draw_path_flower.rs

// This example is a port of javascript code made by Ibon Tolosona (@hyperandroid)
// https://codepen.io/hyperandroid/full/yLyRQmw

use notan::draw::*;
use notan::prelude::*;

const CENTER_X: f32 = 400.0;
const CENTER_Y: f32 = 300.0;
const START_RADIUS: usize = 20;
const RADIUS_INCREMENT: usize = 13;
const MAX_RADIUS: usize = 250;
const MAX_LINES: usize = (MAX_RADIUS - START_RADIUS) / RADIUS_INCREMENT;
const AMPLITUDE: f32 = 30.0;
const PERIOD: f32 = 6.0;
const PI: f32 = std::f32::consts::PI;

#[notan_main]
fn main() -> Result<(), String> {
    notan::init()
        .add_config(WindowConfig::new().set_multisampling(8))
        .add_config(DrawConfig)
        .draw(draw)
        .build()
}

fn draw(app: &mut App, gfx: &mut Graphics) {
    let time = app.timer.elapsed_f32() * 1000.0;

    let mut draw = gfx.create_draw();
    draw.clear(Color::BLACK);

    let mut count = 0.0;
    for (line_index, i) in (START_RADIUS..MAX_RADIUS)
        .step_by(RADIUS_INCREMENT as _)
        .enumerate()
    {
        let ti = ((time + line_index as f32 * 79.0) % 2000.0) / 2000.0;
        draw_flower(
            draw.path(),
            i as _,
            ((time % 38000.0) / 38000.0) * 2.0 * PI,
            count,
            (ti * PI * 2.0).cos(),
        );
        count += if line_index <= MAX_LINES / 2 {
            2.0
        } else {
            -2.0
        };
    }

    gfx.render(&draw);
}

fn draw_flower(
    mut path_builder: DrawBuilder<Path>,
    radius: f32,
    initial_angle: f32,
    index: f32,
    amplitude_modifier: f32,
) {
    let segments = (2.0 * PI * radius).floor();
    let mut begin = false;

    for i in 0..segments as usize {
        let n = i as f32;

        let period_segments = segments / PERIOD;
        let current_periods = n % period_segments;

        let radians_period = if current_periods < radius {
            current_periods / radius
        } else {
            0.0
        };

        let c_radius = radius
            + AMPLITUDE
                * (radians_period * (3.0 + index) * PI).sin()
                * ((radians_period * PI).sin() / 2.0 * amplitude_modifier);

        let radians = n / segments * 2.0 * PI + initial_angle;
        let x = CENTER_X + c_radius * radians.cos();
        let y = CENTER_Y + c_radius * radians.sin();

        if !begin {
            path_builder.move_to(x, y);
            begin = true;
        }

        path_builder.line_to(x, y);
    }

    path_builder.close().color(Color::MAGENTA).stroke(3.0);
}