Struct png::Reader

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

PNG reader (mostly high-level interface)

Provides a high level that iterates over lines or whole images.

Implementations§

source§

impl<R: Read> Reader<R>

source

pub fn info(&self) -> &Info<'static>

Get information on the image.

The structure will change as new frames of an animated image are decoded.

source

pub fn next_frame( &mut self, buf: &mut [u8], ) -> Result<OutputInfo, DecodingError>

Decodes the next frame into buf.

Note that this decodes raw subframes that need to be mixed according to blend-op and dispose-op by the caller.

The caller must always provide a buffer large enough to hold a complete frame (the APNG specification restricts subframes to the dimensions given in the image header). The region that has been written be checked afterwards by calling info after a successful call and inspecting the frame_control data. This requirement may be lifted in a later version of png.

Output lines will be written in row-major, packed matrix with width and height of the read frame (or subframe), all samples are in big endian byte order where this matters.

source

pub fn next_row(&mut self) -> Result<Option<Row<'_>>, DecodingError>

Returns the next processed row of the image

source

pub fn next_interlaced_row( &mut self, ) -> Result<Option<InterlacedRow<'_>>, DecodingError>

Returns the next processed row of the image

source

pub fn finish(&mut self) -> Result<(), DecodingError>

Read the rest of the image and chunks and finish up, including text chunks or others This will discard the rest of the image if the image is not read already with Reader::next_frame, Reader::next_row or Reader::next_interlaced_row

source

pub fn output_color_type(&self) -> (ColorType, BitDepth)

Returns the color type and the number of bits per sample of the data returned by Reader::next_row and Reader::frames`.

source

pub fn output_buffer_size(&self) -> usize

Returns the number of bytes required to hold a deinterlaced image frame that is decoded using the given input transformations.

source

pub fn output_line_size(&self, width: u32) -> usize

Returns the number of bytes required to hold a deinterlaced row.

Auto Trait Implementations§

§

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

§

impl<R> !RefUnwindSafe for Reader<R>

§

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

§

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

§

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

§

impl<R> !UnwindSafe for Reader<R>

Blanket Implementations§

source§

impl<T> Any for T
where T: 'static + ?Sized,

source§

fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
source§

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

source§

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
source§

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

source§

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

Mutably borrows from an owned value. Read more
source§

impl<T> From<T> for T

source§

fn from(t: T) -> T

Returns the argument unchanged.

source§

impl<T, U> Into<U> for T
where U: From<T>,

source§

fn into(self) -> U

Calls U::from(self).

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

source§

impl<T, U> TryFrom<U> for T
where U: Into<T>,

§

type Error = Infallible

The type returned in the event of a conversion error.
source§

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
source§

impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

§

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

The type returned in the event of a conversion error.
source§

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

Performs the conversion.