621 lines
16 KiB
C++
Executable file
621 lines
16 KiB
C++
Executable file
//----------------------------------------------------------------------------
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// Anti-Grain Geometry - Version 2.3
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// Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com)
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//
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// Permission to copy, use, modify, sell and distribute this software
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// is granted provided this copyright notice appears in all copies.
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// This software is provided "as is" without express or implied
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// warranty, and with no claim as to its suitability for any purpose.
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//
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// The author gratefully acknowleges the support of David Turner,
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// Robert Wilhelm, and Werner Lemberg - the authors of the FreeType
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// libray - in producing this work. See http://www.freetype.org for details.
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//
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//----------------------------------------------------------------------------
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// Contact: mcseem@antigrain.com
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// mcseemagg@yahoo.com
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// http://www.antigrain.com
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//----------------------------------------------------------------------------
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//
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// Class outline_aa - implementation.
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//
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// Initially the rendering algorithm was designed by David Turner and the
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// other authors of the FreeType library - see the above notice. I nearly
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// created a similar renderer, but still I was far from David's work.
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// I completely redesigned the original code and adapted it for Anti-Grain
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// ideas. Two functions - render_line and render_hline are the core of
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// the algorithm - they calculate the exact coverage of each pixel cell
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// of the polygon. I left these functions almost as is, because there's
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// no way to improve the perfection - hats off to David and his group!
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//
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// All other code is very different from the original.
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//
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//----------------------------------------------------------------------------
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#include <string.h>
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#include "agg_rasterizer_scanline_aa.h"
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namespace agg
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{
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//------------------------------------------------------------------------
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AGG_INLINE void cell_aa::set_cover(int c, int a)
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{
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cover = c;
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area = a;
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}
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//------------------------------------------------------------------------
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AGG_INLINE void cell_aa::add_cover(int c, int a)
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{
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cover += c;
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area += a;
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}
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//------------------------------------------------------------------------
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AGG_INLINE void cell_aa::set_coord(int cx, int cy)
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{
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x = int16(cx);
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y = int16(cy);
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packed_coord = (cy << 16) + cx;
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}
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//------------------------------------------------------------------------
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AGG_INLINE void cell_aa::set(int cx, int cy, int c, int a)
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{
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x = int16(cx);
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y = int16(cy);
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packed_coord = (cy << 16) + cx;
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cover = c;
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area = a;
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}
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//------------------------------------------------------------------------
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outline_aa::~outline_aa()
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{
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delete [] m_sorted_cells;
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if(m_num_blocks)
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{
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cell_aa** ptr = m_cells + m_num_blocks - 1;
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while(m_num_blocks--)
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{
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delete [] *ptr;
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ptr--;
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}
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delete [] m_cells;
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}
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}
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//------------------------------------------------------------------------
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outline_aa::outline_aa() :
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m_num_blocks(0),
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m_max_blocks(0),
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m_cur_block(0),
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m_num_cells(0),
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m_cells(0),
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m_cur_cell_ptr(0),
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m_sorted_cells(0),
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m_sorted_size(0),
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m_cur_x(0),
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m_cur_y(0),
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m_min_x(0x7FFFFFFF),
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m_min_y(0x7FFFFFFF),
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m_max_x(-0x7FFFFFFF),
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m_max_y(-0x7FFFFFFF),
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m_sorted(false)
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{
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m_cur_cell.set(0x7FFF, 0x7FFF, 0, 0);
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}
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//------------------------------------------------------------------------
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void outline_aa::reset()
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{
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m_num_cells = 0;
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m_cur_block = 0;
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m_cur_cell.set(0x7FFF, 0x7FFF, 0, 0);
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m_sorted = false;
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m_min_x = 0x7FFFFFFF;
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m_min_y = 0x7FFFFFFF;
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m_max_x = -0x7FFFFFFF;
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m_max_y = -0x7FFFFFFF;
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}
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//------------------------------------------------------------------------
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void outline_aa::allocate_block()
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{
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if(m_cur_block >= m_num_blocks)
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{
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if(m_num_blocks >= m_max_blocks)
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{
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cell_aa** new_cells = new cell_aa* [m_max_blocks + cell_block_pool];
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if(m_cells)
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{
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memcpy(new_cells, m_cells, m_max_blocks * sizeof(cell_aa*));
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delete [] m_cells;
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}
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m_cells = new_cells;
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m_max_blocks += cell_block_pool;
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}
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m_cells[m_num_blocks++] = new cell_aa [unsigned(cell_block_size)];
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}
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m_cur_cell_ptr = m_cells[m_cur_block++];
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}
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//------------------------------------------------------------------------
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AGG_INLINE void outline_aa::add_cur_cell()
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{
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if(m_cur_cell.area | m_cur_cell.cover)
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{
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if((m_num_cells & cell_block_mask) == 0)
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{
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if(m_num_blocks >= cell_block_limit) return;
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allocate_block();
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}
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*m_cur_cell_ptr++ = m_cur_cell;
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++m_num_cells;
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if(m_cur_cell.x < m_min_x) m_min_x = m_cur_cell.x;
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if(m_cur_cell.x > m_max_x) m_max_x = m_cur_cell.x;
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}
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}
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//------------------------------------------------------------------------
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AGG_INLINE void outline_aa::set_cur_cell(int x, int y)
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{
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if(m_cur_cell.packed_coord != (y << 16) + x)
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{
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add_cur_cell();
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m_cur_cell.set(x, y, 0, 0);
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}
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}
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//------------------------------------------------------------------------
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AGG_INLINE void outline_aa::render_hline(int ey, int x1, int y1, int x2, int y2)
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{
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int ex1 = x1 >> poly_base_shift;
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int ex2 = x2 >> poly_base_shift;
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int fx1 = x1 & poly_base_mask;
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int fx2 = x2 & poly_base_mask;
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int delta, p, first, dx;
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int incr, lift, mod, rem;
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//trivial case. Happens often
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if(y1 == y2)
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{
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set_cur_cell(ex2, ey);
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return;
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}
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//everything is located in a single cell. That is easy!
