Deleted vendor folder

1 files changed, 0 insertions, 1197 deletions

diff --git a/vendor/exr/src/meta/header.rs b/vendor/exr/src/meta/header.rs
deleted file mode 100644
index b322b18..0000000
--- a/vendor/exr/src/meta/header.rs
+++ /dev/null
@@ -1,1197 +0,0 @@
-
-//! Contains collections of common attributes.
-//! Defines some data types that list all standard attributes.
-
-use std::collections::HashMap;
-use crate::meta::attribute::*; // FIXME shouldn't this need some more imports????
-use crate::meta::*;
-use crate::math::Vec2;
-
-// TODO rename header to LayerDescription!
-
-/// Describes a single layer in a file.
-/// A file can have any number of layers.
-/// The meta data contains one header per layer.
-#[derive(Clone, Debug, PartialEq)]
-pub struct Header {
-
-    /// List of channels in this layer.
-    pub channels: ChannelList,
-
-    /// How the pixel data of all channels in this layer is compressed. May be `Compression::Uncompressed`.
-    pub compression: Compression,
-
-    /// Describes how the pixels of this layer are divided into smaller blocks.
-    /// A single block can be loaded without processing all bytes of a file.
-    ///
-    /// Also describes whether a file contains multiple resolution levels: mip maps or rip maps.
-    /// This allows loading not the full resolution, but the smallest sensible resolution.
-    //
-    // Required if file contains deep data or multiple layers.
-    // Note: This value must agree with the version field's tile bit and deep data bit.
-    // In this crate, this attribute will always have a value, for simplicity.
-    pub blocks: BlockDescription,
-
-    /// In what order the tiles of this header occur in the file.
-    pub line_order: LineOrder,
-
-    /// The resolution of this layer. Equivalent to the size of the `DataWindow`.
-    pub layer_size: Vec2<usize>,
-
-    /// Whether this layer contains deep data.
-    pub deep: bool,
-
-    /// This library supports only deep data version 1.
-    pub deep_data_version: Option<i32>,
-
-    /// Number of chunks, that is, scan line blocks or tiles, that this image has been divided into.
-    /// This number is calculated once at the beginning
-    /// of the read process or when creating a header object.
-    ///
-    /// This value includes all chunks of all resolution levels.
-    ///
-    ///
-    /// __Warning__
-    /// _This value is relied upon. You should probably use `Header::with_encoding`,
-    /// which automatically updates the chunk count._
-    pub chunk_count: usize,
-
-    // Required for deep data (deepscanline and deeptile) layers.
-    // Note: Since the value of "maxSamplesPerPixel"
-    // maybe be unknown at the time of opening the
-    // file, the value “ -1 ” is written to the file to
-    // indicate an unknown value. When the file is
-    // closed, this will be overwritten with the correct value.
-    // If file writing does not complete
-    // correctly due to an error, the value -1 will
-    // remain. In this case, the value must be derived
-    // by decoding each chunk in the layer
-    /// Maximum number of samples in a single pixel in a deep image.
-    pub max_samples_per_pixel: Option<usize>,
-
-    /// Includes mandatory fields like pixel aspect or display window
-    /// which must be the same for all layers.
-    pub shared_attributes: ImageAttributes,
-
-    /// Does not include the attributes required for reading the file contents.
-    /// Excludes standard fields that must be the same for all headers.
-    pub own_attributes: LayerAttributes,
-}
-
-/// Includes mandatory fields like pixel aspect or display window
-/// which must be the same for all layers.
-/// For more attributes, see struct `LayerAttributes`.
-#[derive(Clone, PartialEq, Debug)]
-pub struct ImageAttributes {
-
-    /// The rectangle anywhere in the global infinite 2D space
-    /// that clips all contents of the file.
-    pub display_window: IntegerBounds,
-
-    /// Aspect ratio of each pixel in this header.
-    pub pixel_aspect: f32,
-
-    /// The chromaticities attribute of the image. See the `Chromaticities` type.
-    pub chromaticities: Option<Chromaticities>,
-
-    /// The time code of the image.
-    pub time_code: Option<TimeCode>,
-
-    /// Contains custom attributes.
-    /// Does not contain the attributes already present in the `ImageAttributes`.
-    /// Contains only attributes that are standardized to be the same for all headers: chromaticities and time codes.
-    pub other: HashMap<Text, AttributeValue>,
-}
-
-/// Does not include the attributes required for reading the file contents.
-/// Excludes standard fields that must be the same for all headers.
-/// For more attributes, see struct `ImageAttributes`.
-#[derive(Clone, PartialEq)]
-pub struct LayerAttributes {
-
-    /// The name of this layer.
-    /// Required if this file contains deep data or multiple layers.
-    // As this is an attribute value, it is not restricted in length, may even be empty
-    pub layer_name: Option<Text>,
-
-    /// The top left corner of the rectangle that positions this layer
-    /// within the global infinite 2D space of the whole file.
-    /// This represents the position of the `DataWindow`.
-    pub layer_position: Vec2<i32>,
-
-    /// Part of the perspective projection. Default should be `(0, 0)`.
-    // TODO same for all layers?
-    pub screen_window_center: Vec2<f32>,
-
-    // TODO same for all layers?
-    /// Part of the perspective projection. Default should be `1`.
-    pub screen_window_width: f32,
-
-    /// The white luminance of the colors.
-    /// Defines the luminance in candelas per square meter, Nits, of the rgb value `(1, 1, 1)`.
-    // If the chromaticities and the whiteLuminance of an RGB image are
-    // known, then it is possible to convert the image's pixels from RGB
-    // to CIE XYZ tristimulus values (see function RGBtoXYZ() in header
-    // file ImfChromaticities.h).
-    pub white_luminance: Option<f32>,
-
-    /// The adopted neutral of the colors. Specifies the CIE (x,y) frequency coordinates that should
-    /// be considered neutral during color rendering. Pixels in the image
-    /// whose CIE (x,y) frequency coordinates match the adopted neutral value should
-    /// be mapped to neutral values on the given display.
-    pub adopted_neutral: Option<Vec2<f32>>,
-
-    /// Name of the color transform function that is applied for rendering the image.
-    pub rendering_transform_name: Option<Text>,
-
-    /// Name of the color transform function that computes the look modification of the image.
-    pub look_modification_transform_name: Option<Text>,
-
-    /// The horizontal density, in pixels per inch.
