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path-bounder: Simplify code
If the path extents are tight, all the extents computations and approximations become trivial except for the stroke extents.
This commit is contained in:
Andrea Canciani
parent
958c56e2b4
commit
89e1261dd0
2 changed files with 65 additions and 197 deletions
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@ -1,3 +1,4 @@
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/* -*- Mode: c; tab-width: 8; c-basic-offset: 4; indent-tabs-mode: t; -*- */
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/* cairo - a vector graphics library with display and print output
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*
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* Copyright © 2003 University of Southern California
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@ -35,48 +36,16 @@
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*/
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#include "cairoint.h"
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#include "cairo-box-private.h"
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#include "cairo-path-fixed-private.h"
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typedef struct cairo_path_bounder {
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cairo_point_t current_point;
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cairo_bool_t has_initial_point;
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cairo_bool_t has_point;
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typedef struct _cairo_path_bounder {
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cairo_point_t current_point;
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cairo_bool_t has_extents;
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cairo_box_t extents;
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} cairo_path_bounder_t;
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static void
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_cairo_path_bounder_init (cairo_path_bounder_t *bounder)
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{
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bounder->has_initial_point = FALSE;
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bounder->has_point = FALSE;
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}
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static void
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_cairo_path_bounder_add_point (cairo_path_bounder_t *bounder,
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const cairo_point_t *point)
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{
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if (bounder->has_point) {
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if (point->x < bounder->extents.p1.x)
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bounder->extents.p1.x = point->x;
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if (point->y < bounder->extents.p1.y)
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bounder->extents.p1.y = point->y;
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if (point->x > bounder->extents.p2.x)
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bounder->extents.p2.x = point->x;
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if (point->y > bounder->extents.p2.y)
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bounder->extents.p2.y = point->y;
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} else {
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bounder->extents.p1.x = point->x;
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bounder->extents.p1.y = point->y;
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bounder->extents.p2.x = point->x;
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bounder->extents.p2.y = point->y;
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bounder->has_point = TRUE;
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}
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}
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static cairo_status_t
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_cairo_path_bounder_move_to (void *closure,
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const cairo_point_t *point)
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@ -84,7 +53,13 @@ _cairo_path_bounder_move_to (void *closure,
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cairo_path_bounder_t *bounder = closure;
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bounder->current_point = *point;
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bounder->has_initial_point = TRUE;
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if (likely (bounder->has_extents)) {
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_cairo_box_add_point (&bounder->extents, point);
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} else {
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bounder->has_extents = TRUE;
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_cairo_box_set (&bounder->extents, point, point);
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}
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return CAIRO_STATUS_SUCCESS;
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}
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@ -95,13 +70,8 @@ _cairo_path_bounder_line_to (void *closure,
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{
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cairo_path_bounder_t *bounder = closure;
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if (bounder->has_initial_point) {
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_cairo_path_bounder_add_point (bounder, &bounder->current_point);
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bounder->has_initial_point = FALSE;
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}
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_cairo_path_bounder_add_point (bounder, point);
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bounder->current_point = *point;
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_cairo_box_add_point (&bounder->extents, point);
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return CAIRO_STATUS_SUCCESS;
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}
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@ -114,25 +84,12 @@ _cairo_path_bounder_curve_to (void *closure,
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{
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cairo_path_bounder_t *bounder = closure;
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/* If the bbox of the control points is entirely inside, then we
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* do not need to further evaluate the spline.
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*/
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if (! bounder->has_point ||
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b->x < bounder->extents.p1.x || b->x > bounder->extents.p2.x ||
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b->y < bounder->extents.p1.y || b->y > bounder->extents.p2.y ||
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c->x < bounder->extents.p1.x || c->x > bounder->extents.p2.x ||
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c->y < bounder->extents.p1.y || c->y > bounder->extents.p2.y ||
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d->x < bounder->extents.p1.x || d->x > bounder->extents.p2.x ||
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d->y < bounder->extents.p1.y || d->y > bounder->extents.p2.y)
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{
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return _cairo_spline_bound (_cairo_path_bounder_line_to, bounder,
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&bounder->current_point, b, c, d);
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}
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else
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{
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/* All control points are within the current extents. */
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return CAIRO_STATUS_SUCCESS;
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}
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_cairo_box_add_curve_to (&bounder->extents,
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&bounder->current_point,
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b, c, d);
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bounder->current_point = *d;
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return CAIRO_STATUS_SUCCESS;
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}
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static cairo_status_t
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@ -141,53 +98,40 @@ _cairo_path_bounder_close_path (void *closure)
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return CAIRO_STATUS_SUCCESS;
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}
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/* This computes the extents of all the points in the path, not those of
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* the damage area (i.e it does not consider winding and it only inspects
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* the control points of the curves, not the flattened path).
