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mod interlace_info;
mod read_decoder;
pub(crate) mod stream;
pub(crate) mod transform;
mod unfiltering_buffer;
mod zlib;
use self::read_decoder::{ImageDataCompletionStatus, ReadDecoder};
use self::stream::{DecodeOptions, DecodingError, FormatErrorInner};
use self::transform::{create_transform_fn, TransformFn};
use self::unfiltering_buffer::UnfilteringBuffer;
use std::io::{BufRead, Seek};
use std::mem;
use crate::adam7::Adam7Info;
use crate::common::{
BitDepth, BytesPerPixel, ColorType, Info, ParameterErrorKind, Transformations,
};
use crate::FrameControl;
pub use zlib::{UnfilterBuf, UnfilterRegion};
pub use interlace_info::InterlaceInfo;
use interlace_info::InterlaceInfoIter;
/*
pub enum InterlaceHandling {
/// Outputs the raw rows
RawRows,
/// Fill missing the pixels from the existing ones
Rectangle,
/// Only fill the needed pixels
Sparkle
}
*/
/// Output info.
///
/// This describes one particular frame of the image that was written into the output buffer.
#[derive(Debug, PartialEq, Eq)]
pub struct OutputInfo {
/// The pixel width of this frame.
pub width: u32,
/// The pixel height of this frame.
pub height: u32,
/// The chosen output color type.
pub color_type: ColorType,
/// The chosen output bit depth.
pub bit_depth: BitDepth,
/// The byte count of each scan line in the image.
pub line_size: usize,
}
impl OutputInfo {
/// Returns the size needed to hold a decoded frame
/// If the output buffer was larger then bytes after this count should be ignored. They may
/// still have been changed.
pub fn buffer_size(&self) -> usize {
self.line_size * self.height as usize
}
}
#[derive(Clone, Copy, Debug)]
/// Limits on the resources the `Decoder` is allowed too use
pub struct Limits {
/// maximum number of bytes the decoder is allowed to allocate, default is 64Mib
pub bytes: usize,
}
impl Limits {
pub(crate) fn reserve_bytes(&mut self, bytes: usize) -> Result<(), DecodingError> {
if self.bytes >= bytes {
self.bytes -= bytes;
Ok(())
} else {
Err(DecodingError::LimitsExceeded)
}
}
}
impl Default for Limits {
fn default() -> Limits {
Limits {
bytes: 1024 * 1024 * 64,
}
}
}
/// PNG Decoder
pub struct Decoder<R: BufRead + Seek> {
read_decoder: ReadDecoder<R>,
/// Output transformations
transform: Transformations,
}
/// A row of data with interlace information attached.
#[derive(Clone, Copy, Debug)]
pub struct InterlacedRow<'data> {
data: &'data [u8],
interlace: InterlaceInfo,
}
impl<'data> InterlacedRow<'data> {
pub fn data(&self) -> &'data [u8] {
self.data
}
pub fn interlace(&self) -> &InterlaceInfo {
&self.interlace
}
}
/// A row of data without interlace information.
#[derive(Clone, Copy, Debug)]
pub struct Row<'data> {
data: &'data [u8],
}
impl<'data> Row<'data> {
pub fn data(&self) -> &'data [u8] {
self.data
}
}
impl<R: BufRead + Seek> Decoder<R> {
/// Create a new decoder configuration with default limits.
pub fn new(r: R) -> Decoder<R> {
Decoder::new_with_limits(r, Limits::default())
}
/// Create a new decoder configuration with custom limits.
pub fn new_with_limits(r: R, limits: Limits) -> Decoder<R> {
let mut read_decoder = ReadDecoder::new(r);
read_decoder.set_limits(limits);
Decoder {
read_decoder,
transform: Transformations::IDENTITY,
}
}
/// Create a new decoder configuration with custom [`DecodeOptions`].
pub fn new_with_options(r: R, decode_options: DecodeOptions) -> Decoder<R> {
let mut read_decoder = ReadDecoder::with_options(r, decode_options);
read_decoder.set_limits(Limits::default());
Decoder {
read_decoder,
transform: Transformations::IDENTITY,
}
}
/// Limit resource usage.
///
/// Note that your allocations, e.g. when reading into a pre-allocated buffer, are __NOT__
/// considered part of the limits. Nevertheless, required intermediate buffers such as for
/// singular lines is checked against the limit.