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if(ex1 == ex2)
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{
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delta = y2 - y1;
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m_cur_cell.add_cover(delta, (fx1 + fx2) * delta);
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return;
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}
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//ok, we'll have to render a run of adjacent cells on the same
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//hline...
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p = (poly_base_size - fx1) * (y2 - y1);
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first = poly_base_size;
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incr = 1;
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dx = x2 - x1;
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if(dx < 0)
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{
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p = fx1 * (y2 - y1);
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first = 0;
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incr = -1;
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dx = -dx;
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}
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delta = p / dx;
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mod = p % dx;
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if(mod < 0)
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{
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delta--;
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mod += dx;
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}
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m_cur_cell.add_cover(delta, (fx1 + first) * delta);
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ex1 += incr;
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set_cur_cell(ex1, ey);
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y1 += delta;
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if(ex1 != ex2)
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{
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p = poly_base_size * (y2 - y1 + delta);
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lift = p / dx;
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rem = p % dx;
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if (rem < 0)
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{
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lift--;
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rem += dx;
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}
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mod -= dx;
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while (ex1 != ex2)
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{
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delta = lift;
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mod += rem;
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if(mod >= 0)
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{
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mod -= dx;
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delta++;
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}
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m_cur_cell.add_cover(delta, (poly_base_size) * delta);
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y1 += delta;
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ex1 += incr;
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set_cur_cell(ex1, ey);
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}
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}
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delta = y2 - y1;
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m_cur_cell.add_cover(delta, (fx2 + poly_base_size - first) * delta);
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}
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//------------------------------------------------------------------------
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void outline_aa::render_line(int x1, int y1, int x2, int y2)
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{
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int ey1 = y1 >> poly_base_shift;
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int ey2 = y2 >> poly_base_shift;
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int fy1 = y1 & poly_base_mask;
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int fy2 = y2 & poly_base_mask;
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int dx, dy, x_from, x_to;
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int p, rem, mod, lift, delta, first, incr;
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dx = x2 - x1;
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dy = y2 - y1;
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//everything is on a single hline
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if(ey1 == ey2)
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{
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render_hline(ey1, x1, fy1, x2, fy2);
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return;
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}
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//Vertical line - we have to calculate start and end cells,
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//and then - the common values of the area and coverage for
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//all cells of the line. We know exactly there's only one
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//cell, so, we don't have to call render_hline().
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incr = 1;
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if(dx == 0)
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{
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int ex = x1 >> poly_base_shift;
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int two_fx = (x1 - (ex << poly_base_shift)) << 1;
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int area;
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first = poly_base_size;
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if(dy < 0)
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{
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first = 0;
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incr = -1;
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}
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x_from = x1;
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//render_hline(ey1, x_from, fy1, x_from, first);
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delta = first - fy1;
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m_cur_cell.add_cover(delta, two_fx * delta);
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ey1 += incr;
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set_cur_cell(ex, ey1);
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delta = first + first - poly_base_size;
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area = two_fx * delta;
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while(ey1 != ey2)
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{
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//render_hline(ey1, x_from, poly_base_size - first, x_from, first);
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m_cur_cell.set_cover(delta, area);
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ey1 += incr;
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set_cur_cell(ex, ey1);
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}
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//render_hline(ey1, x_from, poly_base_size - first, x_from, fy2);
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delta = fy2 - poly_base_size + first;
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m_cur_cell.add_cover(delta, two_fx * delta);
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return;
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}
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//ok, we have to render several hlines
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p = (poly_base_size - fy1) * dx;
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first = poly_base_size;
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if(dy < 0)
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{
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p = fy1 * dx;
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first = 0;
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incr = -1;
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dy = -dy;
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}
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delta = p / dy;
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mod = p % dy;
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if(mod < 0)
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{
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delta--;
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mod += dy;
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}
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x_from = x1 + delta;
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render_hline(ey1, x1, fy1, x_from, first);
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ey1 += incr;
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set_cur_cell(x_from >> poly_base_shift, ey1);
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if(ey1 != ey2)
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{
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p = poly_base_size * dx;
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lift = p / dy;
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rem = p % dy;
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if(rem < 0)
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{
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lift--;
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rem += dy;
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}
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mod -= dy;
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while(ey1 != ey2)
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{
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delta = lift;
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mod += rem;
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if (mod >= 0)
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{
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mod -= dy;
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delta++;
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}
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x_to = x_from + delta;
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render_hline(ey1, x_from, poly_base_size - first, x_to, first);
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x_from = x_to;
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ey1 += incr;
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set_cur_cell(x_from >> poly_base_shift, ey1);
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}
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}
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render_hline(ey1, x_from, poly_base_size - first, x2, fy2);
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}
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//------------------------------------------------------------------------
