Initial vendor packages

Signed-off-by: Valentin Popov <valentin@popov.link>

4 files changed, 984 insertions, 0 deletions

diff --git a/vendor/exr/src/image/write/channels.rs b/vendor/exr/src/image/write/channels.rs
new file mode 100644
index 0000000..2450f09
--- /dev/null
+++ b/vendor/exr/src/image/write/channels.rs
@@ -0,0 +1,407 @@
+//! How to read arbitrary channels and rgb channels.
+
+use crate::prelude::*;
+use crate::io::*;
+use crate::math::*;
+use crate::meta::{header::*, attribute::*};
+use crate::block::*;
+use crate::image::recursive::*;
+use crate::block::samples::*;
+use crate::image::write::samples::*;
+
+use std::marker::PhantomData;
+
+
+/// Enables an image containing this list of channels to be written to a file.
+pub trait WritableChannels<'slf> {
+
+    /// Generate the file meta data for this list of channel
+    fn infer_channel_list(&self) -> ChannelList;
+
+    ///  Generate the file meta data of whether and how resolution levels should be stored in the file
+    fn infer_level_modes(&self) -> (LevelMode, RoundingMode);
+
+    /// The type of temporary writer
+    type Writer: ChannelsWriter;
+
+    /// Create a temporary writer for this list of channels
+    fn create_writer(&'slf self, header: &Header) -> Self::Writer;
+}
+
+/// A temporary writer for a list of channels
+pub trait ChannelsWriter: Sync {
+
+    /// Deliver a block of pixels, containing all channel data, to be stored in the file
+    fn extract_uncompressed_block(&self, header: &Header, block: BlockIndex) -> Vec<u8>; // TODO return uncompressed block?
+}
+
+
+/// Define how to get a pixel from your custom pixel storage.
+/// Can be a closure of type [`Sync + Fn(Vec2<usize>) -> YourPixel`].
+pub trait GetPixel: Sync {
+
+    /// The pixel tuple containing `f32`, `f16`, `u32` and `Sample` values.
+    /// The length of the tuple must match the number of channels in the image.
+    type Pixel;
+
+    /// Inspect a single pixel at the requested position.
+    /// Will be called exactly once for each pixel in the image.
+    /// The position will not exceed the image dimensions.
+    /// Might be called from multiple threads at the same time.
+    fn get_pixel(&self, position: Vec2<usize>) -> Self::Pixel;
+}
+
+impl<F, P> GetPixel for F where F: Sync + Fn(Vec2<usize>) -> P {
+    type Pixel = P;
+    fn get_pixel(&self, position: Vec2<usize>) -> P { self(position) }
+}
+
+impl<'samples, Samples> WritableChannels<'samples> for AnyChannels<Samples>
+    where Samples: 'samples + WritableSamples<'samples>
+{
+    fn infer_channel_list(&self) -> ChannelList {
+        ChannelList::new(self.list.iter().map(|channel| ChannelDescription {
+            name: channel.name.clone(),
+            sample_type: channel.sample_data.sample_type(),
+            quantize_linearly: channel.quantize_linearly,
+            sampling: channel.sampling
+        }).collect())
+    }
+
+    fn infer_level_modes(&self) -> (LevelMode, RoundingMode) {
+        let mode = self.list.iter().next().expect("zero channels in list").sample_data.infer_level_modes();
+
+        debug_assert!(
+            std::iter::repeat(mode).zip(self.list.iter().skip(1))
+                .all(|(first, other)| other.sample_data.infer_level_modes() == first),
+
+            "level mode must be the same across all levels (do not nest resolution levels!)"
+        );
+
+        mode
+    }
+
+    type Writer = AnyChannelsWriter<Samples::Writer>;
+    fn create_writer(&'samples self, header: &Header) -> Self::Writer {
+        let channels = self.list.iter()
+            .map(|chan| chan.sample_data.create_samples_writer(header))
+            .collect();
+
+        AnyChannelsWriter { channels }
+    }
+}
+
+/// A temporary writer for an arbitrary list of channels
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct AnyChannelsWriter<SamplesWriter> {
+    channels: SmallVec<[SamplesWriter; 4]>
+}
+
+impl<Samples> ChannelsWriter for AnyChannelsWriter<Samples> where Samples: SamplesWriter {
+    fn extract_uncompressed_block(&self, header: &Header, block_index: BlockIndex) -> Vec<u8> {
+        UncompressedBlock::collect_block_data_from_lines(&header.channels, block_index, |line_ref| {
+            self.channels[line_ref.location.channel].extract_line(line_ref)
+        })
+    }
+}
+
+
+
+
+
+
+impl<'c, Channels, Storage>
+WritableChannels<'c> for SpecificChannels<Storage, Channels>
+where
+    Storage: 'c + GetPixel,
+    Storage::Pixel: IntoRecursive,
+    Channels: 'c + Sync + Clone + IntoRecursive,
+    <Channels as IntoRecursive>::Recursive: WritableChannelsDescription<<Storage::Pixel as IntoRecursive>::Recursive>,
+{
+    fn infer_channel_list(&self) -> ChannelList {
+        let mut vec = self.channels.clone().into_recursive().channel_descriptions_list();
+        vec.sort_unstable_by_key(|channel:&ChannelDescription| channel.name.clone()); // TODO no clone?
