1 /*
2 * Inkscape::SVG::PathString - builder for SVG path strings
3 *
4 * Copyright 2008 Jasper van de Gronde <th.v.d.gronde@hccnet.nl>
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version 2
9 * of the License, or (at your option) any later version.
10 *
11 * See the file COPYING for details.
12 *
13 */
15 #include "svg/path-string.h"
16 #include "svg/stringstream.h"
17 #include "svg/svg.h"
18 #include "preferences.h"
19 #include <algorithm>
21 // 1<=numericprecision<=16, doubles are only accurate upto (slightly less than) 16 digits (and less than one digit doesn't make sense)
22 // Please note that these constants are used to allocate sufficient space to hold serialized numbers
23 static int const minprec = 1;
24 static int const maxprec = 16;
26 int Inkscape::SVG::PathString::numericprecision;
27 int Inkscape::SVG::PathString::minimumexponent;
29 Inkscape::SVG::PathString::PathString() :
30 allow_relative_coordinates(Inkscape::Preferences::get()->getBool("/options/svgoutput/allowrelativecoordinates", true)),
31 force_repeat_commands(Inkscape::Preferences::get()->getBool("/options/svgoutput/forcerepeatcommands"))
32 {
33 Inkscape::Preferences *prefs = Inkscape::Preferences::get();
34 numericprecision = std::max<int>(minprec,std::min<int>(maxprec, prefs->getInt("/options/svgoutput/numericprecision", 8)));
35 minimumexponent = prefs->getInt("/options/svgoutput/minimumexponent", -8);
36 }
38 void Inkscape::SVG::PathString::_appendOp(char abs_op, char rel_op) {
39 bool abs_op_repeated = _abs_state.prevop == abs_op && !force_repeat_commands;
40 bool rel_op_repeated = _rel_state.prevop == rel_op && !force_repeat_commands;
41 unsigned int const abs_added_size = abs_op_repeated ? 0 : 2;
42 unsigned int const rel_added_size = rel_op_repeated ? 0 : 2;
43 if ( _rel_state.str.size()+2 < _abs_state.str.size()+abs_added_size && allow_relative_coordinates ) {
44 // Store common prefix
45 commonbase += _rel_state.str;
46 _rel_state.str.clear();
47 // Copy rel to abs
48 _abs_state = _rel_state;
49 _abs_state.switches++;
50 abs_op_repeated = false;
51 // We do not have to copy abs to rel:
52 // _rel_state.str.size()+2 < _abs_state.str.size()+abs_added_size
53 // _rel_state.str.size()+rel_added_size < _abs_state.str.size()+2
54 // _abs_state.str.size()+2 > _rel_state.str.size()+rel_added_size
55 } else if ( _abs_state.str.size()+2 < _rel_state.str.size()+rel_added_size ) {
56 // Store common prefix
57 commonbase += _abs_state.str;
58 _abs_state.str.clear();
59 // Copy abs to rel
60 _rel_state = _abs_state;
61 _abs_state.switches++;
62 rel_op_repeated = false;
63 }
64 if ( !abs_op_repeated ) _abs_state.appendOp(abs_op);
65 if ( !rel_op_repeated ) _rel_state.appendOp(rel_op);
66 }
68 void Inkscape::SVG::PathString::State::append(Geom::Coord v) {
69 str += ' ';
70 appendNumber(v);
71 }
73 void Inkscape::SVG::PathString::State::append(Geom::Point p) {
74 str += ' ';
75 appendNumber(p[Geom::X]);
76 str += ',';
77 appendNumber(p[Geom::Y]);
78 }
80 void Inkscape::SVG::PathString::State::append(Geom::Coord v, Geom::Coord& rv) {
81 str += ' ';
82 appendNumber(v, rv);
83 }
85 void Inkscape::SVG::PathString::State::append(Geom::Point p, Geom::Point &rp) {
86 str += ' ';
87 appendNumber(p[Geom::X], rp[Geom::X]);
88 str += ',';
89 appendNumber(p[Geom::Y], rp[Geom::Y]);
90 }
92 // NOTE: The following appendRelativeCoord function will not be exact if the total number of digits needed
93 // to represent the difference exceeds the precision of a double. This is not very likely though, and if
94 // it does happen the imprecise value is not likely to be chosen (because it will probably be a lot longer
95 // than the absolute value).
97 // NOTE: This assumes v and r are already rounded (this includes flushing to zero if they are < 10^minexp)
98 void Inkscape::SVG::PathString::State::appendRelativeCoord(Geom::Coord v, Geom::Coord r) {
99 int const minexp = minimumexponent-numericprecision+1;
100 int const digitsEnd = (int)floor(log10(std::min(fabs(v),fabs(r)))) - numericprecision; // Position just beyond the last significant digit of the smallest (in absolute sense) number
101 double const roundeddiff = floor((v-r)*pow(10.,-digitsEnd-1)+.5);
102 int const numDigits = (int)floor(log10(fabs(roundeddiff)))+1; // Number of digits in roundeddiff
103 if (r == 0) {
104 appendNumber(v, numericprecision, minexp);
105 } else if (v == 0) {
106 appendNumber(-r, numericprecision, minexp);
107 } else if (numDigits>0) {
108 appendNumber(v-r, numDigits, minexp);
109 } else {
110 // This assumes the input numbers are already rounded to 'precision' digits
111 str += '0';
112 }
113 }
115 void Inkscape::SVG::PathString::State::appendRelative(Geom::Point p, Geom::Point r) {
116 str += ' ';
117 appendRelativeCoord(p[Geom::X], r[Geom::X]);
118 str += ',';
119 appendRelativeCoord(p[Geom::Y], r[Geom::Y]);
120 }
122 void Inkscape::SVG::PathString::State::appendRelative(Geom::Coord v, Geom::Coord r) {
123 str += ' ';
124 appendRelativeCoord(v, r);
125 }
127 void Inkscape::SVG::PathString::State::appendNumber(double v, int precision, int minexp) {
128 size_t const reserve = precision+1+1+1+1+3; // Just large enough to hold the maximum number of digits plus a sign, a period, the letter 'e', another sign and three digits for the exponent
129 size_t const oldsize = str.size();
130 str.append(reserve, (char)0);
131 char* begin_of_num = const_cast<char*>(str.data()+oldsize); // Slightly evil, I know (but std::string should be storing its data in one big block of memory, so...)
132 size_t added = sp_svg_number_write_de(begin_of_num, v, precision, minexp);
133 str.resize(oldsize+added); // remove any trailing characters
134 }
136 void Inkscape::SVG::PathString::State::appendNumber(double v, double &rv, int precision, int minexp) {
137 size_t const oldsize = str.size();
138 appendNumber(v, precision, minexp);
139 char* begin_of_num = const_cast<char*>(str.data()+oldsize); // Slightly evil, I know (but std::string should be storing its data in one big block of memory, so...)
140 sp_svg_number_read_d(begin_of_num, &rv);
141 }
143 /*
144 Local Variables:
145 mode:c++
146 c-file-style:"stroustrup"
147 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
148 indent-tabs-mode:nil
149 fill-column:99
150 End:
151 */
152 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :