Struct cosmic::iced_widget::renderer::graphics::image::image_rs::io::Reader

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pub struct Reader<R>
where R: Read,
{ /* private fields */ }
Expand description

A multi-format image reader.

Wraps an input reader to facilitate automatic detection of an image’s format, appropriate decoding method, and dispatches into the set of supported ImageDecoder implementations.

§Usage

Opening a file, deducing the format based on the file path automatically, and trying to decode the image contained can be performed by constructing the reader and immediately consuming it.

let image = Reader::open("path/to/image.png")?
    .decode()?;

It is also possible to make a guess based on the content. This is especially handy if the source is some blob in memory and you have constructed the reader in another way. Here is an example with a pnm black-and-white subformat that encodes its pixel matrix with ascii values.

use std::io::Cursor;
use image::ImageFormat;

let raw_data = b"P1 2 2\n\
    0 1\n\
    1 0\n";

let mut reader = Reader::new(Cursor::new(raw_data))
    .with_guessed_format()
    .expect("Cursor io never fails");
assert_eq!(reader.format(), Some(ImageFormat::Pnm));

let image = reader.decode()?;

As a final fallback or if only a specific format must be used, the reader always allows manual specification of the supposed image format with set_format.

Implementations§

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impl<R> Reader<R>
where R: Read,

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pub fn new(buffered_reader: R) -> Reader<R>

Create a new image reader without a preset format.

Assumes the reader is already buffered. For optimal performance, consider wrapping the reader with a BufReader::new().

It is possible to guess the format based on the content of the read object with with_guessed_format, or to set the format directly with set_format.

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pub fn with_format(buffered_reader: R, format: ImageFormat) -> Reader<R>

Construct a reader with specified format.

Assumes the reader is already buffered. For optimal performance, consider wrapping the reader with a BufReader::new().

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pub fn format(&self) -> Option<ImageFormat>

Get the currently determined format.

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pub fn set_format(&mut self, format: ImageFormat)

Supply the format as which to interpret the read image.

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pub fn clear_format(&mut self)

Remove the current information on the image format.

Note that many operations require format information to be present and will return e.g. an ImageError::Unsupported when the image format has not been set.

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pub fn no_limits(&mut self)

Disable all decoding limits.

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pub fn limits(&mut self, limits: Limits)

Set a custom set of decoding limits.

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pub fn into_inner(self) -> R

Unwrap the reader.

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impl Reader<BufReader<File>>

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pub fn open<P>(path: P) -> Result<Reader<BufReader<File>>, Error>
where P: AsRef<Path>,

Open a file to read, format will be guessed from path.

This will not attempt any io operation on the opened file.

If you want to inspect the content for a better guess on the format, which does not depend on file extensions, follow this call with a call to with_guessed_format.

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impl<R> Reader<R>
where R: BufRead + Seek,

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pub fn with_guessed_format(self) -> Result<Reader<R>, Error>

Make a format guess based on the content, replacing it on success.

Returns Ok with the guess if no io error occurs. Additionally, replaces the current format if the guess was successful. If the guess was unable to determine a format then the current format of the reader is unchanged.

Returns an error if the underlying reader fails. The format is unchanged. The error is a std::io::Error and not ImageError since the only error case is an error when the underlying reader seeks.

When an error occurs, the reader may not have been properly reset and it is potentially hazardous to continue with more io.

§Usage

This supplements the path based type deduction from open with content based deduction. This is more common in Linux and UNIX operating systems and also helpful if the path can not be directly controlled.

let image = Reader::open("image.unknown")?
    .with_guessed_format()?
    .decode()?;
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pub fn into_dimensions(self) -> Result<(u32, u32), ImageError>

Read the image dimensions.

Uses the current format to construct the correct reader for the format.

If no format was determined, returns an ImageError::Unsupported.

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pub fn decode(self) -> Result<DynamicImage, ImageError>

Read the image (replaces load).

Uses the current format to construct the correct reader for the format.

If no format was determined, returns an ImageError::Unsupported.

Auto Trait Implementations§

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impl<R> Freeze for Reader<R>
where R: Freeze,

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impl<R> RefUnwindSafe for Reader<R>
where R: RefUnwindSafe,

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impl<R> Send for Reader<R>
where R: Send,

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impl<R> Sync for Reader<R>
where R: Sync,

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impl<R> Unpin for Reader<R>
where R: Unpin,

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impl<R> UnwindSafe for Reader<R>
where R: UnwindSafe,

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impl<S, D, Swp, Dwp, T> AdaptInto<D, Swp, Dwp, T> for S
where T: Real + Zero + Arithmetics + Clone, Swp: WhitePoint<T>, Dwp: WhitePoint<T>, D: AdaptFrom<S, Swp, Dwp, T>,

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fn adapt_into_using<M>(self, method: M) -> D
where M: TransformMatrix<T>,

Convert the source color to the destination color using the specified method.
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fn adapt_into(self) -> D

Convert the source color to the destination color using the bradford method by default.
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impl<T> Also for T

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fn also<F>(self, block: F) -> Self
where F: FnOnce(&mut Self),

