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//! Multi-plot example: scale sharing across many plots in a single
//! composition, layered on top of real nesting.
//!
//! Layout: an outer composition wraps a 2×2 inner facet grid `beside` a
//! column-spanning summary patch.
//!
//! ```text
//! ┌─────────────┬─────────────┐
//! │ q1 q2 │ │
//! │ │ summary │
//! │ q3 q4 │ │
//! └─────────────┴─────────────┘
//! ```
//!
//! Five plots total — four facets plus the summary. All five bind their
//! `"x"` channel to the same scale name `"time"`, so a single
//! `view.update_scale("time", |s| ...)` between renders updates every
//! panel at once.
//!
//! Produces:
//! - `examples/faceted_1_initial.png` — full x range, all five panels.
//! - `examples/faceted_2_shared_zoom.png` — shared x narrowed once;
//! propagates to every plot.
//! - `examples/faceted_3_aspect_locked.png` — outer composition gains
//! `.aspect(1, 1)`; selective-respect under nesting locks each leaf
//! panel to 1:1 while the surrounding row/col tracks absorb slack.
//!
//! Renders 1 & 2 also carry **composition-level chrome** — a title,
//! subtitle, caption, one shared bottom axis title, and a single legend
//! — set directly on `PlotComposition`. Each spans the whole five-panel
//! layout rather than repeating per patch.
use hephaestus::backend::vello::VelloRenderer;
use hephaestus::color::{rgb8, Color};
use hephaestus::composition::{beside, grid, Composition, Element, Patch};
use hephaestus::geometry::Size;
use hephaestus::plot::chrome::axis::{Axis, AxisPlacement};
use hephaestus::plot::chrome::legend::{Legend, LegendKeySpec};
use hephaestus::plot::{scale, Plot, PlotComposition, PointGeom};
use hephaestus::scales::chrome::{AxisSide, LegendSide};
use hephaestus::scales::value::Value;
use hephaestus::scene::SceneBuilder;
use hephaestus::Renderer;
fn comp_shape(aspect: Option<(f64, f64)>) -> Composition {
let facets: Vec<Element> = ["q1", "q2", "q3", "q4"]
.into_iter()
.map(|id| Patch::new(id).into())
.collect();
let inner_2x2 = grid(2, 2, facets);
let outer = beside(inner_2x2, Patch::new("summary"));
match aspect {
Some((aw, ah)) => outer.aspect(aw, ah),
None => outer,
}
}
fn main() {
let (w, h) = (1400u32, 700u32);
let dpi = 96.0;
let xs: Vec<f64> = (0..50).map(|i| i as f64 * 2.0).collect();
let make = |phase: f64, amp: f64| -> Vec<f64> {
xs.iter()
.map(|x| 50.0 + amp * (x * 0.05 + phase).sin())
.collect()
};
let datasets = [
("q1", make(0.0, 25.0), rgb8(220, 90, 70)),
("q2", make(1.5, 18.0), rgb8(70, 120, 220)),
("q3", make(3.0, 22.0), rgb8(70, 180, 120)),
("q4", make(4.5, 28.0), rgb8(180, 130, 80)),
("summary", make(0.0, 35.0), rgb8(130, 80, 180)),
];
let mut renderer = VelloRenderer::new().expect("vello renderer init");
let bg: Color = rgb8(248, 248, 252);
// ── Renders 1 & 2: shared "time" scale across the unlocked layout
{
#[allow(unused_mut)]
let mut view = PlotComposition::new(&comp_shape(None))
.add_scale("time", scale::continuous(0.0..=100.0))
.add_scale("y", scale::continuous(0.0..=100.0))
.title("Sensor array")
.subtitle("Four quadrants and a summary, sharing one time scale")
.caption("Composition-level chrome spans every panel");
attach_all(&mut view, &xs, &datasets);
// One axis title and one legend for the whole grid, set on the
// composition rather than on any single plot. The legend reads
// its rows from the "series" scale's domain; no plot needs to
// bind that scale for the legend to resolve it.
let mut view = {
let series: Vec<Value> = datasets.iter().map(|(id, _, _)| Value::from(*id)).collect();
let colors: Vec<Color> = datasets.iter().map(|(_, _, c)| *c).collect();
let mut view = view
.add_scale("series", scale::discrete(series).range_colors(colors))
.axis_title(AxisSide::Bottom, "Time (s)");
view.add_legend(
Legend::new("series")
.side(LegendSide::Right)
.title("Series")
.key(
LegendKeySpec::point()
.scaled("fill", "series")
.fixed("size", 6.0_f64),
),
);
view
};
let issues = view.validate();
if !issues.is_empty() {
panic!("validate() reported issues: {issues:?}");
}
render_to(
&mut renderer,
&mut view,
w,
h,
dpi,
bg,
"examples/faceted_1_initial.png",
);
view.update_scale("time", |s| s.set_domain_continuous(20.0, 60.0));
render_to(
&mut renderer,
&mut view,
w,
h,
dpi,
bg,
"examples/faceted_2_shared_zoom.png",
);
}
// ── Render 3: aspect-locked. Outer `.aspect(1, 1)` propagates to
// every leaf panel; selective respect on the layout solver
// couples panel col/row at the locked ratio and lets unmarked
// fr tracks absorb slack. Wider viewport (1800×600) makes the
// lock visually obvious — without it, the 1×2 outer would give
// half the width to each side; with it, the leaf panels land
// at the locked ratio and the surrounding tracks soak up the
// horizontal slack.
{
let (lw, lh) = (1800u32, 600u32);
let mut view = PlotComposition::new(&comp_shape(Some((1.0, 1.0))))
.add_scale("time", scale::continuous(20.0..=60.0))
.add_scale("y", scale::continuous(0.0..=100.0));
attach_all(&mut view, &xs, &datasets);
render_to(
&mut renderer,
&mut view,
lw,
lh,
dpi,
bg,
"examples/faceted_3_aspect_locked.png",
);
}
}
fn attach_all(view: &mut PlotComposition, xs: &[f64], datasets: &[(&str, Vec<f64>, Color)]) {
// `Plot::new` reads the composition only to check that the patch id
// exists, so one shape serves every plot here. A plot's own aspect
// lock would come from `Plot::aspect_ratio`; render 3 instead locks
// the outer composition and lets it cascade to the leaves.
let shape = comp_shape(None);
for (id, ys, color) in datasets {
let mut p = Plot::new(&shape, *id).bind("x", "time").bind("y", "y");
p.add_geom(
PointGeom::builder()
.set("x", xs.to_vec())
.set("y", ys.clone())
.set("fill", *color)
.set("size", 4.0_f64)
.build(),
);
{
p.add_axis(Axis::rail(
"time",
AxisPlacement::Cartesian(AxisSide::Bottom),
));
p.add_axis(Axis::rail("y", AxisPlacement::Cartesian(AxisSide::Left)));
}
view.attach_plot(p);
}
}
fn render_to(
renderer: &mut VelloRenderer,
view: &mut PlotComposition,
w: u32,
h: u32,
dpi: f64,
bg: Color,
out_relative: &str,
) {
{
let scene = renderer.scene();
scene.clear();
view.render(scene, Size::new(w as f64, h as f64), dpi);
}
let mut pixels = vec![0u8; (w * h * 4) as usize];
renderer
.render_to_buffer(w, h, bg, &mut pixels)
.expect("render");
let path = std::env::current_dir().unwrap().join(out_relative);
hephaestus::image::write_png(&path, w, h, &pixels).expect("write png");
println!("wrote {}", path.display());
}