Initial vendor packages

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

1 files changed, 1915 insertions, 0 deletions

diff --git a/vendor/image/src/image.rs b/vendor/image/src/image.rs
new file mode 100644
index 0000000..d131b98
--- /dev/null
+++ b/vendor/image/src/image.rs
@@ -0,0 +1,1915 @@
+#![allow(clippy::too_many_arguments)]
+use std::convert::TryFrom;
+use std::ffi::OsStr;
+use std::io;
+use std::io::Read;
+use std::ops::{Deref, DerefMut};
+use std::path::Path;
+use std::usize;
+
+use crate::color::{ColorType, ExtendedColorType};
+use crate::error::{
+    ImageError, ImageFormatHint, ImageResult, LimitError, LimitErrorKind, ParameterError,
+    ParameterErrorKind,
+};
+use crate::math::Rect;
+use crate::traits::Pixel;
+use crate::ImageBuffer;
+
+use crate::animation::Frames;
+
+#[cfg(feature = "pnm")]
+use crate::codecs::pnm::PnmSubtype;
+
+/// An enumeration of supported image formats.
+/// Not all formats support both encoding and decoding.
+#[derive(Clone, Copy, PartialEq, Eq, Debug, Hash)]
+#[non_exhaustive]
+pub enum ImageFormat {
+    /// An Image in PNG Format
+    Png,
+
+    /// An Image in JPEG Format
+    Jpeg,
+
+    /// An Image in GIF Format
+    Gif,
+
+    /// An Image in WEBP Format
+    WebP,
+
+    /// An Image in general PNM Format
+    Pnm,
+
+    /// An Image in TIFF Format
+    Tiff,
+
+    /// An Image in TGA Format
+    Tga,
+
+    /// An Image in DDS Format
+    Dds,
+
+    /// An Image in BMP Format
+    Bmp,
+
+    /// An Image in ICO Format
+    Ico,
+
+    /// An Image in Radiance HDR Format
+    Hdr,
+
+    /// An Image in OpenEXR Format
+    OpenExr,
+
+    /// An Image in farbfeld Format
+    Farbfeld,
+
+    /// An Image in AVIF format.
+    Avif,
+
+    /// An Image in QOI format.
+    Qoi,
+}
+
+impl ImageFormat {
+    /// Return the image format specified by a path's file extension.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use image::ImageFormat;
+    ///
+    /// let format = ImageFormat::from_extension("jpg");
+    /// assert_eq!(format, Some(ImageFormat::Jpeg));
+    /// ```
+    #[inline]
+    pub fn from_extension<S>(ext: S) -> Option<Self>
+    where
+        S: AsRef<OsStr>,
+    {
+        // thin wrapper function to strip generics
+        fn inner(ext: &OsStr) -> Option<ImageFormat> {
+            let ext = ext.to_str()?.to_ascii_lowercase();
+
+            Some(match ext.as_str() {
+                "avif" => ImageFormat::Avif,
+                "jpg" | "jpeg" => ImageFormat::Jpeg,
+                "png" => ImageFormat::Png,
+                "gif" => ImageFormat::Gif,
+                "webp" => ImageFormat::WebP,
+                "tif" | "tiff" => ImageFormat::Tiff,
+                "tga" => ImageFormat::Tga,
+                "dds" => ImageFormat::Dds,
+                "bmp" => ImageFormat::Bmp,
+                "ico" => ImageFormat::Ico,
+                "hdr" => ImageFormat::Hdr,
+                "exr" => ImageFormat::OpenExr,
+                "pbm" | "pam" | "ppm" | "pgm" => ImageFormat::Pnm,
+                "ff" | "farbfeld" => ImageFormat::Farbfeld,
+                "qoi" => ImageFormat::Qoi,
+                _ => return None,
+            })
+        }
+
+        inner(ext.as_ref())
+    }
+
+    /// Return the image format specified by the path's file extension.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use image::ImageFormat;
+    ///
+    /// let format = ImageFormat::from_path("images/ferris.png")?;
+    /// assert_eq!(format, ImageFormat::Png);
+    ///
+    /// # Ok::<(), image::error::ImageError>(())
+    /// ```
+    #[inline]
+    pub fn from_path<P>(path: P) -> ImageResult<Self>
+    where
+        P: AsRef<Path>,
+    {
+        // thin wrapper function to strip generics
+        fn inner(path: &Path) -> ImageResult<ImageFormat> {
+            let exact_ext = path.extension();
+            exact_ext
+                .and_then(ImageFormat::from_extension)
+                .ok_or_else(|| {
+                    let format_hint = match exact_ext {
+                        None => ImageFormatHint::Unknown,
+                        Some(os) => ImageFormatHint::PathExtension(os.into()),
+                    };
+                    ImageError::Unsupported(format_hint.into())
+                })
+        }
+
+        inner(path.as_ref())
+    }
+
+    /// Return the image format specified by a MIME type.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use image::ImageFormat;
+    ///
+    /// let format = ImageFormat::from_mime_type("image/png").unwrap();
+    /// assert_eq!(format, ImageFormat::Png);
+    /// ```
+    pub fn from_mime_type<M>(mime_type: M) -> Option<Self>
+    where
+        M: AsRef<str>,
+    {
+        match mime_type.as_ref() {
+            "image/avif" => Some(ImageFormat::Avif),
+            "image/jpeg" => Some(ImageFormat::Jpeg),
+            "image/png" => Some(ImageFormat::Png),
+            "image/gif" => Some(ImageFormat::Gif),
+            "image/webp" => Some(ImageFormat::WebP),
+            "image/tiff" => Some(ImageFormat::Tiff),
+            "image/x-targa" | "image/x-tga" => Some(ImageFormat::Tga),
+            "image/vnd-ms.dds" => Some(ImageFormat::Dds),
+            "image/bmp" => Some(ImageFormat::Bmp),
+            "image/x-icon" => Some(ImageFormat::Ico),
+            "image/vnd.radiance" => Some(ImageFormat::Hdr),
+            "image/x-exr" => Some(ImageFormat::OpenExr),
+            "image/x-portable-bitmap"
+            | "image/x-portable-graymap"
+            | "image/x-portable-pixmap"
+            | "image/x-portable-anymap" => Some(ImageFormat::Pnm),
+            // Qoi's MIME type is being worked on.