+
+        debug_assert!(
+            // check for equal neighbors in sorted vec
+            vec.iter().zip(vec.iter().skip(1)).all(|(prev, next)| prev.name != next.name),
+            "specific channels contain duplicate channel names"
+        );
+
+        ChannelList::new(vec)
+    }
+
+    fn infer_level_modes(&self) -> (LevelMode, RoundingMode) {
+        (LevelMode::Singular, RoundingMode::Down) // TODO
+    }
+
+    type Writer = SpecificChannelsWriter<
+        'c,
+        <<Channels as IntoRecursive>::Recursive as WritableChannelsDescription<<Storage::Pixel as IntoRecursive>::Recursive>>::RecursiveWriter,
+        Storage,
+        Channels
+    >;
+
+    fn create_writer(&'c self, header: &Header) -> Self::Writer {
+        SpecificChannelsWriter {
+            channels: self,
+            recursive_channel_writer: self.channels.clone().into_recursive().create_recursive_writer(&header.channels),
+        }
+    }
+}
+
+
+
+/// A temporary writer for a layer of channels, alpha being optional
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct SpecificChannelsWriter<'channels, PixelWriter, Storage, Channels> {
+    channels: &'channels SpecificChannels<Storage, Channels>, // TODO this need not be a reference?? impl writer for specific_channels directly?
+    recursive_channel_writer: PixelWriter,
+}
+
+
+impl<'channels, PxWriter, Storage, Channels> ChannelsWriter
+for SpecificChannelsWriter<'channels, PxWriter, Storage, Channels>
+    where
+        Channels: Sync,
+        Storage: GetPixel,
+        Storage::Pixel: IntoRecursive,
+        PxWriter: Sync + RecursivePixelWriter<<Storage::Pixel as IntoRecursive>::Recursive>,
+{
+    fn extract_uncompressed_block(&self, header: &Header, block_index: BlockIndex) -> Vec<u8> {
+        let block_bytes = block_index.pixel_size.area() * header.channels.bytes_per_pixel;
+        let mut block_bytes = vec![0_u8; block_bytes];
+
+        let width = block_index.pixel_size.0;
+        let line_bytes = width * header.channels.bytes_per_pixel;
+        let byte_lines = block_bytes.chunks_exact_mut(line_bytes);
+        assert_eq!(byte_lines.len(), block_index.pixel_size.height(), "invalid block line splits");
+
+        //dbg!(width, line_bytes, header.channels.bytes_per_pixel, byte_lines.len());
+
+        let mut pixel_line = Vec::with_capacity(width);
+
+        for (y, line_bytes) in byte_lines.enumerate() {
+            pixel_line.clear();
+            pixel_line.extend((0 .. width).map(|x|
+                self.channels.pixels.get_pixel(block_index.pixel_position + Vec2(x, y)).into_recursive()
+            ));
+
+            self.recursive_channel_writer.write_pixels(line_bytes, pixel_line.as_slice(), |px| px);
+        }
+
+        block_bytes
+    }
+}
+
+/// A tuple containing either `ChannelsDescription` or `Option<ChannelsDescription>` entries.
+/// Use an `Option` if you want to dynamically omit a single channel (probably only for roundtrip tests).
+/// The number of entries must match the number of channels.
+pub trait WritableChannelsDescription<Pixel>: Sync {
+
+    /// A type that has a recursive entry for each channel in the image,
+    /// which must accept the desired pixel type.
+    type RecursiveWriter: RecursivePixelWriter<Pixel>;
+
+    /// Create the temporary writer, accepting the sorted list of channels from `channel_descriptions_list`.
+    fn create_recursive_writer(&self, channels: &ChannelList) -> Self::RecursiveWriter;
+
+    /// Return all the channels that should actually end up in the image, in any order.
+    fn channel_descriptions_list(&self) -> SmallVec<[ChannelDescription; 5]>;
+}
+
+impl WritableChannelsDescription<NoneMore> for NoneMore {
+    type RecursiveWriter = NoneMore;
+    fn create_recursive_writer(&self, _: &ChannelList) -> Self::RecursiveWriter { NoneMore }
+    fn channel_descriptions_list(&self) -> SmallVec<[ChannelDescription; 5]> { SmallVec::new() }
+}
+
+impl<InnerDescriptions, InnerPixel, Sample: IntoNativeSample>
+    WritableChannelsDescription<Recursive<InnerPixel, Sample>>
+    for Recursive<InnerDescriptions, ChannelDescription>
+    where InnerDescriptions: WritableChannelsDescription<InnerPixel>
+{
+    type RecursiveWriter = RecursiveWriter<InnerDescriptions::RecursiveWriter, Sample>;
+
+    fn create_recursive_writer(&self, channels: &ChannelList) -> Self::RecursiveWriter {
+        // this linear lookup is required because the order of the channels changed, due to alphabetical sorting
+        let (start_byte_offset, target_sample_type) = channels.channels_with_byte_offset()
+            .find(|(_offset, channel)| channel.name == self.value.name)
+            .map(|(offset, channel)| (offset, channel.sample_type))
+            .expect("a channel has not been put into channel list");
+
+        Recursive::new(self.inner.create_recursive_writer(channels), SampleWriter {
