main.rs

use std::f64::consts::PI;

use gtk::prelude::*;
use gtk::DrawingArea;

use gtk::cairo::{Context, FontSlant, FontWeight};

fn build_ui(application: &gtk::Application) {
    drawable(application, 500, 500, |_, cr| {
        cr.set_dash(&[3., 2., 1.], 1.);
        assert_eq!(cr.dash(), (vec![3., 2., 1.], 1.));

        cr.scale(500f64, 500f64);

        cr.set_source_rgb(250.0 / 255.0, 224.0 / 255.0, 55.0 / 255.0);
        cr.paint().expect("Invalid cairo surface state");

        cr.set_line_width(0.05);

        // border
        cr.set_source_rgb(0.3, 0.3, 0.3);
        cr.rectangle(0.0, 0.0, 1.0, 1.0);
        cr.stroke().expect("Invalid cairo surface state");

        cr.set_line_width(0.03);

        // draw circle
        cr.arc(0.5, 0.5, 0.4, 0.0, PI * 2.);
        cr.stroke().expect("Invalid cairo surface state");

        // mouth
        let mouth_top = 0.68;
        let mouth_width = 0.38;

        let mouth_dx = 0.10;
        let mouth_dy = 0.10;

        cr.move_to(0.50 - mouth_width / 2.0, mouth_top);
        cr.curve_to(
            0.50 - mouth_dx,
            mouth_top + mouth_dy,
            0.50 + mouth_dx,
            mouth_top + mouth_dy,
            0.50 + mouth_width / 2.0,
            mouth_top,
        );

        println!("Extents: {:?}", cr.fill_extents());

        cr.stroke().expect("Invalid cairo surface state");

        let eye_y = 0.38;
        let eye_dx = 0.15;
        cr.arc(0.5 - eye_dx, eye_y, 0.05, 0.0, PI * 2.);
        cr.fill().expect("Invalid cairo surface state");

        cr.arc(0.5 + eye_dx, eye_y, 0.05, 0.0, PI * 2.);
        cr.fill().expect("Invalid cairo surface state");

        glib::Propagation::Proceed
    });

    drawable(application, 500, 500, |_, cr| {
        cr.scale(500f64, 500f64);

        cr.select_font_face("Sans", FontSlant::Normal, FontWeight::Normal);
        cr.set_font_size(0.35);

        cr.move_to(0.04, 0.53);
        cr.show_text("Hello").expect("Invalid cairo surface state");

        cr.move_to(0.27, 0.65);
        cr.text_path("void");
        cr.set_source_rgb(0.5, 0.5, 1.0);
        cr.fill_preserve().expect("Invalid cairo surface state");
        cr.set_source_rgb(0.0, 0.0, 0.0);
        cr.set_line_width(0.01);
        cr.stroke().expect("Invalid cairo surface state");

        cr.set_source_rgba(1.0, 0.2, 0.2, 0.6);
        cr.arc(0.04, 0.53, 0.02, 0.0, PI * 2.);
        cr.arc(0.27, 0.65, 0.02, 0.0, PI * 2.);
        cr.fill().expect("Invalid cairo surface state");

        glib::Propagation::Proceed
    });
}

fn main() {
    let application = gtk::Application::new(
        Some("com.github.gtk-rs.examples.cairotest"),
        Default::default(),
    );

    application.connect_activate(build_ui);

    application.run();
}

pub fn drawable<F>(application: &gtk::Application, width: i32, height: i32, draw_fn: F)
where
    F: Fn(&DrawingArea, &Context) -> glib::Propagation + 'static,
{
    let window = gtk::ApplicationWindow::new(application);
    let drawing_area = DrawingArea::new();

    drawing_area.connect_draw(draw_fn);

    window.set_default_size(width, height);

    window.add(&drawing_area);
    window.show_all();
}