| /* |
| * Copyright © 2004 Carl Worth |
| * Copyright © 2006 Red Hat, Inc. |
| * Copyright © 2007 David Turner |
| * Copyright © 2008 M Joonas Pihlaja |
| * Copyright © 2008 Chris Wilson |
| * Copyright © 2009 Intel Corporation |
| * |
| * This library is free software; you can redistribute it and/or |
| * modify it either under the terms of the GNU Lesser General Public |
| * License version 2.1 as published by the Free Software Foundation |
| * (the "LGPL") or, at your option, under the terms of the Mozilla |
| * Public License Version 1.1 (the "MPL"). If you do not alter this |
| * notice, a recipient may use your version of this file under either |
| * the MPL or the LGPL. |
| * |
| * You should have received a copy of the LGPL along with this library |
| * in the file COPYING-LGPL-2.1; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA |
| * You should have received a copy of the MPL along with this library |
| * in the file COPYING-MPL-1.1 |
| * |
| * The contents of this file are subject to the Mozilla Public License |
| * Version 1.1 (the "License"); you may not use this file except in |
| * compliance with the License. You may obtain a copy of the License at |
| * http://www.mozilla.org/MPL/ |
| * |
| * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY |
| * OF ANY KIND, either express or implied. See the LGPL or the MPL for |
| * the specific language governing rights and limitations. |
| * |
| * The Original Code is the cairo graphics library. |
| * |
| * The Initial Developer of the Original Code is Carl Worth |
| * |
| * Contributor(s): |
| * Carl D. Worth <cworth@cworth.org> |
| * M Joonas Pihlaja <jpihlaja@cc.helsinki.fi> |
| * Chris Wilson <chris@chris-wilson.co.uk> |
| */ |
| |
| /* Provide definitions for standalone compilation */ |
| #include "cairoint.h" |
| |
| #include "cairo-error-private.h" |
| #include "cairo-list-private.h" |
| #include "cairo-freelist-private.h" |
| #include "cairo-combsort-private.h" |
| |
| #include <setjmp.h> |
| |
| #define STEP_X CAIRO_FIXED_ONE |
| #define STEP_Y CAIRO_FIXED_ONE |
| #define UNROLL3(x) x x x |
| |
| #define STEP_XY (2*STEP_X*STEP_Y) /* Unit area in the step. */ |
| #define AREA_TO_ALPHA(c) (((c)*255 + STEP_XY/2) / STEP_XY) |
| |
| typedef struct _cairo_bo_intersect_ordinate { |
| int32_t ordinate; |
| enum { EXACT, INEXACT } exactness; |
| } cairo_bo_intersect_ordinate_t; |
| |
| typedef struct _cairo_bo_intersect_point { |
| cairo_bo_intersect_ordinate_t x; |
| cairo_bo_intersect_ordinate_t y; |
| } cairo_bo_intersect_point_t; |
| |
| struct quorem { |
| cairo_fixed_t quo; |
| cairo_fixed_t rem; |
| }; |
| |
| struct run { |
| struct run *next; |
| int sign; |
| cairo_fixed_t y; |
| }; |
| |
| typedef struct edge { |
| cairo_list_t link; |
| |
| cairo_edge_t edge; |
| |
| /* Current x coordinate and advancement. |
| * Initialised to the x coordinate of the top of the |
| * edge. The quotient is in cairo_fixed_t units and the |
| * remainder is mod dy in cairo_fixed_t units. |
| */ |
| cairo_fixed_t dy; |
| struct quorem x; |
| struct quorem dxdy; |
| struct quorem dxdy_full; |
| |
| cairo_bool_t vertical; |
| unsigned int flags; |
| |
| int current_sign; |
| struct run *runs; |
| } edge_t; |
| |
| enum { |
| START = 0x1, |
| STOP = 0x2, |
| }; |
| |
| /* the parent is always given by index/2 */ |
| #define PQ_PARENT_INDEX(i) ((i) >> 1) |
| #define PQ_FIRST_ENTRY 1 |
| |
| /* left and right children are index * 2 and (index * 2) +1 respectively */ |
| #define PQ_LEFT_CHILD_INDEX(i) ((i) << 1) |
| |
| typedef enum { |
| EVENT_TYPE_STOP, |
| EVENT_TYPE_INTERSECTION, |
| EVENT_TYPE_START |
| } event_type_t; |
| |
| typedef struct _event { |
| cairo_fixed_t y; |
| event_type_t type; |
| } event_t; |
| |
| typedef struct _start_event { |
| cairo_fixed_t y; |
| event_type_t type; |
| edge_t *edge; |
| } start_event_t; |
| |
| typedef struct _queue_event { |
| cairo_fixed_t y; |
| event_type_t type; |
| edge_t *e1; |
| edge_t *e2; |
| } queue_event_t; |
| |
| typedef struct _pqueue { |
| int size, max_size; |
| |
| event_t **elements; |
| event_t *elements_embedded[1024]; |
| } pqueue_t; |
| |
| struct cell { |
| struct cell *prev; |
| struct cell *next; |
| int x; |
| int uncovered_area; |
| int covered_height; |
| }; |
| |
| typedef struct _sweep_line { |
| cairo_list_t active; |
| cairo_list_t stopped; |
| cairo_list_t *insert_cursor; |
| cairo_bool_t is_vertical; |
| |
| cairo_fixed_t current_row; |
| cairo_fixed_t current_subrow; |
| |
| struct coverage { |
| struct cell head; |
| struct cell tail; |
| |
| struct cell *cursor; |
| int count; |
| |
| cairo_freepool_t pool; |
| } coverage; |
| |
| struct event_queue { |
| pqueue_t pq; |
| event_t **start_events; |
| |
| cairo_freepool_t pool; |
| } queue; |
| |
| cairo_freepool_t runs; |
| |
| jmp_buf unwind; |
| } sweep_line_t; |
| |
| cairo_always_inline static struct quorem |
| floored_divrem (int a, int b) |
| { |
| struct quorem qr; |
| qr.quo = a/b; |
| qr.rem = a%b; |
| if ((a^b)<0 && qr.rem) { |
| qr.quo--; |
| qr.rem += b; |
| } |
| return qr; |
| } |
| |
| static struct quorem |
| floored_muldivrem(int x, int a, int b) |
| { |
| struct quorem qr; |
| long long xa = (long long)x*a; |
| qr.quo = xa/b; |
| qr.rem = xa%b; |
| if ((xa>=0) != (b>=0) && qr.rem) { |
| qr.quo--; |
| qr.rem += b; |
| } |
| return qr; |
| } |
| |
| static cairo_fixed_t |
| line_compute_intersection_x_for_y (const cairo_line_t *line, |
| cairo_fixed_t y) |
| { |
| cairo_fixed_t x, dy; |
| |
| if (y == line->p1.y) |
| return line->p1.x; |
| if (y == line->p2.y) |
| return line->p2.x; |
| |
| x = line->p1.x; |
| dy = line->p2.y - line->p1.y; |
| if (dy != 0) { |
| x += _cairo_fixed_mul_div_floor (y - line->p1.y, |
| line->p2.x - line->p1.x, |
| dy); |
| } |
| |
| return x; |
| } |
| |
| /* |
| * We need to compare the x-coordinates of a pair of lines for a particular y, |
| * without loss of precision. |
| * |
| * The x-coordinate along an edge for a given y is: |
| * X = A_x + (Y - A_y) * A_dx / A_dy |
| * |
| * So the inequality we wish to test is: |
| * A_x + (Y - A_y) * A_dx / A_dy ∘ B_x + (Y - B_y) * B_dx / B_dy, |
| * where ∘ is our inequality operator. |
| * |
| * By construction, we know that A_dy and B_dy (and (Y - A_y), (Y - B_y)) are |
| * all positive, so we can rearrange it thus without causing a sign change: |
| * A_dy * B_dy * (A_x - B_x) ∘ (Y - B_y) * B_dx * A_dy |
| * - (Y - A_y) * A_dx * B_dy |
| * |
| * Given the assumption that all the deltas fit within 32 bits, we can compute |
| * this comparison directly using 128 bit arithmetic. For certain, but common, |
| * input we can reduce this down to a single 32 bit compare by inspecting the |
| * deltas. |
| * |
| * (And put the burden of the work on developing fast 128 bit ops, which are |
| * required throughout the tessellator.) |
| * |
| * See the similar discussion for _slope_compare(). |
| */ |
| static int |
| edges_compare_x_for_y_general (const cairo_edge_t *a, |
| const cairo_edge_t *b, |
| int32_t y) |
| { |
| /* XXX: We're assuming here that dx and dy will still fit in 32 |
| * bits. That's not true in general as there could be overflow. We |
| * should prevent that before the tessellation algorithm |
| * begins. |
| */ |
| int32_t dx; |
| int32_t adx, ady; |