///
/// Note that this is a best-effort basis.
///
/// ```
/// use std::fs::File;
/// use std::io::BufReader;
/// use png::{Decoder, Limits};
/// // This image is 32×32, 1bit per pixel. The reader buffers one row which requires 4 bytes.
/// let mut limits = Limits::default();
/// limits.bytes = 3;
/// let mut decoder = Decoder::new_with_limits(BufReader::new(File::open("tests/pngsuite/basi0g01.png").unwrap()), limits);
/// assert!(decoder.read_info().is_err());
///
/// // This image is 32x32 pixels, so the decoder will allocate less than 10Kib
/// let mut limits = Limits::default();
/// limits.bytes = 10*1024;
/// let mut decoder = Decoder::new_with_limits(BufReader::new(File::open("tests/pngsuite/basi0g01.png").unwrap()), limits);
/// assert!(decoder.read_info().is_ok());
/// ```
pub fn set_limits(&mut self, limits: Limits) {
self.read_decoder.set_limits(limits);
}
/// Read the PNG header and return the information contained within.
///
/// Most image metadata will not be read until [`read_info`] is called, so those fields will be
/// None or empty.
///
/// [`read_info`]: Self::read_info
pub fn read_header_info(&mut self) -> Result<&Info<'static>, DecodingError> {
self.read_decoder.read_header_info()
}
/// Reads all meta data until the first IDAT chunk
pub fn read_info(mut self) -> Result<Reader<R>, DecodingError> {
let info = self.read_header_info()?;
let unfiltering_buffer = UnfilteringBuffer::new(info);
let mut reader = Reader {
decoder: self.read_decoder,
bpp: BytesPerPixel::One,
subframe: SubframeInfo::not_yet_init(),
remaining_frames: 0, // Temporary value - fixed below after reading `acTL` and `fcTL`.
unfiltering_buffer,
transform: self.transform,
transform_fn: None,
scratch_buffer: Vec::new(),
finished: false,
};
// Check if the decoding buffer of a single raw line has a valid size.
//
// FIXME: this check and the next can be delayed until processing image data. This would
// allow usage where only the metadata is processes, or where the image is processed
// line-by-line even on targets that can not fit the whole image into their address space.
// We should strive for a balance between implementation complexity (still ensure that the
// no-overflow preconditions are met for internal calculation) and use possibilities.
if reader.info().checked_raw_row_length().is_none() {
return Err(DecodingError::LimitsExceeded);
}
// Check if the output buffer has a valid size.
//
// FIXME: see above and
if reader.output_buffer_size().is_none() {
return Err(DecodingError::LimitsExceeded);
}
reader.read_until_image_data()?;
reader.remaining_frames = match reader.info().animation_control.as_ref() {
None => 1, // No `acTL` => only expecting `IDAT` frame.
Some(animation) => {
// Note: limited to (2^32 - 1) frames by the APNG spec so addition does not
// overflow on 32-bit targets nor 64-bit targets.
let mut num_frames = animation.num_frames;
if reader.info().frame_control.is_none() {
// No `fcTL` before `IDAT` => `IDAT` is not part of the animation, but
// represents an *extra*, default frame for non-APNG-aware decoders.
num_frames += 1;
}
num_frames
}
};
Ok(reader)
}
/// Set the allowed and performed transformations.
///
/// A transformation is a pre-processing on the raw image data modifying content or encoding.
/// Many options have an impact on memory or CPU usage during decoding.
pub fn set_transformations(&mut self, transform: Transformations) {
self.transform = transform;
}
/// Set the decoder to ignore all text chunks while parsing.
///
/// eg.
/// ```
/// use std::fs::File;
/// use std::io::BufReader;
/// use png::Decoder;
/// let mut decoder = Decoder::new(BufReader::new(File::open("tests/pngsuite/basi0g01.png").unwrap()));
/// decoder.set_ignore_text_chunk(true);
/// assert!(decoder.read_info().is_ok());
/// ```
pub fn set_ignore_text_chunk(&mut self, ignore_text_chunk: bool) {
self.read_decoder.set_ignore_text_chunk(ignore_text_chunk);
}
/// Set the decoder to ignore iccp chunks while parsing.
///
/// eg.
