| |
| //---------------------------------------------------------------------------- |
| // XYQ: 2006-01-22 Copied from AGG project. |
| // This file uses only integer data, so it's suitable for all platforms. |
| //---------------------------------------------------------------------------- |
| //---------------------------------------------------------------------------- |
| // 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 |
| //---------------------------------------------------------------------------- |
| // |
| // Adaptation for 32-bit screen coordinates 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. |
| // |
| //---------------------------------------------------------------------------- |
| // |
| // 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 <limits.h> |
| #include "agg_rasterizer_scanline_aa.h" |
| #include "third_party/base/numerics/safe_math.h" |
| namespace pdfium |
| { |
| 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 = cx; |
| y = cy; |
| } |
| AGG_INLINE void cell_aa::set(int cx, int cy, int c, int a) |
| { |
| x = cx; |
| y = cy; |
| cover = c; |
| area = a; |
| } |
| outline_aa::~outline_aa() |
| { |
| if(m_num_blocks) { |
| cell_aa** ptr = m_cells + m_num_blocks - 1; |
| while(m_num_blocks--) { |
| FX_Free(*ptr); |
| ptr--; |
| } |
| FX_Free(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_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 = FX_Alloc( cell_aa*, m_max_blocks + cell_block_pool); |
| if(m_cells) { |
| memcpy(new_cells, m_cells, m_max_blocks * sizeof(cell_aa*)); |
| FX_Free(m_cells); |
| } |
| m_cells = new_cells; |
| m_max_blocks += cell_block_pool; |
| } |
| m_cells[m_num_blocks++] = FX_AllocUninit(cell_aa, 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; |
| } |
| } |
| AGG_INLINE void outline_aa::set_cur_cell(int x, int y) |
| { |
| if(m_cur_cell.x != x || m_cur_cell.y != y) { |
| add_cur_cell(); |
| m_cur_cell.set(x, y, 0, 0); |
| if(x < m_min_x) { |
| m_min_x = x; |
| } |
| if(x > m_max_x) { |
| m_max_x = x; |
| } |
| if(y < m_min_y) { |
| m_min_y = y; |
| } |
| if(y > m_max_y) { |
| m_max_y = y; |
| } |
| } |
| } |
| 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; |
| if(y1 == y2) { |
| set_cur_cell(ex2, ey); |
| return; |
| } |
| if(ex1 == ex2) { |
| delta = y2 - y1; |
| m_cur_cell.add_cover(delta, (fx1 + fx2) * delta); |
| return; |
| } |
| 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) |
| { |
| enum dx_limit_e { dx_limit = 16384 << poly_base_shift }; |
| pdfium::base::CheckedNumeric<int> safe_dx = x2; |
| safe_dx -= x1; |
| if (!safe_dx.IsValid()) |
| return; |
| |
| int dx = safe_dx.ValueOrDie(); |
| if(dx >= dx_limit || dx <= -dx_limit) { |
| pdfium::base::CheckedNumeric<int> safe_cx = x1; |
| safe_cx += x2; |
| safe_cx /= 2; |
| if (!safe_cx.IsValid()) |
| return; |
| |
| pdfium::base::CheckedNumeric<int> safe_cy = y1; |
| safe_cy += y2; |
| safe_cy /= 2; |
| if (!safe_cy.IsValid()) |
| return; |
| |
| int cx = safe_cx.ValueOrDie(); |
| int cy = safe_cy.ValueOrDie(); |
| render_line(x1, y1, cx, cy); |
| render_line(cx, cy, x2, y2); |
| } |
| int dy = y2 - y1; |
| 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 x_from, x_to; |
| int rem, mod, lift, delta, first, incr; |
| if(ey1 == ey2) { |
| render_hline(ey1, x1, fy1, x2, fy2); |
| return; |
| } |
| 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; |
| 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) { |
| m_cur_cell.set_cover(delta, area); |
| ey1 += incr; |
| set_cur_cell(ex, ey1); |
| } |
| delta = fy2 - poly_base_size + first; |
| m_cur_cell.add_cover(delta, two_fx * delta); |
| return; |
| } |
| pdfium::base::CheckedNumeric<int> safeP = poly_base_size - fy1; |
| safeP *= dx; |
| if (!safeP.IsValid()) |
