summaryrefslogtreecommitdiff
path: root/agg/source/agg_rasterizer_scanline_aa.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'agg/source/agg_rasterizer_scanline_aa.cpp')
-rwxr-xr-xagg/source/agg_rasterizer_scanline_aa.cpp621
1 files changed, 621 insertions, 0 deletions
diff --git a/agg/source/agg_rasterizer_scanline_aa.cpp b/agg/source/agg_rasterizer_scanline_aa.cpp
new file mode 100755
index 000000000000..421c0187d0aa
--- /dev/null
+++ b/agg/source/agg_rasterizer_scanline_aa.cpp
@@ -0,0 +1,621 @@
+//----------------------------------------------------------------------------
+// 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.
+//
+// The author gratefully acknowleges the support of David Turner,
+// Robert Wilhelm, and Werner Lemberg - the authors of the FreeType
+// libray - in producing this work. See http://www.freetype.org for details.
+//
+//----------------------------------------------------------------------------
+// Contact: mcseem@antigrain.com
+// mcseemagg@yahoo.com
+// http://www.antigrain.com
+//----------------------------------------------------------------------------
+//
+// Class outline_aa - implementation.
+//
+// Initially the rendering algorithm was designed by David Turner and the
+// other authors of the FreeType library - see the above notice. I nearly
+// created a similar renderer, but still I was far from David's work.
+// I completely redesigned the original code and adapted it for Anti-Grain
+// ideas. Two functions - render_line and render_hline are the core of
+// the algorithm - they calculate the exact coverage of each pixel cell
+// of the polygon. I left these functions almost as is, because there's
+// no way to improve the perfection - hats off to David and his group!
+//
+// All other code is very different from the original.
+//
+//----------------------------------------------------------------------------
+
+#include <string.h>
+#include "agg_rasterizer_scanline_aa.h"
+
+
+namespace agg
+{
+
+ //------------------------------------------------------------------------
+ AGG_INLINE void cell_aa::set_cover(int c, int a)
+ {
+ cover = c;
+ area = a;
+ }
+
+ //------------------------------------------------------------------------
+ AGG_INLINE void cell_aa::add_cover(int c, int a)
+ {
+ cover += c;
+ area += a;
+ }
+
+ //------------------------------------------------------------------------
+ AGG_INLINE void cell_aa::set_coord(int cx, int cy)
+ {
+ x = int16(cx);
+ y = int16(cy);
+ packed_coord = (cy << 16) + cx;
+ }
+
+ //------------------------------------------------------------------------
+ AGG_INLINE void cell_aa::set(int cx, int cy, int c, int a)
+ {
+ x = int16(cx);
+ y = int16(cy);
+ packed_coord = (cy << 16) + cx;
+ cover = c;
+ area = a;
+ }
+
+ //------------------------------------------------------------------------
+ outline_aa::~outline_aa()
+ {
+ delete [] m_sorted_cells;
+ if(m_num_blocks)
+ {
+ cell_aa** ptr = m_cells + m_num_blocks - 1;
+ while(m_num_blocks--)
+ {
+ delete [] *ptr;
+ ptr--;
+ }
+ delete [] m_cells;
+ }
+ }
+
+
+ //------------------------------------------------------------------------
+ outline_aa::outline_aa() :
+ m_num_blocks(0),
+ m_max_blocks(0),
+ m_cur_block(0),
+ m_num_cells(0),
+ m_cells(0),
+ m_cur_cell_ptr(0),
+ m_sorted_cells(0),
+ m_sorted_size(0),
+ m_cur_x(0),
+ m_cur_y(0),
+ m_min_x(0x7FFFFFFF),
+ m_min_y(0x7FFFFFFF),
+ m_max_x(-0x7FFFFFFF),
+ m_max_y(-0x7FFFFFFF),
+ m_sorted(false)
+ {
+ m_cur_cell.set(0x7FFF, 0x7FFF, 0, 0);
+ }
+
+
+ //------------------------------------------------------------------------
+ void outline_aa::reset()
+ {
+ m_num_cells = 0;
+ m_cur_block = 0;
+ m_cur_cell.set(0x7FFF, 0x7FFF, 0, 0);
