extern crate cairo;
extern crate palette;
extern crate rand;
use rand::Rng;
use cairo::Gradient;
const WIDTH: i32 = 3840;
const HEIGHT: i32 = 2160;
fn cloud(ctx: &cairo::Context, rng: &mut rand::ThreadRng) {
let x_scale = rng.gen::<f64>() * 2.0 + 1.0;
let x = (rng.gen::<f64>() * WIDTH as f64) / x_scale;
let y = rng.gen::<f64>() * HEIGHT as f64;
let num_circles = 2 + (rng.gen::<isize>() % 2);
let vec: Vec<(f64, f64)> = (0..num_circles).map(|_| {
let width = 60.0 + rng.gen::<f64>() * 200.0;
let dist = 30.0 + rng.gen::<f64>() * 30.0;
(width, dist)
}).collect();
let surf = cairo::Context::new(&ctx.get_target().create_similar(cairo::Content::Alpha, WIDTH, HEIGHT));
surf.save();
let mut max_y = 0.0;
let mut offset = x;
surf.scale(x_scale, 1.0);
surf.set_source_rgba(1.0, 1.0, 1.0, 1.0);
for (width, dist) in vec {
surf.arc(offset, y, width, 0.0, 3.14159 * 2.0);
surf.fill();
offset = offset + width + dist;
max_y = if width > max_y { width } else { max_y };
}
surf.set_source_rgba(0.0, 0.0, 0.0, 0.0);
surf.set_operator(cairo::Operator::Source);
surf.rectangle(x - 260.0, y, offset + 260.0, max_y);
surf.fill();
surf.restore();
surf.set_source_rgba(1.0, 1.0, 1.0, 0.8);
ctx.mask(&cairo::SurfacePattern::create(&surf.get_target()));
}
fn shinedies(ctx: &cairo::Context, rng: &mut rand::ThreadRng) {
let r = rng.gen::<f64>();
for _ in 0..20 {
let surf = cairo::Context::new(&ctx.get_target().create_similar(cairo::Content::Alpha, WIDTH, HEIGHT));
surf.save();
surf.scale(0.5, 0.5);
surf.translate(rng.gen::<f64>() * WIDTH as f64 * 2.0, rng.gen::<f64>() * HEIGHT as f64 * 2.0);
surf.rotate(r);
surf.set_source_rgba(1.0, 1.0, 1.0, 1.0);
let w = 300.0 + rng.gen::<f64>() * 1200.0;
let r = rng.gen::<f64>() * 300.0;
surf.arc(0.0, 0.0, r, 0.0, 3.14159 * 2.0);
surf.fill();
surf.arc(w, 0.0, r, 0.0, 3.14159 * 2.0);
surf.fill();
surf.rectangle(0.0, -r, w, r * 2.0);
surf.fill();
surf.restore();
ctx.set_source_rgba(1.0, 1.0, 1.0, 0.3);
ctx.mask(&cairo::SurfacePattern::create(&surf.get_target()));
}
}
fn stars(ctx: &cairo::Context, rng: &mut rand::ThreadRng) {
ctx.set_source_rgba(1.0, 1.0, 1.0, 0.8);
for _ in 0..200 {
let x = rng.gen::<f64>() * WIDTH as f64;
let y = rng.gen::<f64>() * HEIGHT as f64;
let s = 4.0 + rng.gen::<f64>() * 6.0 as f64;
ctx.arc(x, y, s, 0.0, 3.14159 * 2.0);
ctx.fill();
}
}
fn get_sky_colors(rng: &mut rand::ThreadRng) -> (palette::Rgb, palette::Rgb) {
use palette::{RgbHue, Hsv, Hue};
let default_dark: Hsv = Hsv::from(palette::Rgb::new(0.188, 0.333, 0.51));
let default_light: Hsv = Hsv::from(palette::Rgb::new(0.482, 0.749, 0.839));
let shift = RgbHue::from_radians(rng.gen::<f32>() * 3.14159 * 2.0);
(default_dark.shift_hue(shift).into(), default_light.shift_hue(shift).into())
}
fn main() {
let surf = cairo::ImageSurface::create(
cairo::Format::Rgb24,
WIDTH,
HEIGHT
).unwrap();
let mut rng = rand::thread_rng();
let ctx = cairo::Context::new(&surf);
let w = rng.gen::<u8>() % 3;
ctx.set_source_rgb(
if w == 0 { 0.4 } else { 0.2 },
if w == 1 { 0.4 } else { 0.2 },
if w == 2 { 0.4 } else { 0.2 },
);
ctx.paint();
let g = cairo::LinearGradient::new(
0.0, 0.0, 0.0, HEIGHT as f64
);
let (dark, light) = get_sky_colors(&mut rng);
g.add_color_stop_rgb(0.0, dark.red as f64, dark.green as f64, dark.blue as f64);
g.add_color_stop_rgb(1.0, light.red as f64, light.green as f64, light.blue as f64);
ctx.set_source(&g);
ctx.paint();
stars(&ctx, &mut rng);
for _ in 0..10 {
cloud(&ctx, &mut rng);
}
shinedies(&ctx, &mut rng);
{
let mut f = std::fs::File::create("image.png").unwrap();
surf.write_to_png(&mut f).unwrap();
}
}