+            // See: https://github.com/phoboslab/qoi/issues/167
+            "image/x-qoi" => Some(ImageFormat::Qoi),
+            _ => None,
+        }
+    }
+
+    /// Return the MIME type for this image format or "application/octet-stream" if no MIME type
+    /// exists for the format.
+    ///
+    /// Some notes on a few of the MIME types:
+    ///
+    /// - The portable anymap format has a separate MIME type for the pixmap, graymap and bitmap
+    ///   formats, but this method returns the general "image/x-portable-anymap" MIME type.
+    /// - The Targa format has two common MIME types, "image/x-targa"  and "image/x-tga"; this
+    ///   method returns "image/x-targa" for that format.
+    /// - The QOI MIME type is still a work in progress. This method returns "image/x-qoi" for
+    ///   that format.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use image::ImageFormat;
+    ///
+    /// let mime_type = ImageFormat::Png.to_mime_type();
+    /// assert_eq!(mime_type, "image/png");
+    /// ```
+    pub fn to_mime_type(&self) -> &'static str {
+        match self {
+            ImageFormat::Avif => "image/avif",
+            ImageFormat::Jpeg => "image/jpeg",
+            ImageFormat::Png => "image/png",
+            ImageFormat::Gif => "image/gif",
+            ImageFormat::WebP => "image/webp",
+            ImageFormat::Tiff => "image/tiff",
+            // the targa MIME type has two options, but this one seems to be used more
+            ImageFormat::Tga => "image/x-targa",
+            ImageFormat::Dds => "image/vnd-ms.dds",
+            ImageFormat::Bmp => "image/bmp",
+            ImageFormat::Ico => "image/x-icon",
+            ImageFormat::Hdr => "image/vnd.radiance",
+            ImageFormat::OpenExr => "image/x-exr",
+            // return the most general MIME type
+            ImageFormat::Pnm => "image/x-portable-anymap",
+            // Qoi's MIME type is being worked on.
+            // See: https://github.com/phoboslab/qoi/issues/167
+            ImageFormat::Qoi => "image/x-qoi",
+            // farbfield's MIME type taken from https://www.wikidata.org/wiki/Q28206109
+            ImageFormat::Farbfeld => "application/octet-stream",
+        }
+    }
+
+    /// Return if the ImageFormat can be decoded by the lib.
+    #[inline]
+    pub fn can_read(&self) -> bool {
+        // Needs to be updated once a new variant's decoder is added to free_functions.rs::load
+        match self {
+            ImageFormat::Png => true,
+            ImageFormat::Gif => true,
+            ImageFormat::Jpeg => true,
+            ImageFormat::WebP => true,
+            ImageFormat::Tiff => true,
+            ImageFormat::Tga => true,
+            ImageFormat::Dds => false,
+            ImageFormat::Bmp => true,
+            ImageFormat::Ico => true,
+            ImageFormat::Hdr => true,
+            ImageFormat::OpenExr => true,
+            ImageFormat::Pnm => true,
+            ImageFormat::Farbfeld => true,
+            ImageFormat::Avif => true,
+            ImageFormat::Qoi => true,
+        }
+    }
+
+    /// Return if the ImageFormat can be encoded by the lib.
+    #[inline]
+    pub fn can_write(&self) -> bool {
+        // Needs to be updated once a new variant's encoder is added to free_functions.rs::save_buffer_with_format_impl
+        match self {
+            ImageFormat::Gif => true,
+            ImageFormat::Ico => true,
+            ImageFormat::Jpeg => true,
+            ImageFormat::Png => true,
+            ImageFormat::Bmp => true,
+            ImageFormat::Tiff => true,
+            ImageFormat::Tga => true,
+            ImageFormat::Pnm => true,
+            ImageFormat::Farbfeld => true,
+            ImageFormat::Avif => true,
+            ImageFormat::WebP => true,
+            ImageFormat::Hdr => false,
+            ImageFormat::OpenExr => true,
+            ImageFormat::Dds => false,
+            ImageFormat::Qoi => true,
+        }
+    }
+
+    /// Return a list of applicable extensions for this format.
+    ///
+    /// All currently recognized image formats specify at least on extension but for future
+    /// compatibility you should not rely on this fact. The list may be empty if the format has no
+    /// recognized file representation, for example in case it is used as a purely transient memory
+    /// format.
+    ///
+    /// The method name `extensions` remains reserved for introducing another method in the future
+    /// that yields a slice of `OsStr` which is blocked by several features of const evaluation.
+    pub fn extensions_str(self) -> &'static [&'static str] {
+        match self {
+            ImageFormat::Png => &["png"],
+            ImageFormat::Jpeg => &["jpg", "jpeg"],
+            ImageFormat::Gif => &["gif"],
+            ImageFormat::WebP => &["webp"],
+            ImageFormat::Pnm => &["pbm", "pam", "ppm", "pgm"],
+            ImageFormat::Tiff => &["tiff", "tif"],
+            ImageFormat::Tga => &["tga"],
+            ImageFormat::Dds => &["dds"],
+            ImageFormat::Bmp => &["bmp"],
+            ImageFormat::Ico => &["ico"],
+            ImageFormat::Hdr => &["hdr"],
+            ImageFormat::OpenExr => &["exr"],
+            ImageFormat::Farbfeld => &["ff"],
+            // According to: https://aomediacodec.github.io/av1-avif/#mime-registration
+            ImageFormat::Avif => &["avif"],
+            ImageFormat::Qoi => &["qoi"],
+        }
+    }
+}
+
+/// An enumeration of supported image formats for encoding.
+#[derive(Clone, PartialEq, Eq, Debug)]
+#[non_exhaustive]
+pub enum ImageOutputFormat {
+    #[cfg(feature = "png")]
+    /// An Image in PNG Format
+    Png,
+
+    #[cfg(feature = "jpeg")]
+    /// An Image in JPEG Format with specified quality, up to 100
+    Jpeg(u8),
+
+    #[cfg(feature = "pnm")]
+    /// An Image in one of the PNM Formats
+    Pnm(PnmSubtype),
+
+    #[cfg(feature = "gif")]
+    /// An Image in GIF Format
+    Gif,
+
+    #[cfg(feature = "ico")]
+    /// An Image in ICO Format
+    Ico,
+
+    #[cfg(feature = "bmp")]
+    /// An Image in BMP Format
+    Bmp,
+
+    #[cfg(feature = "farbfeld")]
+    /// An Image in farbfeld Format
+    Farbfeld,
+
+    #[cfg(feature = "tga")]
+    /// An Image in TGA Format
+    Tga,
+
+    #[cfg(feature = "exr")]
+    /// An Image in OpenEXR Format
+    OpenExr,
+
+    #[cfg(feature = "tiff")]
+    /// An Image in TIFF Format
+    Tiff,
+
+    #[cfg(feature = "avif-encoder")]
+    /// An image in AVIF Format
+    Avif,
+
+    #[cfg(feature = "qoi")]
+    /// An image in QOI Format
+    Qoi,
+
+    #[cfg(feature = "webp-encoder")]
+    /// An image in WebP Format.