+ m_sorted = false;
+ m_min_x = 0x7FFFFFFF;
+ m_min_y = 0x7FFFFFFF;
+ m_max_x = -0x7FFFFFFF;
+ m_max_y = -0x7FFFFFFF;
+ }
+
+
+
+ //------------------------------------------------------------------------
+ void outline_aa::allocate_block()
+ {
+ if(m_cur_block >= m_num_blocks)
+ {
+ if(m_num_blocks >= m_max_blocks)
+ {
+ cell_aa** new_cells = new cell_aa* [m_max_blocks + cell_block_pool];
+ if(m_cells)
+ {
+ memcpy(new_cells, m_cells, m_max_blocks * sizeof(cell_aa*));
+ delete [] m_cells;
+ }
+ m_cells = new_cells;
+ m_max_blocks += cell_block_pool;
+ }
+ m_cells[m_num_blocks++] = new cell_aa [unsigned(cell_block_size)];
+ }
+ m_cur_cell_ptr = m_cells[m_cur_block++];
+ }
+
+
+ //------------------------------------------------------------------------
+ AGG_INLINE void outline_aa::add_cur_cell()
+ {
+ if(m_cur_cell.area | m_cur_cell.cover)
+ {
+ if((m_num_cells & cell_block_mask) == 0)
+ {
+ if(m_num_blocks >= cell_block_limit) return;
+ allocate_block();
+ }
+ *m_cur_cell_ptr++ = m_cur_cell;
+ ++m_num_cells;
+ if(m_cur_cell.x < m_min_x) m_min_x = m_cur_cell.x;
+ if(m_cur_cell.x > m_max_x) m_max_x = m_cur_cell.x;
+ }
+ }
+
+
+
+ //------------------------------------------------------------------------
+ AGG_INLINE void outline_aa::set_cur_cell(int x, int y)
+ {
+ if(m_cur_cell.packed_coord != (y << 16) + x)
+ {
+ add_cur_cell();
+ m_cur_cell.set(x, y, 0, 0);
+ }
+ }
+
+
+
+ //------------------------------------------------------------------------
+ AGG_INLINE void outline_aa::render_hline(int ey, int x1, int y1, int x2, int y2)
+ {
+ int ex1 = x1 >> poly_base_shift;
+ int ex2 = x2 >> poly_base_shift;
+ int fx1 = x1 & poly_base_mask;
+ int fx2 = x2 & poly_base_mask;
+
+ int delta, p, first, dx;
+ int incr, lift, mod, rem;
+
+ //trivial case. Happens often
+ if(y1 == y2)
+ {
+ set_cur_cell(ex2, ey);
+ return;
+ }
+
+ //everything is located in a single cell. That is easy!
+ if(ex1 == ex2)
+ {
+ delta = y2 - y1;
+ m_cur_cell.add_cover(delta, (fx1 + fx2) * delta);
+ return;
+ }
+
+ //ok, we'll have to render a run of adjacent cells on the same
+ //hline...
+ p = (poly_base_size - fx1) * (y2 - y1);
+ first = poly_base_size;
+ incr = 1;
+
+ dx = x2 - x1;
+
+ if(dx < 0)
+ {
+ p = fx1 * (y2 - y1);
+ first = 0;
+ incr = -1;
+ dx = -dx;
+ }
+
+ delta = p / dx;
+ mod = p % dx;
+
+ if(mod < 0)
+ {
+ delta--;
+ mod += dx;
+ }
+
+ m_cur_cell.add_cover(delta, (fx1 + first) * delta);
+
+ ex1 += incr;
+ set_cur_cell(ex1, ey);
+ y1 += delta;
+
+ if(ex1 != ex2)
+ {
+ p = poly_base_size * (y2 - y1 + delta);
+ lift = p / dx;
+ rem = p % dx;
+
+ if (rem < 0)
+ {
+ lift--;
+ rem += dx;
+ }
+
+ mod -= dx;
+
+ while (ex1 != ex2)
+ {
+ delta = lift;
+ mod += rem;
+ if(mod >= 0)
+ {
+ mod -= dx;
+ delta++;
+ }
+
+ m_cur_cell.add_cover(delta, (poly_base_size) * delta);
+ y1 += delta;
+ ex1 += incr;
+ set_cur_cell(ex1, ey);
+ }
+ }
+ delta = y2 - y1;
+ m_cur_cell.add_cover(delta, (fx2 + poly_base_size - first) * delta);
+ }
+
+
+
+
+
+
+ //------------------------------------------------------------------------
+ void outline_aa::render_line(int x1, int y1, int x2, int y2)
+ {
+ int ey1 = y1 >> poly_base_shift;
+ int ey2 = y2 >> poly_base_shift;
+ int fy1 = y1 & poly_base_mask;
+ int fy2 = y2 & poly_base_mask;
+
+ int dx, dy, x_from, x_to;
+ int p, rem, mod, lift, delta, first, incr;
+
+ dx = x2 - x1;
+ dy = y2 - y1;
+
+ //everything is on a single hline
+ if(ey1 == ey2)
+ {
+ render_hline(ey1, x1, fy1, x2, fy2);
+ return;
+ }
+
+ //Vertical line - we have to calculate start and end cells,
+ //and then - the common values of the area and coverage for
+ //all cells of the line. We know exactly there's only one
+ //cell, so, we don't have to call render_hline().
