1//----------------------------------------------------------------------------
2// Anti-Grain Geometry - Version 2.4
3// Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com)
4//
5// Permission to copy, use, modify, sell and distribute this software
6// is granted provided this copyright notice appears in all copies.
7// This software is provided "as is" without express or implied
8// warranty, and with no claim as to its suitability for any purpose.
9//
10//----------------------------------------------------------------------------
11// Contact: mcseem@antigrain.com
12//          mcseemagg@yahoo.com
13//          http://www.antigrain.com
14//----------------------------------------------------------------------------
15
16#include "agg_math.h"
17#include "agg_vertex_sequence.h"
18#include "agg_trans_single_path.h"
19
20namespace agg
21{
22
23    //------------------------------------------------------------------------
24    trans_single_path::trans_single_path() :
25        m_base_length(0.0),
26        m_kindex(0.0),
27        m_status(initial),
28        m_preserve_x_scale(true)
29    {
30    }
31
32    //------------------------------------------------------------------------
33    void trans_single_path::reset()
34    {
35        m_src_vertices.remove_all();
36        m_kindex = 0.0;
37        m_status = initial;
38    }
39
40    //------------------------------------------------------------------------
41    void trans_single_path::move_to(double x, double y)
42    {
43        if(m_status == initial)
44        {
45            m_src_vertices.modify_last(vertex_dist(x, y));
46            m_status = making_path;
47        }
48        else
49        {
50            line_to(x, y);
51        }
52    }
53
54    //------------------------------------------------------------------------
55    void trans_single_path::line_to(double x, double y)
56    {
57        if(m_status == making_path)
58        {
59            m_src_vertices.add(vertex_dist(x, y));
60        }
61    }
62
63
64    //------------------------------------------------------------------------
65    void trans_single_path::finalize_path()
66    {
67        if(m_status == making_path && m_src_vertices.size() > 1)
68        {
69            unsigned i;
70            double dist;
71            double d;
72
73            m_src_vertices.close(false);
74            if(m_src_vertices.size() > 2)
75            {
76                if(m_src_vertices[m_src_vertices.size() - 2].dist * 10.0 <
77                   m_src_vertices[m_src_vertices.size() - 3].dist)
78                {
79                    d = m_src_vertices[m_src_vertices.size() - 3].dist +
80                        m_src_vertices[m_src_vertices.size() - 2].dist;
81
82                    m_src_vertices[m_src_vertices.size() - 2] =
83                        m_src_vertices[m_src_vertices.size() - 1];
84
85                    m_src_vertices.remove_last();
86                    m_src_vertices[m_src_vertices.size() - 2].dist = d;
87                }
88            }
89
90            dist = 0.0;
91            for(i = 0; i < m_src_vertices.size(); i++)
92            {
93                vertex_dist& v = m_src_vertices[i];
94                double d = v.dist;
95                v.dist = dist;
96                dist += d;
97            }
98            m_kindex = (m_src_vertices.size() - 1) / dist;
99            m_status = ready;
100        }
101    }
102
103
104
105    //------------------------------------------------------------------------
106    double trans_single_path::total_length() const
107    {
108        if(m_base_length >= 1e-10) return m_base_length;
109        return (m_status == ready) ?
110            m_src_vertices[m_src_vertices.size() - 1].dist :
111            0.0;
112    }
113
114
115    //------------------------------------------------------------------------
116    void trans_single_path::transform(double *x, double *y) const
117    {
118        if(m_status == ready)
119        {
120            if(m_base_length > 1e-10)
121            {
122                *x *= m_src_vertices[m_src_vertices.size() - 1].dist /
123                      m_base_length;
124            }
125
126            double x1 = 0.0;
127            double y1 = 0.0;
128            double dx = 1.0;
129            double dy = 1.0;
130            double d  = 0.0;
131            double dd = 1.0;
132            if(*x < 0.0)
133            {
134                // Extrapolation on the left
135                //--------------------------
136                x1 = m_src_vertices[0].x;
137                y1 = m_src_vertices[0].y;
138                dx = m_src_vertices[1].x - x1;
139                dy = m_src_vertices[1].y - y1;
140                dd = m_src_vertices[1].dist - m_src_vertices[0].dist;
141                d  = *x;
142            }
143            else
144            if(*x > m_src_vertices[m_src_vertices.size() - 1].dist)
145            {
146                // Extrapolation on the right
147                //--------------------------
148                unsigned i = m_src_vertices.size() - 2;
149                unsigned j = m_src_vertices.size() - 1;
150                x1 = m_src_vertices[j].x;
151                y1 = m_src_vertices[j].y;
152                dx = x1 - m_src_vertices[i].x;
153                dy = y1 - m_src_vertices[i].y;
154                dd = m_src_vertices[j].dist - m_src_vertices[i].dist;
155                d  = *x - m_src_vertices[j].dist;
156            }
157            else
158            {
159                // Interpolation
160                //--------------------------
161                unsigned i = 0;
162                unsigned j = m_src_vertices.size() - 1;
163                if(m_preserve_x_scale)
164                {
165                    unsigned k;
166                    for(i = 0; (j - i) > 1; )
167                    {
168                        if(*x < m_src_vertices[k = (i + j) >> 1].dist)
169                        {
170                            j = k;
171                        }
172                        else
173                        {
174                            i = k;
175                        }
176                    }
177                    d  = m_src_vertices[i].dist;
178                    dd = m_src_vertices[j].dist - d;
179                    d  = *x - d;
180                }
181                else
182                {
183                    i = unsigned(*x * m_kindex);
184                    j = i + 1;
185                    dd = m_src_vertices[j].dist - m_src_vertices[i].dist;
186                    d = ((*x * m_kindex) - i) * dd;
187                }
188                x1 = m_src_vertices[i].x;
189                y1 = m_src_vertices[i].y;
190                dx = m_src_vertices[j].x - x1;
191                dy = m_src_vertices[j].y - y1;
192            }
193            double x2 = x1 + dx * d / dd;
194            double y2 = y1 + dy * d / dd;
195            *x = x2 - *y * dy / dd;
196            *y = y2 + *y * dx / dd;
197        }
198    }
199
200
201}
202
203