/// ```
/// use std::fs::File;
/// use std::io::BufReader;
/// use png::Decoder;
/// let mut decoder = Decoder::new(BufReader::new(File::open("tests/iccp/broken_iccp.png").unwrap()));
/// decoder.set_ignore_iccp_chunk(true);
/// assert!(decoder.read_info().is_ok());
/// ```
pub fn set_ignore_iccp_chunk(&mut self, ignore_iccp_chunk: bool) {
self.read_decoder.set_ignore_iccp_chunk(ignore_iccp_chunk);
}
/// Set the decoder to ignore and not verify the Adler-32 checksum
/// and CRC code.
pub fn ignore_checksums(&mut self, ignore_checksums: bool) {
self.read_decoder.ignore_checksums(ignore_checksums);
}
}
/// PNG reader (mostly high-level interface)
///
/// Provides a high level that iterates over lines or whole images.
pub struct Reader<R: BufRead + Seek> {
decoder: ReadDecoder<R>,
bpp: BytesPerPixel,
subframe: SubframeInfo,
/// How many frames remain to be decoded. Decremented after each `IDAT` or `fdAT` sequence.
remaining_frames: u32,
/// Buffer with not-yet-`unfilter`-ed image rows
unfiltering_buffer: UnfilteringBuffer,
/// Output transformations
transform: Transformations,
/// Function that can transform decompressed, unfiltered rows into final output.
/// See the `transform.rs` module for more details.
transform_fn: Option<TransformFn>,
/// This buffer is only used so that `next_row` and `next_interlaced_row` can return reference
/// to a byte slice. In a future version of this library, this buffer will be removed and
/// `next_row` and `next_interlaced_row` will write directly into a user provided output buffer.
scratch_buffer: Vec<u8>,
/// Whether `ImageEnd` was already reached by `fn finish`.
finished: bool,
}
/// The subframe specific information.
///
/// In APNG the frames are constructed by combining previous frame and a new subframe (through a
/// combination of `dispose_op` and `overlay_op`). These sub frames specify individual dimension
/// information and reuse the global interlace options. This struct encapsulates the state of where
/// in a particular IDAT-frame or subframe we are.
struct SubframeInfo {
width: u32,
height: u32,
rowlen: usize,
current_interlace_info: Option<InterlaceInfo>,
interlace_info_iter: InterlaceInfoIter,
consumed_and_flushed: bool,
}
impl<R: BufRead + Seek> Reader<R> {
/// Advances to the start of the next animation frame and
/// returns a reference to the [`FrameControl`] info that describes it.
/// Skips and discards the image data of the previous frame if necessary.
///
/// Returns a [`ParameterError`] when there are no more animation frames.
/// To avoid this the caller can check if [`Info::animation_control`] exists
/// and consult [`AnimationControl::num_frames`].
///
/// [`ParameterError`]: crate::ParameterError
/// [`AnimationControl::num_frames`]: crate::AnimationControl::num_frames
pub fn next_frame_info(&mut self) -> Result<&FrameControl, DecodingError> {
let remaining_frames = if self.subframe.consumed_and_flushed {
self.remaining_frames
} else {
// One remaining frame will be consumed by the `finish_decoding` call below.
self.remaining_frames - 1
};
if remaining_frames == 0 {
return Err(DecodingError::Parameter(
ParameterErrorKind::PolledAfterEndOfImage.into(),
));
}
if !self.subframe.consumed_and_flushed {
self.subframe.current_interlace_info = None;
self.finish_decoding()?;
}
self.read_until_image_data()?;
// The PNG standard (and `StreamingDecoder `) guarantes that there is an `fcTL` chunk
// before the start of image data in a sequence of `fdAT` chunks. Therefore `unwrap`
// below is guaranteed to not panic.
Ok(self.info().frame_control.as_ref().unwrap())
}
/// Reads all meta data until the next frame data starts.