| int32_t bdx, bdy; |
| enum { |
| HAVE_NONE = 0x0, |
| HAVE_DX = 0x1, |
| HAVE_ADX = 0x2, |
| HAVE_DX_ADX = HAVE_DX | HAVE_ADX, |
| HAVE_BDX = 0x4, |
| HAVE_DX_BDX = HAVE_DX | HAVE_BDX, |
| HAVE_ADX_BDX = HAVE_ADX | HAVE_BDX, |
| HAVE_ALL = HAVE_DX | HAVE_ADX | HAVE_BDX |
| } have_dx_adx_bdx = HAVE_ALL; |
| |
| /* don't bother solving for abscissa if the edges' bounding boxes |
| * can be used to order them. */ |
| { |
| int32_t amin, amax; |
| int32_t bmin, bmax; |
| if (a->line.p1.x < a->line.p2.x) { |
| amin = a->line.p1.x; |
| amax = a->line.p2.x; |
| } else { |
| amin = a->line.p2.x; |
| amax = a->line.p1.x; |
| } |
| if (b->line.p1.x < b->line.p2.x) { |
| bmin = b->line.p1.x; |
| bmax = b->line.p2.x; |
| } else { |
| bmin = b->line.p2.x; |
| bmax = b->line.p1.x; |
| } |
| if (amax < bmin) return -1; |
| if (amin > bmax) return +1; |
| } |
| |
| ady = a->line.p2.y - a->line.p1.y; |
| adx = a->line.p2.x - a->line.p1.x; |
| if (adx == 0) |
| have_dx_adx_bdx &= ~HAVE_ADX; |
| |
| bdy = b->line.p2.y - b->line.p1.y; |
| bdx = b->line.p2.x - b->line.p1.x; |
| if (bdx == 0) |
| have_dx_adx_bdx &= ~HAVE_BDX; |
| |
| dx = a->line.p1.x - b->line.p1.x; |
| if (dx == 0) |
| have_dx_adx_bdx &= ~HAVE_DX; |
| |
| #define L _cairo_int64x32_128_mul (_cairo_int32x32_64_mul (ady, bdy), dx) |
| #define A _cairo_int64x32_128_mul (_cairo_int32x32_64_mul (adx, bdy), y - a->line.p1.y) |
| #define B _cairo_int64x32_128_mul (_cairo_int32x32_64_mul (bdx, ady), y - b->line.p1.y) |
| switch (have_dx_adx_bdx) { |
| default: |
| case HAVE_NONE: |
| return 0; |
| case HAVE_DX: |
| /* A_dy * B_dy * (A_x - B_x) ∘ 0 */ |
| return dx; /* ady * bdy is positive definite */ |
| case HAVE_ADX: |
| /* 0 ∘ - (Y - A_y) * A_dx * B_dy */ |
| return adx; /* bdy * (y - a->top.y) is positive definite */ |
| case HAVE_BDX: |
| /* 0 ∘ (Y - B_y) * B_dx * A_dy */ |
| return -bdx; /* ady * (y - b->top.y) is positive definite */ |
| case HAVE_ADX_BDX: |
| /* 0 ∘ (Y - B_y) * B_dx * A_dy - (Y - A_y) * A_dx * B_dy */ |
| if ((adx ^ bdx) < 0) { |
| return adx; |
| } else if (a->line.p1.y == b->line.p1.y) { /* common origin */ |
| cairo_int64_t adx_bdy, bdx_ady; |
| |
| /* ∴ A_dx * B_dy ∘ B_dx * A_dy */ |
| |
| adx_bdy = _cairo_int32x32_64_mul (adx, bdy); |
| bdx_ady = _cairo_int32x32_64_mul (bdx, ady); |
| |
| return _cairo_int64_cmp (adx_bdy, bdx_ady); |
| } else |
| return _cairo_int128_cmp (A, B); |
| case HAVE_DX_ADX: |
| /* A_dy * (A_x - B_x) ∘ - (Y - A_y) * A_dx */ |
| if ((-adx ^ dx) < 0) { |
| return dx; |
| } else { |
| cairo_int64_t ady_dx, dy_adx; |
| |
| ady_dx = _cairo_int32x32_64_mul (ady, dx); |
| dy_adx = _cairo_int32x32_64_mul (a->line.p1.y - y, adx); |
| |
| return _cairo_int64_cmp (ady_dx, dy_adx); |
| } |
| case HAVE_DX_BDX: |
| /* B_dy * (A_x - B_x) ∘ (Y - B_y) * B_dx */ |
| if ((bdx ^ dx) < 0) { |
| return dx; |
| } else { |
| cairo_int64_t bdy_dx, dy_bdx; |
| |
| bdy_dx = _cairo_int32x32_64_mul (bdy, dx); |
| dy_bdx = _cairo_int32x32_64_mul (y - b->line.p1.y, bdx); |
| |
| return _cairo_int64_cmp (bdy_dx, dy_bdx); |
| } |
| case HAVE_ALL: |
| /* XXX try comparing (a->line.p2.x - b->line.p2.x) et al */ |
| return _cairo_int128_cmp (L, _cairo_int128_sub (B, A)); |
| } |
| #undef B |
| #undef A |
| #undef L |
| } |
| |
| /* |
| * We need to compare the x-coordinate of a line for a particular y wrt to a |
| * given x, without loss of precision. |
| * |
| * The x-coordinate along an edge for a given y is: |
| * X = A_x + (Y - A_y) * A_dx / A_dy |
| * |
| * So the inequality we wish to test is: |
| * A_x + (Y - A_y) * A_dx / A_dy ∘ X |
| * where ∘ is our inequality operator. |
| * |
| * By construction, we know that A_dy (and (Y - A_y)) are |
| * all positive, so we can rearrange it thus without causing a sign change: |
| * (Y - A_y) * A_dx ∘ (X - A_x) * A_dy |
| * |
| * Given the assumption that all the deltas fit within 32 bits, we can compute |
| * this comparison directly using 64 bit arithmetic. |
| * |
| * See the similar discussion for _slope_compare() and |
| * edges_compare_x_for_y_general(). |
| */ |
| static int |
| edge_compare_for_y_against_x (const cairo_edge_t *a, |
| int32_t y, |
| int32_t x) |
| { |
| int32_t adx, ady; |
| int32_t dx, dy; |
| cairo_int64_t L, R; |
| |
| if (a->line.p1.x <= a->line.p2.x) { |
| if (x < a->line.p1.x) |
| return 1; |
| if (x > a->line.p2.x) |
| return -1; |
| } else { |
| if (x < a->line.p2.x) |
| return 1; |
| if (x > a->line.p1.x) |
| return -1; |
| } |
| |
| adx = a->line.p2.x - a->line.p1.x; |
| dx = x - a->line.p1.x; |
| |
| if (adx == 0) |
| return -dx; |
| if (dx == 0 || (adx ^ dx) < 0) |
| return adx; |
| |
| dy = y - a->line.p1.y; |
| ady = a->line.p2.y - a->line.p1.y; |
| |
| L = _cairo_int32x32_64_mul (dy, adx); |
| R = _cairo_int32x32_64_mul (dx, ady); |
| |
| return _cairo_int64_cmp (L, R); |
| } |
| |
| static int |
| edges_compare_x_for_y (const cairo_edge_t *a, |
| const cairo_edge_t *b, |
| int32_t y) |
| { |
| /* If the sweep-line is currently on an end-point of a line, |
| * then we know its precise x value (and considering that we often need to |
| * compare events at end-points, this happens frequently enough to warrant |
| * special casing). |
| */ |
| enum { |
| HAVE_NEITHER = 0x0, |
| HAVE_AX = 0x1, |
| HAVE_BX = 0x2, |
| HAVE_BOTH = HAVE_AX | HAVE_BX |
| } have_ax_bx = HAVE_BOTH; |
| int32_t ax, bx; |
| |
| /* XXX given we have x and dx? */ |
| |
| if (y == a->line.p1.y) |
| ax = a->line.p1.x; |
| else if (y == a->line.p2.y) |
| ax = a->line.p2.x; |
| else |
| have_ax_bx &= ~HAVE_AX; |
| |
| if (y == b->line.p1.y) |
| bx = b->line.p1.x; |
| else if (y == b->line.p2.y) |
| bx = b->line.p2.x; |
| else |
| have_ax_bx &= ~HAVE_BX; |
| |
| switch (have_ax_bx) { |
| default: |
| case HAVE_NEITHER: |
| return edges_compare_x_for_y_general (a, b, y); |
| case HAVE_AX: |
| return -edge_compare_for_y_against_x (b, y, ax); |
| case HAVE_BX: |
| return edge_compare_for_y_against_x (a, y, bx); |
| case HAVE_BOTH: |
| return ax - bx; |
| } |
| } |
| |
| static inline int |
| slope_compare (const edge_t *a, |
| const edge_t *b) |
| { |
| cairo_int64_t L, R; |
| int cmp; |
| |
| cmp = a->dxdy.quo - b->dxdy.quo; |
| if (cmp) |
| return cmp; |
| |
| if (a->dxdy.rem == 0) |
| return -b->dxdy.rem; |
| if (b->dxdy.rem == 0) |
| return a->dxdy.rem; |
| |
| L = _cairo_int32x32_64_mul (b->dy, a->dxdy.rem); |
| R = _cairo_int32x32_64_mul (a->dy, b->dxdy.rem); |
| return _cairo_int64_cmp (L, R); |
| } |
| |
| static inline int |
| line_equal (const cairo_line_t *a, const cairo_line_t *b) |
| { |
| return a->p1.x == b->p1.x && a->p1.y == b->p1.y && |
| a->p2.x == b->p2.x && a->p2.y == b->p2.y; |
| } |
| |
| static inline int |
| sweep_line_compare_edges (const edge_t *a, |
| const edge_t *b, |
| cairo_fixed_t y) |
| { |
| int cmp; |
| |
| if (line_equal (&a->edge.line, &b->edge.line)) |
| return 0; |
| |
| cmp = edges_compare_x_for_y (&a->edge, &b->edge, y); |
| if (cmp) |
| return cmp; |
| |
| return slope_compare (a, b); |
| } |
| |
| static inline cairo_int64_t |
| det32_64 (int32_t a, int32_t b, |
| int32_t c, int32_t d) |
| { |
| /* det = a * d - b * c */ |
| return _cairo_int64_sub (_cairo_int32x32_64_mul (a, d), |
| _cairo_int32x32_64_mul (b, c)); |
| } |
| |
| static inline cairo_int128_t |
| det64x32_128 (cairo_int64_t a, int32_t b, |
