Making a Nannou App that draws a line to the screen.

My model only contains the window itself and a vector of tuples describing the points and color. Similar to this example(under Drawing Lines) I want to use polyline() to draw a vector of (point, color) tuples to the screen. Unlike the example I want the vector to not be generated in the view() function but to be part of the model. (empty update function is added for completeness' sake)

use nannou::prelude::*;

fn main() {
    nannou::app(model).update(update).run();
}

struct Model {
    // so this is a window id called _window -- I guess.
    _window: window::Id,
    my_line: Vec<(Point2, Hsl)>,
}

fn model(app: &App) -> Model {
    let _window = app.new_window().size(512, 512).view(view).build().unwrap();
     // where I define the line that I want to draw to the screen.
    let my_line = vec![
        (pt2(1.3, 2.5), hsl(28.0 / 360.0, 1.0, 0.68)),
        (pt2(-7.0, 2.5), hsl(28.0 / 360.0, 1.0, 0.68)),
    ];
    Model { _window, my_line }
}

fn update(_app: &App, _model: &mut Model, _update: Update) {
    // empty for now
}

The problem is when wanting to draw the line to the screen in the view() function.

fn view(app: &App, _model: &Model, frame: Frame) {
    let draw = app.draw();
    draw.background().color(GRAY);
    draw.polyline().weight(3.0).points_colored(_model.my_line);
    draw.to_frame(app, &frame).unwrap();
}

The compiler tells me something about wanting to move out of my_line but that it is not possible because the copy trait is not implemented.

error[E0507]: cannot move out of `_model.my_line` which is behind a shared reference
  --> src/main.rs:30:48
   |
30 |     draw.polyline().weight(3.0).points_colored(_model.my_line);
   |                                                ^^^^^^^^^^^^^^ move occurs because `_model.my_line` has type `Vec<(Vec2, nannou::prelude::Hsl)>`, which does not implement the `Copy` trait

I am fairly new to rust and do not understand what is going on.

posted over 3 years ago

CC BY-SA 4.0

3y ago

telefza‭

149 reputation 4 2 23 2