gpui: Introduce dash array support for PathBuilder (#31678)

A simple way to draw dashed lines.


https://github.com/user-attachments/assets/2105d7b2-42d0-4d73-bb29-83a4a6bd7029

Release Notes:

- N/A
This commit is contained in:
Floyd Wang 2025-06-07 00:54:21 +08:00 committed by GitHub
parent 73cd6ef92c
commit ac806d982b
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GPG key ID: B5690EEEBB952194
2 changed files with 84 additions and 15 deletions

View file

@ -1,13 +1,14 @@
use gpui::{
Application, Background, Bounds, ColorSpace, Context, MouseDownEvent, Path, PathBuilder,
PathStyle, Pixels, Point, Render, StrokeOptions, Window, WindowOptions, canvas, div,
linear_color_stop, linear_gradient, point, prelude::*, px, rgb, size,
PathStyle, Pixels, Point, Render, SharedString, StrokeOptions, Window, WindowOptions, canvas,
div, linear_color_stop, linear_gradient, point, prelude::*, px, rgb, size,
};
struct PaintingViewer {
default_lines: Vec<(Path<Pixels>, Background)>,
lines: Vec<Vec<Point<Pixels>>>,
start: Point<Pixels>,
dashed: bool,
_painting: bool,
}
@ -140,7 +141,7 @@ impl PaintingViewer {
.with_line_join(lyon::path::LineJoin::Bevel);
let mut builder = PathBuilder::stroke(px(1.)).with_style(PathStyle::Stroke(options));
builder.move_to(point(px(40.), px(320.)));
for i in 0..50 {
for i in 1..50 {
builder.line_to(point(
px(40.0 + i as f32 * 10.0),
px(320.0 + (i as f32 * 10.0).sin() * 40.0),
@ -153,6 +154,7 @@ impl PaintingViewer {
default_lines: lines.clone(),
lines: vec![],
start: point(px(0.), px(0.)),
dashed: false,
_painting: false,
}
}
@ -162,10 +164,30 @@ impl PaintingViewer {
cx.notify();
}
}
fn button(
text: &str,
cx: &mut Context<PaintingViewer>,
on_click: impl Fn(&mut PaintingViewer, &mut Context<PaintingViewer>) + 'static,
) -> impl IntoElement {
div()
.id(SharedString::from(text.to_string()))
.child(text.to_string())
.bg(gpui::black())
.text_color(gpui::white())
.active(|this| this.opacity(0.8))
.flex()
.px_3()
.py_1()
.on_click(cx.listener(move |this, _, _, cx| on_click(this, cx)))
}
impl Render for PaintingViewer {
fn render(&mut self, _: &mut Window, cx: &mut Context<Self>) -> impl IntoElement {
let default_lines = self.default_lines.clone();
let lines = self.lines.clone();
let dashed = self.dashed;
div()
.font_family(".SystemUIFont")
.bg(gpui::white())
@ -182,17 +204,14 @@ impl Render for PaintingViewer {
.child("Mouse down any point and drag to draw lines (Hold on shift key to draw straight lines)")
.child(
div()
.id("clear")
.child("Clean up")
.bg(gpui::black())
.text_color(gpui::white())
.active(|this| this.opacity(0.8))
.flex()
.px_3()
.py_1()
.on_click(cx.listener(|this, _, _, cx| {
this.clear(cx);
})),
.gap_x_2()
.child(button(
if dashed { "Solid" } else { "Dashed" },
cx,
move |this, _| this.dashed = !dashed,
))
.child(button("Clear", cx, |this, cx| this.clear(cx))),
),
)
.child(
@ -202,7 +221,6 @@ impl Render for PaintingViewer {
canvas(
move |_, _, _| {},
move |_, _, window, _| {
for (path, color) in default_lines {
window.paint_path(path, color);
}
@ -213,6 +231,9 @@ impl Render for PaintingViewer {
}
let mut builder = PathBuilder::stroke(px(1.));
if dashed {
builder = builder.dash_array(&[px(4.), px(2.)]);
}
for (i, p) in points.into_iter().enumerate() {
if i == 0 {
builder.move_to(p);

View file

@ -27,6 +27,7 @@ pub struct PathBuilder {
transform: Option<lyon::math::Transform>,
/// PathStyle of the PathBuilder
pub style: PathStyle,
dash_array: Option<Vec<Pixels>>,
}
impl From<lyon::path::Builder> for PathBuilder {
@ -77,6 +78,7 @@ impl Default for PathBuilder {
raw: lyon::path::Path::builder().with_svg(),
style: PathStyle::Fill(FillOptions::default()),
transform: None,
dash_array: None,
}
}
}
@ -100,6 +102,24 @@ impl PathBuilder {
Self { style, ..self }
}
/// Sets the dash array of the [`PathBuilder`].
///
/// [MDN](https://developer.mozilla.org/en-US/docs/Web/SVG/Reference/Attribute/stroke-dasharray)
pub fn dash_array(mut self, dash_array: &[Pixels]) -> Self {
// If an odd number of values is provided, then the list of values is repeated to yield an even number of values.
// Thus, 5,3,2 is equivalent to 5,3,2,5,3,2.
let array = if dash_array.len() % 2 == 1 {
let mut new_dash_array = dash_array.to_vec();
new_dash_array.extend_from_slice(dash_array);
new_dash_array
} else {
dash_array.to_vec()
};
self.dash_array = Some(array);
self
}
/// Move the current point to the given point.
#[inline]
pub fn move_to(&mut self, to: Point<Pixels>) {
@ -229,7 +249,7 @@ impl PathBuilder {
};
match self.style {
PathStyle::Stroke(options) => Self::tessellate_stroke(&path, &options),
PathStyle::Stroke(options) => Self::tessellate_stroke(self.dash_array, &path, &options),
PathStyle::Fill(options) => Self::tessellate_fill(&path, &options),
}
}
@ -253,9 +273,37 @@ impl PathBuilder {
}
fn tessellate_stroke(
dash_array: Option<Vec<Pixels>>,
path: &lyon::path::Path,
options: &StrokeOptions,
) -> Result<Path<Pixels>, Error> {
let path = if let Some(dash_array) = dash_array {
let measurements = lyon::algorithms::measure::PathMeasurements::from_path(&path, 0.01);
let mut sampler = measurements
.create_sampler(path, lyon::algorithms::measure::SampleType::Normalized);
let mut builder = lyon::path::Path::builder();
let total_length = sampler.length();
let dash_array_len = dash_array.len();
let mut pos = 0.;
let mut dash_index = 0;
while pos < total_length {
let dash_length = dash_array[dash_index % dash_array_len].0;
let next_pos = (pos + dash_length).min(total_length);
if dash_index % 2 == 0 {
let start = pos / total_length;
let end = next_pos / total_length;
sampler.split_range(start..end, &mut builder);
}
pos = next_pos;
dash_index += 1;
}
&builder.build()
} else {
path
};
// Will contain the result of the tessellation.
let mut buf: VertexBuffers<lyon::math::Point, u16> = VertexBuffers::new();
let mut tessellator = StrokeTessellator::new();