| cairo_int64_t c, int32_t d) |
| { |
| /* det = a * d - b * c */ |
| return _cairo_int128_sub (_cairo_int64x32_128_mul (a, d), |
| _cairo_int64x32_128_mul (c, b)); |
| } |
| |
| /* Compute the intersection of two lines as defined by two edges. The |
| * result is provided as a coordinate pair of 128-bit integers. |
| * |
| * Returns %CAIRO_BO_STATUS_INTERSECTION if there is an intersection or |
| * %CAIRO_BO_STATUS_PARALLEL if the two lines are exactly parallel. |
| */ |
| static cairo_bool_t |
| intersect_lines (const edge_t *a, const edge_t *b, |
| cairo_bo_intersect_point_t *intersection) |
| { |
| cairo_int64_t a_det, b_det; |
| |
| /* XXX: We're assuming here that dx and dy will still fit in 32 |
| * bits. That's not true in general as there could be overflow. We |
| * should prevent that before the tessellation algorithm begins. |
| * What we're doing to mitigate this is to perform clamping in |
| * cairo_bo_tessellate_polygon(). |
| */ |
| int32_t dx1 = a->edge.line.p1.x - a->edge.line.p2.x; |
| int32_t dy1 = a->edge.line.p1.y - a->edge.line.p2.y; |
| |
| int32_t dx2 = b->edge.line.p1.x - b->edge.line.p2.x; |
| int32_t dy2 = b->edge.line.p1.y - b->edge.line.p2.y; |
| |
| cairo_int64_t den_det; |
| cairo_int64_t R; |
| cairo_quorem64_t qr; |
| |
| den_det = det32_64 (dx1, dy1, dx2, dy2); |
| |
| /* Q: Can we determine that the lines do not intersect (within range) |
| * much more cheaply than computing the intersection point i.e. by |
| * avoiding the division? |
| * |
| * X = ax + t * adx = bx + s * bdx; |
| * Y = ay + t * ady = by + s * bdy; |
| * ∴ t * (ady*bdx - bdy*adx) = bdx * (by - ay) + bdy * (ax - bx) |
| * => t * L = R |
| * |
| * Therefore we can reject any intersection (under the criteria for |
| * valid intersection events) if: |
| * L^R < 0 => t < 0, or |
| * L<R => t > 1 |
| * |
| * (where top/bottom must at least extend to the line endpoints). |
| * |
| * A similar substitution can be performed for s, yielding: |
| * s * (ady*bdx - bdy*adx) = ady * (ax - bx) - adx * (ay - by) |
| */ |
| R = det32_64 (dx2, dy2, |
| b->edge.line.p1.x - a->edge.line.p1.x, |
| b->edge.line.p1.y - a->edge.line.p1.y); |
| if (_cairo_int64_negative (den_det)) { |
| if (_cairo_int64_ge (den_det, R)) |
| return FALSE; |
| } else { |
| if (_cairo_int64_le (den_det, R)) |
| return FALSE; |
| } |
| |
| R = det32_64 (dy1, dx1, |
| a->edge.line.p1.y - b->edge.line.p1.y, |
| a->edge.line.p1.x - b->edge.line.p1.x); |
| if (_cairo_int64_negative (den_det)) { |
| if (_cairo_int64_ge (den_det, R)) |
| return FALSE; |
| } else { |
| if (_cairo_int64_le (den_det, R)) |
| return FALSE; |
| } |
| |
| /* We now know that the two lines should intersect within range. */ |
| |
| a_det = det32_64 (a->edge.line.p1.x, a->edge.line.p1.y, |
| a->edge.line.p2.x, a->edge.line.p2.y); |
| b_det = det32_64 (b->edge.line.p1.x, b->edge.line.p1.y, |
| b->edge.line.p2.x, b->edge.line.p2.y); |
| |
| /* x = det (a_det, dx1, b_det, dx2) / den_det */ |
| qr = _cairo_int_96by64_32x64_divrem (det64x32_128 (a_det, dx1, |
| b_det, dx2), |
| den_det); |
| if (_cairo_int64_eq (qr.rem, den_det)) |
| return FALSE; |
| #if 0 |
| intersection->x.exactness = _cairo_int64_is_zero (qr.rem) ? EXACT : INEXACT; |
| #else |
| intersection->x.exactness = EXACT; |
| if (! _cairo_int64_is_zero (qr.rem)) { |
| if (_cairo_int64_negative (den_det) ^ _cairo_int64_negative (qr.rem)) |
| qr.rem = _cairo_int64_negate (qr.rem); |
| qr.rem = _cairo_int64_mul (qr.rem, _cairo_int32_to_int64 (2)); |
| if (_cairo_int64_ge (qr.rem, den_det)) { |
| qr.quo = _cairo_int64_add (qr.quo, |
| _cairo_int32_to_int64 (_cairo_int64_negative (qr.quo) ? -1 : 1)); |
| } else |
| intersection->x.exactness = INEXACT; |
| } |
| #endif |
| intersection->x.ordinate = _cairo_int64_to_int32 (qr.quo); |
| |
| /* y = det (a_det, dy1, b_det, dy2) / den_det */ |
| qr = _cairo_int_96by64_32x64_divrem (det64x32_128 (a_det, dy1, |
| b_det, dy2), |
| den_det); |
| if (_cairo_int64_eq (qr.rem, den_det)) |
| return FALSE; |
| #if 0 |
| intersection->y.exactness = _cairo_int64_is_zero (qr.rem) ? EXACT : INEXACT; |
| #else |
| intersection->y.exactness = EXACT; |
| if (! _cairo_int64_is_zero (qr.rem)) { |
| /* compute ceiling away from zero */ |
| qr.quo = _cairo_int64_add (qr.quo, |
| _cairo_int32_to_int64 (_cairo_int64_negative (qr.quo) ? -1 : 1)); |
| intersection->y.exactness = INEXACT; |
| } |
| #endif |
| intersection->y.ordinate = _cairo_int64_to_int32 (qr.quo); |
| |
| return TRUE; |
| } |
| |
| static int |
| bo_intersect_ordinate_32_compare (int32_t a, int32_t b, int exactness) |
| { |
| int cmp; |
| |
| /* First compare the quotient */ |
| cmp = a - b; |
| if (cmp) |
| return cmp; |
| |
| /* With quotient identical, if remainder is 0 then compare equal */ |
| /* Otherwise, the non-zero remainder makes a > b */ |
| return -(INEXACT == exactness); |
| } |
| |
| /* Does the given edge contain the given point. The point must already |
| * be known to be contained within the line determined by the edge, |
| * (most likely the point results from an intersection of this edge |
| * with another). |
| * |
| * If we had exact arithmetic, then this function would simply be a |
| * matter of examining whether the y value of the point lies within |
| * the range of y values of the edge. But since intersection points |
| * are not exact due to being rounded to the nearest integer within |
| * the available precision, we must also examine the x value of the |
| * point. |
| * |
| * The definition of "contains" here is that the given intersection |
| * point will be seen by the sweep line after the start event for the |
| * given edge and before the stop event for the edge. See the comments |
| * in the implementation for more details. |
| */ |
| static cairo_bool_t |
| bo_edge_contains_intersect_point (const edge_t *edge, |
| cairo_bo_intersect_point_t *point) |
| { |
| int cmp_top, cmp_bottom; |
| |
| /* XXX: When running the actual algorithm, we don't actually need to |
| * compare against edge->top at all here, since any intersection above |
| * top is eliminated early via a slope comparison. We're leaving these |
| * here for now only for the sake of the quadratic-time intersection |
| * finder which needs them. |
| */ |
| |
| cmp_top = bo_intersect_ordinate_32_compare (point->y.ordinate, |
| edge->edge.top, |
| point->y.exactness); |
| if (cmp_top < 0) |
| return FALSE; |
| |
| cmp_bottom = bo_intersect_ordinate_32_compare (point->y.ordinate, |
| edge->edge.bottom, |
| point->y.exactness); |
| if (cmp_bottom > 0) |
| return FALSE; |
| |
| if (cmp_top > 0 && cmp_bottom < 0) |
| return TRUE; |
| |
| /* At this stage, the point lies on the same y value as either |
| * edge->top or edge->bottom, so we have to examine the x value in |
| * order to properly determine containment. */ |
| |
| /* If the y value of the point is the same as the y value of the |
| * top of the edge, then the x value of the point must be greater |
| * to be considered as inside the edge. Similarly, if the y value |
| * of the point is the same as the y value of the bottom of the |
| * edge, then the x value of the point must be less to be |
| * considered as inside. */ |
| |
| if (cmp_top == 0) { |
| cairo_fixed_t top_x; |
| |