Apply a function to this value and return the (possibly) modified value.
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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T, Res> Apply<Res> for T
where T: ?Sized,

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fn apply<F>(self, f: F) -> Res
where F: FnOnce(Self) -> Res, Self: Sized,

Apply a function which takes the parameter by value.
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fn apply_ref<F>(&self, f: F) -> Res
where F: FnOnce(&Self) -> Res,

Apply a function which takes the parameter by reference.
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fn apply_mut<F>(&mut self, f: F) -> Res
where F: FnOnce(&mut Self) -> Res,

Apply a function which takes the parameter by mutable reference.
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impl<T, C> ArraysFrom<C> for T
where C: IntoArrays<T>,

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fn arrays_from(colors: C) -> T

Cast a collection of colors into a collection of arrays.
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impl<T, C> ArraysInto<C> for T
where C: FromArrays<T>,

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fn arrays_into(self) -> C

Cast this collection of arrays into a collection of colors.
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<WpParam, T, U> Cam16IntoUnclamped<WpParam, T> for U
where T: FromCam16Unclamped<WpParam, U>,

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type Scalar = <T as FromCam16Unclamped<WpParam, U>>::Scalar

The number type that’s used in parameters when converting.
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fn cam16_into_unclamped( self, parameters: BakedParameters<WpParam, <U as Cam16IntoUnclamped<WpParam, T>>::Scalar>, ) -> T

Converts self into C, using the provided parameters.
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impl<T, C> ComponentsFrom<C> for T
where C: IntoComponents<T>,

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fn components_from(colors: C) -> T

Cast a collection of colors into a collection of color components.
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where T: Any,

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fn into_any(self: Box<T>) -> Box<dyn Any>

Convert Box<dyn Trait> (where Trait: Downcast) to Box<dyn Any>. Box<dyn Any> can then be further downcast into Box<ConcreteType> where ConcreteType implements Trait.
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Convert &Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &Any’s vtable from &Trait’s.
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> FromAngle<T> for T

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fn from_angle(angle: T) -> T

Performs a conversion from angle.
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impl<T, U> FromStimulus<U> for T
where U: IntoStimulus<T>,

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fn from_stimulus(other: U) -> T

Converts other into Self, while performing the appropriate scaling, rounding and clamping.
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impl<T> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
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Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T, U> IntoAngle<U> for T
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fn into_angle(self) -> U

Performs a conversion into T.
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impl<WpParam, T, U> IntoCam16Unclamped<WpParam, T> for U
where T: Cam16FromUnclamped<WpParam, U>,

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type Scalar = <T as Cam16FromUnclamped<WpParam, U>>::Scalar

The number type that’s used in parameters when converting.
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fn into_cam16_unclamped( self, parameters: BakedParameters<WpParam, <U as IntoCam16Unclamped<WpParam, T>>::Scalar>, ) -> T

Converts self into C, using the provided parameters.
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impl<T, U> IntoColor<U> for T
where U: FromColor<T>,

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fn into_color(self) -> U

Convert into T with values clamped to the color defined bounds Read more
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impl<T, U> IntoColorUnclamped<U> for T
where U: FromColorUnclamped<T>,

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fn into_color_unclamped(self) -> U

Convert into T. The resulting color might be invalid in its color space Read more
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impl<T> IntoEither for T

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fn into_either(self, into_left: bool) -> Either<Self, Self>

Converts self into a Left variant of Either<Self, Self> if into_left is true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
where F: FnOnce(&Self) -> bool,

Converts self into a Left variant of Either<Self, Self> if into_left(&self) returns true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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impl<T> IntoStimulus<T> for T

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fn into_stimulus(self) -> T

Converts self into T, while performing the appropriate scaling, rounding and clamping.
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impl<T> Pointable for T

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const ALIGN: usize = _

The alignment of pointer.
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type Init = T

The type for initializers.
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unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
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Dereferences the given pointer. Read more
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type Output = T

Should always be Self
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impl<T, C> TryComponentsInto<C> for T
where C: TryFromComponents<T>,

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type Error = <C as TryFromComponents<T>>::Error

The error for when try_into_colors fails to cast.
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fn try_components_into(self) -> Result<C, <T as TryComponentsInto<C>>::Error>

Try to cast this collection of color components into a collection of colors. Read more
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impl<T, U> TryFrom<U> for T
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type Error = Infallible

The type returned in the event of a conversion error.
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Performs the conversion.
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type Error = <U as TryFrom<T>>::Error

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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<T, U> TryIntoColor<U> for T
where U: TryFromColor<T>,

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fn try_into_color(self) -> Result<U, OutOfBounds<U>>

Convert into T, returning ok if the color is inside of its defined range, otherwise an OutOfBounds error is returned which contains the unclamped color. Read more
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impl<C, U> UintsFrom<C> for U
where C: IntoUints<U>,

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fn uints_from(colors: C) -> U

Cast a collection of colors into a collection of unsigned integers.
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impl<C, U> UintsInto<C> for U
where C: FromUints<U>,

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fn uints_into(self) -> C

Cast this collection of unsigned integers into a collection of colors.
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impl<V, T> VZip<V> for T
where V: MultiLane<T>,

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fn vzip(self) -> V

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