//---------------------------------------------------------------------------- // Anti-Grain Geometry (AGG) - Version 2.5 // A high quality rendering engine for C++ // Copyright (C) 2002-2006 Maxim Shemanarev // Contact: mcseem@antigrain.com // mcseemagg@yahoo.com // http://antigrain.com // // AGG is free software; you can redistribute it and/or // modify it under the terms of the GNU General Public License // as published by the Free Software Foundation; either version 2 // of the License, or (at your option) any later version. // // AGG is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // // You should have received a copy of the GNU General Public License // along with AGG; if not, write to the Free Software // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, // MA 02110-1301, USA. //---------------------------------------------------------------------------- #include <math.h> #include "agg_line_aa_basics.h" namespace agg { //------------------------------------------------------------------------- // The number of the octant is determined as a 3-bit value as follows: // bit 0 = vertical flag // bit 1 = sx < 0 // bit 2 = sy < 0 // // [N] shows the number of the orthogonal quadrant // <M> shows the number of the diagonal quadrant // <1> // [1] | [0] // . (3)011 | 001(1) . // . | . // . | . // . | . // (2)010 .|. 000(0) // <2> ----------.+.----------- <0> // (6)110 . | . 100(4) // . | . // . | . // . | . // (7)111 | 101(5) // [2] | [3] // <3> // 0,1,2,3,4,5,6,7 const int8u line_parameters::s_orthogonal_quadrant[8] = { 0,0,1,1,3,3,2,2 }; const int8u line_parameters::s_diagonal_quadrant[8] = { 0,1,2,1,0,3,2,3 }; //------------------------------------------------------------------------- void bisectrix(const line_parameters& l1, const line_parameters& l2, int* x, int* y) { double k = double(l2.len) / double(l1.len); double tx = l2.x2 - (l2.x1 - l1.x1) * k; double ty = l2.y2 - (l2.y1 - l1.y1) * k; //All bisectrices must be on the right of the line //If the next point is on the left (l1 => l2.2) //then the bisectix should be rotated by 180 degrees. if(double(l2.x2 - l2.x1) * double(l2.y1 - l1.y1) < double(l2.y2 - l2.y1) * double(l2.x1 - l1.x1) + 100.0) { tx -= (tx - l2.x1) * 2.0; ty -= (ty - l2.y1) * 2.0; } // Check if the bisectrix is too short double dx = tx - l2.x1; double dy = ty - l2.y1; if((int)sqrt(dx * dx + dy * dy) < line_subpixel_scale) { *x = (l2.x1 + l2.x1 + (l2.y1 - l1.y1) + (l2.y2 - l2.y1)) >> 1; *y = (l2.y1 + l2.y1 - (l2.x1 - l1.x1) - (l2.x2 - l2.x1)) >> 1; return; } *x = iround(tx); *y = iround(ty); } } |