| top_x = line_compute_intersection_x_for_y (&edge->edge.line, |
| edge->edge.top); |
| return bo_intersect_ordinate_32_compare (top_x, point->x.ordinate, point->x.exactness) < 0; |
| } else { /* cmp_bottom == 0 */ |
| cairo_fixed_t bot_x; |
| |
| bot_x = line_compute_intersection_x_for_y (&edge->edge.line, |
| edge->edge.bottom); |
| return bo_intersect_ordinate_32_compare (point->x.ordinate, bot_x, point->x.exactness) < 0; |
| } |
| } |
| |
| static cairo_bool_t |
| edge_intersect (const edge_t *a, |
| const edge_t *b, |
| cairo_point_t *intersection) |
| { |
| cairo_bo_intersect_point_t quorem; |
| |
| if (! intersect_lines (a, b, &quorem)) |
| return FALSE; |
| |
| if (a->edge.top != a->edge.line.p1.y || a->edge.bottom != a->edge.line.p2.y) { |
| if (! bo_edge_contains_intersect_point (a, &quorem)) |
| return FALSE; |
| } |
| |
| if (b->edge.top != b->edge.line.p1.y || b->edge.bottom != b->edge.line.p2.y) { |
| if (! bo_edge_contains_intersect_point (b, &quorem)) |
| return FALSE; |
| } |
| |
| /* Now that we've correctly compared the intersection point and |
| * determined that it lies within the edge, then we know that we |
| * no longer need any more bits of storage for the intersection |
| * than we do for our edge coordinates. We also no longer need the |
| * remainder from the division. */ |
| intersection->x = quorem.x.ordinate; |
| intersection->y = quorem.y.ordinate; |
| |
| return TRUE; |
| } |
| |
| static inline int |
| event_compare (const event_t *a, const event_t *b) |
| { |
| return a->y - b->y; |
| } |
| |
| static void |
| pqueue_init (pqueue_t *pq) |
| { |
| pq->max_size = ARRAY_LENGTH (pq->elements_embedded); |
| pq->size = 0; |
| |
| pq->elements = pq->elements_embedded; |
| } |
| |
| static void |
| pqueue_fini (pqueue_t *pq) |
| { |
| if (pq->elements != pq->elements_embedded) |
| free (pq->elements); |
| } |
| |
| static cairo_bool_t |
| pqueue_grow (pqueue_t *pq) |
| { |
| event_t **new_elements; |
| pq->max_size *= 2; |
| |
| if (pq->elements == pq->elements_embedded) { |
| new_elements = _cairo_malloc_ab (pq->max_size, |
| sizeof (event_t *)); |
| if (unlikely (new_elements == NULL)) |
| return FALSE; |
| |
| memcpy (new_elements, pq->elements_embedded, |
| sizeof (pq->elements_embedded)); |
| } else { |
| new_elements = _cairo_realloc_ab (pq->elements, |
| pq->max_size, |
| sizeof (event_t *)); |
| if (unlikely (new_elements == NULL)) |
| return FALSE; |
| } |
| |
| pq->elements = new_elements; |
| return TRUE; |
| } |
| |
| static inline void |
| pqueue_push (sweep_line_t *sweep_line, event_t *event) |
| { |
| event_t **elements; |
| int i, parent; |
| |
| if (unlikely (sweep_line->queue.pq.size + 1 == sweep_line->queue.pq.max_size)) { |
| if (unlikely (! pqueue_grow (&sweep_line->queue.pq))) { |
| longjmp (sweep_line->unwind, |
| _cairo_error (CAIRO_STATUS_NO_MEMORY)); |
| } |
| } |
| |
| elements = sweep_line->queue.pq.elements; |
| for (i = ++sweep_line->queue.pq.size; |
| i != PQ_FIRST_ENTRY && |
| event_compare (event, |
| elements[parent = PQ_PARENT_INDEX (i)]) < 0; |
| i = parent) |
| { |
| elements[i] = elements[parent]; |
| } |
| |
| elements[i] = event; |
| } |
| |
| static inline void |
| pqueue_pop (pqueue_t *pq) |
| { |
| event_t **elements = pq->elements; |
| event_t *tail; |
| int child, i; |
| |
| tail = elements[pq->size--]; |
| if (pq->size == 0) { |
| elements[PQ_FIRST_ENTRY] = NULL; |
| return; |
| } |
| |
| for (i = PQ_FIRST_ENTRY; |
| (child = PQ_LEFT_CHILD_INDEX (i)) <= pq->size; |
| i = child) |
| { |
| if (child != pq->size && |
| event_compare (elements[child+1], |
| elements[child]) < 0) |
| { |
| child++; |
| } |
| |
| if (event_compare (elements[child], tail) >= 0) |
| break; |
| |
| elements[i] = elements[child]; |
| } |
| elements[i] = tail; |
| } |
| |
| static inline void |
| event_insert (sweep_line_t *sweep_line, |
| event_type_t type, |
| edge_t *e1, |
| edge_t *e2, |
| cairo_fixed_t y) |
| { |
| queue_event_t *event; |
| |
| event = _cairo_freepool_alloc (&sweep_line->queue.pool); |
| if (unlikely (event == NULL)) { |
| longjmp (sweep_line->unwind, |
| _cairo_error (CAIRO_STATUS_NO_MEMORY)); |
| } |
| |
| event->y = y; |
| event->type = type; |
| event->e1 = e1; |
| event->e2 = e2; |
| |
| pqueue_push (sweep_line, (event_t *) event); |
| } |
| |
| static void |
| event_delete (sweep_line_t *sweep_line, |
| event_t *event) |
| { |
| _cairo_freepool_free (&sweep_line->queue.pool, event); |
| } |
| |
| static inline event_t * |
| event_next (sweep_line_t *sweep_line) |
| { |
| event_t *event, *cmp; |
| |
| event = sweep_line->queue.pq.elements[PQ_FIRST_ENTRY]; |
| cmp = *sweep_line->queue.start_events; |
| if (event == NULL || |
| (cmp != NULL && event_compare (cmp, event) < 0)) |
| { |
| event = cmp; |
| sweep_line->queue.start_events++; |
| } |
| else |
| { |
| pqueue_pop (&sweep_line->queue.pq); |
| } |
| |
| return event; |
| } |
| |
| CAIRO_COMBSORT_DECLARE (start_event_sort, event_t *, event_compare) |
| |
| static inline void |
| event_insert_stop (sweep_line_t *sweep_line, |
| edge_t *edge) |
| { |
| event_insert (sweep_line, |
| EVENT_TYPE_STOP, |
| edge, NULL, |
| edge->edge.bottom); |
| } |
| |
| static inline void |
| event_insert_if_intersect_below_current_y (sweep_line_t *sweep_line, |
| edge_t *left, |
| edge_t *right) |
| { |
| cairo_point_t intersection; |
| |
| /* start points intersect */ |
| if (left->edge.line.p1.x == right->edge.line.p1.x && |
| left->edge.line.p1.y == right->edge.line.p1.y) |
| { |
| return; |
| } |
| |
| /* end points intersect, process DELETE events first */ |
| if (left->edge.line.p2.x == right->edge.line.p2.x && |
| left->edge.line.p2.y == right->edge.line.p2.y) |
| { |
| return; |
| } |
| |
| if (slope_compare (left, right) <= 0) |
| return; |
| |
| if (! edge_intersect (left, right, &intersection)) |
| return; |
| |
| event_insert (sweep_line, |
| EVENT_TYPE_INTERSECTION, |
| left, right, |
| intersection.y); |
| } |
| |
| static inline edge_t * |
| link_to_edge (cairo_list_t *link) |
| { |
| return (edge_t *) link; |
| } |
| |
| static void |
| sweep_line_insert (sweep_line_t *sweep_line, |
| edge_t *edge) |
| { |
| cairo_list_t *pos; |
| cairo_fixed_t y = sweep_line->current_subrow; |
| |
| pos = sweep_line->insert_cursor; |
| if (pos == &sweep_line->active) |
| pos = sweep_line->active.next; |
| if (pos != &sweep_line->active) { |
| int cmp; |
| |
| cmp = sweep_line_compare_edges (link_to_edge (pos), |
| edge, |
| y); |
| if (cmp < 0) { |
| while (pos->next != &sweep_line->active && |
| sweep_line_compare_edges (link_to_edge (pos->next), |
| edge, |
| y) < 0) |
| { |
| pos = pos->next; |
| } |
| } else if (cmp > 0) { |
| do { |
| pos = pos->prev; |
| } while (pos != &sweep_line->active && |
| sweep_line_compare_edges (link_to_edge (pos), |
| edge, |
| y) > 0); |
| } |
| } |
| cairo_list_add (&edge->link, pos); |
| sweep_line->insert_cursor = &edge->link; |
| } |
| |
| inline static void |
| coverage_rewind (struct coverage *cells) |
| { |
| cells->cursor = &cells->head; |
| } |
| |
| static void |
| coverage_init (struct coverage *cells) |
| { |
| _cairo_freepool_init (&cells->pool, |
| sizeof (struct cell)); |
| cells->head.prev = NULL; |
| cells->head.next = &cells->tail; |
| cells->head.x = INT_MIN; |
| cells->tail.prev = &cells->head; |
