/* Adjusts the fill extents (above) by the device-space pen. */
void
_cairo_path_fixed_approximate_stroke_extents (const cairo_path_fixed_t *path,
cairo_stroke_style_t *style,
const cairo_matrix_t *ctm,
cairo_rectangle_int_t *extents)
{
cairo_path_bounder_t bounder;
cairo_status_t status;
_cairo_path_bounder_init (&bounder);
status = _cairo_path_fixed_interpret (path, CAIRO_DIRECTION_FORWARD,
_cairo_path_bounder_move_to,
_cairo_path_bounder_line_to,
_cairo_path_bounder_curve_to,
_cairo_path_bounder_close_path,
&bounder);
assert (status == CAIRO_STATUS_SUCCESS);
if (bounder.has_point) {
double dx, dy;
_cairo_stroke_style_max_distance_from_path (style, ctm, &dx, &dy);
bounder.extents.p1.x -= _cairo_fixed_from_double (dx);
bounder.extents.p2.x += _cairo_fixed_from_double (dx);
bounder.extents.p1.y -= _cairo_fixed_from_double (dy);
bounder.extents.p2.y += _cairo_fixed_from_double (dy);
_cairo_box_round_to_rectangle (&bounder.extents, extents);
} else if (bounder.has_initial_point) {
double dx, dy;
/* accommodate capping of degenerate paths */
_cairo_stroke_style_max_distance_from_path (style, ctm, &dx, &dy);
bounder.extents.p1.x = bounder.current_point.x - _cairo_fixed_from_double (dx);
bounder.extents.p2.x = bounder.current_point.x + _cairo_fixed_from_double (dx);
bounder.extents.p1.y = bounder.current_point.y - _cairo_fixed_from_double (dy);
bounder.extents.p2.y = bounder.current_point.y + _cairo_fixed_from_double (dy);
_cairo_box_round_to_rectangle (&bounder.extents, extents);
} else {
extents->x = extents->y = 0;
extents->width = extents->height = 0;
}
}
static void
_cairo_stroker_limit (cairo_stroker_t *stroker,
const cairo_path_fixed_t *path,
const cairo_box_t *boxes,
int num_boxes)
{
double dx, dy;
cairo_fixed_t fdx, fdy;
stroker->has_bounds = TRUE;
_cairo_boxes_get_extents (boxes, num_boxes, &stroker->bounds);
/* Extend the bounds in each direction to account for the maximum area
* we might generate trapezoids, to capture line segments that are outside
* of the bounds but which might generate rendering that's within bounds.
*/
_cairo_stroke_style_max_distance_from_path (&stroker->style, path,
stroker->ctm, &dx, &dy);
fdx = _cairo_fixed_from_double (dx);
fdy = _cairo_fixed_from_double (dy);
stroker->bounds.p1.x -= fdx;
stroker->bounds.p2.x += fdx;
stroker->bounds.p1.y -= fdy;
stroker->bounds.p2.y += fdy;
}
static cairo_status_t
_cairo_stroker_init (cairo_stroker_t *stroker,
cairo_stroke_style_t *stroke_style,
cairo_matrix_t *ctm,
cairo_matrix_t *ctm_inverse,
double tolerance,
cairo_traps_t *traps)
{
cairo_status_t status;
stroker->style = stroke_style;
stroker->ctm = ctm;
stroker->ctm_inverse = ctm_inverse;
stroker->tolerance = tolerance;
stroker->traps = traps;
stroker->ctm_determinant = _cairo_matrix_compute_determinant (stroker->ctm);
stroker->ctm_det_positive = stroker->ctm_determinant >= 0.0;
status = _cairo_pen_init (&stroker->pen,
stroke_style->line_width / 2.0,
tolerance, ctm);
if (status)
return status;
stroker->has_current_face = FALSE;
stroker->has_first_face = FALSE;
stroker->has_initial_sub_path = FALSE;
if (stroker->style->dash)
_cairo_stroker_start_dash (stroker);
else
stroker->dashed = FALSE;
stroker->has_bounds = _cairo_traps_get_limit (traps, &stroker->bounds);
if (stroker->has_bounds) {
/* Extend the bounds in each direction to account for the maximum area
* we might generate trapezoids, to capture line segments that are outside
* of the bounds but which might generate rendering that's within bounds.
