ducartes/src/view/picker.rs

use gdk;
use gtk::{
    self,
    WidgetExt
};
use std::cell::RefCell;
use std::rc::Rc;

pub struct Picker {
    pub canvas: gtk::DrawingArea,
    pub mouse_loc: Rc<RefCell<Option<(i32, i32)>>>,
}

impl Picker {
    pub fn new() -> Picker {
        let canvas = gtk::DrawingArea::new();
        let mouse_loc = Rc::new(RefCell::new(Some((2, 2))));
        let reader_mouse = mouse_loc.clone();
        let writer_mouse = mouse_loc.clone();

        canvas.connect_draw(move |cv, ctx| {
            let w = cv.get_allocated_width();
            let h = cv.get_allocated_height();
            ctx.set_source_rgb(1.0, 1.0, 1.0);
            ctx.rectangle(0.0, 0.0, w as f64, h as f64);
            ctx.fill();

            reader_mouse.borrow().map(|(x, y)| {
                ctx.set_source_rgb(0.9, 0.9, 0.9);
                ctx.rectangle(
                    x as f64 * 32.0,
                    y as f64 * 32.0,
                    32.0,
                    32.0,
                );
                ctx.fill();
            });
            gtk::Inhibit(false)
        });

        canvas.connect_motion_notify_event(move |cv, motion| {
            let (x, y) = motion.get_position();
            *writer_mouse.borrow_mut() =
                Some((x as i32 / 32, y as i32 / 32));
            cv.queue_draw();
            gtk::Inhibit(false)
        });

        canvas.add_events(gdk::POINTER_MOTION_MASK.bits() as i32);

        Picker {
            canvas,
            mouse_loc,
        }
    }
}