michael/pathfinder
michael
/
pathfinder
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Implement miter limit

This commit is contained in:
Patrick Walton 2019-05-30 13:08:30 -07:00
parent 8d078ff345
commit 5974aeba7b
1 changed files with 39 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

54
geometry/src/stroke.rs
View File

@ -41,7 +41,7 @@ pub enum LineCap {
#[derive(Clone, Copy, Debug, PartialEq)] #[derive(Clone, Copy, Debug, PartialEq)]
pub enum LineJoin { pub enum LineJoin {
Miter, Miter(f32),
Bevel, Bevel,
Round, Round,
} }
@ -97,11 +97,12 @@ impl<'a> OutlineStrokeToFill<'a> {
mut stroker: ContourStrokeToFill, mut stroker: ContourStrokeToFill,
closed: bool) { closed: bool) {
// Add join if necessary. // Add join if necessary.
if closed && stroker.output.needs_join(self.style.line_join) { if closed && stroker.output.might_need_join(self.style.line_join) {
let (p1, p0) = (stroker.output.position_of(1), stroker.output.position_of(0)); let (p1, p0) = (stroker.output.position_of(1), stroker.output.position_of(0));
let final_segment = LineSegmentF::new(p1, p0); let final_segment = LineSegmentF::new(p1, p0);
stroker.output.add_join(self.style.line_width * 0.5, stroker.output.add_join(self.style.line_width * 0.5,
self.style.line_join, self.style.line_join,
stroker.input.position_of(0),
&final_segment); &final_segment);
} }
@ -180,21 +181,26 @@ impl<'a> ContourStrokeToFill<'a> {
trait Offset { trait Offset {
fn offset(&self, distance: f32, join: LineJoin, contour: &mut Contour); fn offset(&self, distance: f32, join: LineJoin, contour: &mut Contour);
fn add_to_contour(&self, distance: f32, join: LineJoin, contour: &mut Contour); fn add_to_contour(&self,
distance: f32,
join: LineJoin,
join_point: Point2DF,
contour: &mut Contour);
fn offset_once(&self, distance: f32) -> Self; fn offset_once(&self, distance: f32) -> Self;
fn error_is_within_tolerance(&self, other: &Segment, distance: f32) -> bool; fn error_is_within_tolerance(&self, other: &Segment, distance: f32) -> bool;
} }
impl Offset for Segment { impl Offset for Segment {
fn offset(&self, distance: f32, join: LineJoin, contour: &mut Contour) { fn offset(&self, distance: f32, join: LineJoin, contour: &mut Contour) {
let join_point = self.baseline.from();
if self.baseline.square_length() < TOLERANCE * TOLERANCE { if self.baseline.square_length() < TOLERANCE * TOLERANCE {
self.add_to_contour(distance, join, contour); self.add_to_contour(distance, join, join_point, contour);
return; return;
} }
let candidate = self.offset_once(distance); let candidate = self.offset_once(distance);
if self.error_is_within_tolerance(&candidate, distance) { if self.error_is_within_tolerance(&candidate, distance) {
candidate.add_to_contour(distance, join, contour); candidate.add_to_contour(distance, join, join_point, contour);
return; return;
} }
@ -206,9 +212,13 @@ impl Offset for Segment {
after.offset(distance, join, contour); after.offset(distance, join, contour);
} }
fn add_to_contour(&self, distance: f32, join: LineJoin, contour: &mut Contour) { fn add_to_contour(&self,
distance: f32,
join: LineJoin,
join_point: Point2DF,
contour: &mut Contour) {
// Add join if necessary. // Add join if necessary.
if contour.needs_join(join) { if contour.might_need_join(join) {
let p3 = self.baseline.from(); let p3 = self.baseline.from();
let p4 = if self.is_line() { let p4 = if self.is_line() {
self.baseline.to() self.baseline.to()
@ -218,7 +228,7 @@ impl Offset for Segment {
self.ctrl.from() self.ctrl.from()
}; };
contour.add_join(distance, join, &LineSegmentF::new(p4, p3)); contour.add_join(distance, join, join_point, &LineSegmentF::new(p4, p3));
} }
// Push segment. // Push segment.
@ -324,20 +334,34 @@ impl Offset for Segment {
} }
impl Contour { impl Contour {
fn needs_join(&self, join: LineJoin) -> bool { fn might_need_join(&self, join: LineJoin) -> bool {
// TODO(pcwalton): Miter limit. if self.len() < 2 {
(join == LineJoin::Miter || join == LineJoin::Round) && self.len() >= 2 false
} else {
match join {
LineJoin::Miter(_) | LineJoin::Round => true,
LineJoin::Bevel => false,
}
}
} }
fn add_join(&mut self, distance: f32, join: LineJoin, next_tangent: &LineSegmentF) { fn add_join(&mut self,
distance: f32,
join: LineJoin,
join_point: Point2DF,
next_tangent: &LineSegmentF) {
let (p0, p1) = (self.position_of_last(2), self.position_of_last(1)); let (p0, p1) = (self.position_of_last(2), self.position_of_last(1));
let prev_tangent = LineSegmentF::new(p0, p1); let prev_tangent = LineSegmentF::new(p0, p1);
match join { match join {
LineJoin::Bevel => {} LineJoin::Bevel => {}
LineJoin::Miter => { LineJoin::Miter(miter_limit) => {
if let Some(prev_tangent_t) = prev_tangent.intersection_t(&next_tangent) { if let Some(prev_tangent_t) = prev_tangent.intersection_t(&next_tangent) {
self.push_endpoint(prev_tangent.sample(prev_tangent_t)); let miter_endpoint = prev_tangent.sample(prev_tangent_t);
let threshold = miter_limit * distance;
if (miter_endpoint - join_point).square_length() <= threshold * threshold {
self.push_endpoint(miter_endpoint);
}
} }
} }
LineJoin::Round => { LineJoin::Round => {
@ -366,5 +390,5 @@ impl Default for LineCap {
impl Default for LineJoin { impl Default for LineJoin {
#[inline] #[inline]
fn default() -> LineJoin { LineJoin::Miter } fn default() -> LineJoin { LineJoin::Miter(10.0) }
} }