diff options
Diffstat (limited to 'vendor/image/src/codecs/webp/extended.rs')
| -rw-r--r-- | vendor/image/src/codecs/webp/extended.rs | 839 |
1 files changed, 0 insertions, 839 deletions
diff --git a/vendor/image/src/codecs/webp/extended.rs b/vendor/image/src/codecs/webp/extended.rs deleted file mode 100644 index 3dc6b34..0000000 --- a/vendor/image/src/codecs/webp/extended.rs +++ /dev/null @@ -1,839 +0,0 @@ -use std::convert::TryInto; -use std::io::{self, Cursor, Error, Read}; -use std::{error, fmt}; - -use super::decoder::{ - read_chunk, read_fourcc, read_len_cursor, DecoderError::ChunkHeaderInvalid, WebPRiffChunk, -}; -use super::lossless::{LosslessDecoder, LosslessFrame}; -use super::vp8::{Frame as VP8Frame, Vp8Decoder}; -use crate::error::{DecodingError, ParameterError, ParameterErrorKind}; -use crate::image::ImageFormat; -use crate::{ - ColorType, Delay, Frame, Frames, ImageError, ImageResult, Rgb, RgbImage, Rgba, RgbaImage, -}; -use byteorder::{LittleEndian, ReadBytesExt}; - -//all errors that can occur while parsing extended chunks in a WebP file -#[derive(Debug, Clone, Copy)] -enum DecoderError { - // Some bits were invalid - InfoBitsInvalid { name: &'static str, value: u32 }, - // Alpha chunk doesn't match the frame's size - AlphaChunkSizeMismatch, - // Image is too large, either for the platform's pointer size or generally - ImageTooLarge, - // Frame would go out of the canvas - FrameOutsideImage, -} - -impl fmt::Display for DecoderError { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - match self { - DecoderError::InfoBitsInvalid { name, value } => f.write_fmt(format_args!( - "Info bits `{}` invalid, received value: {}", - name, value - )), - DecoderError::AlphaChunkSizeMismatch => { - f.write_str("Alpha chunk doesn't match the size of the frame") - } - DecoderError::ImageTooLarge => f.write_str("Image is too large to be decoded"), - DecoderError::FrameOutsideImage => { - f.write_str("Frame is too large and would go outside the image") - } - } - } -} - -impl From<DecoderError> for ImageError { - fn from(e: DecoderError) -> ImageError { - ImageError::Decoding(DecodingError::new(ImageFormat::WebP.into(), e)) - } -} - -impl error::Error for DecoderError {} - -#[derive(Debug, Clone)] -pub(crate) struct WebPExtendedInfo { - _icc_profile: bool, - _alpha: bool, - _exif_metadata: bool, - _xmp_metadata: bool, - _animation: bool, - canvas_width: u32, - canvas_height: u32, - icc_profile: Option<Vec<u8>>, -} - -#[derive(Debug)] -enum ExtendedImageData { - Animation { - frames: Vec<AnimatedFrame>, - anim_info: WebPAnimatedInfo, - }, - Static(WebPStatic), -} - -#[derive(Debug)] -pub(crate) struct ExtendedImage { - info: WebPExtendedInfo, - image: ExtendedImageData, -} - -impl ExtendedImage { - pub(crate) fn dimensions(&self) -> (u32, u32) { - (self.info.canvas_width, self.info.canvas_height) - } - - pub(crate) fn has_animation(&self) -> bool { - self.info._animation - } - - pub(crate) fn icc_profile(&self) -> Option<Vec<u8>> { - self.info.icc_profile.clone() - } - - pub(crate) fn color_type(&self) -> ColorType { - match &self.image { - ExtendedImageData::Animation { frames, .. } => &frames[0].image, - ExtendedImageData::Static(image) => image, - } - .color_type() - } - - pub(crate) fn into_frames<'a>(self) -> Frames<'a> { - struct FrameIterator { - image: ExtendedImage, - index: usize, - canvas: RgbaImage, - } - - impl Iterator for FrameIterator { - type Item = ImageResult<Frame>; - - fn next(&mut self) -> Option<Self::Item> { - if let ExtendedImageData::Animation { frames, anim_info } = &self.image.image { - let frame = frames.get(self.index); - match frame { - Some(anim_image) => { - self.index += 1; - ExtendedImage::draw_subimage( - &mut