+    WebP,
+
+    /// A value for signalling an error: An unsupported format was requested
+    // Note: When TryFrom is stabilized, this value should not be needed, and
+    // a TryInto<ImageOutputFormat> should be used instead of an Into<ImageOutputFormat>.
+    Unsupported(String),
+}
+
+impl From<ImageFormat> for ImageOutputFormat {
+    fn from(fmt: ImageFormat) -> Self {
+        match fmt {
+            #[cfg(feature = "png")]
+            ImageFormat::Png => ImageOutputFormat::Png,
+            #[cfg(feature = "jpeg")]
+            ImageFormat::Jpeg => ImageOutputFormat::Jpeg(75),
+            #[cfg(feature = "pnm")]
+            ImageFormat::Pnm => ImageOutputFormat::Pnm(PnmSubtype::ArbitraryMap),
+            #[cfg(feature = "gif")]
+            ImageFormat::Gif => ImageOutputFormat::Gif,
+            #[cfg(feature = "ico")]
+            ImageFormat::Ico => ImageOutputFormat::Ico,
+            #[cfg(feature = "bmp")]
+            ImageFormat::Bmp => ImageOutputFormat::Bmp,
+            #[cfg(feature = "farbfeld")]
+            ImageFormat::Farbfeld => ImageOutputFormat::Farbfeld,
+            #[cfg(feature = "tga")]
+            ImageFormat::Tga => ImageOutputFormat::Tga,
+            #[cfg(feature = "exr")]
+            ImageFormat::OpenExr => ImageOutputFormat::OpenExr,
+            #[cfg(feature = "tiff")]
+            ImageFormat::Tiff => ImageOutputFormat::Tiff,
+
+            #[cfg(feature = "avif-encoder")]
+            ImageFormat::Avif => ImageOutputFormat::Avif,
+            #[cfg(feature = "webp-encoder")]
+            ImageFormat::WebP => ImageOutputFormat::WebP,
+
+            #[cfg(feature = "qoi")]
+            ImageFormat::Qoi => ImageOutputFormat::Qoi,
+
+            f => ImageOutputFormat::Unsupported(format!("{:?}", f)),
+        }
+    }
+}
+
+// This struct manages buffering associated with implementing `Read` and `Seek` on decoders that can
+// must decode ranges of bytes at a time.
+#[allow(dead_code)]
+// When no image formats that use it are enabled
+pub(crate) struct ImageReadBuffer {
+    scanline_bytes: usize,
+    buffer: Vec<u8>,
+    consumed: usize,
+
+    total_bytes: u64,
+    offset: u64,
+}
+impl ImageReadBuffer {
+    /// Create a new ImageReadBuffer.
+    ///
+    /// Panics if scanline_bytes doesn't fit into a usize, because that would mean reading anything
+    /// from the image would take more RAM than the entire virtual address space. In other words,
+    /// actually using this struct would instantly OOM so just get it out of the way now.
+    #[allow(dead_code)]
+    // When no image formats that use it are enabled
+    pub(crate) fn new(scanline_bytes: u64, total_bytes: u64) -> Self {
+        Self {
+            scanline_bytes: usize::try_from(scanline_bytes).unwrap(),
+            buffer: Vec::new(),
+            consumed: 0,
+            total_bytes,
+            offset: 0,
+        }
+    }
+
+    #[allow(dead_code)]
+    // When no image formats that use it are enabled
+    pub(crate) fn read<F>(&mut self, buf: &mut [u8], mut read_scanline: F) -> io::Result<usize>
+    where
+        F: FnMut(&mut [u8]) -> io::Result<usize>,
+    {
+        if self.buffer.len() == self.consumed {
+            if self.offset == self.total_bytes {
+                return Ok(0);
+            } else if buf.len() >= self.scanline_bytes {
+                // If there is nothing buffered and the user requested a full scanline worth of
+                // data, skip buffering.
+                let bytes_read = read_scanline(&mut buf[..self.scanline_bytes])?;
+                self.offset += u64::try_from(bytes_read).unwrap();
+                return Ok(bytes_read);
+            } else {
+                // Lazily allocate buffer the first time that read is called with a buffer smaller
+                // than the scanline size.
+                if self.buffer.is_empty() {
+                    self.buffer.resize(self.scanline_bytes, 0);
+                }
+
+                self.consumed = 0;
+                let bytes_read = read_scanline(&mut self.buffer[..])?;
+                self.buffer.resize(bytes_read, 0);
+                self.offset += u64::try_from(bytes_read).unwrap();
+
+                assert!(bytes_read == self.scanline_bytes || self.offset == self.total_bytes);
+            }
+        }
+
+        // Finally, copy bytes into output buffer.
