OrthogonalShapesFilter.java

// License: GPL. For details, see LICENSE file.
package pdfimport;

import java.awt.geom.Point2D;

public class OrthogonalShapesFilter {
    private double tolerance;

    public OrthogonalShapesFilter(double toleranceDegrees) {
        tolerance = Math.toRadians(toleranceDegrees);
    }

    public boolean isOrthogonal(PdfPath path) {

        if (path.points.size() < 3)
            return false;

        int targetPos = path.isClosed() ? path.points.size() : path.points.size() - 1;

        for (int pos = 1; pos < targetPos; pos++) {
            Point2D p1 = path.points.get(pos -1);
            Point2D p2 = path.points.get(pos);
            Point2D p3 = pos+1 == path.points.size() ? path.points.get(1) : path.points.get(pos+1);

            double angle1 = Math.atan2(p2.getY() - p1.getY(), p2.getX() - p1.getX());
            double angle2 = Math.atan2(p3.getY() - p2.getY(), p3.getX() - p2.getX());

            double angleDifference = angle1 - angle2;
            while (angleDifference < 0) angleDifference += Math.PI;

            //test straight angles
            boolean hasGoodVariant = false;

            for (int quadrant = 0; quadrant <= 4; quadrant++) {
                double difference = angleDifference - Math.PI / 2 * quadrant;
                if (Math.abs(difference) <= tolerance)
                    hasGoodVariant = true;
            }

            if (!hasGoodVariant)
                return false;
        }

        return true;
    }
}