Struct image::codecs::jpeg::decoder::JpegDecoder

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pub struct JpegDecoder<R> {
    decoder: Decoder<R>,
    metadata: ImageInfo,
}
Expand description

JPEG decoder

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§decoder: Decoder<R>§metadata: ImageInfo

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impl<R: Read> JpegDecoder<R>

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pub fn new(r: R) -> ImageResult<JpegDecoder<R>>

Create a new decoder that decodes from the stream r

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pub fn scale( &mut self, requested_width: u16, requested_height: u16, ) -> ImageResult<(u16, u16)>

Configure the decoder to scale the image during decoding.

This efficiently scales the image by the smallest supported scale factor that produces an image larger than or equal to the requested size in at least one axis. The currently implemented scale factors are 1/8, 1/4, 1/2 and 1.

To generate a thumbnail of an exact size, pass the desired size and then scale to the final size using a traditional resampling algorithm.

The size of the image to be loaded, with the scale factor applied, is returned.

Trait Implementations§

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impl<'a, R: 'a + Read> ImageDecoder<'a> for JpegDecoder<R>

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type Reader = JpegReader<R>

The type of reader produced by into_reader.
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fn dimensions(&self) -> (u32, u32)

Returns a tuple containing the width and height of the image
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fn color_type(&self) -> ColorType

Returns the color type of the image data produced by this decoder
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fn icc_profile(&mut self) -> Option<Vec<u8>>

Returns the ICC color profile embedded in the image Read more
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fn into_reader(self) -> ImageResult<Self::Reader>

👎Deprecated: Planned for removal. See https://github.com/image-rs/image/issues/1989
Returns a reader that can be used to obtain the bytes of the image. For the best performance, always try to read at least scanline_bytes from the reader at a time. Reading fewer bytes will cause the reader to perform internal buffering.
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fn read_image(self, buf: &mut [u8]) -> ImageResult<()>

Returns all the bytes in the image. Read more
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fn original_color_type(&self) -> ExtendedColorType

Returns the color type of the image file before decoding
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fn total_bytes(&self) -> u64

Returns the total number of bytes in the decoded image. Read more
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fn scanline_bytes(&self) -> u64

👎Deprecated: Planned for removal. See https://github.com/image-rs/image/issues/1989
Returns the minimum number of bytes that can be efficiently read from this decoder. This may be as few as 1 or as many as total_bytes().
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fn read_image_with_progress<F: Fn(Progress)>( self, buf: &mut [u8], progress_callback: F, ) -> ImageResult<()>

👎Deprecated: Use read_image instead. See https://github.com/image-rs/image/issues/1989
Same as read_image but periodically calls the provided callback to give updates on loading progress.
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fn set_limits(&mut self, limits: Limits) -> ImageResult<()>

Set decoding limits for this decoder. See Limits for the different kinds of limits that is possible to set. Read more

Auto Trait Implementations§

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

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

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

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

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

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

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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> 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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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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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, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

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> 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> 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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unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
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unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

Mutably dereferences the given pointer. Read more
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unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.