Struct image::codecs::png::PngDecoder

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pub struct PngDecoder<R: Read> { /* private fields */ }
Expand description

PNG decoder

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impl<R: Read> PngDecoder<R>

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

Creates a new decoder that decodes from the stream r

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pub fn with_limits(r: R, limits: Limits) -> ImageResult<PngDecoder<R>>

Creates a new decoder that decodes from the stream r with the given limits.

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pub fn apng(self) -> ApngDecoder<R>

Turn this into an iterator over the animation frames.

Reading the complete animation requires more memory than reading the data from the IDAT frame–multiple frame buffers need to be reserved at the same time. We further do not support compositing 16-bit colors. In any case this would be lossy as the interface of animation decoders does not support 16-bit colors.

If something is not supported or a limit is violated then the decoding step that requires them will fail and an error will be returned instead of the frame. No further frames will be returned.

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pub fn is_apng(&self) -> bool

Returns if the image contains an animation.

Note that the file itself decides if the default image is considered to be part of the animation. When it is not the common interpretation is to use it as a thumbnail.

If a non-animated image is converted into an ApngDecoder then its iterator is empty.

Trait Implementations§

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

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type Reader = PngReader<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>

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 scanline_bytes(&self) -> u64

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 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 read_image_with_progress<F: Fn(Progress)>( self, buf: &mut [u8], progress_callback: F ) -> ImageResult<()>

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> RefUnwindSafe for PngDecoder<R>where R: RefUnwindSafe,

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

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

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

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

Blanket Implementations§

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impl<T> Any for Twhere 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 Twhere 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 Twhere 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 Twhere 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, U> TryFrom<U> for Twhere 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 Twhere 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.