//----------------------------------------------------------------------------
// Anti-Grain Geometry - Version 2.4
// 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
//----------------------------------------------------------------------------
//
// Adaptation for 32-bit screen coordinates (scanline32_u) has been sponsored by
// Liberty Technology Systems, Inc., visit http://lib-sys.com
//
// Liberty Technology Systems, Inc. is the provider of
// PostScript and PDF technology for software developers.
//
//----------------------------------------------------------------------------
#ifndef AGG_SCANLINE_U_INCLUDED
#define AGG_SCANLINE_U_INCLUDED
#include "agg_array.h"
namespace agg
{
//=============================================================scanline_u8
//
// Unpacked scanline container class
//
// This class is used to transfer data from a scanline rasterizer
// to the rendering buffer. It's organized very simple. The class stores
// information of horizontal spans to render it into a pixel-map buffer.
// Each span has staring X, length, and an array of bytes that determine the
// cover-values for each pixel.
// Before using this class you should know the minimal and maximal pixel
// coordinates of your scanline. The protocol of using is:
// 1. reset(min_x, max_x)
// 2. add_cell() / add_span() - accumulate scanline.
// When forming one scanline the next X coordinate must be always greater
// than the last stored one, i.e. it works only with ordered coordinates.
// 3. Call finalize(y) and render the scanline.
// 3. Call reset_spans() to prepare for the new scanline.
//
// 4. Rendering:
//
// Scanline provides an iterator class that allows you to extract
// the spans and the cover values for each pixel. Be aware that clipping
// has not been done yet, so you should perform it yourself.
// Use scanline_u8::iterator to render spans:
//-------------------------------------------------------------------------
//
// int y = sl.y(); // Y-coordinate of the scanline
//
// ************************************
// ...Perform vertical clipping here...
// ************************************
//
// scanline_u8::const_iterator span = sl.begin();
//
// unsigned char* row = m_rbuf->row(y); // The the address of the beginning
// // of the current row
//
// unsigned num_spans = sl.num_spans(); // Number of spans. It's guaranteed that
// // num_spans is always greater than 0.
//
// do
// {
// const scanline_u8::cover_type* covers =
// span->covers; // The array of the cover values
//
// int num_pix = span->len; // Number of pixels of the span.
// // Always greater than 0, still it's
// // better to use "int" instead of
// // "unsigned" because it's more
// // convenient for clipping
// int x = span->x;
//
// **************************************
// ...Perform horizontal clipping here...
// ...you have x, covers, and pix_count..
// **************************************
//
// unsigned char* dst = row + x; // Calculate the start address of the row.
// // In this case we assume a simple
// // grayscale image 1-byte per pixel.
// do
// {
// *dst++ = *covers++; // Hypotetical rendering.
// }
// while(--num_pix);
//
// ++span;
// }
// while(--num_spans); // num_spans cannot be 0, so this loop is quite safe
//------------------------------------------------------------------------
//
// The question is: why should we accumulate the whole scanline when we
// could render just separate spans when they're ready?
// That's because using the scanline is generally faster. When is consists
// of more than one span the conditions for the processor cash system
// are better, because switching between two different areas of memory
// (that can be very large) occurs less frequently.