| cells->tail.next = NULL; |
| cells->tail.x = INT_MAX; |
| cells->count = 0; |
| coverage_rewind (cells); |
| } |
| |
| static void |
| coverage_fini (struct coverage *cells) |
| { |
| _cairo_freepool_fini (&cells->pool); |
| } |
| |
| inline static void |
| coverage_reset (struct coverage *cells) |
| { |
| cells->head.next = &cells->tail; |
| cells->tail.prev = &cells->head; |
| cells->count = 0; |
| _cairo_freepool_reset (&cells->pool); |
| coverage_rewind (cells); |
| } |
| |
| inline static struct cell * |
| coverage_alloc (sweep_line_t *sweep_line, |
| struct cell *tail, |
| int x) |
| { |
| struct cell *cell; |
| |
| cell = _cairo_freepool_alloc (&sweep_line->coverage.pool); |
| if (unlikely (NULL == cell)) { |
| longjmp (sweep_line->unwind, |
| _cairo_error (CAIRO_STATUS_NO_MEMORY)); |
| } |
| |
| tail->prev->next = cell; |
| cell->prev = tail->prev; |
| cell->next = tail; |
| tail->prev = cell; |
| cell->x = x; |
| cell->uncovered_area = 0; |
| cell->covered_height = 0; |
| sweep_line->coverage.count++; |
| return cell; |
| } |
| |
| inline static struct cell * |
| coverage_find (sweep_line_t *sweep_line, int x) |
| { |
| struct cell *cell; |
| |
| cell = sweep_line->coverage.cursor; |
| if (unlikely (cell->x > x)) { |
| do { |
| if (cell->prev->x < x) |
| break; |
| cell = cell->prev; |
| } while (TRUE); |
| } else { |
| if (cell->x == x) |
| return cell; |
| |
| do { |
| UNROLL3({ |
| cell = cell->next; |
| if (cell->x >= x) |
| break; |
| }); |
| } while (TRUE); |
| } |
| |
| if (cell->x != x) |
| cell = coverage_alloc (sweep_line, cell, x); |
| |
| return sweep_line->coverage.cursor = cell; |
| } |
| |
| static void |
| coverage_render_cells (sweep_line_t *sweep_line, |
| cairo_fixed_t left, cairo_fixed_t right, |
| cairo_fixed_t y1, cairo_fixed_t y2, |
| int sign) |
| { |
| int fx1, fx2; |
| int ix1, ix2; |
| int dx, dy; |
| |
| /* Orient the edge left-to-right. */ |
| dx = right - left; |
| if (dx >= 0) { |
| ix1 = _cairo_fixed_integer_part (left); |
| fx1 = _cairo_fixed_fractional_part (left); |
| |
| ix2 = _cairo_fixed_integer_part (right); |
| fx2 = _cairo_fixed_fractional_part (right); |
| |
| dy = y2 - y1; |
| } else { |
| ix1 = _cairo_fixed_integer_part (right); |
| fx1 = _cairo_fixed_fractional_part (right); |
| |
| ix2 = _cairo_fixed_integer_part (left); |
| fx2 = _cairo_fixed_fractional_part (left); |
| |
| dx = -dx; |
| sign = -sign; |
| dy = y1 - y2; |
| y1 = y2 - dy; |
| y2 = y1 + dy; |
| } |
| |
| /* Add coverage for all pixels [ix1,ix2] on this row crossed |
| * by the edge. */ |
| { |
| struct quorem y = floored_divrem ((STEP_X - fx1)*dy, dx); |
| struct cell *cell; |
| |
| cell = sweep_line->coverage.cursor; |
| if (cell->x != ix1) { |
| if (unlikely (cell->x > ix1)) { |
| do { |
| if (cell->prev->x < ix1) |
| break; |
| cell = cell->prev; |
| } while (TRUE); |
| } else do { |
| UNROLL3({ |
| if (cell->x >= ix1) |
| break; |
| cell = cell->next; |
| }); |
| } while (TRUE); |
| |
| if (cell->x != ix1) |
| cell = coverage_alloc (sweep_line, cell, ix1); |
| } |
| |
| cell->uncovered_area += sign * y.quo * (STEP_X + fx1); |
| cell->covered_height += sign * y.quo; |
| y.quo += y1; |
| |
| cell = cell->next; |
| if (cell->x != ++ix1) |
| cell = coverage_alloc (sweep_line, cell, ix1); |
| if (ix1 < ix2) { |
| struct quorem dydx_full = floored_divrem (STEP_X*dy, dx); |
| |
| do { |
| cairo_fixed_t y_skip = dydx_full.quo; |
| y.rem += dydx_full.rem; |
| if (y.rem >= dx) { |
| ++y_skip; |
| y.rem -= dx; |
| } |
| |
| y.quo += y_skip; |
| |
| y_skip *= sign; |
| cell->covered_height += y_skip; |
| cell->uncovered_area += y_skip*STEP_X; |
| |
| cell = cell->next; |
| if (cell->x != ++ix1) |
| cell = coverage_alloc (sweep_line, cell, ix1); |
| } while (ix1 != ix2); |
| } |
| cell->uncovered_area += sign*(y2 - y.quo)*fx2; |
| cell->covered_height += sign*(y2 - y.quo); |
| sweep_line->coverage.cursor = cell; |
| } |
| } |
| |
| inline static void |
| full_inc_edge (edge_t *edge) |
| { |
| edge->x.quo += edge->dxdy_full.quo; |
| edge->x.rem += edge->dxdy_full.rem; |
| if (edge->x.rem >= 0) { |
| ++edge->x.quo; |
| edge->x.rem -= edge->dy; |
| } |
| } |
| |
| static void |
| full_add_edge (sweep_line_t *sweep_line, edge_t *edge, int sign) |
| { |
| struct cell *cell; |
| cairo_fixed_t x1, x2; |
| int ix1, ix2; |
| int frac; |
| |
| edge->current_sign = sign; |
| |
| ix1 = _cairo_fixed_integer_part (edge->x.quo); |
| |
| if (edge->vertical) { |
| frac = _cairo_fixed_fractional_part (edge->x.quo); |
| cell = coverage_find (sweep_line, ix1); |
| cell->covered_height += sign * STEP_Y; |
| cell->uncovered_area += sign * 2 * frac * STEP_Y; |
| return; |
| } |
| |
| x1 = edge->x.quo; |
| full_inc_edge (edge); |
| x2 = edge->x.quo; |
| |
| ix2 = _cairo_fixed_integer_part (edge->x.quo); |
| |
| /* Edge is entirely within a column? */ |
| if (likely (ix1 == ix2)) { |
| frac = _cairo_fixed_fractional_part (x1) + |
| _cairo_fixed_fractional_part (x2); |
| cell = coverage_find (sweep_line, ix1); |
| cell->covered_height += sign * STEP_Y; |
| cell->uncovered_area += sign * frac * STEP_Y; |
| return; |
| } |
| |
| coverage_render_cells (sweep_line, x1, x2, 0, STEP_Y, sign); |
| } |
| |
| static void |
| full_nonzero (sweep_line_t *sweep_line) |
| { |
| cairo_list_t *pos; |
| |
| sweep_line->is_vertical = TRUE; |
| pos = sweep_line->active.next; |
| do { |
| edge_t *left = link_to_edge (pos), *right; |
| int winding = left->edge.dir; |
| |
| sweep_line->is_vertical &= left->vertical; |
| |
| pos = left->link.next; |
| do { |
| if (unlikely (pos == &sweep_line->active)) { |
| full_add_edge (sweep_line, left, +1); |
| return; |
| } |
| |
| right = link_to_edge (pos); |
| pos = pos->next; |
| sweep_line->is_vertical &= right->vertical; |
| |
| winding += right->edge.dir; |
| if (0 == winding) { |
| if (pos == &sweep_line->active || |
| link_to_edge (pos)->x.quo != right->x.quo) |
| { |
| break; |
| } |
| } |
| |
| if (! right->vertical) |
| full_inc_edge (right); |
| } while (TRUE); |
| |
| full_add_edge (sweep_line, left, +1); |
| full_add_edge (sweep_line, right, -1); |
| } while (pos != &sweep_line->active); |
| } |
| |
| static void |
| full_evenodd (sweep_line_t *sweep_line) |
| { |
| cairo_list_t *pos; |
| |
| sweep_line->is_vertical = TRUE; |
| pos = sweep_line->active.next; |
| do { |
| edge_t *left = link_to_edge (pos), *right; |
| int winding = 0; |
| |
| sweep_line->is_vertical &= left->vertical; |
| |
| pos = left->link.next; |
| do { |
| if (pos == &sweep_line->active) { |
| full_add_edge (sweep_line, left, +1); |
| return; |
| } |
| |
| right = link_to_edge (pos); |
| pos = pos->next; |
| sweep_line->is_vertical &= right->vertical; |
| |
| if (++winding & 1) { |
| if (pos == &sweep_line->active || |
| link_to_edge (pos)->x.quo != right->x.quo) |
| { |
| break; |
| } |
| } |
| |
| if (! right->vertical) |
| full_inc_edge (right); |
| } while (TRUE); |
| |
| full_add_edge (sweep_line, left, +1); |
| full_add_edge (sweep_line, right, -1); |
| } while (pos != &sweep_line->active); |
| } |
| |
| static void |
| render_rows (cairo_botor_scan_converter_t *self, |
| sweep_line_t *sweep_line, |
| int y, int height, |
| cairo_span_renderer_t *renderer) |
| { |
| cairo_half_open_span_t spans_stack[CAIRO_STACK_ARRAY_LENGTH (cairo_half_open_span_t)]; |