+            start_byte_offset, target_sample_type,
+            px: PhantomData::default()
+        })
+    }
+
+    fn channel_descriptions_list(&self) -> SmallVec<[ChannelDescription; 5]> {
+        let mut inner_list = self.inner.channel_descriptions_list();
+        inner_list.push(self.value.clone());
+        inner_list
+    }
+}
+
+impl<InnerDescriptions, InnerPixel, Sample: IntoNativeSample>
+WritableChannelsDescription<Recursive<InnerPixel, Sample>>
+for Recursive<InnerDescriptions, Option<ChannelDescription>>
+    where InnerDescriptions: WritableChannelsDescription<InnerPixel>
+{
+    type RecursiveWriter = OptionalRecursiveWriter<InnerDescriptions::RecursiveWriter, Sample>;
+
+    fn create_recursive_writer(&self, channels: &ChannelList) -> Self::RecursiveWriter {
+        // this linear lookup is required because the order of the channels changed, due to alphabetical sorting
+
+        let channel = self.value.as_ref().map(|required_channel|
+            channels.channels_with_byte_offset()
+                .find(|(_offset, channel)| channel == &required_channel)
+                .map(|(offset, channel)| (offset, channel.sample_type))
+                .expect("a channel has not been put into channel list")
+        );
+
+        Recursive::new(
+            self.inner.create_recursive_writer(channels),
+            channel.map(|(start_byte_offset, target_sample_type)| SampleWriter {
+                start_byte_offset, target_sample_type,
+                px: PhantomData::default(),
+            })
+        )
+    }
+
+    fn channel_descriptions_list(&self) -> SmallVec<[ChannelDescription; 5]> {
+        let mut inner_list = self.inner.channel_descriptions_list();
+        if let Some(value) = &self.value { inner_list.push(value.clone()); }
+        inner_list
+    }
+}
+
+/// Write pixels to a slice of bytes. The top level writer contains all the other channels,
+/// the most inner channel is `NoneMore`.
+pub trait RecursivePixelWriter<Pixel>: Sync {
+
+    /// Write pixels to a slice of bytes. Recursively do this for all channels.
+    fn write_pixels<FullPixel>(&self, bytes: &mut [u8], pixels: &[FullPixel], get_pixel: impl Fn(&FullPixel) -> &Pixel);
+}
+
+type RecursiveWriter<Inner, Sample> = Recursive<Inner, SampleWriter<Sample>>;
+type OptionalRecursiveWriter<Inner, Sample> = Recursive<Inner, Option<SampleWriter<Sample>>>;
+
+/// Write the pixels of a single channel, unconditionally. Generic over the concrete sample type (f16, f32, u32).
+#[derive(Debug, Clone)]
+pub struct SampleWriter<Sample> {
+    target_sample_type: SampleType,
+    start_byte_offset: usize,
+    px: PhantomData<Sample>,
+}
+
+impl<Sample> SampleWriter<Sample> where Sample: IntoNativeSample {
+    fn write_own_samples(&self, bytes: &mut [u8], samples: impl ExactSizeIterator<Item=Sample>) {
+        let byte_start_index = samples.len() * self.start_byte_offset;
+        let byte_count = samples.len() * self.target_sample_type.bytes_per_sample();
+        let ref mut byte_writer = &mut bytes[byte_start_index..byte_start_index + byte_count];
+
+        let write_error_msg = "invalid memory buffer length when writing";
+
+        // match outside the loop to avoid matching on every single sample
+        match self.target_sample_type {
+            // TODO does this boil down to a `memcpy` where the sample type equals the type parameter?
+            SampleType::F16 => for sample in samples { sample.to_f16().write(byte_writer).expect(write_error_msg); },
+            SampleType::F32 => for sample in samples { sample.to_f32().write(byte_writer).expect(write_error_msg); },
+            SampleType::U32 => for sample in samples { sample.to_u32().write(byte_writer).expect(write_error_msg); },
+        };
+
+        debug_assert!(byte_writer.is_empty(), "all samples are written, but more were expected");
+    }
+}
+
+impl RecursivePixelWriter<NoneMore> for NoneMore {
+    fn write_pixels<FullPixel>(&self, _: &mut [u8], _: &[FullPixel], _: impl Fn(&FullPixel) -> &NoneMore) {}
+}
+
+impl<Inner, InnerPixel, Sample: IntoNativeSample>
+    RecursivePixelWriter<Recursive<InnerPixel, Sample>>
+    for RecursiveWriter<Inner, Sample>
+    where Inner: RecursivePixelWriter<InnerPixel>
+{
+    // TODO impl exact size iterator <item = Self::Pixel>
+    fn write_pixels<FullPixel>(&self, bytes: &mut [u8], pixels: &[FullPixel], get_pixel: impl Fn(&FullPixel) -> &Recursive<InnerPixel, Sample>){
+        self.value.write_own_samples(bytes, pixels.iter().map(|px| get_pixel(px).value));
+        self.inner.write_pixels(bytes, pixels, |px| &get_pixel(px).inner);
+    }
+}
+
+impl<Inner, InnerPixel, Sample> RecursivePixelWriter<Recursive<InnerPixel, Sample>>
+    for OptionalRecursiveWriter<Inner, Sample>
+    where Inner: RecursivePixelWriter<InnerPixel>,
+        Sample: IntoNativeSample
+{