-    /// The image's vertical output density can be computed using `horizontal_density * pixel_aspect_ratio`.
-    pub horizontal_density: Option<f32>,
-
-    /// Name of the owner.
-    pub owner: Option<Text>,
-
-    /// Additional textual information.
-    pub comments: Option<Text>,
-
-    /// The date of image creation, in `YYYY:MM:DD hh:mm:ss` format.
-    // TODO parse!
-    pub capture_date: Option<Text>,
-
-    /// Time offset from UTC.
-    pub utc_offset: Option<f32>,
-
-    /// Geographical image location.
-    pub longitude: Option<f32>,
-
-    /// Geographical image location.
-    pub latitude: Option<f32>,
-
-    /// Geographical image location.
-    pub altitude: Option<f32>,
-
-    /// Camera focus in meters.
-    pub focus: Option<f32>,
-
-    /// Exposure time in seconds.
-    pub exposure: Option<f32>,
-
-    /// Camera aperture measured in f-stops. Equals the focal length
-    /// of the lens divided by the diameter of the iris opening.
-    pub aperture: Option<f32>,
-
-    /// Iso-speed of the camera sensor.
-    pub iso_speed: Option<f32>,
-
-    /// If this is an environment map, specifies how to interpret it.
-    pub environment_map: Option<EnvironmentMap>,
-
-    /// Identifies film manufacturer, film type, film roll and frame position within the roll.
-    pub film_key_code: Option<KeyCode>,
-
-    /// Specifies how texture map images are extrapolated.
-    /// Values can be `black`, `clamp`, `periodic`, or `mirror`.
-    pub wrap_mode_name: Option<Text>,
-
-    /// Frames per second if this is a frame in a sequence.
-    pub frames_per_second: Option<Rational>,
-
-    /// Specifies the view names for multi-view, for example stereo, image files.
-    pub multi_view_names: Option<Vec<Text>>,
-
-    /// The matrix that transforms 3D points from the world to the camera coordinate space.
-    /// Left-handed coordinate system, y up, z forward.
-    pub world_to_camera: Option<Matrix4x4>,
-
-    /// The matrix that transforms 3D points from the world to the "Normalized Device Coordinate" space.
-    /// Left-handed coordinate system, y up, z forward.
-    pub world_to_normalized_device: Option<Matrix4x4>,
-
-    /// Specifies whether the pixels in a deep image are sorted and non-overlapping.
-    pub deep_image_state: Option<Rational>,
-
-    /// If the image was cropped, contains the original data window.
-    pub original_data_window: Option<IntegerBounds>,
-
-    /// An 8-bit rgba image representing the rendered image.
-    pub preview: Option<Preview>,
-
-    /// Name of the view, which is typically either `"right"` or `"left"` for a stereoscopic image.
-    pub view_name: Option<Text>,
-
-    /// The name of the software that produced this image.
-    pub software_name: Option<Text>,
-
-    /// The near clip plane of the virtual camera projection.
-    pub near_clip_plane: Option<f32>,
-
-    /// The far clip plane of the virtual camera projection.
-    pub far_clip_plane: Option<f32>,
-
-    /// The field of view angle, along the horizontal axis, in degrees.
-    pub horizontal_field_of_view: Option<f32>,
-
-    /// The field of view angle, along the horizontal axis, in degrees.
-    pub vertical_field_of_view: Option<f32>,
-
-    /// Contains custom attributes.
-    /// Does not contain the attributes already present in the `Header` or `LayerAttributes` struct.
-    /// Does not contain attributes that are standardized to be the same for all layers: no chromaticities and no time codes.
-    pub other: HashMap<Text, AttributeValue>,
-}
-
-
-impl LayerAttributes {
-
-    /// Create default layer attributes with a data position of zero.
-    pub fn named(layer_name: impl Into<Text>) -> Self {
-        Self {
-            layer_name: Some(layer_name.into()),
-            .. Self::default()
-        }
-    }
-
-    /// Set the data position of this layer.
-    pub fn with_position(self, data_position: Vec2<i32>) -> Self {
-        Self { layer_position: data_position, ..self }
-    }
-
-    /// Set all common camera projection attributes at once.
-    pub fn with_camera_frustum(
-        self,
-        world_to_camera: Matrix4x4,
-        world_to_normalized_device: Matrix4x4,
-        field_of_view: impl Into<Vec2<f32>>,
-        depth_clip_range: std::ops::Range<f32>,
-    ) -> Self
-    {
-        let fov = field_of_view.into();
-
-        Self {
-            world_to_normalized_device: Some(world_to_normalized_device),
-            world_to_camera: Some(world_to_camera),
-            horizontal_field_of_view: Some(fov.x()),
-            vertical_field_of_view: Some(fov.y()),
-            near_clip_plane: Some(depth_clip_range.start),
-            far_clip_plane: Some(depth_clip_range.end),
-            ..self
-        }
-    }
-}
-
-impl ImageAttributes {
-
-    /// Set the display position and size of this image.
-    pub fn new(display_window: IntegerBounds) -> Self {
-        Self {
-            pixel_aspect: 1.0,
-            chromaticities: None,
-            time_code: None,
-            other: Default::default(),
-            display_window,
-        }
-    }
-
-    /// Set the display position to zero and use the specified size for this image.
-    pub fn with_size(size: impl Into<Vec2<usize>>) -> Self {
-        Self::new(IntegerBounds::from_dimensions(size))
-    }
-}
-
-
-
-
-impl Header {
-
-    /// Create a new Header with the specified name, display window and channels.
-    /// Use `Header::with_encoding` and the similar methods to add further properties to the header.
-    ///
-    /// The other settings are left to their default values:
-    /// - RLE compression
-    /// - display window equal to data window
-    /// - tiles (64 x 64 px)
-    /// - unspecified line order
-    /// - no custom attributes
-    pub fn new(name: Text, data_size: impl Into<Vec2<usize>>, channels: SmallVec<[ChannelDescription; 5]>) -> Self {
-        let data_size: Vec2<usize> = data_size.into();
-
-        let compression = Compression::RLE;
-        let blocks = BlockDescription::Tiles(TileDescription {
-            tile_size: Vec2(64, 64),
-            level_mode: LevelMode::Singular,
-            rounding_mode: RoundingMode::Down
-        });
-
-        Self {
-            layer_size: data_size,
-            compression,
-            blocks,
-
-            channels: ChannelList::new(channels),
-            line_order: LineOrder::Unspecified,
-
-            shared_attributes: ImageAttributes::with_size(data_size),
-            own_attributes: LayerAttributes::named(name),
-
-            chunk_count: compute_chunk_count(compression, data_size, blocks),
-
-            deep: false,
-            deep_data_version: None,
-            max_samples_per_pixel: None,
-        }
-    }
-
-    /// Set the display window, that is, the global clipping rectangle.