+        let bytes_buffered = self.buffer.len() - self.consumed;
+        if bytes_buffered > buf.len() {
+            buf.copy_from_slice(&self.buffer[self.consumed..][..buf.len()]);
+            self.consumed += buf.len();
+            Ok(buf.len())
+        } else {
+            buf[..bytes_buffered].copy_from_slice(&self.buffer[self.consumed..][..bytes_buffered]);
+            self.consumed = self.buffer.len();
+            Ok(bytes_buffered)
+        }
+    }
+}
+
+/// Decodes a specific region of the image, represented by the rectangle
+/// starting from ```x``` and ```y``` and having ```length``` and ```width```
+#[allow(dead_code)]
+// When no image formats that use it are enabled
+pub(crate) fn load_rect<'a, D, F, F1, F2, E>(
+    x: u32,
+    y: u32,
+    width: u32,
+    height: u32,
+    buf: &mut [u8],
+    progress_callback: F,
+    decoder: &mut D,
+    mut seek_scanline: F1,
+    mut read_scanline: F2,
+) -> ImageResult<()>
+where
+    D: ImageDecoder<'a>,
+    F: Fn(Progress),
+    F1: FnMut(&mut D, u64) -> io::Result<()>,
+    F2: FnMut(&mut D, &mut [u8]) -> Result<(), E>,
+    ImageError: From<E>,
+{
+    let (x, y, width, height) = (
+        u64::from(x),
+        u64::from(y),
+        u64::from(width),
+        u64::from(height),
+    );
+    let dimensions = decoder.dimensions();
+    let bytes_per_pixel = u64::from(decoder.color_type().bytes_per_pixel());
+    let row_bytes = bytes_per_pixel * u64::from(dimensions.0);
+    let scanline_bytes = decoder.scanline_bytes();
+    let total_bytes = width * height * bytes_per_pixel;
+
+    if buf.len() < usize::try_from(total_bytes).unwrap_or(usize::max_value()) {
+        panic!(
+            "output buffer too short\n expected `{}`, provided `{}`",
+            total_bytes,
+            buf.len()
+        );
+    }
+
+    let mut bytes_read = 0u64;
+    let mut current_scanline = 0;
+    let mut tmp = Vec::new();
+    let mut tmp_scanline = None;
+
+    {
+        // Read a range of the image starting from byte number `start` and continuing until byte
+        // number `end`. Updates `current_scanline` and `bytes_read` appropriately.
+        let mut read_image_range = |mut start: u64, end: u64| -> ImageResult<()> {
+            // If the first scanline we need is already stored in the temporary buffer, then handle
+            // it first.
+            let target_scanline = start / scanline_bytes;
+            if tmp_scanline == Some(target_scanline) {
+                let position = target_scanline * scanline_bytes;
+                let offset = start.saturating_sub(position);
+                let len = (end - start)
+                    .min(scanline_bytes - offset)
+                    .min(end - position);
+
+                buf[(bytes_read as usize)..][..len as usize]
+                    .copy_from_slice(&tmp[offset as usize..][..len as usize]);
+                bytes_read += len;
+                start += len;
+
+                progress_callback(Progress {
+                    current: bytes_read,
+                    total: total_bytes,
+                });
+
+                if start == end {
+                    return Ok(());
+                }
+            }
+
+            let target_scanline = start / scanline_bytes;
+            if target_scanline != current_scanline {
+                seek_scanline(decoder, target_scanline)?;
+                current_scanline = target_scanline;
+            }
+
+            let mut position = current_scanline * scanline_bytes;
+            while position < end {
+                if position >= start && end - position >= scanline_bytes {
+                    read_scanline(
+                        decoder,
+                        &mut buf[(bytes_read as usize)..][..(scanline_bytes as usize)],
+                    )?;
+                    bytes_read += scanline_bytes;
+                } else {
+                    tmp.resize(scanline_bytes as usize, 0u8);
+                    read_scanline(decoder, &mut tmp)?;
+                    tmp_scanline = Some(current_scanline);
+
+                    let offset = start.saturating_sub(position);
+                    let len = (end - start)
+                        .min(scanline_bytes - offset)
+                        .min(end - position);
+
+                    buf[(bytes_read as usize)..][..len as usize]
+                        .copy_from_slice(&tmp[offset as usize..][..len as usize]);
+                    bytes_read += len;
+                }
+
+                current_scanline += 1;
+                position += scanline_bytes;
+                progress_callback(Progress {
+                    current: bytes_read,
+                    total: total_bytes,
+                });
+            }
+            Ok(())
+        };
+
+        if x + width > u64::from(dimensions.0)
+            || y + height > u64::from(dimensions.1)
+            || width == 0
+            || height == 0
+        {
+            return Err(ImageError::Parameter(ParameterError::from_kind(
+                ParameterErrorKind::DimensionMismatch,
+            )));
+        }
+        if scanline_bytes > usize::max_value() as u64 {
+            return Err(ImageError::Limits(LimitError::from_kind(
+                LimitErrorKind::InsufficientMemory,
+            )));
+        }
+
+        progress_callback(Progress {
+            current: 0,
+            total: total_bytes,
+        });
+        if x == 0 && width == u64::from(dimensions.0) {
+            let start = x * bytes_per_pixel + y * row_bytes;
+            let end = (x + width) * bytes_per_pixel + (y + height - 1) * row_bytes;
+            read_image_range(start, end)?;
+        } else {
+            for row in y..(y + height) {
+                let start = x * bytes_per_pixel + row * row_bytes;
+                let end = (x + width) * bytes_per_pixel + row * row_bytes;
+                read_image_range(start, end)?;
+            }
+        }
+    }
+
+    // Seek back to the start
+    Ok(seek_scanline(decoder, 0)?)
+}
+
+/// Reads all of the bytes of a decoder into a Vec<T>. No particular alignment
+/// of the output buffer is guaranteed.
+///
+/// Panics if there isn't enough memory to decode the image.
+pub(crate) fn decoder_to_vec<'a, T>(decoder: impl ImageDecoder<'a>) -> ImageResult<Vec<T>>
+where
+    T: crate::traits::Primitive + bytemuck::Pod,
+{
+    let total_bytes = usize::try_from(decoder.total_bytes());
+    if total_bytes.is_err() || total_bytes.unwrap() > isize::max_value() as usize {
+        return Err(ImageError::Limits(LimitError::from_kind(
+            LimitErrorKind::InsufficientMemory,
+        )));
+    }
+
+    let mut buf = vec![num_traits::Zero::zero(); total_bytes.unwrap() / std::mem::size_of::<T>()];
+    decoder.read_image(bytemuck::cast_slice_mut(buf.as_mut_slice()))?;
+    Ok(buf)
+}
+
+/// Represents the progress of an image operation.
+///
+/// Note that this is not necessarily accurate and no change to the values passed to the progress
+/// function during decoding will be considered breaking. A decoder could in theory report the
+/// progress `(0, 0)` if progress is unknown, without violating the interface contract of the type.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub struct Progress {
+    current: u64,
+    total: u64,
+}
+
+impl Progress {
+    /// Create Progress. Result in invalid progress if you provide a greater `current` than `total`.
+    pub(crate) fn new(current: u64, total: u64) -> Self {
+        Self { current, total }
+    }
+
+    /// A measure of completed decoding.
