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Diffstat (limited to 'vendor/image/src/codecs/openexr.rs')
| -rw-r--r-- | vendor/image/src/codecs/openexr.rs | 592 |
1 files changed, 592 insertions, 0 deletions
diff --git a/vendor/image/src/codecs/openexr.rs b/vendor/image/src/codecs/openexr.rs new file mode 100644 index 0000000..52d6ba9 --- /dev/null +++ b/vendor/image/src/codecs/openexr.rs @@ -0,0 +1,592 @@ +//! Decoding of OpenEXR (.exr) Images +//! +//! OpenEXR is an image format that is widely used, especially in VFX, +//! because it supports lossless and lossy compression for float data. +//! +//! This decoder only supports RGB and RGBA images. +//! If an image does not contain alpha information, +//! it is defaulted to `1.0` (no transparency). +//! +//! # Related Links +//! * <https://www.openexr.com/documentation.html> - The OpenEXR reference. +//! +//! +//! Current limitations (July 2021): +//! - only pixel type `Rgba32F` and `Rgba16F` are supported +//! - only non-deep rgb/rgba files supported, no conversion from/to YCbCr or similar +//! - only the first non-deep rgb layer is used +//! - only the largest mip map level is used +//! - pixels outside display window are lost +//! - meta data is lost +//! - dwaa/dwab compressed images not supported yet by the exr library +//! - (chroma) subsampling not supported yet by the exr library +use exr::prelude::*; + +use crate::error::{DecodingError, EncodingError, ImageFormatHint}; +use crate::image::decoder_to_vec; +use crate::{ + ColorType, ExtendedColorType, ImageDecoder, ImageEncoder, ImageError, ImageFormat, ImageResult, + Progress, +}; +use std::convert::TryInto; +use std::io::{Cursor, Read, Seek, Write}; + +/// An OpenEXR decoder. Immediately reads the meta data from the file. +#[derive(Debug)] +pub struct OpenExrDecoder<R> { + exr_reader: exr::block::reader::Reader<R>, + + // select a header that is rgb and not deep + header_index: usize, + + // decode either rgb or rgba. + // can be specified to include or discard alpha channels. + // if none, the alpha channel will only be allocated where the file contains data for it. + alpha_preference: Option<bool>, + + alpha_present_in_file: bool, +} + +impl<R: Read + Seek> OpenExrDecoder<R> { + /// Create a decoder. Consumes the first few bytes of the source to extract image dimensions. + /// Assumes the reader is buffered. In most cases, + /// you should wrap your reader in a `BufReader` for best performance. + /// Loads an alpha channel if the file has alpha samples. + /// Use `with_alpha_preference` if you want to load or not load alpha unconditionally. + pub fn new(source: R) -> ImageResult<Self> { + Self::with_alpha_preference(source, None) + } + + /// Create a decoder. Consumes the first few bytes of the source to extract image dimensions. + /// Assumes the reader is buffered. In most cases, + /// you should wrap your reader in a `BufReader` for best performance. + /// If alpha preference is specified, an alpha channel will + /// always be present or always be not present in the returned image. + /// If alpha preference is none, the alpha channel will only be returned if it is found in the file. + pub fn with_alpha_preference(source: R, alpha_preference: Option<bool>) -> ImageResult<Self> { + // read meta data, then wait for further instructions, keeping the file open and ready + let exr_reader = exr::block::read(source, false).map_err(to_image_err)?; + + let header_index = exr_reader + .headers() + .iter() + .position(|header| { + // check if r/g/b exists in the channels + let has_rgb = ["R", "G", "B"] + .iter() + .all(|&required| // alpha will be optional + header.channels.find_index_of_channel(&Text::from(required)).is_some()); + + // we currently dont support deep images, or images with other color spaces than rgb + !header.deep && has_rgb + }) + .ok_or_else(|| { + ImageError::Decoding(DecodingError::new( + ImageFormatHint::Exact(ImageFormat::OpenExr), + "image does not contain non-deep rgb channels", + )) + })?; + + let has_alpha = exr_reader.headers()[header_index] + .channels + .find_index_of_channel(&Text::from("A")) + .is_some(); + + Ok(Self { + alpha_preference, + exr_reader, + header_index, + alpha_present_in_file: has_alpha, + }) + } + + // does not leak exrs-specific meta data into public api, just does it for this module + fn selected_exr_header(&self) -> &exr::meta::header::Header { + &self.exr_reader.meta_data().headers[self.header_index] + } +} + +impl<'a, R: 'a + Read + Seek> ImageDecoder<'a> for OpenExrDecoder<R> { + type Reader = Cursor<Vec<u8>>; + + fn dimensions(&self) -> (u32, u32) { + let size = self + .selected_exr_header() + .shared_attributes + .display_window + .size; + (size.width() as u32, size.height() as u32) + } + + fn color_type(&self) -> ColorType { + let returns_alpha = self.alpha_preference.unwrap_or(self.alpha_present_in_file); + if returns_alpha { + ColorType::Rgba32F + } else { + ColorType::Rgb32F + } + } + + fn original_color_type(&self) -> ExtendedColorType { + if self.alpha_present_in_file { + ExtendedColorType::Rgba32F + } else { + ExtendedColorType::Rgb32F + } + } + + /// Use `read_image` instead if possible, + /// as this method creates a whole new buffer just to contain the entire image. + fn into_reader(self) -> ImageResult<Self::Reader> { + Ok(Cursor::new(decoder_to_vec(self)?)) + } + + fn scanline_bytes(&self) -> u64 { + // we cannot always read individual scan lines for every file, + // as the tiles or lines in the file could be in random or reversed order. + // therefore we currently read all lines at once + // Todo: optimize for specific exr.line_order? + self.total_bytes() + } + + // reads with or without alpha, depending on `self.alpha_preference` and `self.alpha_present_in_file` + fn read_image_with_progress<F: Fn(Progress)>( + self, + unaligned_bytes: &mut [u8], + progress_callback: F, + ) -> ImageResult<()> { + let blocks_in_header = self.selected_exr_header().chunk_count as u64; + let channel_count = self.color_type().channel_count() as usize; + + let display_window = self.selected_exr_header().shared_attributes.display_window; + let data_window_offset = + self.selected_exr_header().own_attributes.layer_position - display_window.position; + + { + // check whether the buffer is large enough for the dimensions of the file + let (width, height) = self.dimensions(); + let bytes_per_pixel = self.color_type().bytes_per_pixel() as usize; + let expected_byte_count = (width as usize) + .checked_mul(height as usize) + .and_then(|size| size.checked_mul(bytes_per_pixel)); + + // if the width and height does not match the length of the bytes, the arguments are invalid + let has_invalid_size_or_overflowed = expected_byte_count + .map(|expected_byte_count| unaligned_bytes.len() != expected_byte_count) + // otherwise, size calculation overflowed, is bigger than memory, + // therefore data is too small, so it is invalid. + .unwrap_or(true); + + if has_invalid_size_or_overflowed { + panic!("byte buffer not large enough for the specified dimensions and f32 pixels"); + } + } + + let result = read() + .no_deep_data() + .largest_resolution_level() + .rgba_channels( + move |_size, _channels| vec![0_f32; display_window.size.area() * channel_count], + move |buffer, index_in_data_window, (r, g, b, a_or_1): (f32, f32, f32, f32)| { + let index_in_display_window = + index_in_data_window.to_i32() + data_window_offset; + + // only keep pixels inside the data window + // TODO filter chunks based on this + if index_in_display_window.x() >= 0 + && index_in_display_window.y() >= 0 + && index_in_display_window.x() < display_window.size.width() as i32 + && index_in_display_window.y() < display_window.size.height() as i32 + { + let index_in_display_window = + index_in_display_window.to_usize("index bug").unwrap(); + let first_f32_index = + index_in_display_window.flat_index_for_size(display_window.size); + + buffer[first_f32_index * channel_count + ..