-    /// __Must be the same for all headers of a file.__
-    pub fn with_display_window(mut self, display_window: IntegerBounds) -> Self {
-        self.shared_attributes.display_window = display_window;
-        self
-    }
-
-    /// Set the offset of this layer.
-    pub fn with_position(mut self, position: Vec2<i32>) -> Self {
-        self.own_attributes.layer_position = position;
-        self
-    }
-
-    /// Set compression, tiling, and line order. Automatically computes chunk count.
-    pub fn with_encoding(self, compression: Compression, blocks: BlockDescription, line_order: LineOrder) -> Self {
-        Self {
-            chunk_count: compute_chunk_count(compression, self.layer_size, blocks),
-            compression, blocks, line_order,
-            .. self
-        }
-    }
-
-    /// Set **all** attributes of the header that are not shared with all other headers in the image.
-    pub fn with_attributes(self, own_attributes: LayerAttributes) -> Self {
-        Self { own_attributes, .. self }
-    }
-
-    /// Set **all** attributes of the header that are shared with all other headers in the image.
-    pub fn with_shared_attributes(self, shared_attributes: ImageAttributes) -> Self {
-        Self { shared_attributes, .. self }
-    }
-
-    /// Iterate over all blocks, in the order specified by the headers line order attribute.
-    /// Unspecified line order is treated as increasing line order.
-    /// Also enumerates the index of each block in the header, as if it were sorted in increasing line order.
-    pub fn enumerate_ordered_blocks(&self) -> impl Iterator<Item=(usize, TileIndices)> + Send {
-        let increasing_y = self.blocks_increasing_y_order().enumerate();
-
-        // TODO without box?
-        let ordered: Box<dyn Send + Iterator<Item=(usize, TileIndices)>> = {
-            if self.line_order == LineOrder::Decreasing { Box::new(increasing_y.rev()) }
-            else { Box::new(increasing_y) }
-        };
-
-        ordered
-    }
-
-    /*/// Iterate over all blocks, in the order specified by the headers line order attribute.
-    /// Also includes an index of the block if it were `LineOrder::Increasing`, starting at zero for this header.
-    pub fn enumerate_ordered_blocks(&self) -> impl Iterator<Item = (usize, TileIndices)> + Send {
-        let increasing_y = self.blocks_increasing_y_order().enumerate();
-
-        let ordered: Box<dyn Send + Iterator<Item = (usize, TileIndices)>> = {
-            if self.line_order == LineOrder::Decreasing {
-                Box::new(increasing_y.rev()) // TODO without box?
-            }
-            else {
-                Box::new(increasing_y)
-            }
-        };
-
-        ordered
-    }*/
-
-    /// Iterate over all tile indices in this header in `LineOrder::Increasing` order.
-    pub fn blocks_increasing_y_order(&self) -> impl Iterator<Item = TileIndices> + ExactSizeIterator + DoubleEndedIterator {
-        fn tiles_of(image_size: Vec2<usize>, tile_size: Vec2<usize>, level_index: Vec2<usize>) -> impl Iterator<Item=TileIndices> {
-            fn divide_and_rest(total_size: usize, block_size: usize) -> impl Iterator<Item=(usize, usize)> {
-                let block_count = compute_block_count(total_size, block_size);
-                (0..block_count).map(move |block_index| (
-                    block_index, calculate_block_size(total_size, block_size, block_index).expect("block size calculation bug")
-                ))
-            }
-
-            divide_and_rest(image_size.height(), tile_size.height()).flat_map(move |(y_index, tile_height)|{
-                divide_and_rest(image_size.width(), tile_size.width()).map(move |(x_index, tile_width)|{
-                    TileIndices {
-                        size: Vec2(tile_width, tile_height),
-                        location: TileCoordinates { tile_index: Vec2(x_index, y_index), level_index, },
-                    }
-                })
-            })
-        }
-
-        let vec: Vec<TileIndices> = {
-            if let BlockDescription::Tiles(tiles) = self.blocks {
-                match tiles.level_mode {
-                    LevelMode::Singular => {
-                        tiles_of(self.layer_size, tiles.tile_size, Vec2(0, 0)).collect()
-                    },
-                    LevelMode::MipMap => {
-                        mip_map_levels(tiles.rounding_mode, self.layer_size)
-                            .flat_map(move |(level_index, level_size)|{
-                                tiles_of(level_size, tiles.tile_size, Vec2(level_index, level_index))
-                            })
-                            .collect()
-                    },
-                    LevelMode::RipMap => {
-                        rip_map_levels(tiles.rounding_mode, self.layer_size)
-                            .flat_map(move |(level_index, level_size)| {
-                                tiles_of(level_size, tiles.tile_size, level_index)
-                            })
-                            .collect()
-                    }
-                }
-            }
-            else {
-                let tiles = Vec2(self.layer_size.0, self.compression.scan_lines_per_block());
-                tiles_of(self.layer_size, tiles, Vec2(0, 0)).collect()
-            }
-        };
-
-        vec.into_iter() // TODO without collect
-    }
-
-    /* TODO
-    /// The block indices of this header, ordered as they would appear in the file.
-    pub fn ordered_block_indices<'s>(&'s self, layer_index: usize) -> impl 's + Iterator<Item=BlockIndex> {
-        self.enumerate_ordered_blocks().map(|(chunk_index, tile)|{
-            let data_indices = self.get_absolute_block_pixel_coordinates(tile.location).expect("tile coordinate bug");
-
-            BlockIndex {
-                layer: layer_index,
-                level: tile.location.level_index,
-                pixel_position: data_indices.position.to_usize("data indices start").expect("data index bug"),
-                pixel_size: data_indices.size,
-            }
-        })
-    }*/
-
-    // TODO reuse this function everywhere
-    /// The default pixel resolution of a single block (tile or scan line block).
-    /// Not all blocks have this size, because they may be cutoff at the end of the image.
