Esempio n. 1
0
    // Generates a new polygon by dragging a polygon through an angle, and taking all the points it
    // touched (and a few extras for overestimation)
    // Only valid for convex polygons, and small rotations (20 degrees or less)
    // stroke from theta1 to theta2
    public static Polygon strokeRot(double theta1, double theta2, Polygon poly) {
      Polygon poly1 = mul(Mat.rotation(theta1), poly);
      Polygon poly2 = mul(Mat.rotation(theta2), poly);
      Polygon stroked = combine(poly1, poly2);
      ArrayList<Mat> cornerVerts;
      Polygon corner;
      int thisVertex, prevVertex, nextVertex;
      Mat origin = Mat.encodePoint(0, 0);
      Mat cornerVert1a, cornerVert1b;
      Mat cornerVert2a, cornerVert2b;
      double actualDist, desiredDist;
      Mat cornerTransform;
      for (thisVertex = 0; thisVertex < poly.vertices.size(); thisVertex++) {
        if (thisVertex == 0) {
          prevVertex = poly.vertices.size() - 1;
        } else {
          prevVertex = thisVertex - 1;
        }

        if (thisVertex == poly.vertices.size() - 1) {
          nextVertex = 0;
        } else {
          nextVertex = thisVertex + 1;
        }

        cornerVerts = new ArrayList<Mat>();
        cornerVerts.add(poly2.vertices.get(nextVertex));
        cornerVerts.add(origin);
        cornerVerts.add(poly1.vertices.get(prevVertex));

        cornerVert1a = poly1.vertices.get(thisVertex);
        cornerVert2a = poly2.vertices.get(thisVertex);

        actualDist = ptSegDistance(cornerVert1a, cornerVert2a, origin);
        desiredDist = Mat.dist(cornerVert1a, Mat.encodePoint(0, 0));

        cornerTransform = Mat.mul(desiredDist / actualDist, Mat.eye(4));
        cornerVert1b = Mat.mul(cornerTransform, cornerVert1a);
        cornerVert2b = Mat.mul(cornerTransform, cornerVert2a);

        cornerVert1b =
            lineSegIntersection(
                cornerVert1b, cornerVert2b, poly1.vertices.get(prevVertex), cornerVert1a);
        cornerVert2b =
            lineSegIntersection(
                cornerVert1b, cornerVert2b, poly2.vertices.get(nextVertex), cornerVert2a);

        cornerVerts.add(cornerVert1b);
        cornerVerts.add(cornerVert2b);

        corner = new Polygon(cornerVerts);
        stroked = combine(stroked, corner);
      }

      return stroked;
    }
Esempio n. 2
0
    public static double ptSegDistance(Mat e0, Mat e1, Mat p) {
      double x0 = e0.data[0][0];
      double y0 = e0.data[1][0];
      double x1 = e1.data[0][0];
      double y1 = e1.data[1][0];
      double xp = p.data[0][0];
      double yp = p.data[1][0];

      e0 = new Mat(2, 1);
      e0.data[0][0] = x0;
      e0.data[1][0] = y0;
      e1 = new Mat(2, 1);
      e1.data[0][0] = x1;
      e1.data[1][0] = y1;
      p = new Mat(2, 1);
      p.data[0][0] = xp;
      p.data[1][0] = yp;

      e1 = Mat.sub(e1, e0);
      p = Mat.sub(p, e0);
      e0.data[0][0] = 0;
      e0.data[1][0] = 0;

      Mat e0b = Mat.sub(e0, e1);
      Mat pb = Mat.sub(p, e1);
      Mat e1b = new Mat(2, 1);
      e1b.data[0][0] = 0;
      e1b.data[1][0] = 0;

      if (Mat.dot(e1, p) > 0) {
        if (Mat.dot(e0b, pb) > 0) {
          Mat e1u = Mat.mul(1 / Mat.l2(e1), e1);
          return Mat.dist(p, Mat.mul(Mat.dot(e1u, p), e1u));
        } else {
          return Mat.dist(p, e1);
        }
      } else {
        return Mat.dist(p, e0);
      }
    }
Esempio n. 3
0
 public static boolean ptsEqual(Mat p0, Mat p1, double tolerance) {
   return tolerance > Mat.dist(p0, p1);
 }