+    fn write_pixels<FullPixel>(&self, bytes: &mut [u8], pixels: &[FullPixel], get_pixel: impl Fn(&FullPixel) -> &Recursive<InnerPixel, Sample>) {
+        if let Some(writer) = &self.value {
+            writer.write_own_samples(bytes, pixels.iter().map(|px| get_pixel(px).value));
+        }
+
+        self.inner.write_pixels(bytes, pixels, |px| &get_pixel(px).inner);
+    }
+}
+
+
+
+
+
+
+
+#[cfg(test)]
+pub mod test {
+    use crate::image::write::channels::WritableChannels;
+    use crate::image::SpecificChannels;
+    use crate::prelude::{f16};
+    use crate::meta::attribute::{ChannelDescription, SampleType};
+    use crate::image::pixel_vec::PixelVec;
+
+    #[test]
+    fn compiles(){
+        let x = 3_f32;
+        let y = f16::from_f32(4.0);
+        let z = 2_u32;
+        let s = 1.3_f32;
+        let px = (x,y,z,s);
+
+        assert_is_writable_channels(
+            SpecificChannels::rgba(|_pos| px)
+        );
+
+        assert_is_writable_channels(SpecificChannels::rgba(
+            PixelVec::new((3, 2), vec![px, px, px, px, px, px])
+        ));
+
+        let px = (2333_u32, 4_f32);
+        assert_is_writable_channels(
+            SpecificChannels::build()
+                .with_channel("A")
+                .with_channel("C")
+                .with_pixels(PixelVec::new((3, 2), vec![px, px, px, px, px, px]))
+        );
+
+        let px = (3_f32, f16::ONE, 2333_u32, 4_f32);
+        assert_is_writable_channels(SpecificChannels::new(
+            (
+                ChannelDescription::named("x", SampleType::F32),
+                ChannelDescription::named("y", SampleType::F16),
+                Some(ChannelDescription::named("z", SampleType::U32)),
+                Some(ChannelDescription::named("p", SampleType::F32)),
+            ),
+
+            PixelVec::new((3, 2), vec![px, px, px, px, px, px])
+        ));
+
+
+
+        fn assert_is_writable_channels<'s>(_channels: impl WritableChannels<'s>){}
+
+    }
+}
+
+
+
+
diff --git a/vendor/exr/src/image/write/layers.rs b/vendor/exr/src/image/write/layers.rs
new file mode 100644
index 0000000..85648ff
--- /dev/null
+++ b/vendor/exr/src/image/write/layers.rs
@@ -0,0 +1,188 @@
+//! How to write either a single or a list of layers.
+
+use crate::meta::header::{ImageAttributes, Header};
+use crate::meta::{Headers, compute_chunk_count};
+use crate::block::BlockIndex;
+use crate::image::{Layers, Layer};
+use crate::meta::attribute::{TileDescription};
+use crate::prelude::{SmallVec};
+use crate::image::write::channels::{WritableChannels, ChannelsWriter};
+use crate::image::recursive::{Recursive, NoneMore};
+
+/// Enables an image containing this list of layers to be written to a file.
+pub trait WritableLayers<'slf> {
+
+    /// Generate the file meta data for this list of layers
+    fn infer_headers(&self, image_attributes: &ImageAttributes) -> Headers;
+
+    /// The type of temporary writer
+    type Writer: LayersWriter;
+
+    /// Create a temporary writer for this list of layers
+    fn create_writer(&'slf self, headers: &[Header]) -> Self::Writer;
+}
+
+/// A temporary writer for a list of channels
+pub trait LayersWriter: Sync {
+
+    /// Deliver a block of pixels from a single layer to be stored in the file
+    fn extract_uncompressed_block(&self, headers: &[Header], block: BlockIndex) -> Vec<u8>;
+}
+
+/// A temporary writer for an arbitrary list of layers
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct AllLayersWriter<ChannelsWriter> {
+    layers: SmallVec<[LayerWriter<ChannelsWriter>; 2]>
+}
+
+/// A temporary writer for a single layer
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct LayerWriter<ChannelsWriter> {
+    channels: ChannelsWriter, // impl ChannelsWriter
+}
+
+// impl for smallvec
+impl<'slf, Channels: 'slf> WritableLayers<'slf> for Layers<Channels> where Channels: WritableChannels<'slf> {
+    fn infer_headers(&self, image_attributes: &ImageAttributes) -> Headers {
+        slice_infer_headers(self.as_slice(), image_attributes)
+    }
+
+    type Writer = AllLayersWriter<Channels::Writer>;
+    fn create_writer(&'slf self, headers: &[Header]) -> Self::Writer {
+        slice_create_writer(self.as_slice(), headers)
+    }
+}
+
+fn slice_infer_headers<'slf, Channels:'slf + WritableChannels<'slf>>(
+    slice: &[Layer<Channels>], image_attributes: &ImageAttributes
+) -> Headers
+{
+    slice.iter().map(|layer| layer.infer_headers(image_attributes).remove(0)).collect() // TODO no array-vs-first
+}
+
+fn slice_create_writer<'slf, Channels:'slf + WritableChannels<'slf>>(
+    slice: &'slf [Layer<Channels>], headers: &[Header]
+) -> AllLayersWriter<Channels::Writer>
+{
+    AllLayersWriter {
+        layers: slice.iter().zip(headers.chunks_exact(1)) // TODO no array-vs-first
+            .map(|(layer, header)| layer.create_writer(header))
+            .collect()
+    }
+}
+
+
+impl<'slf, Channels: WritableChannels<'slf>> WritableLayers<'slf> for Layer<Channels> {