-    pub fn max_block_pixel_size(&self) -> Vec2<usize> {
-        match self.blocks {
-            BlockDescription::ScanLines => Vec2(self.layer_size.0, self.compression.scan_lines_per_block()),
-            BlockDescription::Tiles(tiles) => tiles.tile_size,
-        }
-    }
-
-    /// Calculate the position of a block in the global infinite 2D space of a file. May be negative.
-    pub fn get_block_data_window_pixel_coordinates(&self, tile: TileCoordinates) -> Result<IntegerBounds> {
-        let data = self.get_absolute_block_pixel_coordinates(tile)?;
-        Ok(data.with_origin(self.own_attributes.layer_position))
-    }
-
-    /// Calculate the pixel index rectangle inside this header. Is not negative. Starts at `0`.
-    pub fn get_absolute_block_pixel_coordinates(&self, tile: TileCoordinates) -> Result<IntegerBounds> {
-        if let BlockDescription::Tiles(tiles) = self.blocks {
-            let Vec2(data_width, data_height) = self.layer_size;
-
-            let data_width = compute_level_size(tiles.rounding_mode, data_width, tile.level_index.x());
-            let data_height = compute_level_size(tiles.rounding_mode, data_height, tile.level_index.y());
-            let absolute_tile_coordinates = tile.to_data_indices(tiles.tile_size, Vec2(data_width, data_height))?;
-
-            if absolute_tile_coordinates.position.x() as i64 >= data_width as i64 || absolute_tile_coordinates.position.y() as i64 >= data_height as i64 {
-                return Err(Error::invalid("data block tile index"))
-            }
-
-            Ok(absolute_tile_coordinates)
-        }
-        else { // this is a scanline image
-            debug_assert_eq!(tile.tile_index.0, 0, "block index calculation bug");
-
-            let (y, height) = calculate_block_position_and_size(
-                self.layer_size.height(),
-                self.compression.scan_lines_per_block(),
-                tile.tile_index.y()
-            )?;
-
-            Ok(IntegerBounds {
-                position: Vec2(0, usize_to_i32(y)),
-                size: Vec2(self.layer_size.width(), height)
-            })
-        }
-
-        // TODO deep data?
-    }
-
-    /// Return the tile index, converting scan line block coordinates to tile indices.
-    /// Starts at `0` and is not negative.
-    pub fn get_block_data_indices(&self, block: &CompressedBlock) -> Result<TileCoordinates> {
-        Ok(match block {
-            CompressedBlock::Tile(ref tile) => {
-                tile.coordinates
-            },
-
-            CompressedBlock::ScanLine(ref block) => {
-                let size = self.compression.scan_lines_per_block() as i32;
-
-                let diff = block.y_coordinate.checked_sub(self.own_attributes.layer_position.y()).ok_or(Error::invalid("invalid header"))?;
-                let y = diff.checked_div(size).ok_or(Error::invalid("invalid header"))?;
-
-                if y < 0 {
-                    return Err(Error::invalid("scan block y coordinate"));
-                }
-
-                TileCoordinates {
-                    tile_index: Vec2(0, y as usize),
-                    level_index: Vec2(0, 0)
-                }
-            },
-
-            _ => return Err(Error::unsupported("deep data not supported yet"))
-        })
-    }
-
-    /// Computes the absolute tile coordinate data indices, which start at `0`.
-    pub fn get_scan_line_block_tile_coordinates(&self, block_y_coordinate: i32) -> Result<TileCoordinates> {
-        let size = self.compression.scan_lines_per_block() as i32;
-
-        let diff = block_y_coordinate.checked_sub(self.own_attributes.layer_position.1).ok_or(Error::invalid("invalid header"))?;
-        let y = diff.checked_div(size).ok_or(Error::invalid("invalid header"))?;
-
-        if y < 0 {
-            return Err(Error::invalid("scan block y coordinate"));
-        }
-
-        Ok(TileCoordinates {
-            tile_index: Vec2(0, y as usize),
-            level_index: Vec2(0, 0)
-        })
-    }
-
-    /// Maximum byte length of an uncompressed or compressed block, used for validation.
-    pub fn max_block_byte_size(&self) -> usize {
-        self.channels.bytes_per_pixel * match self.blocks {
-            BlockDescription::Tiles(tiles) => tiles.tile_size.area(),
-            BlockDescription::ScanLines => self.compression.scan_lines_per_block() * self.layer_size.width()
-            // TODO What about deep data???
-        }
-    }
-
-    /// Returns the number of bytes that the pixels of this header will require
-    /// when stored without compression. Respects multi-resolution levels and subsampling.
-    pub fn total_pixel_bytes(&self) -> usize {
-        assert!(!self.deep);
-
-        let pixel_count_of_levels = |size: Vec2<usize>| -> usize {
-            match self.blocks {
-                BlockDescription::ScanLines => size.area(),
-                BlockDescription::Tiles(tile_description) => match tile_description.level_mode {
-                    LevelMode::Singular => size.area(),
-
-                    LevelMode::MipMap => mip_map_levels(tile_description.rounding_mode, size)
-                        .map(|(_, size)| size.area()).sum(),
-
-                    LevelMode::RipMap => rip_map_levels(tile_description.rounding_mode, size)
-                        .map(|(_, size)| size.area()).sum(),
-                }
-            }
-        };
-
-        self.channels.list.iter()
-            .map(|channel: &ChannelDescription|
-                pixel_count_of_levels(channel.subsampled_resolution(self.layer_size)) * channel.sample_type.bytes_per_sample()
-            )
-            .sum()
-
-    }
-
-    /// Approximates the maximum number of bytes that the pixels of this header will consume in a file.
-    /// Due to compression, the actual byte size may be smaller.
-    pub fn max_pixel_file_bytes(&self) -> usize {
-        assert!(!self.deep);
-
-        self.chunk_count * 64 // at most 64 bytes overhead for each chunk (header index, tile description, chunk size, and more)
-            + self.total_pixel_bytes()
-    }
-
-    /// Validate this instance.
