613 lines
17 KiB
C++
613 lines
17 KiB
C++
//----------------------------------------------------------------------------
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// Anti-Grain Geometry - Version 2.4
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// Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com)
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//
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// Permission to copy, use, modify, sell and distribute this software
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// is granted provided this copyright notice appears in all copies.
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// This software is provided "as is" without express or implied
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// warranty, and with no claim as to its suitability for any purpose.
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//
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//----------------------------------------------------------------------------
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// Contact: mcseem@antigrain.com
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// mcseemagg@yahoo.com
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// http://www.antigrain.com
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//----------------------------------------------------------------------------
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#include <math.h>
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#include "agg_curves.h"
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#include "agg_math.h"
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namespace agg
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{
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//------------------------------------------------------------------------
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const double curve_distance_epsilon = 1e-30;
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const double curve_collinearity_epsilon = 1e-30;
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const double curve_angle_tolerance_epsilon = 0.01;
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enum curve_recursion_limit_e { curve_recursion_limit = 32 };
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//------------------------------------------------------------------------
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void curve3_inc::approximation_scale(double s)
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{
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m_scale = s;
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}
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//------------------------------------------------------------------------
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double curve3_inc::approximation_scale() const
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{
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return m_scale;
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}
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//------------------------------------------------------------------------
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void curve3_inc::init(double x1, double y1,
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double x2, double y2,
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double x3, double y3)
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{
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m_start_x = x1;
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m_start_y = y1;
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m_end_x = x3;
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m_end_y = y3;
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double dx1 = x2 - x1;
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double dy1 = y2 - y1;
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double dx2 = x3 - x2;
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double dy2 = y3 - y2;
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double len = sqrt(dx1 * dx1 + dy1 * dy1) + sqrt(dx2 * dx2 + dy2 * dy2);
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m_num_steps = uround(len * 0.25 * m_scale);
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if(m_num_steps < 4)
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{
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m_num_steps = 4;
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}
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double subdivide_step = 1.0 / m_num_steps;
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double subdivide_step2 = subdivide_step * subdivide_step;
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double tmpx = (x1 - x2 * 2.0 + x3) * subdivide_step2;
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double tmpy = (y1 - y2 * 2.0 + y3) * subdivide_step2;
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m_saved_fx = m_fx = x1;
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m_saved_fy = m_fy = y1;
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m_saved_dfx = m_dfx = tmpx + (x2 - x1) * (2.0 * subdivide_step);
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m_saved_dfy = m_dfy = tmpy + (y2 - y1) * (2.0 * subdivide_step);
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m_ddfx = tmpx * 2.0;
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m_ddfy = tmpy * 2.0;
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m_step = m_num_steps;
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}
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//------------------------------------------------------------------------
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void curve3_inc::rewind(unsigned)
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{
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if(m_num_steps == 0)
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{
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m_step = -1;
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return;
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}
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m_step = m_num_steps;
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m_fx = m_saved_fx;
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m_fy = m_saved_fy;
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m_dfx = m_saved_dfx;
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m_dfy = m_saved_dfy;
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}
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//------------------------------------------------------------------------
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unsigned curve3_inc::vertex(double* x, double* y)
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{
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if(m_step < 0) return path_cmd_stop;
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if(m_step == m_num_steps)
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{
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*x = m_start_x;
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*y = m_start_y;
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--m_step;
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return path_cmd_move_to;
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}
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if(m_step == 0)
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{
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*x = m_end_x;
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*y = m_end_y;
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--m_step;
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return path_cmd_line_to;
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}
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m_fx += m_dfx;
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m_fy += m_dfy;
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m_dfx += m_ddfx;
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m_dfy += m_ddfy;
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*x = m_fx;
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*y = m_fy;
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--m_step;
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return path_cmd_line_to;
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}
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//------------------------------------------------------------------------
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void curve3_div::init(double x1, double y1,
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double x2, double y2,
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double x3, double y3)
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{
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m_points.remove_all();
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m_distance_tolerance_square = 0.5 / m_approximation_scale;
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m_distance_tolerance_square *= m_distance_tolerance_square;
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bezier(x1, y1, x2, y2, x3, y3);
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m_count = 0;
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}
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//------------------------------------------------------------------------
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void curve3_div::recursive_bezier(double x1, double y1,
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double x2, double y2,
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double x3, double y3,
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unsigned level)
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{
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if(level > curve_recursion_limit)
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{
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return;
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}
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// Calculate all the mid-points of the line segments
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//----------------------
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double x12 = (x1 + x2) / 2;
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double y12 = (y1 + y2) / 2;
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double x23 = (x2 + x3) / 2;
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double y23 = (y2 + y3) / 2;
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double x123 = (x12 + x23) / 2;
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double y123 = (y12 + y23) / 2;
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double dx = x3-x1;
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double dy = y3-y1;
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double d = fabs(((x2 - x3) * dy - (y2 - y3) * dx));
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double da;
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if(d > curve_collinearity_epsilon)
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{
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// Regular case
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//-----------------
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if(d * d <= m_distance_tolerance_square * (dx*dx + dy*dy))
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{
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// If the curvature doesn't exceed the distance_tolerance value
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// we tend to finish subdivisions.