/// Requires IHDR before the IDAT and fcTL before fdAT.
fn read_until_image_data(&mut self) -> Result<(), DecodingError> {
self.decoder.read_until_image_data()?;
self.subframe = SubframeInfo::new(self.info());
self.bpp = self.info().bpp_in_prediction();
let frame_bytes = if self.info().interlaced {
let mut bytes = 0u64;
for pass in crate::adam7::PassConstants::PASSES {
bytes += self
.info()
.raw_row_length_from_width(pass.count_samples(self.subframe.width))
as u64
* pass.count_lines(self.subframe.height) as u64;
}
bytes
} else {
(self.subframe.rowlen as u64) * self.subframe.height as u64
};
self.unfiltering_buffer.start_frame(frame_bytes);
// Allocate output buffer.
let buflen = self.unguarded_output_line_size(self.subframe.width);
self.decoder.reserve_bytes(buflen)?;
Ok(())
}
/// Get information on the image.
///
/// The structure will change as new frames of an animated image are decoded.
pub fn info(&self) -> &Info<'static> {
self.decoder.info().unwrap()
}
/// 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 [`Reader::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.
pub fn next_frame(&mut self, buf: &mut [u8]) -> Result<OutputInfo, DecodingError> {
if self.remaining_frames == 0 {
return Err(DecodingError::Parameter(
ParameterErrorKind::PolledAfterEndOfImage.into(),
));
} else if self.subframe.consumed_and_flushed {
// Advance until the next `fdAT`
// (along the way we should encounter the fcTL for this frame).
self.read_until_image_data()?;
}
// Note that we only check if the buffer size calculation holds in a call to decoding the
// frame. Consequently, we can represent the `Info` and frameless decoding even when the
// target architecture's address space is too small for a frame. However reading the actual
let required_len = self
.output_buffer_size()
.ok_or(DecodingError::LimitsExceeded)?;
if buf.len() < required_len {
return Err(DecodingError::Parameter(
ParameterErrorKind::ImageBufferSize {
expected: required_len,
actual: buf.len(),
}
.into(),
));
}
let (color_type, bit_depth) = self.output_color_type();
let output_info = OutputInfo {
width: self.subframe.width,
height: self.subframe.height,
color_type,
bit_depth,
line_size: self.unguarded_output_line_size(self.subframe.width),
};
if self.info().interlaced {
let stride = self.unguarded_output_line_size(self.info().width);
let samples = color_type.samples() as u8;
let bits_pp = samples * (bit_depth as u8);
let expand = crate::adam7::expand_pass;
while let Some(InterlacedRow {
data: row,
interlace,
..
}) = self.next_interlaced_row()?
{
// `unwrap` won't panic, because we checked `self.info().interlaced` above.
let adam7info = interlace.get_adam7_info().unwrap();
expand(buf, stride, row, adam7info, bits_pp);
}
} else {
let current_interlace_info = self.subframe.current_interlace_info.as_ref();
let already_done_rows = current_interlace_info
.map(|info| info.line_number())
.unwrap_or(self.subframe.height);
for row in buf
.chunks_exact_mut(output_info.line_size)
.take(self.subframe.height as usize)
.skip(already_done_rows as usize)
{
self.next_interlaced_row_impl(self.subframe.rowlen, row)?;
}
}
// Advance over the rest of data for this (sub-)frame.
self.finish_decoding()?;
Ok(output_info)
}
fn mark_subframe_as_consumed_and_flushed(&mut self) {
assert!(self.remaining_frames > 0);
self.remaining_frames -= 1;
self.subframe.consumed_and_flushed = true;
}
/// Advance over the rest of data for this (sub-)frame.
/// Called after decoding the last row of a frame.
fn finish_decoding(&mut self) -> Result<(), DecodingError> {
// Double-check that all rows of this frame have been decoded (i.e. that the potential
// `finish_decoding` call below won't be discarding any data).
assert!(self.subframe.current_interlace_info.is_none());
// Discard the remaining data in the current sequence of `IDAT` or `fdAT` chunks.
if !self.subframe.consumed_and_flushed {
self.decoder.finish_decoding_image_data()?;
self.mark_subframe_as_consumed_and_flushed();
}
Ok(())
}
/// Returns the next processed row of the image (discarding [`InterlaceInfo`]).
///
/// See also [`Reader::read_row`], which reads into a caller-provided buffer.
pub fn next_row(&mut self) -> Result<Option<Row<'_>>, DecodingError> {
self.next_interlaced_row()
.map(|v| v.map(|v| Row { data: v.data }))
}
/// Returns the next processed row of the image.
