hephaestus 0.2.0

Backend-agnostic 2D scene renderer for data visualization.
Documentation 
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//! Demonstrates `Element::Blank` — every chrome element set to
//! `Blank` is skipped at render time. Here we strip the panel
//! border and the minor grid, leaving a clean major-grid look.

use hephaestus::backend::vello::VelloRenderer;
use hephaestus::color::{rgb8, Color};
use hephaestus::composition::{Composition, Patch, Span};
use hephaestus::geometry::Size;
use hephaestus::plot::chrome::axis::{Axis, AxisPlacement};
use hephaestus::plot::theme::{Element, PerChannel, Theme};
use hephaestus::plot::{scale, Plot, PlotComposition, PointGeom};
use hephaestus::scales::chrome::AxisSide;
use hephaestus::scene::SceneBuilder;
use hephaestus::Renderer;

fn main() {
    let (w, h) = (900u32, 600u32);
    let dpi = 96.0;

    let comp = || Composition::empty(1, 1).place(1, 1, Span::cell(), Patch::new("p"));

    let n = 60;
    let xs: Vec<f64> = (0..n).map(|i| i as f64 * 0.1).collect();
    let ys: Vec<f64> = (0..n)
        .map(|i| ((i as f64) * 0.4).sin() * 0.4 + 0.5)
        .collect();

    let mut plot = Plot::new(&comp(), "p")
        .bind("x", "x_scale")
        .bind("y", "y_scale")
        .title("Element::Blank — strip panel border and minor grid");
    plot.add_geom(
        PointGeom::builder()
            .set("x", xs)
            .set("y", ys)
            .set("fill", rgb8(80, 130, 200))
            .set("size", 8.0_f64)
            .build(),
    );
    plot.add_axis(Axis::rail(
        "x_scale",
        AxisPlacement::Cartesian(AxisSide::Bottom),
    ));
    plot.add_axis(Axis::rail(
        "y_scale",
        AxisPlacement::Cartesian(AxisSide::Left),
    ));

    // Strip the chrome we don't want — Element::Blank short-circuits
    // the render path so the drawing for that piece is skipped
    // entirely.
    let theme = Theme {
        panel_border: Element::Blank,
        panel_grid_minor: PerChannel {
            all: Element::Blank,
            by_channel: [Element::Inherit, Element::Inherit],
        },
        ..Theme::default()
    };

    let mut view = PlotComposition::new(&comp())
        .add_scale("x_scale", scale::continuous(0.0..=6.0))
        .add_scale("y_scale", scale::continuous(0.0..=1.0))
        .theme(theme);
    view.attach_plot(plot);

    let mut renderer = VelloRenderer::new().expect("vello renderer init");
    let bg: Color = rgb8(252, 252, 252);
    {
        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("examples/theme_blank.png");
    hephaestus::image::write_png(&path, w, h, &pixels).expect("write png");
    println!("wrote {}", path.display());
}