134 lines
3.9 KiB
Rust
134 lines
3.9 KiB
Rust
// pathfinder/content/src/dash.rs
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//
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// Copyright © 2019 The Pathfinder Project Developers.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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//! Line dashing support.
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use crate::outline::{Contour, Outline, PushSegmentFlags};
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use std::mem;
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const EPSILON: f32 = 0.0001;
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pub struct OutlineDash<'a> {
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input: &'a Outline,
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output: Outline,
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state: DashState<'a>,
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}
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impl<'a> OutlineDash<'a> {
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#[inline]
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pub fn new(input: &'a Outline, dashes: &'a [f32], offset: f32) -> OutlineDash<'a> {
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OutlineDash { input, output: Outline::new(), state: DashState::new(dashes, offset) }
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}
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pub fn dash(&mut self) {
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for contour in &self.input.contours {
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ContourDash::new(contour, &mut self.output, &mut self.state).dash()
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}
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}
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pub fn into_outline(mut self) -> Outline {
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if self.state.is_on() {
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self.output.push_contour(self.state.output);
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}
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self.output
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}
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}
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struct ContourDash<'a, 'b, 'c> {
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input: &'a Contour,
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output: &'b mut Outline,
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state: &'c mut DashState<'a>,
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}
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impl<'a, 'b, 'c> ContourDash<'a, 'b, 'c> {
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fn new(input: &'a Contour, output: &'b mut Outline, state: &'c mut DashState<'a>)
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-> ContourDash<'a, 'b, 'c> {
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ContourDash { input, output, state }
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}
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fn dash(&mut self) {
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let (mut iterator, mut queued_segment) = (self.input.iter(), None);
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loop {
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if queued_segment.is_none() {
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match iterator.next() {
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None => break,
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Some(segment) => queued_segment = Some(segment),
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}
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}
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let mut current_segment = queued_segment.take().unwrap();
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let mut distance = self.state.distance_left;
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let t = current_segment.time_for_distance(distance);
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if t < 1.0 {
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let (prev_segment, next_segment) = current_segment.split(t);
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current_segment = prev_segment;
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queued_segment = Some(next_segment);
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} else {
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distance = current_segment.arc_length();
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}
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if self.state.is_on() {
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self.state.output.push_segment(¤t_segment, PushSegmentFlags::empty());
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}
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self.state.distance_left -= distance;
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if self.state.distance_left < EPSILON {
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if self.state.is_on() {
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self.output.push_contour(mem::replace(&mut self.state.output, Contour::new()));
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}
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self.state.current_dash_index += 1;
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if self.state.current_dash_index == self.state.dashes.len() {
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self.state.current_dash_index = 0;
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}
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self.state.distance_left = self.state.dashes[self.state.current_dash_index];
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}
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}
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}
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}
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struct DashState<'a> {
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output: Contour,
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dashes: &'a [f32],
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current_dash_index: usize,
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distance_left: f32,
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}
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impl<'a> DashState<'a> {
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fn new(dashes: &'a [f32], mut offset: f32) -> DashState<'a> {
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let total: f32 = dashes.iter().cloned().sum();
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offset %= total;
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let mut current_dash_index = 0;
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while current_dash_index < dashes.len() {
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let dash = dashes[current_dash_index];
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if offset < dash {
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break;
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}
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offset -= dash;
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current_dash_index += 1;
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}
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DashState {
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output: Contour::new(),
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dashes,
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current_dash_index,
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distance_left: offset,
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}
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}
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#[inline]
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fn is_on(&self) -> bool {
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self.current_dash_index % 2 == 0
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}
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}
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