-    pub fn validate(&self, is_multilayer: bool, long_names: &mut bool, strict: bool) -> UnitResult {
-
-        self.data_window().validate(None)?;
-        self.shared_attributes.display_window.validate(None)?;
-
-        if strict {
-            if is_multilayer {
-                if self.own_attributes.layer_name.is_none() {
-                    return Err(missing_attribute("layer name for multi layer file"));
-                }
-            }
-
-            if self.blocks == BlockDescription::ScanLines && self.line_order == LineOrder::Unspecified {
-                return Err(Error::invalid("unspecified line order in scan line images"));
-            }
-
-            if self.layer_size == Vec2(0, 0) {
-                return Err(Error::invalid("empty data window"));
-            }
-
-            if self.shared_attributes.display_window.size == Vec2(0,0) {
-                return Err(Error::invalid("empty display window"));
-            }
-
-            if !self.shared_attributes.pixel_aspect.is_normal() || self.shared_attributes.pixel_aspect < 1.0e-6 || self.shared_attributes.pixel_aspect > 1.0e6 {
-                return Err(Error::invalid("pixel aspect ratio"));
-            }
-
-            if self.own_attributes.screen_window_width < 0.0 {
-                return Err(Error::invalid("screen window width"));
-            }
-        }
-
-        let allow_subsampling = !self.deep && self.blocks == BlockDescription::ScanLines;
-        self.channels.validate(allow_subsampling, self.data_window(), strict)?;
-
-        for (name, value) in &self.shared_attributes.other {
-            attribute::validate(name, value, long_names, allow_subsampling, self.data_window(), strict)?;
-        }
-
-        for (name, value) in &self.own_attributes.other {
-            attribute::validate(name, value, long_names, allow_subsampling, self.data_window(), strict)?;
-        }
-
-        // this is only to check whether someone tampered with our precious values, to avoid writing an invalid file
-        if self.chunk_count != compute_chunk_count(self.compression, self.layer_size, self.blocks) {
-            return Err(Error::invalid("chunk count attribute")); // TODO this may be an expensive check?
-        }
-
-        // check if attribute names appear twice
-        if strict {
-            for (name, _) in &self.shared_attributes.other {
-                if self.own_attributes.other.contains_key(name) {
-                    return Err(Error::invalid(format!("duplicate attribute name: `{}`", name)));
-                }
-            }
-
-            for &reserved in header::standard_names::ALL.iter() {
-                let name  = Text::from_bytes_unchecked(SmallVec::from_slice(reserved));
-                if self.own_attributes.other.contains_key(&name) || self.shared_attributes.other.contains_key(&name) {
-                    return Err(Error::invalid(format!(
-                        "attribute name `{}` is reserved and cannot be custom",
-                        Text::from_bytes_unchecked(reserved.into())
-                    )));
-                }
-            }
-        }
-
-        if self.deep {
-            if strict {
-                if self.own_attributes.layer_name.is_none() {
-                    return Err(missing_attribute("layer name for deep file"));
-                }
-
-                if self.max_samples_per_pixel.is_none() {
-                    return Err(Error::invalid("missing max samples per pixel attribute for deepdata"));
-                }
-            }
-
-            match self.deep_data_version {
-                Some(1) => {},
-                Some(_) => return Err(Error::unsupported("deep data version")),
-                None => return Err(missing_attribute("deep data version")),
-            }
-
-            if !self.compression.supports_deep_data() {
-                return Err(Error::invalid("compression method does not support deep data"));
-            }
-        }
-
-        Ok(())
-    }
-
-    /// Read the headers without validating them.
-    pub fn read_all(read: &mut PeekRead<impl Read>, version: &Requirements, pedantic: bool) -> Result<Headers> {
-        if !version.is_multilayer() {
-            Ok(smallvec![ Header::read(read, version, pedantic)? ])
-        }
-        else {
-            let mut headers = SmallVec::new();
-
-            while !sequence_end::has_come(read)? {
-                headers.push(Header::read(read, version, pedantic)?);
-            }
-
-            Ok(headers)
-        }
-    }
-
-    /// Without validation, write the headers to the byte stream.
-    pub fn write_all(headers: &[Header], write: &mut impl Write, is_multilayer: bool) -> UnitResult {
-        for header in headers {
-            header.write(write)?;
-        }
-
-        if is_multilayer {
-            sequence_end::write(write)?;
-        }
-
-        Ok(())
-    }
-
-    /// Read the value without validating.
-    pub fn read(read: &mut PeekRead<impl Read>, requirements: &Requirements, pedantic: bool) -> Result<Self> {
-        let max_string_len = if requirements.has_long_names { 256 } else { 32 }; // TODO DRY this information
-
-        // these required attributes will be filled when encountered while parsing
-        let mut tiles = None;
-        let mut block_type = None;
-        let mut version = None;
-        let mut chunk_count = None;
-        let mut max_samples_per_pixel = None;
-        let mut channels = None;
-        let mut compression = None;
-        let mut data_window = None;
-        let mut display_window = None;
-        let mut line_order = None;
-
-        let mut dwa_compression_level = None;
-
-        let mut layer_attributes = LayerAttributes::default();
-        let mut image_attributes = ImageAttributes::new(IntegerBounds::zero());
-
-        // read each attribute in this header
-        while !sequence_end::has_come(read)? {
-            let (attribute_name, value) = attribute::read(read, max_string_len)?;
-
-            // if the attribute value itself is ok, record it
-            match value {
-                Ok(value) => {
-                    use crate::meta::header::standard_names as name;
-                    use crate::meta::attribute::AttributeValue::*;
-
-                    // if the attribute is a required attribute, set the corresponding variable directly.
-                    // otherwise, add the attribute to the vector of custom attributes
-
-                    // the following attributes will only be set if the type matches the commonly used type for that attribute
-                    match (attribute_name.as_slice(), value) {
-                        (name::BLOCK_TYPE, Text(value)) => block_type = Some(attribute::BlockType::parse(value)?),
-                        (name::TILES, TileDescription(value)) => tiles = Some(value),
-                        (name::CHANNELS, ChannelList(value)) => channels = Some(value),
-                        (name::COMPRESSION, Compression(value)) => compression = Some(value),
-                        (name::DATA_WINDOW, IntegerBounds(value)) => data_window = Some(value),
-                        (name::DISPLAY_WINDOW, IntegerBounds(value)) => display_window = Some(value),
-                        (name::LINE_ORDER, LineOrder(value)) => line_order = Some(value),
-                        (name::DEEP_DATA_VERSION, I32(value)) => version = Some(value),
-
-                        (name::MAX_SAMPLES, I32(value)) => max_samples_per_pixel = Some(
-                            i32_to_usize(value, "max sample count")?