+ incr = 1;
+ if(dx == 0)
+ {
+ int ex = x1 >> poly_base_shift;
+ int two_fx = (x1 - (ex << poly_base_shift)) << 1;
+ int area;
+
+ first = poly_base_size;
+ if(dy < 0)
+ {
+ first = 0;
+ incr = -1;
+ }
+
+ x_from = x1;
+
+ //render_hline(ey1, x_from, fy1, x_from, first);
+ delta = first - fy1;
+ m_cur_cell.add_cover(delta, two_fx * delta);
+
+ ey1 += incr;
+ set_cur_cell(ex, ey1);
+
+ delta = first + first - poly_base_size;
+ area = two_fx * delta;
+ while(ey1 != ey2)
+ {
+ //render_hline(ey1, x_from, poly_base_size - first, x_from, first);
+ m_cur_cell.set_cover(delta, area);
+ ey1 += incr;
+ set_cur_cell(ex, ey1);
+ }
+ //render_hline(ey1, x_from, poly_base_size - first, x_from, fy2);
+ delta = fy2 - poly_base_size + first;
+ m_cur_cell.add_cover(delta, two_fx * delta);
+ return;
+ }
+
+ //ok, we have to render several hlines
+ p = (poly_base_size - fy1) * dx;
+ first = poly_base_size;
+
+ if(dy < 0)
+ {
+ p = fy1 * dx;
+ first = 0;
+ incr = -1;
+ dy = -dy;
+ }
+
+ delta = p / dy;
+ mod = p % dy;
+
+ if(mod < 0)
+ {
+ delta--;
+ mod += dy;
+ }
+
+ x_from = x1 + delta;
+ render_hline(ey1, x1, fy1, x_from, first);
+
+ ey1 += incr;
+ set_cur_cell(x_from >> poly_base_shift, ey1);
+
+ if(ey1 != ey2)
+ {
+ p = poly_base_size * dx;
+ lift = p / dy;
+ rem = p % dy;
+
+ if(rem < 0)
+ {
+ lift--;
+ rem += dy;
+ }
+ mod -= dy;
+
+ while(ey1 != ey2)
+ {
+ delta = lift;
+ mod += rem;
+ if (mod >= 0)
+ {
+ mod -= dy;
+ delta++;
+ }
+
+ x_to = x_from + delta;
+ render_hline(ey1, x_from, poly_base_size - first, x_to, first);
+ x_from = x_to;
+
+ ey1 += incr;
+ set_cur_cell(x_from >> poly_base_shift, ey1);
+ }
+ }
+ render_hline(ey1, x_from, poly_base_size - first, x2, fy2);
+ }
+
+
+ //------------------------------------------------------------------------
+ void outline_aa::move_to(int x, int y)
+ {
+ if(m_sorted) reset();
+ set_cur_cell(x >> poly_base_shift, y >> poly_base_shift);
+ m_cur_x = x;
+ m_cur_y = y;
+ }
+
+
+
+ //------------------------------------------------------------------------
+ void outline_aa::line_to(int x, int y)
+ {
+ render_line(m_cur_x, m_cur_y, x, y);
+ m_cur_x = x;
+ m_cur_y = y;
+ m_sorted = false;
+ }
+
+
+ //------------------------------------------------------------------------
+ enum
+ {
+ qsort_threshold = 9
+ };
+
+
+ //------------------------------------------------------------------------
+ template <class T> AGG_INLINE void swap_cells(T* a, T* b)
+ {
+ T temp = *a;
+ *a = *b;
+ *b = temp;
+ }
+
+ //------------------------------------------------------------------------
+ template <class T> AGG_INLINE bool less_than(T* a, T* b)
+ {
