When it comes to specifying the size of the canvas, I firmly believe that CSS provides superior tools compared to JavaScript or HTML. CSS should be the primary driver for styling decisions, with HTML serving a supportive role especially in scenarios where adjustments need to be made within the canvas dimensions.
CSS introduces the !important rule which allows for overriding other styling rules, including those defined in HTML. While typically discouraged, using this method as a workaround can be deemed justifiable in certain cases.
In working with Rust module for WebAssembly, a practical approach involves:
fn update_buffer(canvas: &HtmlCanvasElement) {
canvas.set_width(canvas.client_width() as u32);
canvas.set_height(canvas.client_height() as u32);
}
//..
#[wasm_bindgen(start)]
pub fn start() -> Result<(), JsValue> {
// ...
let canvas: Rc<_> = document
.query_selector("canvas")
.unwrap()
.unwrap()
.dyn_into::<HtmlCanvasElement>()
.unwrap()
.into();
update_buffer(&canvas);
// ...
// create resizing handler for window
{
let on_resize = Closure::<dyn FnMut(_)>::new(move |_event: Event| {
let canvas = canvas.clone();
// ...
update_buffer(&canvas);
// ...
window.add_event_listener_with_callback("resize", on_resize.as_ref().unchecked_ref())?;
on_resize.forget();
}
}
The canvas buffer is dynamically updated upon the loading of the WASM module and whenever the window undergoes a resize event. This involves setting the canvas width and height based on the current values of clientWidth and clientHeight. While alternative solutions may exist, this method stands out due to:
- Dependency on CSS for element styling rather than HTML markup.
- Adaptable to different sizing contexts, such as when canvas elements are part of flex or grid layouts, unlike approaches relying solely on style manipulation.
- A holistic handling of both initial sizing and subsequent resizing, offering a comprehensive solution.
- Embracing the promising future prospects of WebAssembly (WASM).
Note: The frequent use of .unwrap() in Rust denotes an explicit handling of potential errors during execution.
Furthermore,
{
let on_resize = Closure::<dyn FnMut(_)>::new(move |_event: Event| {
let canvas = canvas.clone();
// ...
update_buffer(&canvas);
// ...
window.add_event_listener_with_callback("resize", on_resize.as_ref().unchecked_ref())?;
on_resize.forget();
}
This block of code could be streamlined using more sophisticated libraries, for example:
add_resize_handler(&window, move |e: ResizeEvent| {
let canvas = canvas.clone();
// ...
update_buffer(&canvas);
})