public math_stroke() { m_width = 0.5; m_width_abs = 0.5; m_width_eps = 0.5 / 1024.0; m_width_sign = 1; m_miter_limit = 4.0; m_inner_miter_limit = 1.01; m_approx_scale = 1.0; m_line_cap = line_cap_e.butt_cap; m_line_join = line_join_e.miter_join; m_inner_join = inner_join_e.inner_miter; }
public void line_join(line_join_e lj) { m_line_join = lj; }
void calc_miter(IVertexDest vc, VertexWithDistance v0, VertexWithDistance v1, VertexWithDistance v2, double dx1, double dy1, double dx2, double dy2, line_join_e lj, double mlimit, double dbevel) { double xi = v1.x; double yi = v1.y; double di = 1; double lim = m_width_abs * mlimit; bool miter_limit_exceeded = true; // Assume the worst bool intersection_failed = true; // Assume the worst if (agg_math.calc_intersection(v0.x + dx1, v0.y - dy1, v1.x + dx1, v1.y - dy1, v1.x + dx2, v1.y - dy2, v2.x + dx2, v2.y - dy2, out xi, out yi)) { // Calculation of the intersection succeeded //--------------------- di = agg_math.calc_distance(v1.x, v1.y, xi, yi); if (di <= lim) { // Inside the miter limit //--------------------- add_vertex(vc, xi, yi); miter_limit_exceeded = false; } intersection_failed = false; } else { // Calculation of the intersection failed, most probably // the three points lie one straight line. // First check if v0 and v2 lie on the opposite sides of vector: // (v1.x, v1.y) -> (v1.x+dx1, v1.y-dy1), that is, the perpendicular // to the line determined by vertices v0 and v1. // This condition determines whether the next line segments continues // the previous one or goes back. //---------------- double x2 = v1.x + dx1; double y2 = v1.y - dy1; if ((agg_math.cross_product(v0.x, v0.y, v1.x, v1.y, x2, y2) < 0.0) == (agg_math.cross_product(v1.x, v1.y, v2.x, v2.y, x2, y2) < 0.0)) { // This case means that the next segment continues // the previous one (straight line) //----------------- add_vertex(vc, v1.x + dx1, v1.y - dy1); miter_limit_exceeded = false; } } if (miter_limit_exceeded) { // Miter limit exceeded //------------------------ switch (lj) { case line_join_e.miter_join_revert: // For the compatibility with SVG, PDF, etc, // we use a simple bevel join instead of // "smart" bevel //------------------- add_vertex(vc, v1.x + dx1, v1.y - dy1); add_vertex(vc, v1.x + dx2, v1.y - dy2); break; case line_join_e.miter_join_round: calc_arc(vc, v1.x, v1.y, dx1, -dy1, dx2, -dy2); break; default: // If no miter-revert, calculate new dx1, dy1, dx2, dy2 //---------------- if (intersection_failed) { mlimit *= m_width_sign; add_vertex(vc, v1.x + dx1 + dy1 * mlimit, v1.y - dy1 + dx1 * mlimit); add_vertex(vc, v1.x + dx2 - dy2 * mlimit, v1.y - dy2 - dx2 * mlimit); } else { double x1 = v1.x + dx1; double y1 = v1.y - dy1; double x2 = v1.x + dx2; double y2 = v1.y - dy2; di = (lim - dbevel) / (di - dbevel); add_vertex(vc, x1 + (xi - x1) * di, y1 + (yi - y1) * di); add_vertex(vc, x2 + (xi - x2) * di, y2 + (yi - y2) * di); } break; } } }