-                        ),
-
-                        (name::CHUNKS, I32(value)) => chunk_count = Some(
-                            i32_to_usize(value, "chunk count")?
-                        ),
-
-                        (name::NAME, Text(value)) => layer_attributes.layer_name = Some(value),
-                        (name::WINDOW_CENTER, FloatVec2(value)) => layer_attributes.screen_window_center = value,
-                        (name::WINDOW_WIDTH, F32(value)) => layer_attributes.screen_window_width = value,
-
-                        (name::WHITE_LUMINANCE, F32(value)) => layer_attributes.white_luminance = Some(value),
-                        (name::ADOPTED_NEUTRAL, FloatVec2(value)) => layer_attributes.adopted_neutral = Some(value),
-                        (name::RENDERING_TRANSFORM, Text(value)) => layer_attributes.rendering_transform_name = Some(value),
-                        (name::LOOK_MOD_TRANSFORM, Text(value)) => layer_attributes.look_modification_transform_name = Some(value),
-                        (name::X_DENSITY, F32(value)) => layer_attributes.horizontal_density = Some(value),
-
-                        (name::OWNER, Text(value)) => layer_attributes.owner = Some(value),
-                        (name::COMMENTS, Text(value)) => layer_attributes.comments = Some(value),
-                        (name::CAPTURE_DATE, Text(value)) => layer_attributes.capture_date = Some(value),
-                        (name::UTC_OFFSET, F32(value)) => layer_attributes.utc_offset = Some(value),
-                        (name::LONGITUDE, F32(value)) => layer_attributes.longitude = Some(value),
-                        (name::LATITUDE, F32(value)) => layer_attributes.latitude = Some(value),
-                        (name::ALTITUDE, F32(value)) => layer_attributes.altitude = Some(value),
-                        (name::FOCUS, F32(value)) => layer_attributes.focus = Some(value),
-                        (name::EXPOSURE_TIME, F32(value)) => layer_attributes.exposure = Some(value),
-                        (name::APERTURE, F32(value)) => layer_attributes.aperture = Some(value),
-                        (name::ISO_SPEED, F32(value)) => layer_attributes.iso_speed = Some(value),
-                        (name::ENVIRONMENT_MAP, EnvironmentMap(value)) => layer_attributes.environment_map = Some(value),
-                        (name::KEY_CODE, KeyCode(value)) => layer_attributes.film_key_code = Some(value),
-                        (name::WRAP_MODES, Text(value)) => layer_attributes.wrap_mode_name = Some(value),
-                        (name::FRAMES_PER_SECOND, Rational(value)) => layer_attributes.frames_per_second = Some(value),
-                        (name::MULTI_VIEW, TextVector(value)) => layer_attributes.multi_view_names = Some(value),
-                        (name::WORLD_TO_CAMERA, Matrix4x4(value)) => layer_attributes.world_to_camera = Some(value),
-                        (name::WORLD_TO_NDC, Matrix4x4(value)) => layer_attributes.world_to_normalized_device = Some(value),
-                        (name::DEEP_IMAGE_STATE, Rational(value)) => layer_attributes.deep_image_state = Some(value),
-                        (name::ORIGINAL_DATA_WINDOW, IntegerBounds(value)) => layer_attributes.original_data_window = Some(value),
-                        (name::DWA_COMPRESSION_LEVEL, F32(value)) => dwa_compression_level = Some(value),
-                        (name::PREVIEW, Preview(value)) => layer_attributes.preview = Some(value),
-                        (name::VIEW, Text(value)) => layer_attributes.view_name = Some(value),
-
-                        (name::NEAR, F32(value)) => layer_attributes.near_clip_plane = Some(value),
-                        (name::FAR, F32(value)) => layer_attributes.far_clip_plane = Some(value),
-                        (name::FOV_X, F32(value)) => layer_attributes.horizontal_field_of_view = Some(value),
-                        (name::FOV_Y, F32(value)) => layer_attributes.vertical_field_of_view = Some(value),
-                        (name::SOFTWARE, Text(value)) => layer_attributes.software_name = Some(value),
-
-                        (name::PIXEL_ASPECT, F32(value)) => image_attributes.pixel_aspect = value,
-                        (name::TIME_CODE, TimeCode(value)) => image_attributes.time_code = Some(value),
-                        (name::CHROMATICITIES, Chromaticities(value)) => image_attributes.chromaticities = Some(value),
-
-                        // insert unknown attributes of these types into image attributes,
-                        // as these must be the same for all headers
-                        (_, value @ Chromaticities(_)) |
-                        (_, value @ TimeCode(_)) => {
-                            image_attributes.other.insert(attribute_name, value);
-                        },
-
-                        // insert unknown attributes into layer attributes
-                        (_, value) => {
-                            layer_attributes.other.insert(attribute_name, value);
-                        },
-
-                    }
-                },
-
-                // in case the attribute value itself is not ok, but the rest of the image is
-                // only abort reading the image if desired
-                Err(error) => {
-                    if pedantic { return Err(error); }
-                }
-            }
-        }
-
-        // construct compression with parameters from properties
-        let compression = match (dwa_compression_level, compression) {
-            (Some(level), Some(Compression::DWAA(_))) => Some(Compression::DWAA(Some(level))),
-            (Some(level), Some(Compression::DWAB(_))) => Some(Compression::DWAB(Some(level))),
-            (_, other) => other,
-            // FIXME dwa compression level gets lost if any other compression is used later in the process
-        };
-
-        let compression = compression.ok_or(missing_attribute("compression"))?;
-        image_attributes.display_window = display_window.ok_or(missing_attribute("display window"))?;
-
-        let data_window = data_window.ok_or(missing_attribute("data window"))?;
-        data_window.validate(None)?; // validate now to avoid errors when computing the chunk_count
-        layer_attributes.layer_position = data_window.position;
-
-
-        // validate now to avoid errors when computing the chunk_count
-        if let Some(tiles) = tiles { tiles.validate()?; }
-        let blocks = match block_type {
-            None if requirements.is_single_layer_and_tiled => {
-                BlockDescription::Tiles(tiles.ok_or(missing_attribute("tiles"))?)
-            },
-            Some(BlockType::Tile) | Some(BlockType::DeepTile) => {
-                BlockDescription::Tiles(tiles.ok_or(missing_attribute("tiles"))?)