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//----------------------
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if(m_angle_tolerance < curve_angle_tolerance_epsilon)
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{
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m_points.add(point_d(x123, y123));
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return;
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}
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// Angle & Cusp Condition
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//----------------------
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da = fabs(atan2(y3 - y2, x3 - x2) - atan2(y2 - y1, x2 - x1));
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if(da >= pi) da = 2*pi - da;
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if(da < m_angle_tolerance)
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{
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// Finally we can stop the recursion
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//----------------------
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m_points.add(point_d(x123, y123));
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return;
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}
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}
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}
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else
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{
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// Collinear case
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//------------------
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da = dx*dx + dy*dy;
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if(da == 0)
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{
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d = calc_sq_distance(x1, y1, x2, y2);
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}
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else
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{
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d = ((x2 - x1)*dx + (y2 - y1)*dy) / da;
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if(d > 0 && d < 1)
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{
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// Simple collinear case, 1---2---3
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// We can leave just two endpoints
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return;
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}
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if(d <= 0) d = calc_sq_distance(x2, y2, x1, y1);
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else if(d >= 1) d = calc_sq_distance(x2, y2, x3, y3);
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else d = calc_sq_distance(x2, y2, x1 + d*dx, y1 + d*dy);
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}
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if(d < m_distance_tolerance_square)
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{
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m_points.add(point_d(x2, y2));
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return;
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}
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}
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// Continue subdivision
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//----------------------
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recursive_bezier(x1, y1, x12, y12, x123, y123, level + 1);
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recursive_bezier(x123, y123, x23, y23, x3, y3, level + 1);
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}
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//------------------------------------------------------------------------
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void curve3_div::bezier(double x1, double y1,
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double x2, double y2,
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double x3, double y3)
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{
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m_points.add(point_d(x1, y1));
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recursive_bezier(x1, y1, x2, y2, x3, y3, 0);
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m_points.add(point_d(x3, y3));
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}
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//------------------------------------------------------------------------
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void curve4_inc::approximation_scale(double s)
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{
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m_scale = s;
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}
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//------------------------------------------------------------------------
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double curve4_inc::approximation_scale() const
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{
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return m_scale;
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}
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#if defined(_MSC_VER) && _MSC_VER <= 1200
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//------------------------------------------------------------------------
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static double MSC60_fix_ICE(double v) { return v; }
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#endif
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//------------------------------------------------------------------------
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void curve4_inc::init(double x1, double y1,
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double x2, double y2,
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double x3, double y3,
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double x4, double y4)
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{
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m_start_x = x1;
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m_start_y = y1;
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m_end_x = x4;
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m_end_y = y4;
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double dx1 = x2 - x1;
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double dy1 = y2 - y1;
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double dx2 = x3 - x2;
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double dy2 = y3 - y2;
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double dx3 = x4 - x3;
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double dy3 = y4 - y3;
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double len = (sqrt(dx1 * dx1 + dy1 * dy1) +
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sqrt(dx2 * dx2 + dy2 * dy2) +
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sqrt(dx3 * dx3 + dy3 * dy3)) * 0.25 * m_scale;
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#if defined(_MSC_VER) && _MSC_VER <= 1200
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m_num_steps = uround(MSC60_fix_ICE(len));
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#else
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m_num_steps = uround(len);
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#endif
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if(m_num_steps < 4)
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{
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m_num_steps = 4;
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}
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double subdivide_step = 1.0 / m_num_steps;
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double subdivide_step2 = subdivide_step * subdivide_step;
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double subdivide_step3 = subdivide_step * subdivide_step * subdivide_step;
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double pre1 = 3.0 * subdivide_step;
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double pre2 = 3.0 * subdivide_step2;
