[Question] What are x_bounds and y_bounds in Canvas?

[rahulwa]

First time, I am working on any UI app so I don't know much about it. I tried to go through examples but unable to understand what are x or y bounds.
Also hacking on my first Rust project :)
Thanks in advance.

[fdehau]

Those are used to define the viewport of the canvas. Only the points whose coordinates are within the viewport are displayed. When you render the canvas using Frame::render_widget, you give an area to draw the widget to (a Rect) and the crate translates the floating point coordinates to those used by our internal terminal representation.

For example, when we draw the entire world map, the bounds are the ranges for latitude and longitude as floats:

            let canvas = Canvas::default()
                .block(Block::default().borders(Borders::ALL).title("World"))
                .paint(|ctx| {
                    ctx.draw(&Map {
                        color: Color::White,
                        resolution: MapResolution::High,
                    });
                    ctx.print(app.x, -app.y, "You are here", Color::Yellow);
                })
                .x_bounds([-180.0, 180.0])
                .y_bounds([-90.0, 90.0]);
            f.render_widget(canvas, chunks[0]);

If you were to "zoom" to a certain part of the world you may want to choose different bounds.

[gmale]

Great explanation. Is it possible to add that explanation to the docs for x_bounds and y_bounds?

[rishadbaniya]

Great explanation. Is it possible to add that explanation to the docs for x_bounds and y_bounds?

was thinking the same