+    pub fn current(self) -> u64 {
+        self.current
+    }
+
+    /// A measure of all necessary decoding work.
+    ///
+    /// This is in general greater or equal than `current`.
+    pub fn total(self) -> u64 {
+        self.total
+    }
+
+    /// Calculate a measure for remaining decoding work.
+    pub fn remaining(self) -> u64 {
+        self.total.max(self.current) - self.current
+    }
+}
+
+/// The trait that all decoders implement
+pub trait ImageDecoder<'a>: Sized {
+    /// The type of reader produced by `into_reader`.
+    type Reader: Read + 'a;
+
+    /// Returns a tuple containing the width and height of the image
+    fn dimensions(&self) -> (u32, u32);
+
+    /// Returns the color type of the image data produced by this decoder
+    fn color_type(&self) -> ColorType;
+
+    /// Returns the color type of the image file before decoding
+    fn original_color_type(&self) -> ExtendedColorType {
+        self.color_type().into()
+    }
+
+    /// Returns the ICC color profile embedded in the image
+    ///
+    /// For formats that don't support embedded profiles this function will always return `None`.
+    /// This feature is currently only supported for the JPEG, PNG, and AVIF formats.
+    fn icc_profile(&mut self) -> Option<Vec<u8>> {
+        None
+    }
+
+    /// Returns a reader that can be used to obtain the bytes of the image. For the best
+    /// performance, always try to read at least `scanline_bytes` from the reader at a time. Reading
+    /// fewer bytes will cause the reader to perform internal buffering.
+    fn into_reader(self) -> ImageResult<Self::Reader>;
+
+    /// Returns the total number of bytes in the decoded image.
+    ///
+    /// This is the size of the buffer that must be passed to `read_image` or
+    /// `read_image_with_progress`. The returned value may exceed usize::MAX, in
+    /// which case it isn't actually possible to construct a buffer to decode all the image data
+    /// into. If, however, the size does not fit in a u64 then u64::MAX is returned.
+    fn total_bytes(&self) -> u64 {
+        let dimensions = self.dimensions();
+        let total_pixels = u64::from(dimensions.0) * u64::from(dimensions.1);
+        let bytes_per_pixel = u64::from(self.color_type().bytes_per_pixel());
+        total_pixels.saturating_mul(bytes_per_pixel)
+    }
+
+    /// Returns the minimum number of bytes that can be efficiently read from this decoder. This may
+    /// be as few as 1 or as many as `total_bytes()`.
+    fn scanline_bytes(&self) -> u64 {
+        self.total_bytes()
+    }
+
+    /// Returns all the bytes in the image.
+    ///
+    /// This function takes a slice of bytes and writes the pixel data of the image into it.
+    /// Although not required, for certain color types callers may want to pass buffers which are
+    /// aligned to 2 or 4 byte boundaries to the slice can be cast to a [u16] or [u32]. To accommodate
+    /// such casts, the returned contents will always be in native endian.
+    ///
+    /// # Panics
+    ///
+    /// This function panics if buf.len() != self.total_bytes().
+    ///
+    /// # Examples
+    ///
+    /// ```no_build
+    /// use zerocopy::{AsBytes, FromBytes};
+    /// fn read_16bit_image(decoder: impl ImageDecoder) -> Vec<16> {
+    ///     let mut buf: Vec<u16> = vec![0; decoder.total_bytes()/2];
+    ///     decoder.read_image(buf.as_bytes());
+    ///     buf
+    /// }
+    /// ```
+    fn read_image(self, buf: &mut [u8]) -> ImageResult<()> {
+        self.read_image_with_progress(buf, |_| {})
+    }
+
+    /// Same as `read_image` but periodically calls the provided callback to give updates on loading
+    /// progress.
+    fn read_image_with_progress<F: Fn(Progress)>(
+        self,
+        buf: &mut [u8],
+        progress_callback: F,
+    ) -> ImageResult<()> {
+        assert_eq!(u64::try_from(buf.len()), Ok(self.total_bytes()));
+
+        let total_bytes = self.total_bytes() as usize;
+        let scanline_bytes = self.scanline_bytes() as usize;
+        let target_read_size = if scanline_bytes < 4096 {
+            (4096 / scanline_bytes) * scanline_bytes
+        } else {
+            scanline_bytes
+        };
+
+        let mut reader = self.into_reader()?;
+
+        let mut bytes_read = 0;
+        while bytes_read < total_bytes {
+            let read_size = target_read_size.min(total_bytes - bytes_read);
+            reader.read_exact(&mut buf[bytes_read..][..read_size])?;
+            bytes_read += read_size;
+
+            progress_callback(Progress {
+                current: bytes_read as u64,
+                total: total_bytes as u64,
+            });
+        }
+
+        Ok(())
+    }
+
+    /// Set decoding limits for this decoder. See [`Limits`] for the different kinds of
+    /// limits that is possible to set.
+    ///
+    /// Note to implementors: make sure you call [`Limits::check_support`] so that
+    /// decoding fails if any unsupported strict limits are set. Also make sure
+    /// you call [`Limits::check_dimensions`] to check the `max_image_width` and
+    /// `max_image_height` limits.
+    ///
+    /// [`Limits`]: ./io/struct.Limits.html
+    /// [`Limits::check_support`]: ./io/struct.Limits.html#method.check_support
+    /// [`Limits::check_dimensions`]: ./io/struct.Limits.html#method.check_dimensions
+    fn set_limits(&mut self, limits: crate::io::Limits) -> ImageResult<()> {
+        limits.check_support(&crate::io::LimitSupport::default())?;
+
+        let (width, height) = self.dimensions();
+        limits.check_dimensions(width, height)?;
+
+        Ok(())
+    }
+}
+
+/// Specialized image decoding not be supported by all formats
+pub trait ImageDecoderRect<'a>: ImageDecoder<'a> + Sized {
+    /// Decode a rectangular section of the image; see [`read_rect_with_progress()`](#fn.read_rect_with_progress).
+    fn read_rect(
+        &mut self,
+        x: u32,
+        y: u32,
+        width: u32,
+        height: u32,
+        buf: &mut [u8],
+    ) -> ImageResult<()> {
+        self.read_rect_with_progress(x, y, width, height, buf, |_| {})
+    }
+
+    /// Decode a rectangular section of the image, periodically reporting progress.