+    fn infer_headers(&self, image_attributes: &ImageAttributes) -> Headers {
+        let blocks = match self.encoding.blocks {
+            crate::image::Blocks::ScanLines => crate::meta::BlockDescription::ScanLines,
+            crate::image::Blocks::Tiles(tile_size) => {
+                let (level_mode, rounding_mode) = self.channel_data.infer_level_modes();
+                crate::meta::BlockDescription::Tiles(TileDescription { level_mode, rounding_mode, tile_size, })
+            },
+        };
+
+        let chunk_count = compute_chunk_count(
+            self.encoding.compression, self.size, blocks
+        );
+
+        let header = Header {
+            channels: self.channel_data.infer_channel_list(),
+            compression: self.encoding.compression,
+
+            blocks,
+            chunk_count,
+
+            line_order: self.encoding.line_order,
+            layer_size: self.size,
+            shared_attributes: image_attributes.clone(),
+            own_attributes: self.attributes.clone(),
+
+
+            deep: false, // TODO deep data
+            deep_data_version: None,
+            max_samples_per_pixel: None,
+        };
+
+        smallvec![ header ]// TODO no array-vs-first
+    }
+
+    type Writer = LayerWriter</*'l,*/ Channels::Writer>;
+    fn create_writer(&'slf self, headers: &[Header]) -> Self::Writer {
+        let channels = self.channel_data
+            .create_writer(headers.first().expect("inferred header error")); // TODO no array-vs-first
+
+        LayerWriter { channels }
+    }
+}
+
+impl<C> LayersWriter for AllLayersWriter<C> where C: ChannelsWriter {
+    fn extract_uncompressed_block(&self, headers: &[Header], block: BlockIndex) -> Vec<u8> {
+        self.layers[block.layer].extract_uncompressed_block(std::slice::from_ref(&headers[block.layer]), block) // TODO no array-vs-first
+    }
+}
+
+impl<C> LayersWriter for LayerWriter<C> where C: ChannelsWriter {
+    fn extract_uncompressed_block(&self, headers: &[Header], block: BlockIndex) -> Vec<u8> {
+        self.channels.extract_uncompressed_block(headers.first().expect("invalid inferred header"), block) // TODO no array-vs-first
+    }
+}
+
+
+
+
+
+impl<'slf> WritableLayers<'slf> for NoneMore {
+    fn infer_headers(&self, _: &ImageAttributes) -> Headers { SmallVec::new() }
+
+    type Writer = NoneMore;
+    fn create_writer(&'slf self, _: &[Header]) -> Self::Writer { NoneMore }
+}
+
+impl<'slf, InnerLayers, Channels> WritableLayers<'slf> for Recursive<InnerLayers, Layer<Channels>>
+    where InnerLayers: WritableLayers<'slf>, Channels: WritableChannels<'slf>
+{
+    fn infer_headers(&self, image_attributes: &ImageAttributes) -> Headers {
+        let mut headers = self.inner.infer_headers(image_attributes);
+        headers.push(self.value.infer_headers(image_attributes).remove(0)); // TODO no unwrap
+        headers
+    }
+
+    type Writer = RecursiveLayersWriter<InnerLayers::Writer, Channels::Writer>;
+
+    fn create_writer(&'slf self, headers: &[Header]) -> Self::Writer {
+        let (own_header, inner_headers) = headers.split_last()
+            .expect("header has not been inferred correctly");
+
+        let layer_index = inner_headers.len();
+        RecursiveLayersWriter {
+            inner: self.inner.create_writer(inner_headers),
+            value: (layer_index, self.value.create_writer(std::slice::from_ref(own_header))) // TODO no slice
+        }
+    }
+}
+
+type RecursiveLayersWriter<InnerLayersWriter, ChannelsWriter> = Recursive<InnerLayersWriter, (usize, LayerWriter<ChannelsWriter>)>;
+
+impl LayersWriter for NoneMore {
+    fn extract_uncompressed_block(&self, _: &[Header], _: BlockIndex) -> Vec<u8> {
+        panic!("recursive length mismatch bug");
+    }
+}
+
+impl<InnerLayersWriter, Channels> LayersWriter for RecursiveLayersWriter<InnerLayersWriter, Channels>
+    where InnerLayersWriter: LayersWriter, Channels: ChannelsWriter
+{
+    fn extract_uncompressed_block(&self, headers: &[Header], block: BlockIndex) -> Vec<u8> {
+        let (layer_index, layer) = &self.value;
+        if *layer_index == block.layer {
+            let header = headers.get(*layer_index).expect("layer index bug");
+            layer.extract_uncompressed_block(std::slice::from_ref(header), block) // TODO no slice?
+        }
+        else {
+            self.inner.extract_uncompressed_block(headers, block)
+        }
+    }
+}
+
+
diff --git a/vendor/exr/src/image/write/mod.rs b/vendor/exr/src/image/write/mod.rs
new file mode 100644
index 0000000..3c20060
--- /dev/null
+++ b/vendor/exr/src/image/write/mod.rs
@@ -0,0 +1,184 @@
+
+//! Write an exr image to a file.
+//!
+//! First, call `my_image.write()`. The resulting value can be customized, like this:
+//! ```no_run
+//!     use exr::prelude::*;
+//! #   let my_image: FlatImage = unimplemented!();
+//!