| cairo_half_open_span_t *spans = spans_stack; |
| struct cell *cell; |
| int prev_x, cover; |
| int num_spans; |
| cairo_status_t status; |
| |
| if (unlikely (sweep_line->coverage.count == 0)) { |
| status = renderer->render_rows (renderer, y, height, NULL, 0); |
| if (unlikely (status)) |
| longjmp (sweep_line->unwind, status); |
| return; |
| } |
| |
| /* Allocate enough spans for the row. */ |
| |
| num_spans = 2*sweep_line->coverage.count+2; |
| if (unlikely (num_spans > ARRAY_LENGTH (spans_stack))) { |
| spans = _cairo_malloc_ab (num_spans, sizeof (cairo_half_open_span_t)); |
| if (unlikely (spans == NULL)) { |
| longjmp (sweep_line->unwind, |
| _cairo_error (CAIRO_STATUS_NO_MEMORY)); |
| } |
| } |
| |
| /* Form the spans from the coverage and areas. */ |
| num_spans = 0; |
| prev_x = self->xmin; |
| cover = 0; |
| cell = sweep_line->coverage.head.next; |
| do { |
| int x = cell->x; |
| int area; |
| |
| if (x > prev_x) { |
| spans[num_spans].x = prev_x; |
| spans[num_spans].coverage = AREA_TO_ALPHA (cover); |
| ++num_spans; |
| } |
| |
| cover += cell->covered_height*STEP_X*2; |
| area = cover - cell->uncovered_area; |
| |
| spans[num_spans].x = x; |
| spans[num_spans].coverage = AREA_TO_ALPHA (area); |
| ++num_spans; |
| |
| prev_x = x + 1; |
| } while ((cell = cell->next) != &sweep_line->coverage.tail); |
| |
| if (prev_x <= self->xmax) { |
| spans[num_spans].x = prev_x; |
| spans[num_spans].coverage = AREA_TO_ALPHA (cover); |
| ++num_spans; |
| } |
| |
| if (cover && prev_x < self->xmax) { |
| spans[num_spans].x = self->xmax; |
| spans[num_spans].coverage = 0; |
| ++num_spans; |
| } |
| |
| status = renderer->render_rows (renderer, y, height, spans, num_spans); |
| |
| if (unlikely (spans != spans_stack)) |
| free (spans); |
| |
| coverage_reset (&sweep_line->coverage); |
| |
| if (unlikely (status)) |
| longjmp (sweep_line->unwind, status); |
| } |
| |
| static void |
| full_repeat (sweep_line_t *sweep) |
| { |
| edge_t *edge; |
| |
| cairo_list_foreach_entry (edge, edge_t, &sweep->active, link) { |
| if (edge->current_sign) |
| full_add_edge (sweep, edge, edge->current_sign); |
| else if (! edge->vertical) |
| full_inc_edge (edge); |
| } |
| } |
| |
| static void |
| full_reset (sweep_line_t *sweep) |
| { |
| edge_t *edge; |
| |
| cairo_list_foreach_entry (edge, edge_t, &sweep->active, link) |
| edge->current_sign = 0; |
| } |
| |
| static void |
| full_step (cairo_botor_scan_converter_t *self, |
| sweep_line_t *sweep_line, |
| cairo_fixed_t row, |
| cairo_span_renderer_t *renderer) |
| { |
| int top, bottom; |
| |
| top = _cairo_fixed_integer_part (sweep_line->current_row); |
| bottom = _cairo_fixed_integer_part (row); |
| if (cairo_list_is_empty (&sweep_line->active)) { |
| cairo_status_t status; |
| |
| status = renderer->render_rows (renderer, top, bottom - top, NULL, 0); |
| if (unlikely (status)) |
| longjmp (sweep_line->unwind, status); |
| |
| return; |
| } |
| |
| if (self->fill_rule == CAIRO_FILL_RULE_WINDING) |
| full_nonzero (sweep_line); |
| else |
| full_evenodd (sweep_line); |
| |
| if (sweep_line->is_vertical || bottom == top + 1) { |
| render_rows (self, sweep_line, top, bottom - top, renderer); |
| full_reset (sweep_line); |
| return; |
| } |
| |
| render_rows (self, sweep_line, top++, 1, renderer); |
| do { |
| full_repeat (sweep_line); |
| render_rows (self, sweep_line, top, 1, renderer); |
| } while (++top != bottom); |
| |
| full_reset (sweep_line); |
| } |
| |
| cairo_always_inline static void |
| sub_inc_edge (edge_t *edge, |
| cairo_fixed_t height) |
| { |
| if (height == 1) { |
| edge->x.quo += edge->dxdy.quo; |
| edge->x.rem += edge->dxdy.rem; |
| if (edge->x.rem >= 0) { |
| ++edge->x.quo; |
| edge->x.rem -= edge->dy; |
| } |
| } else { |
| edge->x.quo += height * edge->dxdy.quo; |
| edge->x.rem += height * edge->dxdy.rem; |
| if (edge->x.rem >= 0) { |
| int carry = edge->x.rem / edge->dy + 1; |
| edge->x.quo += carry; |
| edge->x.rem -= carry * edge->dy; |
| } |
| } |
| } |
| |
| static void |
| sub_add_run (sweep_line_t *sweep_line, edge_t *edge, int y, int sign) |
| { |
| struct run *run; |
| |
| run = _cairo_freepool_alloc (&sweep_line->runs); |
| if (unlikely (run == NULL)) |
| longjmp (sweep_line->unwind, _cairo_error (CAIRO_STATUS_NO_MEMORY)); |
| |
| run->y = y; |
| run->sign = sign; |
| run->next = edge->runs; |
| edge->runs = run; |
| |
| edge->current_sign = sign; |
| } |
| |
| inline static cairo_bool_t |
| edges_coincident (edge_t *left, edge_t *right, cairo_fixed_t y) |
| { |
| /* XXX is compare_x_for_y() worth executing during sub steps? */ |
| return line_equal (&left->edge.line, &right->edge.line); |
| //edges_compare_x_for_y (&left->edge, &right->edge, y) >= 0; |
| } |
| |
| static void |
| sub_nonzero (sweep_line_t *sweep_line) |
| { |
| cairo_fixed_t y = sweep_line->current_subrow; |
| cairo_fixed_t fy = _cairo_fixed_fractional_part (y); |
| cairo_list_t *pos; |
| |
| pos = sweep_line->active.next; |
| do { |
| edge_t *left = link_to_edge (pos), *right; |
| int winding = left->edge.dir; |
| |
| pos = left->link.next; |
| do { |
| if (unlikely (pos == &sweep_line->active)) { |
| if (left->current_sign != +1) |
| sub_add_run (sweep_line, left, fy, +1); |
| return; |
| } |
| |
| right = link_to_edge (pos); |
| pos = pos->next; |
| |
| winding += right->edge.dir; |
| if (0 == winding) { |
| if (pos == &sweep_line->active || |
| ! edges_coincident (right, link_to_edge (pos), y)) |
| { |
| break; |
| } |
| } |
| |
| if (right->current_sign) |
| sub_add_run (sweep_line, right, fy, 0); |
| } while (TRUE); |
| |
| if (left->current_sign != +1) |
| sub_add_run (sweep_line, left, fy, +1); |
| if (right->current_sign != -1) |
| sub_add_run (sweep_line, right, fy, -1); |
| } while (pos != &sweep_line->active); |
| } |
| |
| static void |
| sub_evenodd (sweep_line_t *sweep_line) |
| { |
| cairo_fixed_t y = sweep_line->current_subrow; |
| cairo_fixed_t fy = _cairo_fixed_fractional_part (y); |
| cairo_list_t *pos; |
| |
| pos = sweep_line->active.next; |
| do { |
| edge_t *left = link_to_edge (pos), *right; |
| int winding = 0; |
| |
| pos = left->link.next; |
| do { |
| if (unlikely (pos == &sweep_line->active)) { |
| if (left->current_sign != +1) |
| sub_add_run (sweep_line, left, fy, +1); |
| return; |
| } |
| |
| right = link_to_edge (pos); |
| pos = pos->next; |
| |
| if (++winding & 1) { |
| if (pos == &sweep_line->active || |
| ! edges_coincident (right, link_to_edge (pos), y)) |
| { |
| break; |
| } |
| } |
| |
| if (right->current_sign) |
| sub_add_run (sweep_line, right, fy, 0); |
| } while (TRUE); |
| |
| if (left->current_sign != +1) |
| sub_add_run (sweep_line, left, fy, +1); |
| if (right->current_sign != -1) |
| sub_add_run (sweep_line, right, fy, -1); |
| } while (pos != &sweep_line->active); |
| } |
| |
| cairo_always_inline static void |
| sub_step (cairo_botor_scan_converter_t *self, |
| sweep_line_t *sweep_line) |
| { |
| if (cairo_list_is_empty (&sweep_line->active)) |
| return; |
| |
| if (self->fill_rule == CAIRO_FILL_RULE_WINDING) |
| sub_nonzero (sweep_line); |
| else |
| sub_evenodd (sweep_line); |
| } |
| |
| static void |
| coverage_render_runs (sweep_line_t *sweep, edge_t *edge, |
| cairo_fixed_t y1, cairo_fixed_t y2) |
| { |
| struct run tail; |
| struct run *run = &tail; |