///
/// See also [`Reader::read_row`], which reads into a caller-provided buffer.
pub fn next_interlaced_row(&mut self) -> Result<Option<InterlacedRow<'_>>, DecodingError> {
let mut output_buffer = mem::take(&mut self.scratch_buffer);
let max_line_size = self
.output_line_size(self.info().width)
.ok_or(DecodingError::LimitsExceeded)?;
output_buffer.resize(max_line_size, 0u8);
let result = self.read_row(&mut output_buffer);
self.scratch_buffer = output_buffer;
result.map(move |option| {
option.map(move |interlace| {
let output_line_size = self.output_line_size_for_interlace_info(&interlace);
InterlacedRow {
data: &self.scratch_buffer[..output_line_size],
interlace,
}
})
})
}
/// Reads the next row of the image into the provided `output_buffer`.
/// `Ok(None)` will be returned if the current image frame has no more rows.
///
/// `output_buffer` needs to be long enough to accommodate [`Reader::output_line_size`] for
/// [`Info::width`] (initial interlaced rows may need less than that).
///
/// See also [`Reader::next_row`] and [`Reader::next_interlaced_row`], which read into a
/// `Reader`-owned buffer.
pub fn read_row(
&mut self,
output_buffer: &mut [u8],
) -> Result<Option<InterlaceInfo>, DecodingError> {
let interlace = match self.subframe.current_interlace_info.as_ref() {
None => {
self.finish_decoding()?;
return Ok(None);
}
Some(interlace) => *interlace,
};
if interlace.line_number() == 0 {
self.unfiltering_buffer.reset_prev_row();
}
let rowlen = match interlace {
InterlaceInfo::Null(_) => self.subframe.rowlen,
InterlaceInfo::Adam7(Adam7Info { samples: width, .. }) => {
self.info().raw_row_length_from_width(width)
}
};
let output_line_size = self.output_line_size_for_interlace_info(&interlace);
let output_buffer = &mut output_buffer[..output_line_size];
self.next_interlaced_row_impl(rowlen, output_buffer)?;
Ok(Some(interlace))
}
fn output_line_size_for_interlace_info(&self, interlace: &InterlaceInfo) -> usize {
let width = match interlace {
InterlaceInfo::Adam7(Adam7Info { samples: width, .. }) => *width,
InterlaceInfo::Null(_) => self.subframe.width,
};
self.unguarded_output_line_size(width)
}
/// 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`]
pub fn finish(&mut self) -> Result<(), DecodingError> {
if self.finished {
return Err(DecodingError::Parameter(
ParameterErrorKind::PolledAfterEndOfImage.into(),
));
}
self.remaining_frames = 0;
self.decoder.read_until_end_of_input()?;
self.finished = true;
Ok(())
}
/// Fetch the next interlaced row and filter it according to our own transformations.
fn next_interlaced_row_impl(
&mut self,
rowlen: usize,
output_buffer: &mut [u8],
) -> Result<(), DecodingError> {
self.next_raw_interlaced_row(rowlen)?;
let row = self.unfiltering_buffer.prev_row();
assert_eq!(row.len(), rowlen - 1);
// Apply transformations and write resulting data to buffer.
let transform_fn = {
if self.transform_fn.is_none() {
self.transform_fn = Some(create_transform_fn(self.info(), self.transform)?);
}
self.transform_fn.as_deref().unwrap()
};
transform_fn(row, output_buffer, self.info());
self.subframe.current_interlace_info = self.subframe.interlace_info_iter.next();
Ok(())
}
/// Returns the color type and the number of bits per sample
/// of the data returned by [`Reader::next_row`] and [`Reader::next_frame`].
pub fn output_color_type(&self) -> (ColorType, BitDepth) {
use crate::common::ColorType::*;
let t = self.transform;
let info = self.info();
if t == Transformations::IDENTITY {
(info.color_type, info.bit_depth)
} else {
let bits = match info.bit_depth as u8 {
16 if t.intersects(Transformations::STRIP_16) => 8,
n if n < 8
&& (t.contains(Transformations::EXPAND)
|| t.contains(Transformations::ALPHA)) =>
{
8
}
n => n,
};
let color_type =
if t.contains(Transformations::EXPAND) || t.contains(Transformations::ALPHA) {
let has_trns = info.trns.is_some() || t.contains(Transformations::ALPHA);
match info.color_type {
Grayscale if has_trns => GrayscaleAlpha,
Rgb if has_trns => Rgba,
Indexed if has_trns => Rgba,
Indexed => Rgb,
ct => ct,
}
} else {
info.color_type
};
(color_type, BitDepth::from_u8(bits).unwrap())
}
}
/// Return the number of bytes required to hold a deinterlaced image frame that is decoded
/// using the given input transformations.