+//!     my_image.write()
+//!            .on_progress(|progress| println!("progress: {:.1}", progress*100.0))
+//!            .to_file("image.exr").unwrap();
+//! ```
+//!
+
+pub mod layers;
+pub mod samples;
+pub mod channels;
+
+
+
+use crate::meta::Headers;
+use crate::error::UnitResult;
+use std::io::{Seek, BufWriter};
+use crate::io::Write;
+use crate::image::{Image, ignore_progress, SpecificChannels, IntoSample};
+use crate::image::write::layers::{WritableLayers, LayersWriter};
+use crate::math::Vec2;
+use crate::block::writer::ChunksWriter;
+
+/// An oversimplified function for "just write the damn file already" use cases.
+/// Have a look at the examples to see how you can write an image with more flexibility (it's not that hard).
+/// Use `write_rgb_file` if you do not need an alpha channel.
+///
+/// Each of `R`, `G`, `B` and `A` can be either `f16`, `f32`, `u32`, or `Sample`.
+// TODO explain pixel tuple f32,f16,u32
+pub fn write_rgba_file<R,G,B,A>(
+    path: impl AsRef<std::path::Path>, width: usize, height: usize,
+    colors: impl Sync + Fn(usize, usize) -> (R, G, B, A)
+) -> UnitResult
+    where R: IntoSample, G: IntoSample, B: IntoSample, A: IntoSample,
+{
+    let channels = SpecificChannels::rgba(|Vec2(x,y)| colors(x,y));
+    Image::from_channels((width, height), channels).write().to_file(path)
+}
+
+/// An oversimplified function for "just write the damn file already" use cases.
+/// Have a look at the examples to see how you can write an image with more flexibility (it's not that hard).
+/// Use `write_rgb_file` if you do not need an alpha channel.
+///
+/// Each of `R`, `G`, and `B` can be either `f16`, `f32`, `u32`, or `Sample`.
+// TODO explain pixel tuple f32,f16,u32
+pub fn write_rgb_file<R,G,B>(
+    path: impl AsRef<std::path::Path>, width: usize, height: usize,
+    colors: impl Sync + Fn(usize, usize) -> (R, G, B)
+) -> UnitResult
+    where R: IntoSample, G: IntoSample, B: IntoSample
+{
+    let channels = SpecificChannels::rgb(|Vec2(x,y)| colors(x,y));
+    Image::from_channels((width, height), channels).write().to_file(path)
+}
+
+
+
+/// Enables an image to be written to a file. Call `image.write()` where this trait is implemented.
+pub trait WritableImage<'img, WritableLayers>: Sized {
+
+    /// Create a temporary writer which can be configured and used to write the image to a file.
+    fn write(self) -> WriteImageWithOptions<'img, WritableLayers, fn(f64)>;
+}
+
+impl<'img, WritableLayers> WritableImage<'img, WritableLayers> for &'img Image<WritableLayers> {
+    fn write(self) -> WriteImageWithOptions<'img, WritableLayers, fn(f64)> {
+        WriteImageWithOptions {
+            image: self,
+            check_compatibility: true,
+            parallel: true,
+            on_progress: ignore_progress
+        }
+    }
+}
+
+/// A temporary writer which can be configured and used to write an image to a file.
+// temporary writer with options
+#[derive(Debug, Clone, PartialEq)]
+pub struct WriteImageWithOptions<'img, Layers, OnProgress> {
+    image: &'img Image<Layers>,
+    on_progress: OnProgress,
+    check_compatibility: bool,
+    parallel: bool,
+}
+
+
+impl<'img, L, F> WriteImageWithOptions<'img, L, F>
+    where L: WritableLayers<'img>, F: FnMut(f64)
+{
+    /// Generate file meta data for this image. The meta data structure is close to the data in the file.
+    pub fn infer_meta_data(&self) -> Headers { // TODO this should perform all validity checks? and none after that?
+        self.image.layer_data.infer_headers(&self.image.attributes)
+    }
+
+    /// Do not compress multiple pixel blocks on multiple threads at once.
+    /// Might use less memory and synchronization, but will be slower in most situations.
+    pub fn non_parallel(self) -> Self { Self { parallel: false, ..self } }
+
+    /// Skip some checks that ensure a file can be opened by other exr software.
+    /// For example, it is no longer checked that no two headers or two attributes have the same name,
+    /// which might be an expensive check for images with an exorbitant number of headers.
+    ///
+    /// If you write an uncompressed file and need maximum speed, it might save a millisecond to disable the checks,
+    /// if you know that your file is not invalid any ways. I do not recommend this though,
+    /// as the file might not be readably by any other exr library after that.
+    /// __You must care for not producing an invalid file yourself.__
+    pub fn skip_compatibility_checks(self) -> Self { Self { check_compatibility: false, ..self } }
+
+    /// Specify a function to be called regularly throughout the writing process.
+    /// Replaces all previously specified progress functions in this reader.
+    pub fn on_progress<OnProgress>(self, on_progress: OnProgress) -> WriteImageWithOptions<'img, L, OnProgress>
+        where OnProgress: FnMut(f64)
+    {
+        WriteImageWithOptions {
+            on_progress,
+            image: self.image,
+            check_compatibility: self.check_compatibility,
+            parallel: self.parallel
+        }
+    }
+
+    /// Write the exr image to a file.
+    /// Use `to_unbuffered` instead, if you do not have a file.
+    /// If an error occurs, attempts to delete the partially written file.