(first_f32_index + 1) * channel_count] + .copy_from_slice(&[r, g, b, a_or_1][0..channel_count]); + + // TODO white point chromaticities + srgb/linear conversion? + } + }, + ) + .first_valid_layer() // TODO select exact layer by self.header_index? + .all_attributes() + .on_progress(|progress| { + progress_callback( + Progress::new( + (progress * blocks_in_header as f64) as u64, + blocks_in_header, + ), // TODO precision errors? + ); + }) + .from_chunks(self.exr_reader) + .map_err(to_image_err)?; + + // TODO this copy is strictly not necessary, but the exr api is a little too simple for reading into a borrowed target slice + + // this cast is safe and works with any alignment, as bytes are copied, and not f32 values. + // note: buffer slice length is checked in the beginning of this function and will be correct at this point + unaligned_bytes.copy_from_slice(bytemuck::cast_slice( + result.layer_data.channel_data.pixels.as_slice(), + )); + Ok(()) + } +} + +/// Write a raw byte buffer of pixels, +/// returning an Error if it has an invalid length. +/// +/// Assumes the writer is buffered. In most cases, +/// you should wrap your writer in a `BufWriter` for best performance. +// private. access via `OpenExrEncoder` +fn write_buffer( + mut buffered_write: impl Write + Seek, + unaligned_bytes: &[u8], + width: u32, + height: u32, + color_type: ColorType, +) -> ImageResult<()> { + let width = width as usize; + let height = height as usize; + + { + // check whether the buffer is large enough for the specified dimensions + let expected_byte_count = width + .checked_mul(height) + .and_then(|size| size.checked_mul(color_type.bytes_per_pixel() as usize)); + + // if the width and height does not match the length of the bytes, the arguments are invalid + let has_invalid_size_or_overflowed = expected_byte_count + .map(|expected_byte_count| unaligned_bytes.len() < expected_byte_count) + // otherwise, size calculation overflowed, is bigger than memory, + // therefore data is too small, so it is invalid. + .unwrap_or(true); + + if has_invalid_size_or_overflowed { + return Err(ImageError::Encoding(EncodingError::new( + ImageFormatHint::Exact(ImageFormat::OpenExr), + "byte buffer not large enough for the specified dimensions and f32 pixels", + ))); + } + } + + // bytes might be unaligned so we cannot cast the whole thing, instead lookup each f32 individually + let lookup_f32 = move |f32_index: usize| { + let unaligned_f32_bytes_slice = &unaligned_bytes[f32_index * 4..(f32_index + 1) * 4]; + let f32_bytes_array = unaligned_f32_bytes_slice + .try_into() + .expect("indexing error"); + f32::from_ne_bytes(f32_bytes_array) + }; + + match color_type { + ColorType::Rgb32F => { + exr::prelude::Image // TODO compression method zip?? + ::from_channels( + (width, height), + SpecificChannels::rgb(|pixel: Vec2<usize>| { + let pixel_index = 3 * pixel.flat_index_for_size(Vec2(width, height)); + ( + lookup_f32(pixel_index), + lookup_f32(pixel_index + 1), + lookup_f32(pixel_index + 2), + ) + }), + ) + .write() + // .on_progress(|progress| todo!()) + .to_buffered(&mut buffered_write) + .map_err(to_image_err)?; + } + + ColorType::Rgba32F => { + exr::prelude::Image // TODO compression method zip?? + ::from_channels( + (width, height), + SpecificChannels::rgba(|pixel: Vec2<usize>| { + let pixel_index = 4 * pixel.flat_index_for_size(Vec2(width, height)); + ( + lookup_f32(pixel_index), + lookup_f32(pixel_index + 1), + lookup_f32(pixel_index + 2), + lookup_f32(pixel_index + 3), + ) + }), + ) + .write() + // .on_progress(|progress| todo!()) + .to_buffered(&mut buffered_write) + .map_err(to_image_err)?; + } + + // TODO other color types and channel types + unsupported_color_type => { + return Err(ImageError::Encoding(EncodingError::new( + ImageFormatHint::Exact(ImageFormat::OpenExr), + format!( + "writing color type {:?