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*/
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void
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_cairo_path_fixed_approximate_clip_extents (const cairo_path_fixed_t *path,
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cairo_rectangle_int_t *extents)
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{
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if (path->extents.p1.x < path->extents.p2.x) {
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_cairo_box_round_to_rectangle (&path->extents, extents);
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} else {
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extents->x = extents->y = 0;
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extents->width = extents->height = 0;
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}
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}
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/* A slightly better approximation than above - we actually decompose the
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* Bezier, but we continue to ignore winding.
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*/
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void
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_cairo_path_fixed_approximate_fill_extents (const cairo_path_fixed_t *path,
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cairo_rectangle_int_t *extents)
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cairo_bool_t
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_cairo_path_bounder_extents (const cairo_path_fixed_t *path,
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cairo_box_t *extents)
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{
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cairo_path_bounder_t bounder;
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cairo_status_t status;
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if (! path->has_curve_to) {
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bounder.extents = path->extents;
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bounder.has_point = path->extents.p1.x < path->extents.p2.x;
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} else {
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_cairo_path_bounder_init (&bounder);
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bounder.has_extents = FALSE;
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status = _cairo_path_fixed_interpret (path, CAIRO_DIRECTION_FORWARD,
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_cairo_path_bounder_move_to,
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_cairo_path_bounder_line_to,
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_cairo_path_bounder_curve_to,
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_cairo_path_bounder_close_path,
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&bounder);
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assert (!status);
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status = _cairo_path_fixed_interpret (path, CAIRO_DIRECTION_FORWARD,
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_cairo_path_bounder_move_to,
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_cairo_path_bounder_line_to,
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_cairo_path_bounder_curve_to,
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_cairo_path_bounder_close_path,
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&bounder);
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assert (status == CAIRO_STATUS_SUCCESS);
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}
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if (bounder.has_extents)
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*extents = bounder.extents;
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if (bounder.has_point) {
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_cairo_box_round_to_rectangle (&bounder.extents, extents);
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} else {
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extents->x = extents->y = 0;
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extents->width = extents->height = 0;
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}
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return bounder.has_extents;
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}
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void
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_cairo_path_fixed_approximate_clip_extents (const cairo_path_fixed_t *path,
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cairo_rectangle_int_t *extents)
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{
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_cairo_path_fixed_approximate_fill_extents (path, extents);
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}
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void
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_cairo_path_fixed_approximate_fill_extents (const cairo_path_fixed_t *path,
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cairo_rectangle_int_t *extents)
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{
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_cairo_path_fixed_fill_extents (path, CAIRO_FILL_RULE_WINDING, 0, extents);
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}
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void
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@ -196,25 +140,9 @@ _cairo_path_fixed_fill_extents (const cairo_path_fixed_t *path,
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double tolerance,
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cairo_rectangle_int_t *extents)
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{
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cairo_path_bounder_t bounder;
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cairo_status_t status;
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if (! path->has_curve_to) {
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bounder.extents = path->extents;
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bounder.has_point = path->extents.p1.x < path->extents.p2.x;
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} else {
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_cairo_path_bounder_init (&bounder);
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status = _cairo_path_fixed_interpret_flat (path, CAIRO_DIRECTION_FORWARD,
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_cairo_path_bounder_move_to,
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_cairo_path_bounder_line_to,
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_cairo_path_bounder_close_path,
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&bounder, tolerance);
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assert (status == CAIRO_STATUS_SUCCESS);
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}
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if (bounder.has_point) {
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_cairo_box_round_to_rectangle (&bounder.extents, extents);
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if (path->extents.p1.x < path->extents.p2.x &&
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path->extents.p1.y < path->extents.p2.y) {
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_cairo_box_round_to_rectangle (&path->extents, extents);
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} else {
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extents->x = extents->y = 0;
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extents->width = extents->height = 0;
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@ -228,65 +156,18 @@ _cairo_path_fixed_approximate_stroke_extents (const cairo_path_fixed_t *path,
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const cairo_matrix_t *ctm,
