Struct canvas::CanvasReuseError

pub struct CanvasReuseError<P: AsBytes + FromBytes> { /* fields omitted */ }

Error representation for a failed buffer reuse for a canvas.

Emitted as a result of Canvas::from_rec when the buffer capacity is not large enough to serve as an image of requested layout with causing a reallocation.

It is possible to retrieve the buffer that cause the failure with into_rec. This allows one to manually try to correct the error with additional checks, or implement a fallback strategy which does not require the interpretation as a full image.

let rec = Rec::<u8>::new(16);
let allocation = rec.as_bytes().as_ptr();

let bad_layout = Layout::width_and_height(rec.capacity() + 1, 1).unwrap();
let error = match Canvas::from_reused_rec(rec, bad_layout) {
    Ok(_) => unreachable!("The layout requires one too many pixels"),
    Err(error) => error,
};

// Get back the original buffer.
let rec = error.into_rec();
assert_eq!(rec.as_bytes().as_ptr(), allocation);

Methods

impl<P: AsBytes + FromBytes> CanvasReuseError<P>

pub fn into_rec(self) -> Rec<P>

Unwrap the original buffer.

Trait Implementations

impl<P: AsBytes + FromBytes> Debug for CanvasReuseError<P>

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.

impl<P: Eq + AsBytes + FromBytes> Eq for CanvasReuseError<P>

impl<P: PartialEq + AsBytes + FromBytes> PartialEq<CanvasReuseError<P>> for CanvasReuseError<P>

fn eq(&self, other: &CanvasReuseError<P>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &CanvasReuseError<P>) -> bool

This method tests for !=.

impl<P: AsBytes + FromBytes> StructuralEq for CanvasReuseError<P>

impl<P: AsBytes + FromBytes> StructuralPartialEq for CanvasReuseError<P>