Struct image::codecs::png::PngDecoder
source · pub struct PngDecoder<R: Read> { /* private fields */ }
Expand description
PNG decoder
Implementations§
source§impl<R: Read> PngDecoder<R>
impl<R: Read> PngDecoder<R>
sourcepub fn new(r: R) -> ImageResult<PngDecoder<R>>
pub fn new(r: R) -> ImageResult<PngDecoder<R>>
Creates a new decoder that decodes from the stream r
sourcepub fn with_limits(r: R, limits: Limits) -> ImageResult<PngDecoder<R>>
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.
sourcepub fn gamma_value(&self) -> ImageResult<Option<f64>>
pub fn gamma_value(&self) -> ImageResult<Option<f64>>
Returns the gamma value of the image or None if no gamma value is indicated.
If an sRGB chunk is present this method returns a gamma value of 0.45455 and ignores the value in the gAMA chunk. This is the recommended behavior according to the PNG standard:
When the sRGB chunk is present, […] decoders that recognize the sRGB chunk but are not capable of colour management are recommended to ignore the gAMA and cHRM chunks, and use the values given above as if they had appeared in gAMA and cHRM chunks.
sourcepub fn apng(self) -> ApngDecoder<R>
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.
sourcepub fn is_apng(&self) -> bool
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§
source§impl<'a, R: 'a + Read> ImageDecoder<'a> for PngDecoder<R>
impl<'a, R: 'a + Read> ImageDecoder<'a> for PngDecoder<R>
source§fn dimensions(&self) -> (u32, u32)
fn dimensions(&self) -> (u32, u32)
source§fn color_type(&self) -> ColorType
fn color_type(&self) -> ColorType
source§fn icc_profile(&mut self) -> Option<Vec<u8>>
fn icc_profile(&mut self) -> Option<Vec<u8>>
source§fn into_reader(self) -> ImageResult<Self::Reader>
fn into_reader(self) -> ImageResult<Self::Reader>
scanline_bytes
from the reader at a time. Reading
fewer bytes will cause the reader to perform internal buffering.source§fn read_image(self, buf: &mut [u8]) -> ImageResult<()>
fn read_image(self, buf: &mut [u8]) -> ImageResult<()>
source§fn scanline_bytes(&self) -> u64
fn scanline_bytes(&self) -> u64
total_bytes()
.source§fn set_limits(&mut self, limits: Limits) -> ImageResult<()>
fn set_limits(&mut self, limits: Limits) -> ImageResult<()>
source§fn original_color_type(&self) -> ExtendedColorType
fn original_color_type(&self) -> ExtendedColorType
source§fn total_bytes(&self) -> u64
fn total_bytes(&self) -> u64
source§fn read_image_with_progress<F: Fn(Progress)>(
self,
buf: &mut [u8],
progress_callback: F,
) -> ImageResult<()>
fn read_image_with_progress<F: Fn(Progress)>( self, buf: &mut [u8], progress_callback: F, ) -> ImageResult<()>
read_image
but periodically calls the provided callback to give updates on loading
progress.