} not yet supported", + unsupported_color_type + ), + ))) + } + } + + Ok(()) +} + +// TODO is this struct and trait actually used anywhere? +/// A thin wrapper that implements `ImageEncoder` for OpenEXR images. Will behave like `image::codecs::openexr::write_buffer`. +#[derive(Debug)] +pub struct OpenExrEncoder<W>(W); + +impl<W> OpenExrEncoder<W> { + /// Create an `ImageEncoder`. Does not write anything yet. Writing later will behave like `image::codecs::openexr::write_buffer`. + // use constructor, not public field, for future backwards-compatibility + pub fn new(write: W) -> Self { + Self(write) + } +} + +impl<W> ImageEncoder for OpenExrEncoder<W> +where + W: Write + Seek, +{ + /// Writes the complete image. + /// + /// Returns an Error if it has an invalid length. + /// Assumes the writer is buffered. In most cases, + /// you should wrap your writer in a `BufWriter` for best performance. + fn write_image( + self, + buf: &[u8], + width: u32, + height: u32, + color_type: ColorType, + ) -> ImageResult<()> { + write_buffer(self.0, buf, width, height, color_type) + } +} + +fn to_image_err(exr_error: Error) -> ImageError { + ImageError::Decoding(DecodingError::new( + ImageFormatHint::Exact(ImageFormat::OpenExr), + exr_error.to_string(), + )) +} + +#[cfg(test)] +mod test { + use super::*; + + use std::io::BufReader; + use std::path::{Path, PathBuf}; + + use crate::buffer_::{Rgb32FImage, Rgba32FImage}; + use crate::error::{LimitError, LimitErrorKind}; + use crate::{ImageBuffer, Rgb, Rgba}; + + const BASE_PATH: &[&str] = &[".", "tests", "images", "exr"]; + + /// Write an `Rgb32FImage`. + /// Assumes the writer is buffered. In most cases, + /// you should wrap your writer in a `BufWriter` for best performance. + fn write_rgb_image(write: impl Write + Seek, image: &Rgb32FImage) -> ImageResult<()> { + write_buffer( + write, + bytemuck::cast_slice(image.as_raw().as_slice()), + image.width(), + image.height(), + ColorType::Rgb32F, + ) + } + + /// Write an `Rgba32FImage`. + /// Assumes the writer is buffered. In most cases, + /// you should wrap your writer in a `BufWriter` for best performance. + fn write_rgba_image(write: impl Write + Seek, image: &Rgba32FImage) -> ImageResult<()> { + write_buffer( + write, + bytemuck::cast_slice(image.as_raw().as_slice()), + image.width(), + image.height(), + ColorType::Rgba32F, + ) + } + + /// Read the file from the specified path into an `Rgba32FImage`. + fn read_as_rgba_image_from_file(path: impl AsRef<Path>) -> ImageResult<Rgba32FImage> { + read_as_rgba_image(BufReader::new(std::fs::File::open(path)?)) + } + + /// Read the file from the specified path into an `Rgb32FImage`. + fn read_as_rgb_image_from_file(path: impl AsRef<Path>) -> ImageResult<Rgb32FImage> { + read_as_rgb_image(BufReader::new(std::fs::File::open(path)?)) + } + + /// Read the file from the specified path into an `Rgb32FImage`. + fn read_as_rgb_image(read: impl Read + Seek) -> ImageResult<Rgb32FImage> { + let decoder = OpenExrDecoder::with_alpha_preference(read, Some(false))?; + let (width, height) = decoder.dimensions(); + let buffer: Vec<f32> = decoder_to_vec(decoder)?; + + ImageBuffer::from_raw(width, height, buffer) + // this should be the only reason for the "from raw" call to fail, + // even though such a large allocation would probably cause an error much earlier + .ok_or_else(|| { + ImageError::Limits(LimitError::from_kind(LimitErrorKind::InsufficientMemory)) + }) + } + + /// Read the file from the specified path into an `Rgba32FImage`. + fn read_as_rgba_image(read: impl Read + Seek) -> ImageResult<Rgba32FImage> { + let decoder = OpenExrDecoder::with_alpha_preference(read, Some(true))?; + let (width, height) = decoder.dimensions(); + let buffer: Vec<f32> = decoder_to_vec(decoder)?; + + ImageBuffer::from_raw(width, height, buffer) + // this should be the only reason for the "from raw" call to fail, + // even though such a large allocation would probably cause an error much earlier + .ok_or_else(|| { + ImageError::Limits(LimitError::from_kind(LimitErrorKind::InsufficientMemory)) + }) + } + + #[test] + fn compare_exr_hdr() { + if cfg!(not(feature = "hdr")) { + eprintln!("warning: to run all the openexr tests, activate the hdr feature flag"); + } + + #[cfg(feature = "hdr")] + { + let folder = BASE_PATH.iter().collect::<PathBuf>(); + let reference_path = folder.clone().join("overexposed gradient.hdr"); + let exr_path = folder + .clone() + .join("overexposed gradient - data window equals display window.exr"); + + let hdr: Vec<Rgb<f32>> = crate::codecs::hdr::HdrDecoder::new(std::io::BufReader::new( + std::fs::File::open(&reference_path).unwrap(), + )) + .unwrap() + .read_image_hdr() + .unwrap(); + + let exr_pixels: Rgb32FImage = read_as_rgb_image_from_file(exr_path).unwrap(); + assert_eq!