                            currentChar %= length;
                    }
                }
                next -= distance;
                lastX = thisX;
                lastY = thisY;
                break;
            }
            it.next();
        }

        return result;
    }

    public float measurePathLength(Shape shape) {
        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 total = 0;

        while (!it.isDone()) {
            type = it.currentSegment(points);
            switch (type) {
            case PathIterator.SEG_MOVETO:
                moveX = lastX = points[0];
                moveY = lastY = points[1];
                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;
                total += (float) Math.sqrt(dx * dx + dy * dy);
                lastX = thisX;
                lastY = thisY;
                break;
            }
            it.next();
        }

        return total;
    }

}