+ return (*a)->packed_coord < (*b)->packed_coord;
+ }
+
+
+
+ //------------------------------------------------------------------------
+ void outline_aa::qsort_cells(cell_aa** start, unsigned num)
+ {
+ cell_aa** stack[80];
+ cell_aa*** top;
+ cell_aa** limit;
+ cell_aa** base;
+
+ limit = start + num;
+ base = start;
+ top = stack;
+
+ for (;;)
+ {
+ int len = int(limit - base);
+
+ cell_aa** i;
+ cell_aa** j;
+ cell_aa** pivot;
+
+ if(len > qsort_threshold)
+ {
+ // we use base + len/2 as the pivot
+ pivot = base + len / 2;
+ swap_cells(base, pivot);
+
+ i = base + 1;
+ j = limit - 1;
+
+ // now ensure that *i <= *base <= *j
+ if(less_than(j, i))
+ {
+ swap_cells(i, j);
+ }
+
+ if(less_than(base, i))
+ {
+ swap_cells(base, i);
+ }
+
+ if(less_than(j, base))
+ {
+ swap_cells(base, j);
+ }
+
+ for(;;)
+ {
+ do i++; while( less_than(i, base) );
+ do j--; while( less_than(base, j) );
+
+ if ( i > j )
+ {
+ break;
+ }
+
+ swap_cells(i, j);
+ }
+
+ swap_cells(base, j);
+
+ // now, push the largest sub-array
+ if(j - base > limit - i)
+ {
+ top[0] = base;
+ top[1] = j;
+ base = i;
+ }
+ else
+ {
+ top[0] = i;
+ top[1] = limit;
+ limit = j;
+ }
+ top += 2;
+ }
+ else
+ {
+ // the sub-array is small, perform insertion sort
+ j = base;
+ i = j + 1;
+
+ for(; i < limit; j = i, i++)
+ {
+ for(; less_than(j + 1, j); j--)
+ {
+ swap_cells(j + 1, j);
+ if (j == base)
+ {
+ break;
+ }
+ }
+ }
+ if(top > stack)
+ {
+ top -= 2;
+ base = top[0];
+ limit = top[1];
+ }
+ else
+ {
+ break;
+ }
+ }
+ }
+ }
+
+
+
+
+
+ //------------------------------------------------------------------------
+ void outline_aa::sort_cells()
+ {
+ if(m_num_cells == 0) return;
+ if(m_num_cells > m_sorted_size)
+ {
+ delete [] m_sorted_cells;
+ m_sorted_size = m_num_cells;
+ m_sorted_cells = new cell_aa* [m_num_cells + 1];
+ }
+
+ cell_aa** sorted_ptr = m_sorted_cells;
+ cell_aa** block_ptr = m_cells;
+ cell_aa* cell_ptr;
+
+ unsigned nb = m_num_cells >> cell_block_shift;
+ unsigned i;
+
+ while(nb--)
+ {
+ cell_ptr = *block_ptr++;
+ i = cell_block_size;
+ while(i--)
+ {
+ *sorted_ptr++ = cell_ptr++;
+ }
+ }
+
+ cell_ptr = *block_ptr++;
+ i = m_num_cells & cell_block_mask;
+ while(i--)
+ {
+ *sorted_ptr++ = cell_ptr++;
+ }
+ m_sorted_cells[m_num_cells] = 0;
+ qsort_cells(m_sorted_cells, m_num_cells);
+ m_min_y = m_sorted_cells[0]->y;
+ m_max_y = m_sorted_cells[m_num_cells - 1]->y;
+ }
+
+
+
+
+ //------------------------------------------------------------------------
+ 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;
+ }
+
+
+
+
+
+}
+
+
+
+
+
generated by cgit v1.2.3 (git 2.39.1) at 2024-04-19 01:29:12 +0000