agg_curves.cpp revision ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4 
1
2//----------------------------------------------------------------------------
3// XYQ: 2006-01-22 Copied from AGG project.
4// TODO: This file uses intensive floating point operations, so it's NOT suitable
5// for platforms like Symbian OS. We need to change to FIX format.
6//----------------------------------------------------------------------------
7//----------------------------------------------------------------------------
8// Anti-Grain Geometry - Version 2.3
9// Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com)
10//
11// Permission to copy, use, modify, sell and distribute this software
12// is granted provided this copyright notice appears in all copies.
13// This software is provided "as is" without express or implied
14// warranty, and with no claim as to its suitability for any purpose.
15//
16//----------------------------------------------------------------------------
17// Contact: mcseem@antigrain.com
18//          mcseemagg@yahoo.com
19//          http://www.antigrain.com
20//----------------------------------------------------------------------------
21
22#include "agg_curves.h"
23#include "agg_math.h"
24#include "core/include/fxcrt/fx_basic.h"
25
26namespace agg
27{
28const FX_FLOAT curve_collinearity_epsilon              = 1e-30f;
29enum curve_recursion_limit_e { curve_recursion_limit = 16 };
30void curve4_div::init(FX_FLOAT x1, FX_FLOAT y1,
31                      FX_FLOAT x2, FX_FLOAT y2,
32                      FX_FLOAT x3, FX_FLOAT y3,
33                      FX_FLOAT x4, FX_FLOAT y4)
34{
35    m_points.remove_all();
36    m_distance_tolerance_square = 1.0f / 4;
37    m_distance_tolerance_manhattan = 1.0f * 4;
38    bezier(x1, y1, x2, y2, x3, y3, x4, y4);
39    m_count = 0;
40}
41void curve4_div::recursive_bezier(FX_FLOAT x1, FX_FLOAT y1,
42                                  FX_FLOAT x2, FX_FLOAT y2,
43                                  FX_FLOAT x3, FX_FLOAT y3,
44                                  FX_FLOAT x4, FX_FLOAT y4,
45                                  unsigned level)
46{
47    if(level > curve_recursion_limit) {
48        return;
49    }
50    FX_FLOAT x12   = (x1 + x2) / 2;
51    FX_FLOAT y12   = (y1 + y2) / 2;
52    FX_FLOAT x23   = (x2 + x3) / 2;
53    FX_FLOAT y23   = (y2 + y3) / 2;
54    FX_FLOAT x34   = (x3 + x4) / 2;
55    FX_FLOAT y34   = (y3 + y4) / 2;
56    FX_FLOAT x123  = (x12 + x23) / 2;
57    FX_FLOAT y123  = (y12 + y23) / 2;
58    FX_FLOAT x234  = (x23 + x34) / 2;
59    FX_FLOAT y234  = (y23 + y34) / 2;
60    FX_FLOAT x1234 = (x123 + x234) / 2;
61    FX_FLOAT y1234 = (y123 + y234) / 2;
62    FX_FLOAT dx = x4 - x1;
63    FX_FLOAT dy = y4 - y1;
64    FX_FLOAT d2 = FXSYS_fabs(FXSYS_Mul(x2 - x4, dy) - FXSYS_Mul(y2 - y4, dx));
65    FX_FLOAT d3 = FXSYS_fabs(FXSYS_Mul(x3 - x4, dy) - FXSYS_Mul(y3 - y4, dx));
66    switch((int(d2 > curve_collinearity_epsilon) << 1) +
67            int(d3 > curve_collinearity_epsilon)) {
68        case 0:
69            if(FXSYS_fabs(x1 + x3 - x2 - x2) +
70                    FXSYS_fabs(y1 + y3 - y2 - y2) +
71                    FXSYS_fabs(x2 + x4 - x3 - x3) +
72                    FXSYS_fabs(y2 + y4 - y3 - y3) <= m_distance_tolerance_manhattan) {
73                m_points.add(point_type(x1234, y1234, path_flags_jr));
74                return;
75            }
76            break;
77        case 1:
78            if(FXSYS_Mul(d3, d3) <= FXSYS_Mul(m_distance_tolerance_square,
79                                              FXSYS_Mul(dx, dx) + FXSYS_Mul(dy, dy))) {
80                m_points.add(point_type(x23, y23, path_flags_jr));
81                return;
82            }
83            break;
84        case 2:
85            if(FXSYS_Mul(d2, d2) <= FXSYS_Mul(m_distance_tolerance_square,
86                                              FXSYS_Mul(dx, dx) + FXSYS_Mul(dy, dy))) {
87                m_points.add(point_type(x23, y23, path_flags_jr));
88                return;
89            }
90            break;
91        case 3:
92            if(FXSYS_Mul(d2 + d3, d2 + d3) <= FXSYS_Mul(m_distance_tolerance_square,
93                    FXSYS_Mul(dx, dx) + FXSYS_Mul(dy, dy))) {
94                m_points.add(point_type(x23, y23, path_flags_jr));
95                return;
96            }
97            break;
98    }
99    recursive_bezier(x1, y1, x12, y12, x123, y123, x1234, y1234, level + 1);
100    recursive_bezier(x1234, y1234, x234, y234, x34, y34, x4, y4, level + 1);
101}
102void curve4_div::bezier(FX_FLOAT x1, FX_FLOAT y1,
103                        FX_FLOAT x2, FX_FLOAT y2,
104                        FX_FLOAT x3, FX_FLOAT y3,
105                        FX_FLOAT x4, FX_FLOAT y4)
106{
107    m_points.add(point_type(x1, y1));
108    recursive_bezier(x1, y1, x2, y2, x3, y3, x4, y4, 0);
109    m_points.add(point_type(x4, y4));
110}
111}
112