| |
| tail.next = NULL; |
| tail.y = y2; |
| |
| /* Order the runs top->bottom */ |
| while (edge->runs) { |
| struct run *r; |
| |
| r = edge->runs; |
| edge->runs = r->next; |
| r->next = run; |
| run = r; |
| } |
| |
| if (run->y > y1) |
| sub_inc_edge (edge, run->y - y1); |
| |
| do { |
| cairo_fixed_t x1, x2; |
| |
| y1 = run->y; |
| y2 = run->next->y; |
| |
| x1 = edge->x.quo; |
| if (y2 - y1 == STEP_Y) |
| full_inc_edge (edge); |
| else |
| sub_inc_edge (edge, y2 - y1); |
| x2 = edge->x.quo; |
| |
| if (run->sign) { |
| int ix1, ix2; |
| |
| ix1 = _cairo_fixed_integer_part (x1); |
| ix2 = _cairo_fixed_integer_part (x2); |
| |
| /* Edge is entirely within a column? */ |
| if (likely (ix1 == ix2)) { |
| struct cell *cell; |
| int frac; |
| |
| frac = _cairo_fixed_fractional_part (x1) + |
| _cairo_fixed_fractional_part (x2); |
| cell = coverage_find (sweep, ix1); |
| cell->covered_height += run->sign * (y2 - y1); |
| cell->uncovered_area += run->sign * (y2 - y1) * frac; |
| } else { |
| coverage_render_cells (sweep, x1, x2, y1, y2, run->sign); |
| } |
| } |
| |
| run = run->next; |
| } while (run->next != NULL); |
| } |
| |
| static void |
| coverage_render_vertical_runs (sweep_line_t *sweep, edge_t *edge, cairo_fixed_t y2) |
| { |
| struct cell *cell; |
| struct run *run; |
| int height = 0; |
| |
| for (run = edge->runs; run != NULL; run = run->next) { |
| if (run->sign) |
| height += run->sign * (y2 - run->y); |
| y2 = run->y; |
| } |
| |
| cell = coverage_find (sweep, _cairo_fixed_integer_part (edge->x.quo)); |
| cell->covered_height += height; |
| cell->uncovered_area += 2 * _cairo_fixed_fractional_part (edge->x.quo) * height; |
| } |
| |
| cairo_always_inline static void |
| sub_emit (cairo_botor_scan_converter_t *self, |
| sweep_line_t *sweep, |
| cairo_span_renderer_t *renderer) |
| { |
| edge_t *edge; |
| |
| sub_step (self, sweep); |
| |
| /* convert the runs into coverages */ |
| |
| cairo_list_foreach_entry (edge, edge_t, &sweep->active, link) { |
| if (edge->runs == NULL) { |
| if (! edge->vertical) { |
| if (edge->flags & START) { |
| sub_inc_edge (edge, |
| STEP_Y - _cairo_fixed_fractional_part (edge->edge.top)); |
| edge->flags &= ~START; |
| } else |
| full_inc_edge (edge); |
| } |
| } else { |
| if (edge->vertical) { |
| coverage_render_vertical_runs (sweep, edge, STEP_Y); |
| } else { |
| int y1 = 0; |
| if (edge->flags & START) { |
| y1 = _cairo_fixed_fractional_part (edge->edge.top); |
| edge->flags &= ~START; |
| } |
| coverage_render_runs (sweep, edge, y1, STEP_Y); |
| } |
| } |
| edge->current_sign = 0; |
| edge->runs = NULL; |
| } |
| |
| cairo_list_foreach_entry (edge, edge_t, &sweep->stopped, link) { |
| int y2 = _cairo_fixed_fractional_part (edge->edge.bottom); |
| if (edge->vertical) { |
| coverage_render_vertical_runs (sweep, edge, y2); |
| } else { |
| int y1 = 0; |
| if (edge->flags & START) |
| y1 = _cairo_fixed_fractional_part (edge->edge.top); |
| coverage_render_runs (sweep, edge, y1, y2); |
| } |
| } |
| cairo_list_init (&sweep->stopped); |
| |
| _cairo_freepool_reset (&sweep->runs); |
| |
| render_rows (self, sweep, |
| _cairo_fixed_integer_part (sweep->current_row), 1, |
| renderer); |
| } |
| |
| static void |
| sweep_line_init (sweep_line_t *sweep_line, |
| event_t **start_events, |
| int num_events) |
| { |
| cairo_list_init (&sweep_line->active); |
| cairo_list_init (&sweep_line->stopped); |
| sweep_line->insert_cursor = &sweep_line->active; |
| |
| sweep_line->current_row = INT32_MIN; |
| sweep_line->current_subrow = INT32_MIN; |
| |
| coverage_init (&sweep_line->coverage); |
| _cairo_freepool_init (&sweep_line->runs, sizeof (struct run)); |
| |
| start_event_sort (start_events, num_events); |
| start_events[num_events] = NULL; |
| |
| sweep_line->queue.start_events = start_events; |
| |
| _cairo_freepool_init (&sweep_line->queue.pool, |
| sizeof (queue_event_t)); |
| pqueue_init (&sweep_line->queue.pq); |
| sweep_line->queue.pq.elements[PQ_FIRST_ENTRY] = NULL; |
| } |
| |
| static void |
| sweep_line_delete (sweep_line_t *sweep_line, |
| edge_t *edge) |
| { |
| if (sweep_line->insert_cursor == &edge->link) |
| sweep_line->insert_cursor = edge->link.prev; |
| |
| cairo_list_del (&edge->link); |
| if (edge->runs) |
| cairo_list_add_tail (&edge->link, &sweep_line->stopped); |
| edge->flags |= STOP; |
| } |
| |
| static void |
| sweep_line_swap (sweep_line_t *sweep_line, |
| edge_t *left, |
| edge_t *right) |
| { |
| right->link.prev = left->link.prev; |
| left->link.next = right->link.next; |
| right->link.next = &left->link; |
| left->link.prev = &right->link; |
| left->link.next->prev = &left->link; |
| right->link.prev->next = &right->link; |
| } |
| |
| static void |
| sweep_line_fini (sweep_line_t *sweep_line) |
| { |
| pqueue_fini (&sweep_line->queue.pq); |
| _cairo_freepool_fini (&sweep_line->queue.pool); |
| coverage_fini (&sweep_line->coverage); |
| _cairo_freepool_fini (&sweep_line->runs); |
| } |
| |
| static cairo_status_t |
| botor_generate (cairo_botor_scan_converter_t *self, |
| event_t **start_events, |
| cairo_span_renderer_t *renderer) |
| { |
| cairo_status_t status; |
| sweep_line_t sweep_line; |
| cairo_fixed_t ybot; |
| event_t *event; |
| cairo_list_t *left, *right; |
| edge_t *e1, *e2; |
| int bottom; |
| |
| sweep_line_init (&sweep_line, start_events, self->num_edges); |
| if ((status = setjmp (sweep_line.unwind))) |
| goto unwind; |
| |
| ybot = self->extents.p2.y; |
| sweep_line.current_subrow = self->extents.p1.y; |
| sweep_line.current_row = _cairo_fixed_floor (self->extents.p1.y); |
| event = *sweep_line.queue.start_events++; |
| do { |
| /* Can we process a full step in one go? */ |
| if (event->y >= sweep_line.current_row + STEP_Y) { |
| bottom = _cairo_fixed_floor (event->y); |
| full_step (self, &sweep_line, bottom, renderer); |
| sweep_line.current_row = bottom; |
| sweep_line.current_subrow = bottom; |
| } |
| |
| do { |
| if (event->y > sweep_line.current_subrow) { |
| sub_step (self, &sweep_line); |
| sweep_line.current_subrow = event->y; |
| } |
| |
| do { |
| /* Update the active list using Bentley-Ottmann */ |
| switch (event->type) { |
| case EVENT_TYPE_START: |
| e1 = ((start_event_t *) event)->edge; |
| |
| sweep_line_insert (&sweep_line, e1); |
| event_insert_stop (&sweep_line, e1); |
| |
| left = e1->link.prev; |
| right = e1->link.next; |
| |
| if (left != &sweep_line.active) { |
| event_insert_if_intersect_below_current_y (&sweep_line, |
| link_to_edge (left), e1); |
| } |
| |
| if (right != &sweep_line.active) { |
| event_insert_if_intersect_below_current_y (&sweep_line, |
| e1, link_to_edge (right)); |
| } |
| |
| break; |
| |
| case EVENT_TYPE_STOP: |
| e1 = ((queue_event_t *) event)->e1; |
| event_delete (&sweep_line, event); |
| |
| left = e1->link.prev; |
| right = e1->link.next; |
| |
| sweep_line_delete (&sweep_line, e1); |
| |
| if (left != &sweep_line.active && |
| right != &sweep_line.active) |
| { |
| event_insert_if_intersect_below_current_y (&sweep_line, |
| link_to_edge (left), |
| link_to_edge (right)); |
| } |
| |
| break; |
| |
| case EVENT_TYPE_INTERSECTION: |
| e1 = ((queue_event_t *) event)->e1; |
| e2 = ((queue_event_t *) event)->e2; |
| |
| event_delete (&sweep_line, event); |
| if (e1->flags & STOP) |
| break; |
