static cairo_status_t
_cairo_pen_stroke_spline_half (cairo_pen_t *pen,
cairo_spline_t *spline,
cairo_direction_t dir,
cairo_polygon_t *polygon)
{
int i;
cairo_status_t status;
int start, stop, step;
int active = 0;
cairo_point_t hull_point;
cairo_slope_t slope, initial_slope, final_slope;
cairo_point_t *point = spline->points;
int num_points = spline->num_points;
if (dir == CAIRO_DIRECTION_FORWARD) {
start = 0;
stop = num_points;
step = 1;
initial_slope = spline->initial_slope;
final_slope = spline->final_slope;
} else {
start = num_points - 1;
stop = -1;
step = -1;
initial_slope = spline->final_slope;
initial_slope.dx = -initial_slope.dx;
initial_slope.dy = -initial_slope.dy;
final_slope = spline->initial_slope;
final_slope.dx = -final_slope.dx;
final_slope.dy = -final_slope.dy;
}
_cairo_pen_find_active_cw_vertex_index (pen, &initial_slope, &active);
i = start;
while (i != stop) {
hull_point.x = point[i].x + pen->vertices[active].point.x;
hull_point.y = point[i].y + pen->vertices[active].point.y;
status = _cairo_polygon_line_to (polygon, &hull_point);
if (status)
return status;
if (i + step == stop)
slope = final_slope;
else
_cairo_slope_init (&slope, &point[i], &point[i+step]);
if (_cairo_slope_counter_clockwise (&slope, &pen->vertices[active].slope_ccw)) {
if (++active == pen->num_vertices)
active = 0;
} else if (_cairo_slope_clockwise (&slope, &pen->vertices[active].slope_cw)) {
if (--active == -1)
active = pen->num_vertices - 1;
} else {
i += step;
}
}
return CAIRO_STATUS_SUCCESS;
}
static cairo_status_t
_cairo_filler_curve_to (void *closure,
cairo_point_t *b,
cairo_point_t *c,
cairo_point_t *d)
{
int i;
cairo_status_t status = CAIRO_STATUS_SUCCESS;
cairo_filler_t *filler = closure;
cairo_polygon_t *polygon = &filler->polygon;
cairo_spline_t spline;
status = _cairo_spline_init (&spline, &filler->current_point, b, c, d);
if (status == CAIRO_INT_STATUS_DEGENERATE)
return CAIRO_STATUS_SUCCESS;
_cairo_spline_decompose (&spline, filler->tolerance);
if (status)
goto CLEANUP_SPLINE;
for (i = 1; i < spline.num_points; i++) {
status = _cairo_polygon_line_to (polygon, &spline.points[i]);
if (status)
break;
}
CLEANUP_SPLINE:
_cairo_spline_fini (&spline);
filler->current_point = *d;
return status;
}
static cairo_status_t
_cairo_filler_line_to (void *closure,
const cairo_point_t *point)
{
cairo_filler_t *filler = closure;
return _cairo_polygon_line_to (filler->polygon, point);
}
static cairo_status_t
_cairo_filler_line_to (void *closure, cairo_point_t *point)
{
cairo_filler_t *filler = closure;
cairo_polygon_t *polygon = &filler->polygon;
_cairo_polygon_line_to (polygon, point);
filler->current_point = *point;
return _cairo_polygon_status (&filler->polygon);
}
static cairo_status_t
_cairo_filler_line_to (void *closure, cairo_point_t *point)
{
cairo_status_t status;
cairo_filler_t *filler = closure;
cairo_polygon_t *polygon = &filler->polygon;
status = _cairo_polygon_line_to (polygon, point);
if (status)
return status;
filler->current_point = *point;
return CAIRO_STATUS_SUCCESS;
}
cairo_status_t
_cairo_polygon_close (cairo_polygon_t *polygon)
{
cairo_status_t status;
if (polygon->has_current_point) {
status = _cairo_polygon_line_to (polygon, &polygon->first_point);
polygon->has_current_point = FALSE;
}
if (polygon->has_current_edge) {
_cairo_polygon_add_edge (polygon,
&polygon->last_point,
&polygon->current_point);
polygon->has_current_edge = FALSE;
}
return polygon->status;
}
static cairo_status_t
_cairo_stroker_add_cap (cairo_stroker_t *stroker, cairo_stroke_face_t *f)
{
cairo_status_t status;
if (stroker->style->line_cap == CAIRO_LINE_CAP_BUTT)
return CAIRO_STATUS_SUCCESS;
switch (stroker->style->line_cap) {