//------------------------------------------------------------------------
class scanline_u8
{
public:
typedef scanline_u8 self_type;
typedef int8u cover_type;
typedef int16 coord_type;
//--------------------------------------------------------------------
struct span
{
coord_type x;
coord_type len;
cover_type* covers;
};
typedef span* iterator;
typedef const span* const_iterator;
//--------------------------------------------------------------------
scanline_u8() :
m_min_x(0),
m_last_x(0x7FFFFFF0),
m_cur_span(0)
{}
//--------------------------------------------------------------------
void reset(int min_x, int max_x)
{
unsigned max_len = max_x - min_x + 2;
if(max_len > m_spans.size())
{
m_spans.resize(max_len);
m_covers.resize(max_len);
}
m_last_x = 0x7FFFFFF0;
m_min_x = min_x;
m_cur_span = &m_spans[0];
}
//--------------------------------------------------------------------
void add_cell(int x, unsigned cover)
{
x -= m_min_x;
m_covers[x] = (cover_type)cover;
if(x == m_last_x+1)
{
m_cur_span->len++;
}
else
{
m_cur_span++;
m_cur_span->x = (coord_type)(x + m_min_x);
m_cur_span->len = 1;
m_cur_span->covers = &m_covers[x];
}
m_last_x = x;
}
//--------------------------------------------------------------------
void add_cells(int x, unsigned len, const cover_type* covers)
{
x -= m_min_x;
memcpy(&m_covers[x], covers, len * sizeof(cover_type));
if(x == m_last_x+1)
{
m_cur_span->len += (coord_type)len;
}
else
{
m_cur_span++;
m_cur_span->x = (coord_type)(x + m_min_x);
m_cur_span->len = (coord_type)len;
m_cur_span->covers = &m_covers[x];
}
m_last_x = x + len - 1;
}
//--------------------------------------------------------------------
void add_span(int x, unsigned len, unsigned cover)
{
x -= m_min_x;
memset(&m_covers[x], cover, len);
if(x == m_last_x+1)
{
m_cur_span->len += (coord_type)len;
}
else
{
m_cur_span++;
m_cur_span->x = (coord_type)(x + m_min_x);
m_cur_span->len = (coord_type)len;
m_cur_span->covers = &m_covers[x];
}
m_last_x = x + len - 1;
}
//--------------------------------------------------------------------
void finalize(int y)
{
m_y = y;
}
//--------------------------------------------------------------------
void reset_spans()
{
m_last_x = 0x7FFFFFF0;
m_cur_span = &m_spans[0];
}
//--------------------------------------------------------------------
int y() const { return m_y; }
unsigned num_spans() const { return unsigned(m_cur_span - &m_spans[0]); }
const_iterator begin() const { return &m_spans[1]; }
iterator begin() { return &m_spans[1]; }
private:
scanline_u8(const self_type&);
const self_type& operator = (const self_type&);
private:
int m_min_x;
int m_last_x;
int m_y;
pod_array<cover_type> m_covers;
pod_array<span> m_spans;
span* m_cur_span;
};
//==========================================================scanline_u8_am
//
// The scanline container with alpha-masking
//
//------------------------------------------------------------------------
template<class AlphaMask>
class scanline_u8_am : public scanline_u8
{
public:
typedef scanline_u8 base_type;
typedef AlphaMask alpha_mask_type;
typedef base_type::cover_type cover_type;
typedef base_type::coord_type coord_type;
scanline_u8_am() : base_type(), m_alpha_mask(0) {}
scanline_u8_am(AlphaMask& am) : base_type(), m_alpha_mask(&am) {}
//--------------------------------------------------------------------
void finalize(int span_y)
{
base_type::finalize(span_y);
if(m_alpha_mask)
{
typename base_type::iterator span = base_type::begin();
unsigned count = base_type::num_spans();
do
{
m_alpha_mask->combine_hspan(span->x,
base_type::y(),
span->covers,
span->len);
++span;
}
while(--count);
}
}
private:
AlphaMask* m_alpha_mask;
};
//===========================================================scanline32_u8
class scanline32_u8
{
public:
typedef scanline32_u8 self_type;
typedef int8u cover_type;
typedef int32 coord_type;
//--------------------------------------------------------------------
struct span
{
span() {}
span(coord_type x_, coord_type len_, cover_type* covers_) :
x(x_), len(len_), covers(covers_) {}
coord_type x;
coord_type len;
cover_type* covers;
};
