agg/examples/svg_viewer/agg_svg_path_tokenizer.h

115 lines
3.6 KiB
C++

//----------------------------------------------------------------------------
// Anti-Grain Geometry - Version 2.3
// Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com)
//
// Permission to copy, use, modify, sell and distribute this software
// is granted provided this copyright notice appears in all copies.
// This software is provided "as is" without express or implied
// warranty, and with no claim as to its suitability for any purpose.
//
//----------------------------------------------------------------------------
// Contact: mcseem@antigrain.com
// mcseemagg@yahoo.com
// http://www.antigrain.com
//----------------------------------------------------------------------------
//
// SVG path tokenizer.
//
//----------------------------------------------------------------------------
#ifndef AGG_SVG_PATH_TOKENIZER_INCLUDED
#define AGG_SVG_PATH_TOKENIZER_INCLUDED
#include "agg_svg_exception.h"
namespace agg
{
namespace svg
{
// SVG path tokenizer.
// Example:
//
// agg::svg::path_tokenizer tok;
//
// tok.set_str("M-122.304 84.285L-122.304 84.285 122.203 86.179 ");
// while(tok.next())
// {
// printf("command='%c' number=%f\n",
// tok.last_command(),
// tok.last_number());
// }
//
// The tokenizer does all the routine job of parsing the SVG paths.
// It doesn't recognize any graphical primitives, it even doesn't know
// anything about pairs of coordinates (X,Y). The purpose of this class
// is to tokenize the numeric values and commands. SVG paths can
// have single numeric values for Horizontal or Vertical line_to commands
// as well as more than two coordinates (4 or 6) for Bezier curves
// depending on the semantics of the command.
// The behaviour is as follows:
//
// Each call to next() returns true if there's new command or new numeric
// value or false when the path ends. How to interpret the result
// depends on the sematics of the command. For example, command "C"
// (cubic Bezier curve) implies 6 floating point numbers preceded by this
// command. If the command assumes no arguments (like z or Z) the
// the last_number() values won't change, that is, last_number() always
// returns the last recognized numeric value, so does last_command().
//===============================================================
class path_tokenizer
{
public:
path_tokenizer();
void set_path_str(const char* str);
bool next();
double next(char cmd);
char last_command() const { return m_last_command; }
double last_number() const { return m_last_number; }
private:
static void init_char_mask(char* mask, const char* char_set);
bool contains(const char* mask, unsigned c) const
{
return (mask[(c >> 3) & (256/8-1)] & (1 << (c & 7))) != 0;
}
bool is_command(unsigned c) const
{
return contains(m_commands_mask, c);
}
bool is_numeric(unsigned c) const
{
return contains(m_numeric_mask, c);
}
bool is_separator(unsigned c) const
{
return contains(m_separators_mask, c);
}
bool parse_number();
char m_separators_mask[256/8];
char m_commands_mask[256/8];
char m_numeric_mask[256/8];
const char* m_path;
double m_last_number;
char m_last_command;
static const char s_commands[];
static const char s_numeric[];
static const char s_separators[];
};
} //namespace svg
} //namespace agg
#endif