+    ///
+    /// The output buffer will be filled with fields specified by
+    /// [`ImageDecoder::color_type()`](trait.ImageDecoder.html#fn.color_type),
+    /// in that order, each field represented in native-endian.
+    ///
+    /// The progress callback will be called at least once at the start and the end of decoding,
+    /// implementations are encouraged to call this more often,
+    /// with a frequency meaningful for display to the end-user.
+    ///
+    /// This function will panic if the output buffer isn't at least
+    /// `color_type().bytes_per_pixel() * color_type().channel_count() * width * height` bytes long.
+    fn read_rect_with_progress<F: Fn(Progress)>(
+        &mut self,
+        x: u32,
+        y: u32,
+        width: u32,
+        height: u32,
+        buf: &mut [u8],
+        progress_callback: F,
+    ) -> ImageResult<()>;
+}
+
+/// AnimationDecoder trait
+pub trait AnimationDecoder<'a> {
+    /// Consume the decoder producing a series of frames.
+    fn into_frames(self) -> Frames<'a>;
+}
+
+/// The trait all encoders implement
+pub trait ImageEncoder {
+    /// Writes all the bytes in an image to the encoder.
+    ///
+    /// This function takes a slice of bytes of the pixel data of the image
+    /// and encodes them. Unlike particular format encoders inherent impl encode
+    /// methods where endianness is not specified, here image data bytes should
+    /// always be in native endian. The implementor will reorder the endianness
+    /// as necessary for the target encoding format.
+    ///
+    /// See also `ImageDecoder::read_image` which reads byte buffers into
+    /// native endian.
+    fn write_image(
+        self,
+        buf: &[u8],
+        width: u32,
+        height: u32,
+        color_type: ColorType,
+    ) -> ImageResult<()>;
+}
+
+/// Immutable pixel iterator
+#[derive(Debug)]
+pub struct Pixels<'a, I: ?Sized + 'a> {
+    image: &'a I,
+    x: u32,
+    y: u32,
+    width: u32,
+    height: u32,
+}
+
+impl<'a, I: GenericImageView> Iterator for Pixels<'a, I> {
+    type Item = (u32, u32, I::Pixel);
+
+    fn next(&mut self) -> Option<(u32, u32, I::Pixel)> {
+        if self.x >= self.width {
+            self.x = 0;
+            self.y += 1;
+        }
+
+        if self.y >= self.height {
+            None
+        } else {
+            let pixel = self.image.get_pixel(self.x, self.y);
+            let p = (self.x, self.y, pixel);
+
+            self.x += 1;
+
+            Some(p)
+        }
+    }
+}
+
+impl<I: ?Sized> Clone for Pixels<'_, I> {
+    fn clone(&self) -> Self {
+        Pixels { ..*self }
+    }
+}
+
+/// Trait to inspect an image.
+///
+/// ```
+/// use image::{GenericImageView, Rgb, RgbImage};
+///
+/// let buffer = RgbImage::new(10, 10);
+/// let image: &dyn GenericImageView<Pixel=Rgb<u8>> = &buffer;
+/// ```
+pub trait GenericImageView {
+    /// The type of pixel.
+    type Pixel: Pixel;
+
+    /// The width and height of this image.
+    fn dimensions(&self) -> (u32, u32);
+
+    /// The width of this image.
+    fn width(&self) -> u32 {
+        let (w, _) = self.dimensions();
+        w
+    }
+
+    /// The height of this image.
+    fn height(&self) -> u32 {
+        let (_, h) = self.dimensions();
+        h
+    }
+
+    /// The bounding rectangle of this image.
+    fn bounds(&self) -> (u32, u32, u32, u32);
+
+    /// Returns true if this x, y coordinate is contained inside the image.
+    fn in_bounds(&self, x: u32, y: u32) -> bool {
+        let (ix, iy, iw, ih) = self.bounds();
+        x >= ix && x < ix + iw && y >= iy && y < iy + ih
+    }
+
+    /// Returns the pixel located at (x, y). Indexed from top left.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `(x, y)` is out of bounds.
+    fn get_pixel(&self, x: u32, y: u32) -> Self::Pixel;
+
+    /// Returns the pixel located at (x, y). Indexed from top left.
+    ///
+    /// This function can be implemented in a way that ignores bounds checking.
+    /// # Safety
+    ///
+    /// The coordinates must be [`in_bounds`] of the image.
+    ///
+    /// [`in_bounds`]: #method.in_bounds
+    unsafe fn unsafe_get_pixel(&self, x: u32, y: u32) -> Self::Pixel {
+        self.get_pixel(x, y)
+    }
+
+    /// Returns an Iterator over the pixels of this image.
+    /// The iterator yields the coordinates of each pixel
+    /// along with their value
+    fn pixels(&self) -> Pixels<Self>
+    where
+        Self: Sized,
+    {
+        let (width, height) = self.dimensions();
+
+        Pixels {
+            image: self,
+            x: 0,
+            y: 0,
+            width,
+            height,
+        }
+    }
+
+    /// Returns a subimage that is an immutable view into this image.
+    /// You can use [`GenericImage::sub_image`] if you need a mutable view instead.
+    /// The coordinates set the position of the top left corner of the view.
+    fn view(&self, x: u32, y: u32, width: u32, height: u32) -> SubImage<&Self>
+    where
+        Self: Sized,
+    {
+        assert!(x as u64 + width as u64 <= self.width() as u64);
+        assert!(y as u64 + height as u64 <= self.height() as u64);
+        SubImage::new(self, x, y, width, height)
+    }
+}
+
+/// A trait for manipulating images.
+pub trait GenericImage: GenericImageView {
+    /// Gets a reference to the mutable pixel at location `(x, y)`. Indexed from top left.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `(x, y)` is out of bounds.
+    ///
+    /// Panics for dynamic images (this method is deprecated and will be removed).
+    ///
+    /// ## Known issues
+    ///
+    /// This requires the buffer to contain a unique set of continuous channels in the exact order
+    /// and byte representation that the pixel type requires. This is somewhat restrictive.
+    ///
+    /// TODO: Maybe use some kind of entry API? this would allow pixel type conversion on the fly
+    /// while still doing only one array lookup:
+    ///
+    /// ```ignore
+    /// let px = image.pixel_entry_at(x,y);
+    /// px.set_from_rgba(rgba)
+    /// ```
+    #[deprecated(since = "0.24.0", note = "Use `get_pixel` and `put_pixel` instead.")]