-            },
-
-            _ => BlockDescription::ScanLines,
-        };
-
-        let computed_chunk_count = compute_chunk_count(compression, data_window.size, blocks);
-        if chunk_count.is_some() && pedantic && chunk_count != Some(computed_chunk_count) {
-            return Err(Error::invalid("chunk count not matching data size"));
-        }
-
-        let header = Header {
-            compression,
-
-            // always compute ourselves, because we cannot trust anyone out there 😱
-            chunk_count: computed_chunk_count,
-
-            layer_size: data_window.size,
-
-            shared_attributes: image_attributes,
-            own_attributes: layer_attributes,
-
-            channels: channels.ok_or(missing_attribute("channels"))?,
-            line_order: line_order.unwrap_or(LineOrder::Unspecified),
-
-            blocks,
-            max_samples_per_pixel,
-            deep_data_version: version,
-            deep: block_type == Some(BlockType::DeepScanLine) || block_type == Some(BlockType::DeepTile),
-        };
-
-        Ok(header)
-    }
-
-    /// Without validation, write this instance to the byte stream.
-    pub fn write(&self, write: &mut impl Write) -> UnitResult {
-
-        macro_rules! write_attributes {
-            ( $($name: ident : $variant: ident = $value: expr),* ) => { $(
-                attribute::write($name, & $variant ($value .clone()), write)?; // TODO without clone
-            )* };
-        }
-
-        macro_rules! write_optional_attributes {
-            ( $($name: ident : $variant: ident = $value: expr),* ) => { $(
-                if let Some(value) = $value {
-                    attribute::write($name, & $variant (value.clone()), write)?; // TODO without clone
-                };
-            )* };
-        }
-
-        use crate::meta::header::standard_names::*;
-        use AttributeValue::*;
-
-        let (block_type, tiles) = match self.blocks {
-            BlockDescription::ScanLines => (attribute::BlockType::ScanLine, None),
-            BlockDescription::Tiles(tiles) => (attribute::BlockType::Tile, Some(tiles))
-        };
-
-        fn usize_as_i32(value: usize) -> AttributeValue {
-            I32(i32::try_from(value).expect("u32 exceeds i32 range"))
-        }
-
-        write_optional_attributes!(
-            TILES: TileDescription = &tiles,
-            DEEP_DATA_VERSION: I32 = &self.deep_data_version,
-            MAX_SAMPLES: usize_as_i32 = &self.max_samples_per_pixel
-        );
-
-        write_attributes!(
-            // chunks is not actually required, but always computed in this library anyways
-            CHUNKS: usize_as_i32 = &self.chunk_count,
-
-            BLOCK_TYPE: BlockType = &block_type,
-            CHANNELS: ChannelList = &self.channels,
-            COMPRESSION: Compression = &self.compression,
-            LINE_ORDER: LineOrder = &self.line_order,
-            DATA_WINDOW: IntegerBounds = &self.data_window(),
-
-            DISPLAY_WINDOW: IntegerBounds = &self.shared_attributes.display_window,
-            PIXEL_ASPECT: F32 = &self.shared_attributes.pixel_aspect,
-
-            WINDOW_CENTER: FloatVec2 = &self.own_attributes.screen_window_center,
-            WINDOW_WIDTH: F32 = &self.own_attributes.screen_window_width
-        );
-
-        write_optional_attributes!(
-            NAME: Text = &self.own_attributes.layer_name,
-            WHITE_LUMINANCE: F32 = &self.own_attributes.white_luminance,
-            ADOPTED_NEUTRAL: FloatVec2 = &self.own_attributes.adopted_neutral,
-            RENDERING_TRANSFORM: Text = &self.own_attributes.rendering_transform_name,
-            LOOK_MOD_TRANSFORM: Text = &self.own_attributes.look_modification_transform_name,
-            X_DENSITY: F32 = &self.own_attributes.horizontal_density,
-            OWNER: Text = &self.own_attributes.owner,
-            COMMENTS: Text = &self.own_attributes.comments,
-            CAPTURE_DATE: Text = &self.own_attributes.capture_date,
-            UTC_OFFSET: F32 = &self.own_attributes.utc_offset,
-            LONGITUDE: F32 = &self.own_attributes.longitude,
-            LATITUDE: F32 = &self.own_attributes.latitude,
-            ALTITUDE: F32 = &self.own_attributes.altitude,
-            FOCUS: F32 = &self.own_attributes.focus,
-            EXPOSURE_TIME: F32 = &self.own_attributes.exposure,
-            APERTURE: F32 = &self.own_attributes.aperture,
-            ISO_SPEED: F32 = &self.own_attributes.iso_speed,
-            ENVIRONMENT_MAP: EnvironmentMap = &self.own_attributes.environment_map,
-            KEY_CODE: KeyCode = &self.own_attributes.film_key_code,
-            TIME_CODE: TimeCode = &self.shared_attributes.time_code,
-            WRAP_MODES: Text = &self.own_attributes.wrap_mode_name,
-            FRAMES_PER_SECOND: Rational = &self.own_attributes.frames_per_second,
-            MULTI_VIEW: TextVector = &self.own_attributes.multi_view_names,
-            WORLD_TO_CAMERA: Matrix4x4 = &self.own_attributes.world_to_camera,
-            WORLD_TO_NDC: Matrix4x4 = &self.own_attributes.world_to_normalized_device,
-            DEEP_IMAGE_STATE: Rational = &self.own_attributes.deep_image_state,
-            ORIGINAL_DATA_WINDOW: IntegerBounds = &self.own_attributes.original_data_window,
-            CHROMATICITIES: Chromaticities = &self.shared_attributes.chromaticities,
-            PREVIEW: Preview = &self.own_attributes.preview,
-            VIEW: Text = &self.own_attributes.view_name,
-            NEAR: F32 = &self.own_attributes.near_clip_plane,
-            FAR: F32 = &self.own_attributes.far_clip_plane,
-            FOV_X: F32 = &self.own_attributes.horizontal_field_of_view,
-            FOV_Y: F32 = &self.own_attributes.vertical_field_of_view,
-            SOFTWARE: Text = &self.own_attributes.software_name
-        );
-
-        // dwa writes compression parameters as attribute.