self.canvas, - anim_image, - anim_info.background_color, - ) - } - None => None, - } - } else { - None - } - } - } - - let width = self.info.canvas_width; - let height = self.info.canvas_height; - let background_color = - if let ExtendedImageData::Animation { ref anim_info, .. } = self.image { - anim_info.background_color - } else { - Rgba([0, 0, 0, 0]) - }; - - let frame_iter = FrameIterator { - image: self, - index: 0, - canvas: RgbaImage::from_pixel(width, height, background_color), - }; - - Frames::new(Box::new(frame_iter)) - } - - pub(crate) fn read_extended_chunks<R: Read>( - reader: &mut R, - mut info: WebPExtendedInfo, - ) -> ImageResult<ExtendedImage> { - let mut anim_info: Option<WebPAnimatedInfo> = None; - let mut anim_frames: Vec<AnimatedFrame> = Vec::new(); - let mut static_frame: Option<WebPStatic> = None; - //go until end of file and while chunk headers are valid - while let Some((mut cursor, chunk)) = read_extended_chunk(reader)? { - match chunk { - WebPRiffChunk::EXIF | WebPRiffChunk::XMP => { - //ignore these chunks - } - WebPRiffChunk::ANIM => { - if anim_info.is_none() { - anim_info = Some(Self::read_anim_info(&mut cursor)?); - } - } - WebPRiffChunk::ANMF => { - let frame = read_anim_frame(cursor, info.canvas_width, info.canvas_height)?; - anim_frames.push(frame); - } - WebPRiffChunk::ALPH => { - if static_frame.is_none() { - let alpha_chunk = - read_alpha_chunk(&mut cursor, info.canvas_width, info.canvas_height)?; - - let vp8_frame = read_lossy_with_chunk(reader)?; - - let img = WebPStatic::from_alpha_lossy(alpha_chunk, vp8_frame)?; - - static_frame = Some(img); - } - } - WebPRiffChunk::ICCP => { - let mut icc_profile = Vec::new(); - cursor.read_to_end(&mut icc_profile)?; - info.icc_profile = Some(icc_profile); - } - WebPRiffChunk::VP8 => { - if static_frame.is_none() { - let vp8_frame = read_lossy(cursor)?; - - let img = WebPStatic::from_lossy(vp8_frame)?; - - static_frame = Some(img); - } - } - WebPRiffChunk::VP8L => { - if static_frame.is_none() { - let mut lossless_decoder = LosslessDecoder::new(cursor); - let frame = lossless_decoder.decode_frame()?; - let image = WebPStatic::Lossless(frame.clone()); - - static_frame = Some(image); - } - } - _ => return Err(ChunkHeaderInvalid(chunk.to_fourcc()).into()), - } - } - - let image = if let Some(info) = anim_info { - if anim_frames.is_empty() { - return Err(ImageError::IoError(Error::from( - io::ErrorKind::UnexpectedEof, - ))); - } - ExtendedImageData::Animation { - frames: anim_frames, - anim_info: info, - } - } else if let Some(frame) = static_frame { - ExtendedImageData::Static(frame) - } else { - //reached end of file too early before image data was reached - return Err(ImageError::IoError(Error::from( - io::ErrorKind::UnexpectedEof, - ))); - }; - - let image = ExtendedImage { image, info }; - - Ok(image) - } - - fn read_anim_info<R: Read>(reader: &mut R) -> ImageResult<WebPAnimatedInfo> { - let mut colors: [u8; 4] = [0; 4]; - reader.read_exact(&mut colors)?; - - //background color is [blue, green, red, alpha] - let background_color = Rgba([colors[2], colors[1], colors[0], colors[3]]); - - let loop_count = reader.read_u16::<LittleEndian>()?; - - let info = WebPAnimatedInfo { - background_color, - _loop_count: loop_count, - }; - - Ok(info) - } - - fn draw_subimage( - canvas: &mut RgbaImage, - anim_image: &AnimatedFrame, - background_color: Rgba<u8>, - ) -> Option<ImageResult<Frame>> { - let mut buffer = vec![0; anim_image.image.get_buf_size()]; - anim_image.image.fill_buf(&mut buffer); - let has_alpha = anim_image.image.has_alpha(); - let pixel_len: u32 = anim_image.image.color_type().bytes_per_pixel().into(); - - 'x: for x in 0..anim_image.width { - for y in 0..anim_image.height { - let canvas_index: (u32, u32) = (x + anim_image.offset_x, y + anim_image.offset_y); - // Negative offsets are not possible due to unsigned ints - // If we go out of bounds by height, still continue by x - if canvas_index.1 >= canvas.height() { - continue 'x; - } - // If we go out of bounds by width, it doesn't make sense to continue at all - if canvas_index.0 >= canvas.width() { - break 'x; - } - let index: usize = ((y * anim_image.width + x) * pixel_len).try_into().unwrap(); - canvas[canvas_index] = if anim_image.use_alpha_blending && has_alpha { - let buffer: [u8; 4] = buffer[index..][..4].try_into().unwrap(); - ExtendedImage::do_alpha_blending(buffer, canvas[canvas_index]) - } else { - Rgba([ - buffer[index], - buffer[index + 1], - buffer[index + 2], - if has_alpha { buffer[index + 3] } else { 255 }, - ]) - }; - } - } - - let delay = Delay::from_numer_denom_ms(anim_image.duration, 1); - let img = canvas.clone(); - let frame = Frame::from_parts(img, 0, 0, delay); - - if anim_image.dispose { - for x in 0..anim_image.width { - for y in 0..anim_image.height { - let canvas_index = (x + anim_image.offset_x, y + anim_image.offset_y); - canvas[canvas_index] = background_color; - } - } - } - - Some(Ok(frame)) - } - - fn do_alpha_blending(buffer: [u8; 4], canvas: Rgba<u8>) -> Rgba<u8> { - let canvas_alpha = f64::from(canvas[3]); - let buffer_alpha = f64::from(buffer[3]); - let blend_alpha_f64 = buffer_alpha + canvas_alpha * (1.0 - buffer_alpha / 255.0); - //value should be between 0 and 255, this truncates the fractional part - let blend_alpha: u8 = blend_alpha_f64 as u8; - - let blend_rgb: [u8; 3] = if blend_alpha == 0 { - [0, 0, 0] - } else { - let mut rgb = [0u8; 3]; - for i in 0..3 { - let canvas_f64 = f64::from(canvas[i]); - let buffer_f64 = f64::from(buffer[i]); - - let val = (buffer_f64 * buffer_alpha - + canvas_f64 * canvas_alpha * (1.0 - buffer_alpha / 255.0)) - / blend_alpha_f64; - //value should be between 0 and 255, this truncates the fractional part - rgb[i] = val as u8; - } - - rgb - }; - - Rgba([blend_rgb[0], blend_rgb[1], blend_rgb[2], blend_alpha]) - } - - pub(crate) fn fill_buf(&self, buf: &mut [u8]) { - match &self.image { - // will always have at least one frame - ExtendedImageData::Animation { frames, anim_info } => { - let first_frame = &frames[0]; - let (canvas_width, canvas_height) = self.dimensions(); - if canvas_width == first_frame.width && canvas_height == first_frame.height { - first_frame.image.fill_buf(buf); - } else { - let bg_color = match &self.info._alpha { - true => Rgba::from([0, 0, 0, 0]), - false => anim_info.background_color, - }; - let mut canvas = RgbaImage::from_pixel(canvas_width, canvas_height, bg_color); - let _ = ExtendedImage::draw_subimage(&mut canvas, first_frame, bg_color) - .unwrap() - .unwrap(); - buf.copy_from_slice(canvas.into_raw().as_slice()); - } - } - ExtendedImageData::Static(image) => { - image.fill_buf(buf); - } - } - } - - pub(crate) fn get_buf_size(&self) -> usize { - match &self.image { - // will always have at least one frame - ExtendedImageData::Animation { frames, .. } => &frames[0].image, - ExtendedImageData::Static(image) => image, - } - .get_buf_size() - } - - pub(crate) fn set_background_color(&mut self, color: Rgba<u8>) -> ImageResult<()> { - match &mut self.image { - ExtendedImageData::Animation { anim_info, .. } => { - anim_info.background_color = color; - Ok(()) - } - _ => Err(ImageError::Parameter(ParameterError::from_kind( - ParameterErrorKind::Generic( - "Background color can only be set on animated webp".to_owned(), - ), - ))), - } - } -} - -#[derive(Debug)] -enum WebPStatic { - LossyWithAlpha(RgbaImage), - LossyWithoutAlpha(RgbImage), - Lossless(LosslessFrame), -} - -impl