+    fn get_pixel_mut(&mut self, x: u32, y: u32) -> &mut Self::Pixel;
+
+    /// Put a pixel at location (x, y). Indexed from top left.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `(x, y)` is out of bounds.
+    fn put_pixel(&mut self, x: u32, y: u32, pixel: Self::Pixel);
+
+    /// Puts a pixel at location (x, y). Indexed from top left.
+    ///
+    /// This function can be implemented in a way that ignores bounds checking.
+    /// # Safety
+    ///
+    /// The coordinates must be [`in_bounds`] of the image.
+    ///
+    /// [`in_bounds`]: traits.GenericImageView.html#method.in_bounds
+    unsafe fn unsafe_put_pixel(&mut self, x: u32, y: u32, pixel: Self::Pixel) {
+        self.put_pixel(x, y, pixel);
+    }
+
+    /// Put a pixel at location (x, y), taking into account alpha channels
+    #[deprecated(
+        since = "0.24.0",
+        note = "Use iterator `pixels_mut` to blend the pixels directly"
+    )]
+    fn blend_pixel(&mut self, x: u32, y: u32, pixel: Self::Pixel);
+
+    /// Copies all of the pixels from another image into this image.
+    ///
+    /// The other image is copied with the top-left corner of the
+    /// other image placed at (x, y).
+    ///
+    /// In order to copy only a piece of the other image, use [`GenericImageView::view`].
+    ///
+    /// You can use [`FlatSamples`] to source pixels from an arbitrary regular raster of channel
+    /// values, for example from a foreign interface or a fixed image.
+    ///
+    /// # Returns
+    /// Returns an error if the image is too large to be copied at the given position
+    ///
+    /// [`GenericImageView::view`]: trait.GenericImageView.html#method.view
+    /// [`FlatSamples`]: flat/struct.FlatSamples.html
+    fn copy_from<O>(&mut self, other: &O, x: u32, y: u32) -> ImageResult<()>
+    where
+        O: GenericImageView<Pixel = Self::Pixel>,
+    {
+        // Do bounds checking here so we can use the non-bounds-checking
+        // functions to copy pixels.
+        if self.width() < other.width() + x || self.height() < other.height() + y {
+            return Err(ImageError::Parameter(ParameterError::from_kind(
+                ParameterErrorKind::DimensionMismatch,
+            )));
+        }
+
+        for k in 0..other.height() {
+            for i in 0..other.width() {
+                let p = other.get_pixel(i, k);
+                self.put_pixel(i + x, k + y, p);
+            }
+        }
+        Ok(())
+    }
+
+    /// Copies all of the pixels from one part of this image to another part of this image.
+    ///
+    /// The destination rectangle of the copy is specified with the top-left corner placed at (x, y).
+    ///
+    /// # Returns
+    /// `true` if the copy was successful, `false` if the image could not
+    /// be copied due to size constraints.
+    fn copy_within(&mut self, source: Rect, x: u32, y: u32) -> bool {
+        let Rect {
+            x: sx,
+            y: sy,
+            width,
+            height,
+        } = source;
+        let dx = x;
+        let dy = y;
+        assert!(sx < self.width() && dx < self.width());
+        assert!(sy < self.height() && dy < self.height());
+        if self.width() - dx.max(sx) < width || self.height() - dy.max(sy) < height {
+            return false;
+        }
+        // since `.rev()` creates a new dype we would either have to go with dynamic dispatch for the ranges
+        // or have quite a lot of code bloat. A macro gives us static dispatch with less visible bloat.
+        macro_rules! copy_within_impl_ {
+            ($xiter:expr, $yiter:expr) => {
+                for y in $yiter {
+                    let sy = sy + y;
+                    let dy = dy + y;
+                    for x in $xiter {
+                        let sx = sx + x;
+                        let dx = dx + x;
+                        let pixel = self.get_pixel(sx, sy);
+                        self.put_pixel(dx, dy, pixel);
+                    }
+                }
+            };
+        }
+        // check how target and source rectangles relate to each other so we dont overwrite data before we copied it.
+        match (sx < dx, sy < dy) {
+            (true, true) => copy_within_impl_!((0..width).rev(), (0..height).rev()),
+            (true, false) => copy_within_impl_!((0..width).rev(), 0..height),
+            (false, true) => copy_within_impl_!(0..width, (0..height).rev()),
+            (false, false) => copy_within_impl_!(0..width, 0..height),
+        }
+        true
+    }
+
+    /// Returns a mutable subimage that is a view into this image.
+    /// If you want an immutable subimage instead, use [`GenericImageView::view`]
+    /// The coordinates set the position of the top left corner of the SubImage.
+    fn sub_image(&mut self, x: u32, y: u32, width: u32, height: u32) -> SubImage<&mut Self>
+    where
+        Self: Sized,
+    {
+        assert!(x as u64 + width as u64 <= self.width() as u64);
+        assert!(y as u64 + height as u64 <= self.height() as u64);
+        SubImage::new(self, x, y, width, height)
+    }
+}
+
+/// A View into another image
+///
+/// Instances of this struct can be created using:
+///   - [`GenericImage::sub_image`] to create a mutable view,
+///   - [`GenericImageView::view`] to create an immutable view,
+///   - [`SubImage::new`] to instantiate the struct directly.
+///
+/// Note that this does _not_ implement `GenericImage`, but it dereferences to one which allows you
+/// to use it as if it did. See [Design Considerations](#Design-Considerations) below for details.
+///
+/// # Design Considerations
+///
+/// For reasons relating to coherence, this is not itself a `GenericImage` or a `GenericImageView`.
+/// In short, we want to reserve the ability of adding traits implemented for _all_ generic images
+/// but in a different manner for `SubImage`. This may be required to ensure that stacking
+/// sub-images comes at no double indirect cost.
+///
+/// If, ultimately, this is not needed then a directly implementation of `GenericImage` can and
+/// will get added. This inconvenience may alternatively get resolved if Rust allows some forms of
+/// specialization, which might make this trick unnecessary and thus also allows for a direct
+/// implementation.
+#[derive(Copy, Clone)]
+pub struct SubImage<I> {
+    inner: SubImageInner<I>,
+}
+
+/// The inner type of `SubImage` that implements `GenericImage{,View}`.
+///
+/// This type is _nominally_ `pub` but it is not exported from the crate. It should be regarded as
+/// an existential type in any case.
