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Implement round joins

This commit is contained in:
Patrick Walton 2019-05-29 19:09:15 -07:00
parent acf666b701
commit a75b635722
3 changed files with 37 additions and 19 deletions
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1
examples/canvas_minimal/src/main.rs
View File

@ -12,6 +12,7 @@ use pathfinder_canvas::{CanvasRenderingContext2D, Path2D};
use pathfinder_geometry::basic::point::{Point2DF32, Point2DI32};
use pathfinder_geometry::basic::rect::RectF32;
use pathfinder_geometry::color::ColorF;
use pathfinder_geometry::stroke::LineJoin;
use pathfinder_gl::{GLDevice, GLVersion};
use pathfinder_gpu::resources::FilesystemResourceLoader;
use pathfinder_gpu::{ClearParams, Device};

3
geometry/src/outline.rs
View File

@ -390,6 +390,9 @@ impl Contour {
chord = chord.scale(radius.recip());
let (mut vector, end_vector) = (UnitVector(chord.from()), UnitVector(chord.to()));
debug_assert!(f32::abs(vector.0.length() - 1.0) < EPSILON);
debug_assert!(f32::abs(end_vector.0.length() - 1.0) < EPSILON);
let scale = Transform2DF32::from_scale(Point2DF32::splat(radius));
let translation = Transform2DF32::from_translation(center);

52
geometry/src/stroke.rs
View File

@ -43,6 +43,7 @@ pub enum LineCap {
pub enum LineJoin {
Miter,
Bevel,
Round,
}
impl<'a> OutlineStrokeToFill<'a> {
@ -62,8 +63,8 @@ impl<'a> OutlineStrokeToFill<'a> {
stroker.offset_forward();
if closed {
self.push_stroked_contour(&mut new_contours, stroker.output, true);
stroker = ContourStrokeToFill::new(stroker.input,
self.push_stroked_contour(&mut new_contours, stroker, true);
stroker = ContourStrokeToFill::new(input,
Contour::new(),
self.style.line_width * 0.5,
self.style.line_join);
@ -76,7 +77,7 @@ impl<'a> OutlineStrokeToFill<'a> {
self.add_cap(&mut stroker.output);
}
self.push_stroked_contour(&mut new_contours, stroker.output, closed);
self.push_stroked_contour(&mut new_contours, stroker, closed);
}
let mut new_bounds = None;
@ -93,16 +94,18 @@ impl<'a> OutlineStrokeToFill<'a> {
fn push_stroked_contour(&mut self,
new_contours: &mut Vec<Contour>,
mut contour: Contour,
mut stroker: ContourStrokeToFill,
closed: bool) {
// Add join if necessary.
if closed && contour.needs_join(self.style.line_join) {
let (p1, p0) = (contour.position_of(1), contour.position_of(0));
contour.add_join(self.style.line_join, &LineSegmentF32::new(p0, p1));
if closed && stroker.output.needs_join(self.style.line_join) {
let (p1, p0) = (stroker.output.position_of(1), stroker.output.position_of(0));
let final_segment = LineSegmentF32::new(p1, p0);
let join_point = stroker.input.position_of(0);
stroker.output.add_join(self.style.line_join, join_point, &final_segment);
}
contour.closed = true;
new_contours.push(contour);
stroker.output.closed = true;
new_contours.push(stroker.output);
}
fn add_cap(&mut self, contour: &mut Contour) {
@ -176,21 +179,23 @@ impl<'a> ContourStrokeToFill<'a> {
trait Offset {
fn offset(&self, distance: f32, join: LineJoin, contour: &mut Contour);
fn add_to_contour(&self, join: LineJoin, contour: &mut Contour);
fn add_to_contour(&self, join: LineJoin, join_point: Point2DF32, contour: &mut Contour);
fn offset_once(&self, distance: f32) -> Self;
fn error_is_within_tolerance(&self, other: &Segment, distance: f32) -> bool;
}
impl Offset for Segment {
fn offset(&self, distance: f32, join: LineJoin, contour: &mut Contour) {
let join_point = self.baseline.from();
if self.baseline.square_length() < TOLERANCE * TOLERANCE {
self.add_to_contour(join, contour);
self.add_to_contour(join, join_point, contour);
return;
}
let candidate = self.offset_once(distance);
if self.error_is_within_tolerance(&candidate, distance) {
candidate.add_to_contour(join, contour);
candidate.add_to_contour(join, join_point, contour);
return;
}
@ -202,7 +207,7 @@ impl Offset for Segment {
after.offset(distance, join, contour);
}
fn add_to_contour(&self, join: LineJoin, contour: &mut Contour) {
fn add_to_contour(&self, join: LineJoin, join_point: Point2DF32, contour: &mut Contour) {
// Add join if necessary.
if contour.needs_join(join) {
let p3 = self.baseline.from();
@ -214,7 +219,7 @@ impl Offset for Segment {
self.ctrl.from()
};
contour.add_join(join, &LineSegmentF32::new(p4, p3));
contour.add_join(join, join_point, &LineSegmentF32::new(p4, p3));
}
// Push segment.
@ -322,15 +327,24 @@ impl Offset for Segment {
impl Contour {
fn needs_join(&self, join: LineJoin) -> bool {
// TODO(pcwalton): Miter limit.
join == LineJoin::Miter && self.len() >= 2
(join == LineJoin::Miter || join == LineJoin::Round) && self.len() >= 2
}
fn add_join(&mut self, _: LineJoin, next_tangent: &LineSegmentF32) {
// TODO(pcwalton): Round joins.
fn add_join(&mut self, join: LineJoin, join_point: Point2DF32, next_tangent: &LineSegmentF32) {
let (p0, p1) = (self.position_of_last(2), self.position_of_last(1));
let prev_tangent = LineSegmentF32::new(p0, p1);
if let Some(prev_tangent_t) = prev_tangent.intersection_t(&next_tangent) {
self.push_endpoint(prev_tangent.sample(prev_tangent_t));
match join {
LineJoin::Bevel => {}
LineJoin::Miter => {
if let Some(prev_tangent_t) = prev_tangent.intersection_t(&next_tangent) {
self.push_endpoint(prev_tangent.sample(prev_tangent_t));
}
}
LineJoin::Round => {
self.push_arc_from_chord(join_point, LineSegmentF32::new(prev_tangent.to(),
next_tangent.to()));
}
}
}
}