Mapped image and surface¶

use ironlab::prelude::*;

use crate::fields::*;

pub const TITLE: &str = "Mapped image and surface";
pub const DESCRIPTION: &str = "The Julia field as a scalar image on the floor of a three-dimensional axes, \
     beneath a surface of the same field. An image on a face of the axes box is painted behind everything that lies \
     in front of that face, so the surface covers the image wherever the surface stands above it.";

pub fn figure() -> Figure {
    let (x, y, z) = julia_grid(81);
    let (first_x, last_x) = (x[0], x[x.len() - 1]);
    let (first_y, last_y) = (y[0], y[y.len() - 1]);

    let mut fig = Figure::new()
        .size_mm(160.0, 100.0)
        .title(r"$\ln(1 + |z_3|)$ on the floor beneath its surface")
        .tag("image")
        .tag("surface")
        .tag("depth")
        .tag("overlay")
        .tag("placement")
        .parameter("dimensionality", "3D")
        .parameter("artists", 2)
        .parameter("data_points", 13_284)
        .parameter("has_legend", false);
    let mut ax = fig.axes3(0, 0);
    // A plane without an offset lies at the low end of its third axis, so the image lies on the floor of the box, at
    // the bottom of the z axis. The floor is at the back of the default view, so the image is painted before the
    // surface and shows only where no part of the surface stands above it.
    ax.scalar_image(&z)
        .pixel_columns(first_x, last_x)
        .pixel_rows(first_y, last_y);
    ax.surf(&x, &y, &z).edge_color(None);
    ax.xlabel("$x$")
        .ylabel("$y$")
        .zlabel(r"$\ln(1 + |z_3|)$");
    fig
}