///
/// Returns `None` if the output buffer does not fit into the memory space of the machine,
/// otherwise returns the byte length in `Some`. The length is smaller than [`isize::MAX`].
pub fn output_buffer_size(&self) -> Option<usize> {
let (width, height) = self.info().size();
let (color, depth) = self.output_color_type();
// The subtraction should always work, but we do this for consistency. Also note that by
// calling `checked_raw_row_length` the row buffer is guaranteed to work whereas if we
// ran other function that didn't include the filter byte that could later fail on an image
// that is `1xN`...
let linelen = color.checked_raw_row_length(depth, width)?.checked_sub(1)?;
let height = usize::try_from(height).ok()?;
let imglen = linelen.checked_mul(height)?;
// Ensure that it fits into address space not only `usize` to allocate.
(imglen <= isize::MAX as usize).then_some(imglen)
}
/// Returns the number of bytes required to hold a deinterlaced row.
pub(crate) fn unguarded_output_line_size(&self, width: u32) -> usize {
let (color, depth) = self.output_color_type();
color.raw_row_length_from_width(depth, width) - 1
}
/// Returns the number of bytes required to hold a deinterlaced row.
///
/// Returns `None` if the output buffer does not fit into the memory space of the machine,
/// otherwise returns the byte length in `Some`. The length is smaller than [`isize::MAX`].
pub fn output_line_size(&self, width: u32) -> Option<usize> {
let (color, depth) = self.output_color_type();
let length = color.checked_raw_row_length(depth, width)?.checked_sub(1)?;
// Ensure that it fits into address space not only `usize` to allocate.
(length <= isize::MAX as usize).then_some(length)
}
/// Unfilter the next raw interlaced row into `self.unfiltering_buffer`.
fn next_raw_interlaced_row(&mut self, rowlen: usize) -> Result<(), DecodingError> {
// Read image data until we have at least one full row (but possibly more than one).
while self.unfiltering_buffer.mutable_len_of_curr_row() < rowlen {
if self.subframe.consumed_and_flushed {
return Err(DecodingError::Format(
FormatErrorInner::NoMoreImageData.into(),
));
}
assert!(self.unfiltering_buffer.remaining_bytes() > 0);
let completion_status = self
.unfiltering_buffer
.with_unfilled_buffer(|buffer| self.decoder.decode_image_data(Some(buffer)));
match completion_status {
Ok(ImageDataCompletionStatus::ExpectingMoreData) => (),
Ok(ImageDataCompletionStatus::Done) => self.mark_subframe_as_consumed_and_flushed(),
Err(DecodingError::IoError(e))
if e.kind() == std::io::ErrorKind::UnexpectedEof
&& self.unfiltering_buffer.readable_len_of_curr_row() >= rowlen =>
{
return self
.unfiltering_buffer
.unfilter_curr_row_using_scratch_buffer(rowlen, self.bpp);
}
Err(other_error) => return Err(other_error),
}
}
self.unfiltering_buffer
.unfilter_curr_row_in_place(rowlen, self.bpp)
}
}
impl SubframeInfo {
fn not_yet_init() -> Self {
SubframeInfo {
width: 0,
height: 0,
rowlen: 0,
current_interlace_info: None,
interlace_info_iter: InterlaceInfoIter::empty(),
consumed_and_flushed: false,
}
}
fn new(info: &Info) -> Self {
// The apng fctnl overrides width and height.
// All other data is set by the main info struct.
let (width, height) = if let Some(fc) = info.frame_control {
(fc.width, fc.height)
} else {
(info.width, info.height)
};
let mut interlace_info_iter = InterlaceInfoIter::new(width, height, info.interlaced);
let current_interlace_info = interlace_info_iter.next();
SubframeInfo {
width,
height,
rowlen: info.raw_row_length_from_width(width),
current_interlace_info,
interlace_info_iter,
consumed_and_flushed: false,
}
}
}