case CAIRO_LINE_CAP_ROUND: {
int i;
int start, stop;
cairo_slope_t slope;
cairo_point_t tri[3];
cairo_pen_t *pen = &stroker->pen;
slope = f->dev_vector;
start = _cairo_pen_find_active_cw_vertex_index (pen, &slope);
slope.dx = -slope.dx;
slope.dy = -slope.dy;
stop = _cairo_pen_find_active_cw_vertex_index (pen, &slope);
tri[0] = f->point;
tri[1] = f->cw;
for (i=start; i != stop; i = (i+1) % pen->num_vertices) {
tri[2] = f->point;
_translate_point (&tri[2], &pen->vertices[i].point);
status = _cairo_traps_tessellate_triangle (stroker->traps, tri);
if (unlikely (status))
return status;
tri[1] = tri[2];
}
tri[2] = f->ccw;
return _cairo_traps_tessellate_triangle (stroker->traps, tri);
}
case CAIRO_LINE_CAP_SQUARE: {
double dx, dy;
cairo_slope_t fvector;
cairo_point_t occw, ocw;
cairo_polygon_t polygon;
dx = f->usr_vector.x;
dy = f->usr_vector.y;
dx *= stroker->style->line_width / 2.0;
dy *= stroker->style->line_width / 2.0;
cairo_matrix_transform_distance (stroker->ctm, &dx, &dy);
fvector.dx = _cairo_fixed_from_double (dx);
fvector.dy = _cairo_fixed_from_double (dy);
occw.x = f->ccw.x + fvector.dx;
occw.y = f->ccw.y + fvector.dy;
ocw.x = f->cw.x + fvector.dx;
ocw.y = f->cw.y + fvector.dy;
_cairo_polygon_init (&polygon);
_cairo_polygon_move_to (&polygon, &f->cw);
_cairo_polygon_line_to (&polygon, &ocw);
_cairo_polygon_line_to (&polygon, &occw);
_cairo_polygon_line_to (&polygon, &f->ccw);
_cairo_polygon_close (&polygon);
status = _cairo_polygon_status (&polygon);
if (status == CAIRO_STATUS_SUCCESS) {
status = _cairo_bentley_ottmann_tessellate_polygon (stroker->traps,
&polygon,
CAIRO_FILL_RULE_WINDING);
}
_cairo_polygon_fini (&polygon);
return status;
}
case CAIRO_LINE_CAP_BUTT:
default:
return CAIRO_STATUS_SUCCESS;
}
}
static void
_cairo_pen_stroke_spline_half (cairo_pen_t *pen,
cairo_spline_t *spline,
cairo_direction_t dir,
cairo_polygon_t *polygon)
{
int i;
int start, stop, step;
int active = 0;
cairo_point_t hull_point;
cairo_slope_t slope, initial_slope, final_slope;
cairo_point_t *point = spline->points;
int num_points = spline->num_points;
if (dir == CAIRO_DIRECTION_FORWARD) {
start = 0;
stop = num_points;
step = 1;
initial_slope = spline->initial_slope;
final_slope = spline->final_slope;
} else {
start = num_points - 1;
stop = -1;
step = -1;
initial_slope = spline->final_slope;
initial_slope.dx = -initial_slope.dx;
initial_slope.dy = -initial_slope.dy;
final_slope = spline->initial_slope;
final_slope.dx = -final_slope.dx;
final_slope.dy = -final_slope.dy;
}
_cairo_pen_find_active_cw_vertex_index (pen,
&initial_slope,
&active);
i = start;
while (i != stop) {
hull_point.x = point[i].x + pen->vertices[active].point.x;
hull_point.y = point[i].y + pen->vertices[active].point.y;
_cairo_polygon_line_to (polygon, &hull_point);
if (i + step == stop)
slope = final_slope;
else
_cairo_slope_init (&slope, &point[i], &point[i+step]);
/* The strict inequalities here ensure that if a spline slope
* compares identically with either of the slopes of the
* active vertex, then it remains the active vertex. This is
* very important since otherwise we can trigger an infinite
* loop in the case of a degenerate pen, (a line), where
* neither vertex considers itself active for the slope---one
* will consider it as equal and reject, and the other will
* consider it unequal and reject. This is due to the inherent
* ambiguity when comparing slopes that differ by exactly
* pi. */
if (_cairo_slope_compare (&slope, &pen->vertices[active].slope_ccw) > 0) {
if (++active == pen->num_vertices)
active = 0;
} else if (_cairo_slope_compare (&slope, &pen->vertices[active].slope_cw) < 0) {
if (--active == -1)
active = pen->num_vertices - 1;
} else {
i += step;
}
}
}