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void outline_aa::move_to(int x, int y)
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{
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if(m_sorted) reset();
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set_cur_cell(x >> poly_base_shift, y >> poly_base_shift);
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m_cur_x = x;
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m_cur_y = y;
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}
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//------------------------------------------------------------------------
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void outline_aa::line_to(int x, int y)
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{
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render_line(m_cur_x, m_cur_y, x, y);
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m_cur_x = x;
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m_cur_y = y;
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m_sorted = false;
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}
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//------------------------------------------------------------------------
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enum
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{
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qsort_threshold = 9
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};
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//------------------------------------------------------------------------
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template <class T> AGG_INLINE void swap_cells(T* a, T* b)
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{
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T temp = *a;
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*a = *b;
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*b = temp;
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}
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//------------------------------------------------------------------------
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template <class T> AGG_INLINE bool less_than(T* a, T* b)
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{
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return (*a)->packed_coord < (*b)->packed_coord;
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}
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//------------------------------------------------------------------------
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void outline_aa::qsort_cells(cell_aa** start, unsigned num)
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{
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cell_aa** stack[80];
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cell_aa*** top;
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cell_aa** limit;
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cell_aa** base;
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limit = start + num;
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base = start;
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top = stack;
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for (;;)
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{
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int len = int(limit - base);
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cell_aa** i;
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cell_aa** j;
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cell_aa** pivot;
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if(len > qsort_threshold)
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{
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// we use base + len/2 as the pivot
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pivot = base + len / 2;
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swap_cells(base, pivot);
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i = base + 1;
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j = limit - 1;
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// now ensure that *i <= *base <= *j
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if(less_than(j, i))
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{
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swap_cells(i, j);
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}
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if(less_than(base, i))
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{
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swap_cells(base, i);
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}
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if(less_than(j, base))
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{
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swap_cells(base, j);
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}
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for(;;)
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{
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do i++; while( less_than(i, base) );
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do j--; while( less_than(base, j) );
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if ( i > j )
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{
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break;
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}
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swap_cells(i, j);
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}
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swap_cells(base, j);
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// now, push the largest sub-array
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if(j - base > limit - i)
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{
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top[0] = base;
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top[1] = j;
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base = i;
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}
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else
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{
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top[0] = i;
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top[1] = limit;
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limit = j;
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}
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top += 2;
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}
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else
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{
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// the sub-array is small, perform insertion sort
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j = base;
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i = j + 1;
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for(; i < limit; j = i, i++)
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{
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for(; less_than(j + 1, j); j--)
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{
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swap_cells(j + 1, j);
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if (j == base)
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{
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break;
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}
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}
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}
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if(top > stack)
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{
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top -= 2;
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base = top[0];
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limit = top[1];
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}
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else
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{
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break;
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}
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}
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}
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}
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|
|
|
|
|
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//------------------------------------------------------------------------
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void outline_aa::sort_cells()
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{
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if(m_num_cells == 0) return;
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if(m_num_cells > m_sorted_size)
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{
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delete [] m_sorted_cells;
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m_sorted_size = m_num_cells;
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m_sorted_cells = new cell_aa* [m_num_cells + 1];
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}
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cell_aa** sorted_ptr = m_sorted_cells;
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cell_aa** block_ptr = m_cells;
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cell_aa* cell_ptr;
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unsigned nb = m_num_cells >> cell_block_shift;
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unsigned i;
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while(nb--)
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{
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cell_ptr = *block_ptr++;
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i = cell_block_size;
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while(i--)
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{
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*sorted_ptr++ = cell_ptr++;
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}
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}
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cell_ptr = *block_ptr++;
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i = m_num_cells & cell_block_mask;
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while(i--)
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{
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*sorted_ptr++ = cell_ptr++;
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}
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m_sorted_cells[m_num_cells] = 0;
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qsort_cells(m_sorted_cells, m_num_cells);
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m_min_y = m_sorted_cells[0]->y;
|
|
m_max_y = m_sorted_cells[m_num_cells - 1]->y;
|
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}
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//------------------------------------------------------------------------
|
|
const cell_aa* const* outline_aa::cells()
|
|
{
|
|
//Perform sort only the first time.
|
|
if(!m_sorted)
|
|
{
|
|
add_cur_cell();
|
|
sort_cells();
|
|
m_sorted = true;
|
|
}
|
|
return m_sorted_cells;
|
|
}
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|
|
|
|
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|
|
|
|
|
|
}
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|
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|