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cairo_rectangle_int_t *extents)
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{
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cairo_path_bounder_t bounder;
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cairo_status_t status;
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if (! path->has_curve_to) {
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bounder.extents = path->extents;
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/* include trailing move-to for degenerate segments */
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if (path->needs_move_to) {
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const cairo_point_t *point = &path->current_point;
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if (point->x < bounder.extents.p1.x)
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bounder.extents.p1.x = point->x;
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if (point->y < bounder.extents.p1.y)
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bounder.extents.p1.y = point->y;
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if (point->x > bounder.extents.p2.x)
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bounder.extents.p2.x = point->x;
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if (point->y > bounder.extents.p2.y)
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bounder.extents.p2.y = point->y;
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}
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bounder.has_point = bounder.extents.p1.x <= bounder.extents.p2.x;
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bounder.has_initial_point = FALSE;
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} else {
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_cairo_path_bounder_init (&bounder);
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status = _cairo_path_fixed_interpret (path, CAIRO_DIRECTION_FORWARD,
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_cairo_path_bounder_move_to,
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_cairo_path_bounder_line_to,
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_cairo_path_bounder_curve_to,
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_cairo_path_bounder_close_path,
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&bounder);
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assert (status == CAIRO_STATUS_SUCCESS);
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}
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if (bounder.has_point) {
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if (path->has_extents) {
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cairo_box_t box_extents;
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double dx, dy;
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box_extents = path->extents;
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_cairo_stroke_style_max_distance_from_path (style, ctm, &dx, &dy);
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box_extents.p1.x -= _cairo_fixed_from_double (dx);
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box_extents.p1.y -= _cairo_fixed_from_double (dy);
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box_extents.p2.x += _cairo_fixed_from_double (dx);
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box_extents.p2.y += _cairo_fixed_from_double (dy);
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bounder.extents.p1.x -= _cairo_fixed_from_double (dx);
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bounder.extents.p2.x += _cairo_fixed_from_double (dx);
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bounder.extents.p1.y -= _cairo_fixed_from_double (dy);
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bounder.extents.p2.y += _cairo_fixed_from_double (dy);
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_cairo_box_round_to_rectangle (&bounder.extents, extents);
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} else if (bounder.has_initial_point) {
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double dx, dy;
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/* accommodate capping of degenerate paths */
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_cairo_stroke_style_max_distance_from_path (style, ctm, &dx, &dy);
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bounder.extents.p1.x = bounder.current_point.x - _cairo_fixed_from_double (dx);
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bounder.extents.p2.x = bounder.current_point.x + _cairo_fixed_from_double (dx);
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bounder.extents.p1.y = bounder.current_point.y - _cairo_fixed_from_double (dy);
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bounder.extents.p2.y = bounder.current_point.y + _cairo_fixed_from_double (dy);
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_cairo_box_round_to_rectangle (&bounder.extents, extents);
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_cairo_box_round_to_rectangle (&box_extents, extents);
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} else {
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extents->x = extents->y = 0;
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extents->width = extents->height = 0;
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@ -326,24 +207,6 @@ cairo_bool_t
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_cairo_path_fixed_extents (const cairo_path_fixed_t *path,
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cairo_box_t *box)
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{
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cairo_path_bounder_t bounder;
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cairo_status_t status;
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if (! path->has_curve_to) {
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*box = path->extents;
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return path->has_extents;
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}
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_cairo_path_bounder_init (&bounder);
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status = _cairo_path_fixed_interpret (path, CAIRO_DIRECTION_FORWARD,
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_cairo_path_bounder_move_to,
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_cairo_path_bounder_line_to,
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_cairo_path_bounder_curve_to,
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_cairo_path_bounder_close_path,
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&bounder);
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assert (status == CAIRO_STATUS_SUCCESS);
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*box = bounder.extents;
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return bounder.has_point;
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*box = path->extents;
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return path->has_extents;
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}
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@ -1217,6 +1217,11 @@ _cairo_path_fixed_interpret_flat (const cairo_path_fixed_t *path,
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void *closure,
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double tolerance);
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cairo_private cairo_bool_t
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_cairo_path_bounder_extents (const cairo_path_fixed_t *path,
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cairo_box_t *box);
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cairo_private cairo_bool_t
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_cairo_path_fixed_extents (const cairo_path_fixed_t *path,
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cairo_box_t *box);
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