+    #[inline]
+    #[must_use]
+    pub fn to_file(self, path: impl AsRef<std::path::Path>) -> UnitResult {
+        crate::io::attempt_delete_file_on_write_error(path.as_ref(), move |write|
+            self.to_unbuffered(write)
+        )
+    }
+
+    /// Buffer the writer and then write the exr image to it.
+    /// Use `to_buffered` instead, if your writer is an in-memory buffer.
+    /// Use `to_file` instead, if you have a file path.
+    /// If your writer cannot seek, you can write to an in-memory vector of bytes first, using `to_buffered`.
+    #[inline]
+    #[must_use]
+    pub fn to_unbuffered(self, unbuffered: impl Write + Seek) -> UnitResult {
+        self.to_buffered(BufWriter::new(unbuffered))
+    }
+
+    /// Write the exr image to a writer.
+    /// Use `to_file` instead, if you have a file path.
+    /// Use `to_unbuffered` instead, if this is not an in-memory writer.
+    /// If your writer cannot seek, you can write to an in-memory vector of bytes first.
+    #[must_use]
+    pub fn to_buffered(self, write: impl Write + Seek) -> UnitResult {
+        let headers = self.infer_meta_data();
+        let layers = self.image.layer_data.create_writer(&headers);
+
+        crate::block::write(
+            write, headers, self.check_compatibility,
+            move |meta, chunk_writer|{
+
+                let blocks = meta.collect_ordered_block_data(|block_index|
+                     layers.extract_uncompressed_block(&meta.headers, block_index)
+                );
+
+                let chunk_writer = chunk_writer.on_progress(self.on_progress);
+                if self.parallel { chunk_writer.compress_all_blocks_parallel(&meta, blocks)?; }
+                else { chunk_writer.compress_all_blocks_sequential(&meta, blocks)?; }
+                /*let blocks_writer = chunk_writer.as_blocks_writer(&meta);
+
+                // TODO propagate send requirement further upwards
+                if self.parallel {
+                    blocks_writer.compress_all_blocks_parallel(blocks)?;
+                }
+                else {
+                    blocks_writer.compress_all_blocks_sequential(blocks)?;
+                }*/
+
+                Ok(())
+            }
+        )
+    }
+}
+
diff --git a/vendor/exr/src/image/write/samples.rs b/vendor/exr/src/image/write/samples.rs
new file mode 100644
index 0000000..e74105b
--- /dev/null
+++ b/vendor/exr/src/image/write/samples.rs
@@ -0,0 +1,205 @@
+//! How to write samples (a grid of `f32`, `f16` or `u32` values).
+
+use crate::meta::attribute::{LevelMode, SampleType, TileDescription};
+use crate::meta::header::Header;
+use crate::block::lines::LineRefMut;
+use crate::image::{FlatSamples, Levels, RipMaps};
+use crate::math::{Vec2, RoundingMode};
+use crate::meta::{rip_map_levels, mip_map_levels, rip_map_indices, mip_map_indices, BlockDescription};
+
+/// Enable an image with this sample grid to be written to a file.
+/// Also can contain multiple resolution levels.
+/// Usually contained within `Channels`.
+pub trait WritableSamples<'slf> {
+    // fn is_deep(&self) -> bool;
+
+    /// Generate the file meta data regarding the number type of this storage
+    fn sample_type(&self) -> SampleType;
+
+    /// Generate the file meta data regarding resolution levels
+    fn infer_level_modes(&self) -> (LevelMode, RoundingMode);
+
+    /// The type of the temporary writer for this sample storage
+    type Writer: SamplesWriter;
+
+    /// Create a temporary writer for this sample storage
+    fn create_samples_writer(&'slf self, header: &Header) -> Self::Writer;
+}
+
+/// Enable an image with this single level sample grid to be written to a file.
+/// Only contained within `Levels`.
+pub trait WritableLevel<'slf> {
+
+    /// Generate the file meta data regarding the number type of these samples
+    fn sample_type(&self) -> SampleType;
+
+    /// The type of the temporary writer for this single level of samples
+    type Writer: SamplesWriter;
+
+    /// Create a temporary writer for this single level of samples
+    fn create_level_writer(&'slf self, size: Vec2<usize>) -> Self::Writer;
+}
+
+/// A temporary writer for one or more resolution levels containing samples
+pub trait SamplesWriter: Sync {
+
+    /// Deliver a single short horizontal list of samples for a specific channel.