*/
double dx, dy;
cairo_fixed_t fdx, fdy;
_cairo_stroke_style_max_distance_from_path (stroker->style, stroker->ctm, &dx, &dy);
fdx = _cairo_fixed_from_double (dx);
fdy = _cairo_fixed_from_double (dy);
stroker->bounds.p1.x -= fdx;
stroker->bounds.p2.x += fdx;
stroker->bounds.p1.y -= fdy;
stroker->bounds.p2.y += fdy;
}
return CAIRO_STATUS_SUCCESS;
}
/* Adjusts the fill extents (above) by the device-space pen. */
void
_cairo_path_fixed_approximate_stroke_extents (const cairo_path_fixed_t *path,
const cairo_stroke_style_t *style,
const cairo_matrix_t *ctm,
cairo_rectangle_int_t *extents)
{
if (path->has_extents) {
cairo_box_t box_extents;
double dx, dy;
_cairo_stroke_style_max_distance_from_path (style, path, ctm, &dx, &dy);
box_extents = path->extents;
box_extents.p1.x -= _cairo_fixed_from_double (dx);
box_extents.p1.y -= _cairo_fixed_from_double (dy);
box_extents.p2.x += _cairo_fixed_from_double (dx);
box_extents.p2.y += _cairo_fixed_from_double (dy);
_cairo_box_round_to_rectangle (&box_extents, extents);
} else {
extents->x = extents->y = 0;
extents->width = extents->height = 0;
}
}
/* Adjusts the fill extents (above) by the device-space pen. */
void
_cairo_path_fixed_approximate_stroke_extents (const cairo_path_fixed_t *path,
const cairo_stroke_style_t *style,
const cairo_matrix_t *ctm,
cairo_bool_t is_vector,
cairo_rectangle_int_t *extents)
{
if (path->has_extents) {
cairo_box_t box_extents;
double dx, dy;
_cairo_stroke_style_max_distance_from_path (style, path, ctm, &dx, &dy);
if (is_vector)
{
/* When calculating extents for vector surfaces, ensure lines thinner
* than the fixed point resolution are not optimized away. */
double min = _cairo_fixed_to_double (CAIRO_FIXED_EPSILON*2);
if (dx < min)
dx = min;
if (dy < min)
dy = min;
}
box_extents = path->extents;
box_extents.p1.x -= _cairo_fixed_from_double (dx);
box_extents.p1.y -= _cairo_fixed_from_double (dy);
box_extents.p2.x += _cairo_fixed_from_double (dx);
box_extents.p2.y += _cairo_fixed_from_double (dy);
_cairo_box_round_to_rectangle (&box_extents, extents);
} else {
extents->x = extents->y = 0;
extents->width = extents->height = 0;
}
}
cairo_status_t
_cairo_path_fixed_stroke_to_polygon (const cairo_path_fixed_t *path,
const cairo_stroke_style_t *style,
const cairo_matrix_t *ctm,
const cairo_matrix_t *ctm_inverse,
double tolerance,
cairo_polygon_t *polygon)
{
struct stroker stroker;
cairo_status_t status;
if (style->num_dashes) {
return _cairo_path_fixed_stroke_dashed_to_polygon (path,
style,
ctm,
ctm_inverse,
tolerance,
polygon);
}
stroker.has_bounds = polygon->num_limits;
if (stroker.has_bounds) {
/* Extend the bounds in each direction to account for the maximum area
* we might generate trapezoids, to capture line segments that are
* outside of the bounds but which might generate rendering that's
* within bounds.
*/
double dx, dy;
cairo_fixed_t fdx, fdy;
int i;
stroker.bounds = polygon->limits[0];
for (i = 1; i < polygon->num_limits; i++)
_cairo_box_add_box (&stroker.bounds, &polygon->limits[i]);
_cairo_stroke_style_max_distance_from_path (style, path, ctm, &dx, &dy);
fdx = _cairo_fixed_from_double (dx);
fdy = _cairo_fixed_from_double (dy);
stroker.bounds.p1.x -= fdx;
stroker.bounds.p2.x += fdx;
stroker.bounds.p1.y -= fdy;
stroker.bounds.p2.y += fdy;
}
stroker.style = *style;
stroker.ctm = ctm;
stroker.ctm_inverse = ctm_inverse;
stroker.tolerance = tolerance;
stroker.half_line_width = style->line_width / 2.;
/* To test whether we need to join two segments of a spline using
* a round-join or a bevel-join, we can inspect the angle between the
* two segments. If the difference between the chord distance
* (half-line-width times the cosine of the bisection angle) and the
* half-line-width itself is greater than tolerance then we need to
* inject a point.
*/
stroker.spline_cusp_tolerance = 1 - tolerance / stroker.half_line_width;
stroker.spline_cusp_tolerance *= stroker.spline_cusp_tolerance;
stroker.spline_cusp_tolerance *= 2;
stroker.spline_cusp_tolerance -= 1;
stroker.ctm_det_positive =
_cairo_matrix_compute_determinant (ctm) >= 0.0;
stroker.pen.num_vertices = 0;
if (path->has_curve_to ||
style->line_join == CAIRO_LINE_JOIN_ROUND ||
style->line_cap == CAIRO_LINE_CAP_ROUND) {
status = _cairo_pen_init (&stroker.pen,
stroker.half_line_width,
tolerance, ctm);
if (unlikely (status))
return status;
/* If the line width is so small that the pen is reduced to a
single point, then we have nothing to do. */
if (stroker.pen.num_vertices <= 1)
return CAIRO_STATUS_SUCCESS;
}
stroker.has_current_face = FALSE;
stroker.has_first_face = FALSE;
stroker.has_initial_sub_path = FALSE;
#if DEBUG
remove ("contours.txt");
remove ("polygons.txt");
_cairo_contour_init (&stroker.path, 0);
#endif
_cairo_contour_init (&stroker.cw.contour, 1);
_cairo_contour_init (&stroker.ccw.contour, -1);
tolerance *= CAIRO_FIXED_ONE;
tolerance *= tolerance;
stroker.contour_tolerance = tolerance;
stroker.polygon = polygon;
status = _cairo_path_fixed_interpret (path,
move_to,
line_to,
curve_to,
close_path,
&stroker);
/* Cap the start and end of the final sub path as needed */
if (likely (status == CAIRO_STATUS_SUCCESS))
add_caps (&stroker);
_cairo_contour_fini (&stroker.cw.contour);
_cairo_contour_fini (&stroker.ccw.contour);
if (stroker.pen.num_vertices)
_cairo_pen_fini (&stroker.pen);
#if DEBUG
{
FILE *file = fopen ("polygons.txt", "a");
_cairo_debug_print_polygon (file, polygon);
fclose (file);
}
#endif
return status;
}