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double pre4 = 6.0 * subdivide_step2;
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double pre5 = 6.0 * subdivide_step3;
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double tmp1x = x1 - x2 * 2.0 + x3;
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double tmp1y = y1 - y2 * 2.0 + y3;
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double tmp2x = (x2 - x3) * 3.0 - x1 + x4;
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double tmp2y = (y2 - y3) * 3.0 - y1 + y4;
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m_saved_fx = m_fx = x1;
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m_saved_fy = m_fy = y1;
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m_saved_dfx = m_dfx = (x2 - x1) * pre1 + tmp1x * pre2 + tmp2x * subdivide_step3;
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m_saved_dfy = m_dfy = (y2 - y1) * pre1 + tmp1y * pre2 + tmp2y * subdivide_step3;
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m_saved_ddfx = m_ddfx = tmp1x * pre4 + tmp2x * pre5;
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m_saved_ddfy = m_ddfy = tmp1y * pre4 + tmp2y * pre5;
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m_dddfx = tmp2x * pre5;
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m_dddfy = tmp2y * pre5;
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m_step = m_num_steps;
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}
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//------------------------------------------------------------------------
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void curve4_inc::rewind(unsigned)
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{
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if(m_num_steps == 0)
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{
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m_step = -1;
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return;
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}
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m_step = m_num_steps;
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m_fx = m_saved_fx;
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m_fy = m_saved_fy;
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m_dfx = m_saved_dfx;
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m_dfy = m_saved_dfy;
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m_ddfx = m_saved_ddfx;
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m_ddfy = m_saved_ddfy;
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}
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//------------------------------------------------------------------------
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unsigned curve4_inc::vertex(double* x, double* y)
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{
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if(m_step < 0) return path_cmd_stop;
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if(m_step == m_num_steps)
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{
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*x = m_start_x;
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*y = m_start_y;
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--m_step;
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return path_cmd_move_to;
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}
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if(m_step == 0)
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{
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*x = m_end_x;
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*y = m_end_y;
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--m_step;
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return path_cmd_line_to;
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}
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m_fx += m_dfx;
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m_fy += m_dfy;
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m_dfx += m_ddfx;
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m_dfy += m_ddfy;
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m_ddfx += m_dddfx;
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m_ddfy += m_dddfy;
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*x = m_fx;
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*y = m_fy;
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--m_step;
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return path_cmd_line_to;
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}
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//------------------------------------------------------------------------
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void curve4_div::init(double x1, double y1,
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double x2, double y2,
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double x3, double y3,
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double x4, double y4)
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{
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m_points.remove_all();
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m_distance_tolerance_square = 0.5 / m_approximation_scale;
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m_distance_tolerance_square *= m_distance_tolerance_square;
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bezier(x1, y1, x2, y2, x3, y3, x4, y4);
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m_count = 0;
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}
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//------------------------------------------------------------------------
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void curve4_div::recursive_bezier(double x1, double y1,
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double x2, double y2,
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double x3, double y3,
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double x4, double y4,
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unsigned level)
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{
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if(level > curve_recursion_limit)
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{
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return;
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}
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// Calculate all the mid-points of the line segments
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//----------------------
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double x12 = (x1 + x2) / 2;
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double y12 = (y1 + y2) / 2;
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double x23 = (x2 + x3) / 2;
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double y23 = (y2 + y3) / 2;
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double x34 = (x3 + x4) / 2;
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double y34 = (y3 + y4) / 2;
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double x123 = (x12 + x23) / 2;
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double y123 = (y12 + y23) / 2;
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double x234 = (x23 + x34) / 2;
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double y234 = (y23 + y34) / 2;
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double x1234 = (x123 + x234) / 2;
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double y1234 = (y123 + y234) / 2;
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// Try to approximate the full cubic curve by a single straight line
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//------------------
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double dx = x4-x1;
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double dy = y4-y1;
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double d2 = fabs(((x2 - x4) * dy - (y2 - y4) * dx));
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double d3 = fabs(((x3 - x4) * dy - (y3 - y4) * dx));
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double da1, da2, k;
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switch((int(d2 > curve_collinearity_epsilon) << 1) +
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int(d3 > curve_collinearity_epsilon))