( + exr_pixels.dimensions().0 * exr_pixels.dimensions().1, + hdr.len() as u32 + ); + + for (expected, found) in hdr.iter().zip(exr_pixels.pixels()) { + for (expected, found) in expected.0.iter().zip(found.0.iter()) { + // the large tolerance seems to be caused by + // the RGBE u8x4 pixel quantization of the hdr image format + assert!( + (expected - found).abs() < 0.1, + "expected {}, found {}", + expected, + found + ); + } + } + } + } + + #[test] + fn roundtrip_rgba() { + let mut next_random = vec![1.0, 0.0, -1.0, -3.14, 27.0, 11.0, 31.0] + .into_iter() + .cycle(); + let mut next_random = move || next_random.next().unwrap(); + + let generated_image: Rgba32FImage = ImageBuffer::from_fn(9, 31, |_x, _y| { + Rgba([next_random(), next_random(), next_random(), next_random()]) + }); + + let mut bytes = vec![]; + write_rgba_image(Cursor::new(&mut bytes), &generated_image).unwrap(); + let decoded_image = read_as_rgba_image(Cursor::new(bytes)).unwrap(); + + debug_assert_eq!(generated_image, decoded_image); + } + + #[test] + fn roundtrip_rgb() { + let mut next_random = vec![1.0, 0.0, -1.0, -3.14, 27.0, 11.0, 31.0] + .into_iter() + .cycle(); + let mut next_random = move || next_random.next().unwrap(); + + let generated_image: Rgb32FImage = ImageBuffer::from_fn(9, 31, |_x, _y| { + Rgb([next_random(), next_random(), next_random()]) + }); + + let mut bytes = vec![]; + write_rgb_image(Cursor::new(&mut bytes), &generated_image).unwrap(); + let decoded_image = read_as_rgb_image(Cursor::new(bytes)).unwrap(); + + debug_assert_eq!(generated_image, decoded_image); + } + + #[test] + fn compare_rgba_rgb() { + let exr_path = BASE_PATH + .iter() + .collect::<PathBuf>() + .join("overexposed gradient - data window equals display window.exr"); + + let rgb: Rgb32FImage = read_as_rgb_image_from_file(&exr_path).unwrap(); + let rgba: Rgba32FImage = read_as_rgba_image_from_file(&exr_path).unwrap(); + + assert_eq!(rgba.dimensions(), rgb.dimensions()); + + for (Rgb(rgb), Rgba(rgba)) in rgb.pixels().zip(rgba.pixels()) { + assert_eq!(rgb, &rgba[..3]); + } + } + + #[test] + fn compare_cropped() { + // like in photoshop, exr images may have layers placed anywhere in a canvas. + // we don't want to load the pixels from the layer, but we want to load the pixels from the canvas. + // a layer might be smaller than the canvas, in that case the canvas should be transparent black + // where no layer was covering it. a layer might also be larger than the canvas, + // these pixels should be discarded. + // + // in this test we want to make sure that an + // auto-cropped image will be reproduced to the original. + + let exr_path = BASE_PATH.iter().collect::<PathBuf>(); + let original = exr_path.clone().join("cropping - uncropped original.exr"); + let cropped = exr_path + .clone() + .join("cropping - data window differs display window.exr"); + + // smoke-check that the exr files are actually not the same + { + let original_exr = read_first_flat_layer_from_file(&original).unwrap(); + let cropped_exr = read_first_flat_layer_from_file(&cropped).unwrap(); + assert_eq!( + original_exr.attributes.display_window, + cropped_exr.attributes.display_window + ); + assert_ne!( + original_exr.layer_data.attributes.layer_position, + cropped_exr.layer_data.attributes.layer_position + ); + assert_ne!(original_exr.layer_data.size, cropped_exr.layer_data.size); + } + + // check that they result in the same image + let original: Rgba32FImage = read_as_rgba_image_from_file(&original).unwrap(); + let cropped: Rgba32FImage = read_as_rgba_image_from_file(&cropped).unwrap(); + assert_eq!(original.dimensions(), cropped.dimensions()); + + // the following is not a simple assert_eq, as in case of an error, + // the whole image would be printed to the console, which takes forever + assert!(original.pixels().zip(cropped.pixels()).all(|(a, b)| a == b)); + } +} |