WebPStatic { - pub(crate) fn from_alpha_lossy( - alpha: AlphaChunk, - vp8_frame: VP8Frame, - ) -> ImageResult<WebPStatic> { - if alpha.data.len() != usize::from(vp8_frame.width) * usize::from(vp8_frame.height) { - return Err(DecoderError::AlphaChunkSizeMismatch.into()); - } - - let size = usize::from(vp8_frame.width).checked_mul(usize::from(vp8_frame.height) * 4); - let mut image_vec = match size { - Some(size) => vec![0u8; size], - None => return Err(DecoderError::ImageTooLarge.into()), - }; - - vp8_frame.fill_rgba(&mut image_vec); - - for y in 0..vp8_frame.height { - for x in 0..vp8_frame.width { - let predictor: u8 = WebPStatic::get_predictor( - x.into(), - y.into(), - vp8_frame.width.into(), - alpha.filtering_method, - &image_vec, - ); - let predictor = u16::from(predictor); - - let alpha_index = usize::from(y) * usize::from(vp8_frame.width) + usize::from(x); - let alpha_val = alpha.data[alpha_index]; - let alpha: u8 = ((predictor + u16::from(alpha_val)) % 256) - .try_into() - .unwrap(); - - let alpha_index = alpha_index * 4 + 3; - image_vec[alpha_index] = alpha; - } - } - - let image = RgbaImage::from_vec(vp8_frame.width.into(), vp8_frame.height.into(), image_vec) - .unwrap(); - - Ok(WebPStatic::LossyWithAlpha(image)) - } - - fn get_predictor( - x: usize, - y: usize, - width: usize, - filtering_method: FilteringMethod, - image_slice: &[u8], - ) -> u8 { - match filtering_method { - FilteringMethod::None => 0, - FilteringMethod::Horizontal => { - if x == 0 && y == 0 { - 0 - } else if x == 0 { - let index = (y - 1) * width + x; - image_slice[index * 4 + 3] - } else { - let index = y * width + x - 1; - image_slice[index * 4 + 3] - } - } - FilteringMethod::Vertical => { - if x == 0 && y == 0 { - 0 - } else if y == 0 { - let index = y * width + x - 1; - image_slice[index * 4 + 3] - } else { - let index = (y - 1) * width + x; - image_slice[index * 4 + 3] - } - } - FilteringMethod::Gradient => { - let (left, top, top_left) = match (x, y) { - (0, 0) => (0, 0, 0), - (0, y) => { - let above_index = (y - 1) * width + x; - let val = image_slice[above_index * 4 + 3]; - (val, val, val) - } - (x, 0) => { - let before_index = y * width + x - 1; - let val = image_slice[before_index * 4 + 3]; - (val, val, val) - } - (x, y) => { - let left_index = y * width + x - 1; - let left = image_slice[left_index * 4 + 3]; - let top_index = (y - 1) * width + x; - let top = image_slice[top_index * 4 + 3]; - let top_left_index = (y - 1) * width + x - 1; - let top_left = image_slice[top_left_index * 4 + 3]; - - (left, top, top_left) - } - }; - - let combination = i16::from(left) + i16::from(top) - i16::from(top_left); - i16::clamp(combination, 0, 255).try_into().unwrap() - } - } - } - - pub(crate) fn from_lossy(vp8_frame: VP8Frame) -> ImageResult<WebPStatic> { - let mut image = RgbImage::from_pixel( - vp8_frame.width.into(), - vp8_frame.height.into(), - Rgb([0, 0, 0]), - ); - - vp8_frame.fill_rgb(&mut image); - - Ok(WebPStatic::LossyWithoutAlpha(image)) - } - - pub(crate) fn fill_buf(&self, buf: &mut [u8]) { - match self { - WebPStatic::LossyWithAlpha(image) => { - buf.copy_from_slice(image); - } - WebPStatic::LossyWithoutAlpha(image) => { - buf.copy_from_slice(image); - } - WebPStatic::Lossless(lossless) => { - lossless.fill_rgba(buf); - } - } - } - - pub(crate) fn get_buf_size(&self) -> usize { - match self { - WebPStatic::LossyWithAlpha(rgb_image) => rgb_image.len(), - WebPStatic::LossyWithoutAlpha(rgba_image) => rgba_image.len(), - WebPStatic::Lossless(lossless) => lossless.get_buf_size(), - } - } - - pub(crate) fn color_type(&self) -> ColorType { - if self.has_alpha() { - ColorType::Rgba8 - } else { - ColorType::Rgb8 - } - } - - pub(crate) fn has_alpha(&self) -> bool { - match self { - Self::LossyWithAlpha(..) | Self::Lossless(..) => true, - Self::LossyWithoutAlpha(..) => false, - } - } -} - -#[derive(Debug)] -struct WebPAnimatedInfo { - background_color: Rgba<u8>, - _loop_count: u16, -} - -#[derive(Debug)] -struct AnimatedFrame { - offset_x: u32, - offset_y: u32, - width: u32, - height: u32, - duration: u32, - use_alpha_blending: bool, - dispose: bool, - image: WebPStatic, -} - -/// Reads a chunk, but silently ignores unknown chunks at the end of a file -fn read_extended_chunk<R>(r: &mut R) -> ImageResult<Option<(Cursor<Vec<u8>>, WebPRiffChunk)>> -where - R: Read, -{ - let mut unknown_chunk = Ok(()); - - while let Some(chunk) = read_fourcc(r)? { - let cursor = read_len_cursor(r)?; - match chunk { - Ok(chunk) => return unknown_chunk.and(Ok(Some((cursor, chunk)))), - Err(err) => unknown_chunk = unknown_chunk.and(Err(err)), - } - } - - Ok(None) -} - -pub(crate) fn read_extended_header<R: Read>(reader: &mut R) -> ImageResult<WebPExtendedInfo> { - let chunk_flags = reader.read_u8()?; - - let reserved_first = chunk_flags & 0b11000000; - let icc_profile = chunk_flags & 0b00100000 != 0; - let alpha = chunk_flags & 0b00010000 != 0; - let exif_metadata = chunk_flags & 0b00001000 != 0; - let xmp_metadata = chunk_flags & 0b00000100 != 0; - let animation = chunk_flags & 0b00000010 != 0; - let reserved_second = chunk_flags & 0b00000001; - - let reserved_third = read_3_bytes(reader)?; - - if reserved_first != 0 || reserved_second != 0 || reserved_third != 0 { - let value: u32 = if reserved_first != 0 { - reserved_first.into() - } else if reserved_second != 0 { - reserved_second.into() - } else { - reserved_third - }; - return Err(DecoderError::InfoBitsInvalid { - name: "reserved", - value, - } - .into()); - } - - let canvas_width = read_3_bytes(reader)? + 1; - let canvas_height = read_3_bytes(reader)? + 1; - - //product of canvas dimensions cannot be larger than u32 max - if u32::checked_mul(canvas_width, canvas_height).is_none() { - return Err(DecoderError::ImageTooLarge.into()); - } - - let info = WebPExtendedInfo { - _icc_profile: icc_profile, - _alpha: alpha, - _exif_metadata: exif_metadata, - _xmp_metadata: xmp_metadata, - _animation: animation, - canvas_width, - canvas_height, - icc_profile: None, - }; - - Ok(info) -} - -fn read_anim_frame<R: Read>( - mut reader: R, - canvas_width: u32, - canvas_height: u32, -) -> ImageResult<AnimatedFrame> { - //offsets for the frames are twice the values - let frame_x = read_3_bytes(&mut reader)? * 2; - let frame_y = read_3_bytes(&mut reader)? * 2; - - let frame_width = read_3_bytes(&mut reader)? + 1; - let frame_height = read_3_bytes(&mut reader)? + 1; - - if frame_x + frame_width > canvas_width || frame_y + frame_height > canvas_height { - return Err(DecoderError::FrameOutsideImage.into()); - } - - let duration = read_3_bytes(&mut reader)?; - - let frame_info = reader.read_u8()?; - let reserved = frame_info & 0b11111100; - if reserved != 0 { - return Err(DecoderError::InfoBitsInvalid { - name: "reserved", - value: reserved.into(), - } - .into()); - } - let use_alpha_blending = frame_info & 0b00000010 == 0; - let dispose = frame_info & 0b00000001 != 0; - - //read normal bitstream now - let static_image = read_image(&mut reader, frame_width, frame_height)?; - - let frame = AnimatedFrame { - offset_x: frame_x, - offset_y: frame_y, - width: frame_width, - height: frame_height, - duration, - use_alpha_blending, - dispose, - image: static_image, - }; - - Ok(frame) -} - -fn read_3_bytes<R: Read>(reader: &mut R) -> ImageResult<u32> { - let mut buffer: [u8; 3] = [0; 3]; - reader.read_exact(&mut buffer)?; - let value: u32 = - (u32::from(buffer[2]) << 16) | (u32::from(buffer[1]) << 