| return; |
| first = poly_base_size; |
| if(dy < 0) { |
| safeP = fy1; |
| safeP *= dx; |
| if (!safeP.IsValid()) |
| return; |
| first = 0; |
| incr = -1; |
| dy = -dy; |
| } |
| delta = (safeP / dy).ValueOrDie(); |
| mod = (safeP % dy).ValueOrDie(); |
| 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) { |
| safeP = static_cast<int>(poly_base_size); |
| safeP *= dx; |
| if (!safeP.IsValid()) |
| return; |
| lift = (safeP / dy).ValueOrDie(); |
| rem = (safeP % dy).ValueOrDie(); |
| 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; |
| } |
| template <class T> static AGG_INLINE void swap_cells(T* a, T* b) |
| { |
| T temp = *a; |
| *a = *b; |
| *b = temp; |
| } |
| enum { |
| qsort_threshold = 9 |
| }; |
| static void 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) { |
| pivot = base + len / 2; |
| swap_cells(base, pivot); |
| i = base + 1; |
| j = limit - 1; |
| if((*j)->x < (*i)->x) { |
| swap_cells(i, j); |
| } |
| if((*base)->x < (*i)->x) { |
| swap_cells(base, i); |
| } |
| if((*j)->x < (*base)->x) { |
| swap_cells(base, j); |
| } |
| for(;;) { |
| int x = (*base)->x; |
| do { |
| i++; |
| } while( (*i)->x < x ); |
| do { |
| j--; |
| } while( x < (*j)->x ); |
| if(i > j) { |
| break; |
| } |
| swap_cells(i, j); |
| } |
| swap_cells(base, j); |
| 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 { |
| j = base; |
| i = j + 1; |
| for(; i < limit; j = i, i++) { |
| for(; j[1]->x < (*j)->x; 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_sorted) { |
| return; |
| } |
| add_cur_cell(); |
| if(m_num_cells == 0) { |
| return; |
| } |
| m_sorted_cells.allocate(m_num_cells, 16); |
| if (m_max_y > 0 && m_min_y < 0 && -m_min_y > INT_MAX - m_max_y) { |
| return; |
| } |
| unsigned size = m_max_y - m_min_y; |
| if (size + 1 < size) { |
| return; |
| } |
| size++; |
| m_sorted_y.allocate(size, 16); |
| m_sorted_y.zero(); |
| cell_aa** block_ptr = m_cells; |
| cell_aa* cell_ptr = NULL; |
| unsigned nb = m_num_cells >> cell_block_shift; |
| unsigned i; |
| while(nb--) { |
| cell_ptr = *block_ptr++; |
| i = cell_block_size; |
| while(i--) { |
| m_sorted_y[cell_ptr->y - m_min_y].start++; |
| ++cell_ptr; |
| } |
| } |
| i = m_num_cells & cell_block_mask; |
| if (i) { |
| cell_ptr = *block_ptr++; |
| } |
| while(i--) { |
| m_sorted_y[cell_ptr->y - m_min_y].start++; |
| ++cell_ptr; |
| } |
| unsigned start = 0; |
| for(i = 0; i < m_sorted_y.size(); i++) { |
| unsigned v = m_sorted_y[i].start; |
| m_sorted_y[i].start = start; |
| start += v; |
| } |
| block_ptr = m_cells; |
| nb = m_num_cells >> cell_block_shift; |
| while(nb--) { |
| cell_ptr = *block_ptr++; |
| i = cell_block_size; |
| while(i--) { |
| sorted_y& cur_y = m_sorted_y[cell_ptr->y - m_min_y]; |
| m_sorted_cells[cur_y.start + cur_y.num] = cell_ptr; |
| ++cur_y.num; |
| ++cell_ptr; |
| } |
| } |
| i = m_num_cells & cell_block_mask; |
| if (i) { |
| cell_ptr = *block_ptr++; |
| } |
| while(i--) { |
| sorted_y& cur_y = m_sorted_y[cell_ptr->y - m_min_y]; |
| m_sorted_cells[cur_y.start + cur_y.num] = cell_ptr; |
| ++cur_y.num; |
| ++cell_ptr; |
| } |
| for(i = 0; i < m_sorted_y.size(); i++) { |
| const sorted_y& cur_y = m_sorted_y[i]; |
| if(cur_y.num) { |
| qsort_cells(m_sorted_cells.data() + cur_y.start, cur_y.num); |
| } |
| } |
| m_sorted = true; |
| } |
| // static |
| int rasterizer_scanline_aa::calculate_area(int cover, int shift) |
| { |
| unsigned int result = cover; |
| result <<= shift; |
| return result; |
| } |
| // static |
| bool rasterizer_scanline_aa::safe_add(int* op1, int op2) |
| { |
| pdfium::base::CheckedNumeric<int> safeOp1 = *op1; |
| safeOp1 += op2; |
| if(!safeOp1.IsValid()) { |
| return false; |
| } |
| |
| *op1 = safeOp1.ValueOrDie(); |
| return true; |
| } |
| } |
| } // namespace pdfium |