-        match self.compression {
-            attribute::Compression::DWAA(Some(level)) |
-            attribute::Compression::DWAB(Some(level)) =>
-                attribute::write(DWA_COMPRESSION_LEVEL, &F32(level), write)?,
-
-            _ => {}
-        };
-
-
-        for (name, value) in &self.shared_attributes.other {
-            attribute::write(name.as_slice(), value, write)?;
-        }
-
-        for (name, value) in &self.own_attributes.other {
-            attribute::write(name.as_slice(), value, write)?;
-        }
-
-        sequence_end::write(write)?;
-        Ok(())
-    }
-
-    /// The rectangle describing the bounding box of this layer
-    /// within the infinite global 2D space of the file.
-    pub fn data_window(&self) -> IntegerBounds {
-        IntegerBounds::new(self.own_attributes.layer_position, self.layer_size)
-    }
-}
-
-
-
-/// Collection of required attribute names.
-pub mod standard_names {
-    macro_rules! define_required_attribute_names {
-        ( $($name: ident  :  $value: expr),* ) => {
-
-            /// A list containing all reserved names.
-            pub const ALL: &'static [&'static [u8]] = &[
-                $( $value ),*
-            ];
-
-            $(
-                /// The byte-string name of this required attribute as it appears in an exr file.
-                pub const $name: &'static [u8] = $value;
-            )*
-        };
-    }
-
-    define_required_attribute_names! {
-        TILES: b"tiles",
-        NAME: b"name",
-        BLOCK_TYPE: b"type",
-        DEEP_DATA_VERSION: b"version",
-        CHUNKS: b"chunkCount",
-        MAX_SAMPLES: b"maxSamplesPerPixel",
-        CHANNELS: b"channels",
-        COMPRESSION: b"compression",
-        DATA_WINDOW: b"dataWindow",
-        DISPLAY_WINDOW: b"displayWindow",
-        LINE_ORDER: b"lineOrder",
-        PIXEL_ASPECT: b"pixelAspectRatio",
-        WINDOW_CENTER: b"screenWindowCenter",
-        WINDOW_WIDTH: b"screenWindowWidth",
-        WHITE_LUMINANCE: b"whiteLuminance",
-        ADOPTED_NEUTRAL: b"adoptedNeutral",
-        RENDERING_TRANSFORM: b"renderingTransform",
-        LOOK_MOD_TRANSFORM: b"lookModTransform",
-        X_DENSITY: b"xDensity",
-        OWNER: b"owner",
-        COMMENTS: b"comments",
-        CAPTURE_DATE: b"capDate",
-        UTC_OFFSET: b"utcOffset",
-        LONGITUDE: b"longitude",
-        LATITUDE: b"latitude",
-        ALTITUDE: b"altitude",
-        FOCUS: b"focus",
-        EXPOSURE_TIME: b"expTime",
-        APERTURE: b"aperture",
-        ISO_SPEED: b"isoSpeed",
-        ENVIRONMENT_MAP: b"envmap",
-        KEY_CODE: b"keyCode",
-        TIME_CODE: b"timeCode",
-        WRAP_MODES: b"wrapmodes",
-        FRAMES_PER_SECOND: b"framesPerSecond",
-        MULTI_VIEW: b"multiView",
-        WORLD_TO_CAMERA: b"worldToCamera",
-        WORLD_TO_NDC: b"worldToNDC",
-        DEEP_IMAGE_STATE: b"deepImageState",
-        ORIGINAL_DATA_WINDOW: b"originalDataWindow",
-        DWA_COMPRESSION_LEVEL: b"dwaCompressionLevel",
-        PREVIEW: b"preview",
-        VIEW: b"view",
-        CHROMATICITIES: b"chromaticities",
-        NEAR: b"near",
-        FAR: b"far",
-        FOV_X: b"fieldOfViewHorizontal",
-        FOV_Y: b"fieldOfViewVertical",
-        SOFTWARE: b"software"
-    }
-}
-
-
-impl Default for LayerAttributes {
-    fn default() -> Self {
-        Self {
-            layer_position: Vec2(0, 0),
-            screen_window_center: Vec2(0.0, 0.0),
-            screen_window_width: 1.0,
-            layer_name: None,
-            white_luminance: None,
-            adopted_neutral: None,
-            rendering_transform_name: None,
-            look_modification_transform_name: None,
-            horizontal_density: None,
-            owner: None,
-            comments: None,
-            capture_date: None,
-            utc_offset: None,
-            longitude: None,
-            latitude: None,
-            altitude: None,
-            focus: None,
-            exposure: None,
-            aperture: None,
-            iso_speed: None,
-            environment_map: None,
-            film_key_code: None,
-            wrap_mode_name: None,
-            frames_per_second: None,
-            multi_view_names: None,
-            world_to_camera: None,
-            world_to_normalized_device: None,
-            deep_image_state: None,
-            original_data_window: None,
-            preview: None,
-            view_name: None,
-            software_name: None,
-            near_clip_plane: None,
-            far_clip_plane: None,
-            horizontal_field_of_view: None,
-            vertical_field_of_view: None,
-            other: Default::default()
-        }
-    }
-}
-
-impl std::fmt::Debug for LayerAttributes {
-    fn fmt(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        let default_self = Self::default();
-
-        let mut debug = formatter.debug_struct("LayerAttributes (default values omitted)");
-
-        // always debug the following field
-        debug.field("name", &self.layer_name);
-
-        macro_rules! debug_non_default_fields {
-            ( $( $name: ident ),* ) => { $(
-
-                if self.$name != default_self.$name {
-                    debug.field(stringify!($name), &self.$name);
-                }
-
-            )* };
-        }
-
-        // only debug these fields if they are not the default value
-        debug_non_default_fields! {
-            screen_window_center, screen_window_width,
-            white_luminance, adopted_neutral, horizontal_density,
-            rendering_transform_name, look_modification_transform_name,
-            owner, comments,
-            capture_date, utc_offset,
-            longitude, latitude, altitude,
-            focus, exposure, aperture, iso_speed,
-            environment_map, film_key_code, wrap_mode_name,
-            frames_per_second, multi_view_names,
-            world_to_camera, world_to_normalized_device,
-            deep_image_state, original_data_window,
-            preview, view_name,
-            vertical_field_of_view, horizontal_field_of_view,
-            near_clip_plane, far_clip_plane, software_name
-        }
-
-        for (name, value) in &self.other {
-            debug.field(&format!("\"{}\"", name), value);
-        }
-
-        // debug.finish_non_exhaustive() TODO
-        debug.finish()
-    }
-}