8) | u32::from(buffer[0]); - Ok(value) -} - -fn read_lossy_with_chunk<R: Read>(reader: &mut R) -> ImageResult<VP8Frame> { - let (cursor, chunk) = - read_chunk(reader)?.ok_or_else(|| Error::from(io::ErrorKind::UnexpectedEof))?; - - if chunk != WebPRiffChunk::VP8 { - return Err(ChunkHeaderInvalid(chunk.to_fourcc()).into()); - } - - read_lossy(cursor) -} - -fn read_lossy(cursor: Cursor<Vec<u8>>) -> ImageResult<VP8Frame> { - let mut vp8_decoder = Vp8Decoder::new(cursor); - let frame = vp8_decoder.decode_frame()?; - - Ok(frame.clone()) -} - -fn read_image<R: Read>(reader: &mut R, width: u32, height: u32) -> ImageResult<WebPStatic> { - let chunk = read_chunk(reader)?; - - match chunk { - Some((cursor, WebPRiffChunk::VP8)) => { - let mut vp8_decoder = Vp8Decoder::new(cursor); - let frame = vp8_decoder.decode_frame()?; - - let img = WebPStatic::from_lossy(frame.clone())?; - - Ok(img) - } - Some((cursor, WebPRiffChunk::VP8L)) => { - let mut lossless_decoder = LosslessDecoder::new(cursor); - let frame = lossless_decoder.decode_frame()?; - - let img = WebPStatic::Lossless(frame.clone()); - - Ok(img) - } - Some((mut cursor, WebPRiffChunk::ALPH)) => { - let alpha_chunk = read_alpha_chunk(&mut cursor, width, height)?; - - let vp8_frame = read_lossy_with_chunk(reader)?; - - let img = WebPStatic::from_alpha_lossy(alpha_chunk, vp8_frame)?; - - Ok(img) - } - None => Err(ImageError::IoError(Error::from( - io::ErrorKind::UnexpectedEof, - ))), - Some((_, chunk)) => Err(ChunkHeaderInvalid(chunk.to_fourcc()).into()), - } -} - -#[derive(Debug)] -struct AlphaChunk { - _preprocessing: bool, - filtering_method: FilteringMethod, - data: Vec<u8>, -} - -#[derive(Debug, Copy, Clone)] -enum FilteringMethod { - None, - Horizontal, - Vertical, - Gradient, -} - -fn read_alpha_chunk<R: Read>(reader: &mut R, width: u32, height: u32) -> ImageResult<AlphaChunk> { - let info_byte = reader.read_u8()?; - - let reserved = info_byte & 0b11000000; - let preprocessing = (info_byte & 0b00110000) >> 4; - let filtering = (info_byte & 0b00001100) >> 2; - let compression = info_byte & 0b00000011; - - if reserved != 0 { - return Err(DecoderError::InfoBitsInvalid { - name: "reserved", - value: reserved.into(), - } - .into()); - } - - let preprocessing = match preprocessing { - 0 => false, - 1 => true, - _ => { - return Err(DecoderError::InfoBitsInvalid { - name: "reserved", - value: preprocessing.into(), - } - .into()) - } - }; - - let filtering_method = match filtering { - 0 => FilteringMethod::None, - 1 => FilteringMethod::Horizontal, - 2 => FilteringMethod::Vertical, - 3 => FilteringMethod::Gradient, - _ => unreachable!(), - }; - - let lossless_compression = match compression { - 0 => false, - 1 => true, - _ => { - return Err(DecoderError::InfoBitsInvalid { - name: "lossless compression", - value: compression.into(), - } - .into()) - } - }; - - let mut framedata = Vec::new(); - reader.read_to_end(&mut framedata)?; - - let data = if lossless_compression { - let cursor = io::Cursor::new(framedata); - - let mut decoder = LosslessDecoder::new(cursor); - //this is a potential problem for large images; would require rewriting lossless decoder to use u32 for width and height - let width: u16 = width - .try_into() - .map_err(|_| ImageError::from(DecoderError::ImageTooLarge))?; - let height: u16 = height - .try_into() - .map_err(|_| ImageError::from(DecoderError::ImageTooLarge))?; - let frame = decoder.decode_frame_implicit_dims(width, height)?; - - let mut data = vec![0u8; usize::from(width) * usize::from(height)]; - - frame.fill_green(&mut data); - - data - } else { - framedata - }; - - let chunk = AlphaChunk { - _preprocessing: preprocessing, - filtering_method, - data, - }; - - Ok(chunk) -} |