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{
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case 0:
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// All collinear OR p1==p4
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//----------------------
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k = dx*dx + dy*dy;
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if(k == 0)
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{
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d2 = calc_sq_distance(x1, y1, x2, y2);
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d3 = calc_sq_distance(x4, y4, x3, y3);
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}
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else
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{
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k = 1 / k;
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da1 = x2 - x1;
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da2 = y2 - y1;
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d2 = k * (da1*dx + da2*dy);
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da1 = x3 - x1;
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da2 = y3 - y1;
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d3 = k * (da1*dx + da2*dy);
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if(d2 > 0 && d2 < 1 && d3 > 0 && d3 < 1)
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{
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// Simple collinear case, 1---2---3---4
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// We can leave just two endpoints
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return;
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}
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if(d2 <= 0) d2 = calc_sq_distance(x2, y2, x1, y1);
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else if(d2 >= 1) d2 = calc_sq_distance(x2, y2, x4, y4);
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else d2 = calc_sq_distance(x2, y2, x1 + d2*dx, y1 + d2*dy);
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if(d3 <= 0) d3 = calc_sq_distance(x3, y3, x1, y1);
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else if(d3 >= 1) d3 = calc_sq_distance(x3, y3, x4, y4);
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else d3 = calc_sq_distance(x3, y3, x1 + d3*dx, y1 + d3*dy);
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}
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if(d2 > d3)
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{
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if(d2 < m_distance_tolerance_square)
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{
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m_points.add(point_d(x2, y2));
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return;
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}
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}
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else
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{
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if(d3 < m_distance_tolerance_square)
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{
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m_points.add(point_d(x3, y3));
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return;
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}
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}
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break;
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case 1:
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// p1,p2,p4 are collinear, p3 is significant
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//----------------------
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if(d3 * d3 <= m_distance_tolerance_square * (dx*dx + dy*dy))
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{
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if(m_angle_tolerance < curve_angle_tolerance_epsilon)
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{
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m_points.add(point_d(x23, y23));
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return;
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}
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// Angle Condition
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//----------------------
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da1 = fabs(atan2(y4 - y3, x4 - x3) - atan2(y3 - y2, x3 - x2));
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if(da1 >= pi) da1 = 2*pi - da1;
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if(da1 < m_angle_tolerance)
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{
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m_points.add(point_d(x2, y2));
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m_points.add(point_d(x3, y3));
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return;
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}
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if(m_cusp_limit != 0.0)
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{
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if(da1 > m_cusp_limit)
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{
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m_points.add(point_d(x3, y3));
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return;
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}
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}
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}
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break;
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case 2:
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// p1,p3,p4 are collinear, p2 is significant
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//----------------------
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if(d2 * d2 <= m_distance_tolerance_square * (dx*dx + dy*dy))
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{
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if(m_angle_tolerance < curve_angle_tolerance_epsilon)
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{
|
|
m_points.add(point_d(x23, y23));
|
|
return;
|
|
}
|
|
|
|
// Angle Condition
|
|
//----------------------
|
|
da1 = fabs(atan2(y3 - y2, x3 - x2) - atan2(y2 - y1, x2 - x1));
|
|
if(da1 >= pi) da1 = 2*pi - da1;
|
|
|
|
if(da1 < m_angle_tolerance)
|
|
{
|
|
m_points.add(point_d(x2, y2));
|
|
m_points.add(point_d(x3, y3));
|
|
return;
|
|
}
|
|
|
|
if(m_cusp_limit != 0.0)
|
|
{
|
|
if(da1 > m_cusp_limit)
|
|
{
|
|
m_points.add(point_d(x2, y2));
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
break;
|
|
|
|
case 3:
|
|
// Regular case
|
|
//-----------------
|
|
if((d2 + d3)*(d2 + d3) <= m_distance_tolerance_square * (dx*dx + dy*dy))
|
|
{
|
|
// If the curvature doesn't exceed the distance_tolerance value
|
|
// we tend to finish subdivisions.
|
|
//----------------------
|
|
if(m_angle_tolerance < curve_angle_tolerance_epsilon)
|
|
{
|
|
m_points.add(point_d(x23, y23));
|
|
return;
|
|
}
|
|
|
|
// Angle & Cusp Condition
|
|
//----------------------
|
|
k = atan2(y3 - y2, x3 - x2);
|
|
da1 = fabs(k - atan2(y2 - y1, x2 - x1));
|
|
da2 = fabs(atan2(y4 - y3, x4 - x3) - k);
|
|
if(da1 >= pi) da1 = 2*pi - da1;
|
|
if(da2 >= pi) da2 = 2*pi - da2;
|
|
|
|
if(da1 + da2 < m_angle_tolerance)
|
|
{
|
|
// Finally we can stop the recursion
|
|
//----------------------
|
|
m_points.add(point_d(x23, y23));
|
|
return;
|
|
}
|
|
|
|
if(m_cusp_limit != 0.0)
|
|
{
|
|
if(da1 > m_cusp_limit)
|
|
{
|
|
m_points.add(point_d(x2, y2));
|
|
return;
|
|
}
|
|
|
|
if(da2 > m_cusp_limit)
|
|
{
|
|
m_points.add(point_d(x3, y3));
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
|
|
// Continue subdivision
|
|
//----------------------
|
|
recursive_bezier(x1, y1, x12, y12, x123, y123, x1234, y1234, level + 1);
|
|
recursive_bezier(x1234, y1234, x234, y234, x34, y34, x4, y4, level + 1);
|
|
}
|
|
|
|
//------------------------------------------------------------------------
|
|
void curve4_div::bezier(double x1, double y1,
|
|
double x2, double y2,
|
|
double x3, double y3,
|
|
double x4, double y4)
|
|
{
|
|
m_points.add(point_d(x1, y1));
|
|
recursive_bezier(x1, y1, x2, y2, x3, y3, x4, y4, 0);
|
|
m_points.add(point_d(x4, y4));
|
|
}
|
|
|
|
}
|
|
|