+    fn extract_line(&self, line: LineRefMut<'_>);
+}
+
+/// A temporary writer for a predefined non-deep sample storage
+#[derive(Debug, Copy, Clone, PartialEq)]
+pub struct FlatSamplesWriter<'samples> {
+    resolution: Vec2<usize>, // respects resolution level
+    samples: &'samples FlatSamples
+}
+
+
+
+// used if no layers are used and the flat samples are directly inside the channels
+impl<'samples> WritableSamples<'samples> for FlatSamples {
+    fn sample_type(&self) -> SampleType {
+        match self {
+            FlatSamples::F16(_) => SampleType::F16,
+            FlatSamples::F32(_) => SampleType::F32,
+            FlatSamples::U32(_) => SampleType::U32,
+        }
+    }
+
+    fn infer_level_modes(&self) -> (LevelMode, RoundingMode) { (LevelMode::Singular, RoundingMode::Down) }
+
+    type Writer = FlatSamplesWriter<'samples>; //&'s FlatSamples;
+    fn create_samples_writer(&'samples self, header: &Header) -> Self::Writer {
+        FlatSamplesWriter {
+            resolution: header.layer_size,
+            samples: self
+        }
+    }
+}
+
+// used if layers are used and the flat samples are inside the levels
+impl<'samples> WritableLevel<'samples> for FlatSamples {
+    fn sample_type(&self) -> SampleType {
+        match self {
+            FlatSamples::F16(_) => SampleType::F16,
+            FlatSamples::F32(_) => SampleType::F32,
+            FlatSamples::U32(_) => SampleType::U32,
+        }
+    }
+
+    type Writer = FlatSamplesWriter<'samples>;
+    fn create_level_writer(&'samples self, size: Vec2<usize>) -> Self::Writer {
+        FlatSamplesWriter {
+            resolution: size,
+            samples: self
+        }
+    }
+}
+
+impl<'samples> SamplesWriter for FlatSamplesWriter<'samples> {
+    fn extract_line(&self, line: LineRefMut<'_>) {
+        let image_width = self.resolution.width(); // header.layer_size.width();
+        debug_assert_ne!(image_width, 0, "image width calculation bug");
+
+        let start_index = line.location.position.y() * image_width + line.location.position.x();
+        let end_index = start_index + line.location.sample_count;
+
+        debug_assert!(
+            start_index < end_index && end_index <= self.samples.len(),
+            "for resolution {:?}, this is an invalid line: {:?}",
+            self.resolution, line.location
+        );
+
+        match self.samples {
+            FlatSamples::F16(samples) => line.write_samples_from_slice(&samples[start_index .. end_index]),
+            FlatSamples::F32(samples) => line.write_samples_from_slice(&samples[start_index .. end_index]),
+            FlatSamples::U32(samples) => line.write_samples_from_slice(&samples[start_index .. end_index]),
+        }.expect("writing line bytes failed");
+    }
+}
+
+
+impl<'samples, LevelSamples> WritableSamples<'samples> for Levels<LevelSamples>
+    where LevelSamples: WritableLevel<'samples>
+{
+    fn sample_type(&self) -> SampleType {
+        let sample_type = self.levels_as_slice().first().expect("no levels found").sample_type();
+
+        debug_assert!(
+            self.levels_as_slice().iter().skip(1).all(|ty| ty.sample_type() == sample_type),
+            "sample types must be the same across all levels"
+        );
+
+        sample_type
+    }
+
+    fn infer_level_modes(&self) -> (LevelMode, RoundingMode) {
+        match self {
+            Levels::Singular(_) => (LevelMode::Singular, RoundingMode::Down),
+            Levels::Mip { rounding_mode, .. } => (LevelMode::MipMap, *rounding_mode),
+            Levels::Rip { rounding_mode, .. } => (LevelMode::RipMap, *rounding_mode),
+        }
+    }
+
+    type Writer = LevelsWriter<LevelSamples::Writer>;
+    fn create_samples_writer(&'samples self, header: &Header) -> Self::Writer {
+        let rounding = match header.blocks {
+            BlockDescription::Tiles(TileDescription { rounding_mode, .. }) => Some(rounding_mode),
+            BlockDescription::ScanLines => None,
+        };
+
+        LevelsWriter {
+            levels: match self {
+                Levels::Singular(level) => Levels::Singular(level.create_level_writer(header.layer_size)),
+                Levels::Mip { level_data, rounding_mode } => {
+                    debug_assert_eq!(
+                        level_data.len(),
+                        mip_map_indices(rounding.expect("mip maps only with tiles"), header.layer_size).count(),
+                        "invalid mip map count"
+                    );
+
+                    Levels::Mip { // TODO store level size in image??
+                        rounding_mode: *rounding_mode,
+                        level_data: level_data.iter()
+                            .zip(mip_map_levels(rounding.expect("mip maps only with tiles"), header.layer_size))
+                            // .map(|level| level.create_samples_writer(header))
+                            .map(|(level, (_level_index, level_size))| level.create_level_writer(level_size))
+                            .collect()
+                    }
+                },
+                Levels::Rip { level_data, rounding_mode } => {
+                    debug_assert_eq!(level_data.map_data.len(), level_data.level_count.area(), "invalid rip level count");
+                    debug_assert_eq!(
+                        level_data.map_data.len(),
+                        rip_map_indices(rounding.expect("rip maps only with tiles"), header.layer_size).count(),
+                        "invalid rip map count"
+                    );
+
+                    Levels::Rip {
+                        rounding_mode: *rounding_mode,
+                        level_data: RipMaps {
+                            level_count: level_data.level_count,
+                            map_data: level_data.map_data.iter()
+                                .zip(rip_map_levels(rounding.expect("rip maps only with tiles"), header.layer_size))
+                                .map(|(level, (_level_index, level_size))| level.create_level_writer(level_size))
+                                .collect(),
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
+
+/// A temporary writer for multiple resolution levels
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct LevelsWriter<SamplesWriter> {
+    levels: Levels<SamplesWriter>,
+}
+
+impl<Samples> SamplesWriter for LevelsWriter<Samples> where Samples: SamplesWriter {
+    fn extract_line(&self, line: LineRefMut<'_>) {
+        self.levels.get_level(line.location.level).expect("invalid level index") // TODO compute level size from line index??
+            .extract_line(line)
+    }
+}