typedef pod_bvector<span, 4> span_array_type;
//--------------------------------------------------------------------
class const_iterator
{
public:
const_iterator(const span_array_type& spans) :
m_spans(spans),
m_span_idx(0)
{}
const span& operator*() const { return m_spans[m_span_idx]; }
const span* operator->() const { return &m_spans[m_span_idx]; }
void operator ++ () { ++m_span_idx; }
private:
const span_array_type& m_spans;
unsigned m_span_idx;
};
//--------------------------------------------------------------------
class iterator
{
public:
iterator(span_array_type& spans) :
m_spans(spans),
m_span_idx(0)
{}
span& operator*() { return m_spans[m_span_idx]; }
span* operator->() { return &m_spans[m_span_idx]; }
void operator ++ () { ++m_span_idx; }
private:
span_array_type& m_spans;
unsigned m_span_idx;
};
//--------------------------------------------------------------------
scanline32_u8() :
m_min_x(0),
m_last_x(0x7FFFFFF0),
m_covers()
{}
//--------------------------------------------------------------------
void reset(int min_x, int max_x)
{
unsigned max_len = max_x - min_x + 2;
if(max_len > m_covers.size())
{
m_covers.resize(max_len);
}
m_last_x = 0x7FFFFFF0;
m_min_x = min_x;
m_spans.remove_all();
}
//--------------------------------------------------------------------
void add_cell(int x, unsigned cover)
{
x -= m_min_x;
m_covers[x] = cover_type(cover);
if(x == m_last_x+1)
{
m_spans.last().len++;
}
else
{
m_spans.add(span(coord_type(x + m_min_x), 1, &m_covers[x]));
}
m_last_x = x;
}
//--------------------------------------------------------------------
void add_cells(int x, unsigned len, const cover_type* covers)
{
x -= m_min_x;
memcpy(&m_covers[x], covers, len * sizeof(cover_type));
if(x == m_last_x+1)
{
m_spans.last().len += coord_type(len);
}
else
{
m_spans.add(span(coord_type(x + m_min_x),
coord_type(len),
&m_covers[x]));
}
m_last_x = x + len - 1;
}
//--------------------------------------------------------------------
void add_span(int x, unsigned len, unsigned cover)
{
x -= m_min_x;
memset(&m_covers[x], cover, len);
if(x == m_last_x+1)
{
m_spans.last().len += coord_type(len);
}
else
{
m_spans.add(span(coord_type(x + m_min_x),
coord_type(len),
&m_covers[x]));
}
m_last_x = x + len - 1;
}
//--------------------------------------------------------------------
void finalize(int y)
{
m_y = y;
}
//--------------------------------------------------------------------
void reset_spans()
{
m_last_x = 0x7FFFFFF0;
m_spans.remove_all();
}
//--------------------------------------------------------------------
int y() const { return m_y; }
unsigned num_spans() const { return m_spans.size(); }
const_iterator begin() const { return const_iterator(m_spans); }
iterator begin() { return iterator(m_spans); }
private:
scanline32_u8(const self_type&);
const self_type& operator = (const self_type&);
private:
int m_min_x;
int m_last_x;
int m_y;
pod_array<cover_type> m_covers;
span_array_type m_spans;
};
//========================================================scanline32_u8_am
//
// The scanline container with alpha-masking
//
//------------------------------------------------------------------------
template<class AlphaMask>
class scanline32_u8_am : public scanline32_u8
{
public:
typedef scanline32_u8 base_type;
typedef AlphaMask alpha_mask_type;
typedef base_type::cover_type cover_type;
typedef base_type::coord_type coord_type;
scanline32_u8_am() : base_type(), m_alpha_mask(0) {}
scanline32_u8_am(AlphaMask& am) : base_type(), m_alpha_mask(&am) {}
//--------------------------------------------------------------------
void finalize(int span_y)
{
base_type::finalize(span_y);
if(m_alpha_mask)
{
typename base_type::iterator span = base_type::begin();
unsigned count = base_type::num_spans();
do
{
m_alpha_mask->combine_hspan(span->x,
base_type::y(),
span->covers,
span->len);
++span;
}
while(--count);
}
}
private:
AlphaMask* m_alpha_mask;
};
}
#endif
↑ V730 Not all members of a class are initialized inside the constructor. Consider inspecting: m_y.
↑ V730 Not all members of a class are initialized inside the constructor. Consider inspecting: m_y.