| if (e2->flags & STOP) |
| break; |
| |
| /* skip this intersection if its edges are not adjacent */ |
| if (&e2->link != e1->link.next) |
| break; |
| |
| left = e1->link.prev; |
| right = e2->link.next; |
| |
| sweep_line_swap (&sweep_line, e1, e2); |
| |
| /* after the swap e2 is left of e1 */ |
| if (left != &sweep_line.active) { |
| event_insert_if_intersect_below_current_y (&sweep_line, |
| link_to_edge (left), e2); |
| } |
| |
| if (right != &sweep_line.active) { |
| event_insert_if_intersect_below_current_y (&sweep_line, |
| e1, link_to_edge (right)); |
| } |
| |
| break; |
| } |
| |
| event = event_next (&sweep_line); |
| if (event == NULL) |
| goto end; |
| } while (event->y == sweep_line.current_subrow); |
| } while (event->y < sweep_line.current_row + STEP_Y); |
| |
| bottom = sweep_line.current_row + STEP_Y; |
| sub_emit (self, &sweep_line, renderer); |
| sweep_line.current_subrow = bottom; |
| sweep_line.current_row = sweep_line.current_subrow; |
| } while (TRUE); |
| |
| end: |
| /* flush any partial spans */ |
| if (sweep_line.current_subrow != sweep_line.current_row) { |
| sub_emit (self, &sweep_line, renderer); |
| sweep_line.current_row += STEP_Y; |
| sweep_line.current_subrow = sweep_line.current_row; |
| } |
| /* clear the rest */ |
| if (sweep_line.current_subrow < ybot) { |
| bottom = _cairo_fixed_integer_part (sweep_line.current_row); |
| status = renderer->render_rows (renderer, |
| bottom, _cairo_fixed_integer_ceil (ybot) - bottom, |
| NULL, 0); |
| } |
| |
| unwind: |
| sweep_line_fini (&sweep_line); |
| |
| return status; |
| } |
| |
| static cairo_status_t |
| _cairo_botor_scan_converter_generate (void *converter, |
| cairo_span_renderer_t *renderer) |
| { |
| cairo_botor_scan_converter_t *self = converter; |
| start_event_t stack_events[CAIRO_STACK_ARRAY_LENGTH (start_event_t)]; |
| start_event_t *events; |
| event_t *stack_event_ptrs[ARRAY_LENGTH (stack_events) + 1]; |
| event_t **event_ptrs; |
| struct _cairo_botor_scan_converter_chunk *chunk; |
| cairo_status_t status; |
| int num_events; |
| int i, j; |
| |
| num_events = self->num_edges; |
| if (unlikely (0 == num_events)) { |
| return renderer->render_rows (renderer, |
| _cairo_fixed_integer_floor (self->extents.p1.y), |
| _cairo_fixed_integer_ceil (self->extents.p2.y) - |
| _cairo_fixed_integer_floor (self->extents.p1.y), |
| NULL, 0); |
| } |
| |
| events = stack_events; |
| event_ptrs = stack_event_ptrs; |
| if (unlikely (num_events >= ARRAY_LENGTH (stack_events))) { |
| events = _cairo_malloc_ab_plus_c (num_events, |
| sizeof (start_event_t) + sizeof (event_t *), |
| sizeof (event_t *)); |
| if (unlikely (events == NULL)) |
| return _cairo_error (CAIRO_STATUS_NO_MEMORY); |
| |
| event_ptrs = (event_t **) (events + num_events); |
| } |
| |
| j = 0; |
| for (chunk = &self->chunks; chunk != NULL; chunk = chunk->next) { |
| edge_t *edge; |
| |
| edge = chunk->base; |
| for (i = 0; i < chunk->count; i++) { |
| event_ptrs[j] = (event_t *) &events[j]; |
| |
| events[j].y = edge->edge.top; |
| events[j].type = EVENT_TYPE_START; |
| events[j].edge = edge; |
| |
| edge++, j++; |
| } |
| } |
| |
| status = botor_generate (self, event_ptrs, renderer); |
| |
| if (events != stack_events) |
| free (events); |
| |
| return status; |
| } |
| |
| static edge_t * |
| botor_allocate_edge (cairo_botor_scan_converter_t *self) |
| { |
| struct _cairo_botor_scan_converter_chunk *chunk; |
| |
| chunk = self->tail; |
| if (chunk->count == chunk->size) { |
| int size; |
| |
| size = chunk->size * 2; |
| chunk->next = _cairo_malloc_ab_plus_c (size, |
| sizeof (edge_t), |
| sizeof (struct _cairo_botor_scan_converter_chunk)); |
| if (unlikely (chunk->next == NULL)) |
| return NULL; |
| |
| chunk = chunk->next; |
| chunk->next = NULL; |
| chunk->count = 0; |
| chunk->size = size; |
| chunk->base = chunk + 1; |
| self->tail = chunk; |
| } |
| |
| return (edge_t *) chunk->base + chunk->count++; |
| } |
| |
| static cairo_status_t |
| botor_add_edge (cairo_botor_scan_converter_t *self, |
| const cairo_edge_t *edge) |
| { |
| edge_t *e; |
| cairo_fixed_t dx, dy; |
| |
| e = botor_allocate_edge (self); |
| if (unlikely (e == NULL)) |
| return _cairo_error (CAIRO_STATUS_NO_MEMORY); |
| |
| cairo_list_init (&e->link); |
| e->edge = *edge; |
| |
| dx = edge->line.p2.x - edge->line.p1.x; |
| dy = edge->line.p2.y - edge->line.p1.y; |
| e->dy = dy; |
| |
| if (dx == 0) { |
| e->vertical = TRUE; |
| e->x.quo = edge->line.p1.x; |
| e->x.rem = 0; |
| e->dxdy.quo = 0; |
| e->dxdy.rem = 0; |
| e->dxdy_full.quo = 0; |
| e->dxdy_full.rem = 0; |
| } else { |
| e->vertical = FALSE; |
| e->dxdy = floored_divrem (dx, dy); |
| if (edge->top == edge->line.p1.y) { |
| e->x.quo = edge->line.p1.x; |
| e->x.rem = 0; |
| } else { |
| e->x = floored_muldivrem (edge->top - edge->line.p1.y, |
| dx, dy); |
| e->x.quo += edge->line.p1.x; |
| } |
| |
| if (_cairo_fixed_integer_part (edge->bottom) - _cairo_fixed_integer_part (edge->top) > 1) { |
| e->dxdy_full = floored_muldivrem (STEP_Y, dx, dy); |
| } else { |
| e->dxdy_full.quo = 0; |
| e->dxdy_full.rem = 0; |
| } |
| } |
| |
| e->x.rem = -e->dy; |
| e->current_sign = 0; |
| e->runs = NULL; |
| e->flags = START; |
| |
| self->num_edges++; |
| |
| return CAIRO_STATUS_SUCCESS; |
| } |
| |
| static cairo_status_t |
| _cairo_botor_scan_converter_add_edge (void *converter, |
| const cairo_point_t *p1, |
| const cairo_point_t *p2, |
| int top, int bottom, |
| int dir) |
| { |
| cairo_botor_scan_converter_t *self = converter; |
| cairo_edge_t edge; |
| |
| edge.line.p1 = *p1; |
| edge.line.p2 = *p2; |
| edge.top = top; |
| edge.bottom = bottom; |
| edge.dir = dir; |
| |
| return botor_add_edge (self, &edge); |
| } |
| |
| static cairo_status_t |
| _cairo_botor_scan_converter_add_polygon (void *converter, |
| const cairo_polygon_t *polygon) |
| { |
| cairo_botor_scan_converter_t *self = converter; |
| cairo_status_t status; |
| int i; |
| |
| for (i = 0; i < polygon->num_edges; i++) { |
| status = botor_add_edge (self, &polygon->edges[i]); |
| if (unlikely (status)) |
| return status; |
| } |
| |
| return CAIRO_STATUS_SUCCESS; |
| } |
| |
| static void |
| _cairo_botor_scan_converter_destroy (void *converter) |
| { |
| cairo_botor_scan_converter_t *self = converter; |
| struct _cairo_botor_scan_converter_chunk *chunk, *next; |
| |
| for (chunk = self->chunks.next; chunk != NULL; chunk = next) { |
| next = chunk->next; |
| free (chunk); |
| } |
| } |
| |
| void |
| _cairo_botor_scan_converter_init (cairo_botor_scan_converter_t *self, |
| const cairo_box_t *extents, |
| cairo_fill_rule_t fill_rule) |
| { |
| self->base.destroy = _cairo_botor_scan_converter_destroy; |
| self->base.add_edge = _cairo_botor_scan_converter_add_edge; |
| self->base.add_polygon = _cairo_botor_scan_converter_add_polygon; |
| self->base.generate = _cairo_botor_scan_converter_generate; |
| |
| self->extents = *extents; |
| self->fill_rule = fill_rule; |
| |
| self->xmin = _cairo_fixed_integer_floor (extents->p1.x); |
| self->xmax = _cairo_fixed_integer_ceil (extents->p2.x); |
| |
| self->chunks.base = self->buf; |
| self->chunks.next = NULL; |
| self->chunks.count = 0; |
| self->chunks.size = sizeof (self->buf) / sizeof (edge_t); |
| self->tail = &self->chunks; |
| |
| self->num_edges = 0; |
| } |