+#[derive(Copy, Clone)]
+pub struct SubImageInner<I> {
+    image: I,
+    xoffset: u32,
+    yoffset: u32,
+    xstride: u32,
+    ystride: u32,
+}
+
+/// Alias to access Pixel behind a reference
+type DerefPixel<I> = <<I as Deref>::Target as GenericImageView>::Pixel;
+
+/// Alias to access Subpixel behind a reference
+type DerefSubpixel<I> = <DerefPixel<I> as Pixel>::Subpixel;
+
+impl<I> SubImage<I> {
+    /// Construct a new subimage
+    /// The coordinates set the position of the top left corner of the SubImage.
+    pub fn new(image: I, x: u32, y: u32, width: u32, height: u32) -> SubImage<I> {
+        SubImage {
+            inner: SubImageInner {
+                image,
+                xoffset: x,
+                yoffset: y,
+                xstride: width,
+                ystride: height,
+            },
+        }
+    }
+
+    /// Change the coordinates of this subimage.
+    pub fn change_bounds(&mut self, x: u32, y: u32, width: u32, height: u32) {
+        self.inner.xoffset = x;
+        self.inner.yoffset = y;
+        self.inner.xstride = width;
+        self.inner.ystride = height;
+    }
+
+    /// Convert this subimage to an ImageBuffer
+    pub fn to_image(&self) -> ImageBuffer<DerefPixel<I>, Vec<DerefSubpixel<I>>>
+    where
+        I: Deref,
+        I::Target: GenericImageView + 'static,
+    {
+        let mut out = ImageBuffer::new(self.inner.xstride, self.inner.ystride);
+        let borrowed = self.inner.image.deref();
+
+        for y in 0..self.inner.ystride {
+            for x in 0..self.inner.xstride {
+                let p = borrowed.get_pixel(x + self.inner.xoffset, y + self.inner.yoffset);
+                out.put_pixel(x, y, p);
+            }
+        }
+
+        out
+    }
+}
+
+/// Methods for readable images.
+impl<I> SubImage<I>
+where
+    I: Deref,
+    I::Target: GenericImageView,
+{
+    /// Create a sub-view of the image.
+    ///
+    /// The coordinates given are relative to the current view on the underlying image.
+    ///
+    /// Note that this method is preferred to the one from `GenericImageView`. This is accessible
+    /// with the explicit method call syntax but it should rarely be needed due to causing an
+    /// extra level of indirection.
+    ///
+    /// ```
+    /// use image::{GenericImageView, RgbImage, SubImage};
+    /// let buffer = RgbImage::new(10, 10);
+    ///
+    /// let subimage: SubImage<&RgbImage> = buffer.view(0, 0, 10, 10);
+    /// let subview: SubImage<&RgbImage> = subimage.view(0, 0, 10, 10);
+    ///
+    /// // Less efficient and NOT &RgbImage
+    /// let _: SubImage<&_> = GenericImageView::view(&*subimage, 0, 0, 10, 10);
+    /// ```
+    pub fn view(&self, x: u32, y: u32, width: u32, height: u32) -> SubImage<&I::Target> {
+        use crate::GenericImageView as _;
+        assert!(x as u64 + width as u64 <= self.inner.width() as u64);
+        assert!(y as u64 + height as u64 <= self.inner.height() as u64);
+        let x = self.inner.xoffset + x;
+        let y = self.inner.yoffset + y;
+        SubImage::new(&*self.inner.image, x, y, width, height)
+    }
+
+    /// Get a reference to the underlying image.
+    pub fn inner(&self) -> &I::Target {
+        &self.inner.image
+    }
+}
+
+impl<I> SubImage<I>
+where
+    I: DerefMut,
+    I::Target: GenericImage,
+{
+    /// Create a mutable sub-view of the image.
+    ///
+    /// The coordinates given are relative to the current view on the underlying image.
+    pub fn sub_image(
+        &mut self,
+        x: u32,
+        y: u32,
+        width: u32,
+        height: u32,
+    ) -> SubImage<&mut I::Target> {
+        assert!(x as u64 + width as u64 <= self.inner.width() as u64);
+        assert!(y as u64 + height as u64 <= self.inner.height() as u64);
+        let x = self.inner.xoffset + x;
+        let y = self.inner.yoffset + y;
+        SubImage::new(&mut *self.inner.image, x, y, width, height)
+    }
+
+    /// Get a mutable reference to the underlying image.
+    pub fn inner_mut(&mut self) -> &mut I::Target {
+        &mut self.inner.image
+    }
+}
+
+impl<I> Deref for SubImage<I>
+where
+    I: Deref,
+{
+    type Target = SubImageInner<I>;
+    fn deref(&self) -> &Self::Target {
+        &self.inner
+    }
+}
+
+impl<I> DerefMut for SubImage<I>
+where
+    I: DerefMut,
+{
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.inner
+    }
+}
+
+#[allow(deprecated)]
+impl<I> GenericImageView for SubImageInner<I>
+where
+    I: Deref,
+    I::Target: GenericImageView,
+{
+    type Pixel = DerefPixel<I>;
+
+    fn dimensions(&self) -> (u32, u32) {
+        (self.xstride, self.ystride)
+    }
+
+    fn bounds(&self) -> (u32, u32, u32, u32) {
+        (self.xoffset, self.yoffset, self.xstride, self.ystride)
+    }
+
+    fn get_pixel(&self, x: u32, y: u32) -> Self::Pixel {
+        self.image.get_pixel(x + self.xoffset, y + self.yoffset)
+    }
+}
+
+#[allow(deprecated)]
+impl<I> GenericImage for SubImageInner<I>
+where
+    I: DerefMut,
+    I::Target: GenericImage + Sized,
+{
+    fn get_pixel_mut(&mut self, x: u32, y: u32) -> &mut Self::Pixel {
+        self.image.get_pixel_mut(x + self.xoffset, y + self.yoffset)
+    }
+
+    fn put_pixel(&mut self, x: u32, y: u32, pixel: Self::Pixel) {
+        self.image
+            .put_pixel(x + self.xoffset, y + self.yoffset, pixel)
+    }
+
+    /// DEPRECATED: This method will be removed. Blend the pixel directly instead.
+    fn blend_pixel(&mut self, x: u32, y: u32, pixel: Self::Pixel) {
+        self.image
+            .blend_pixel(x + self.xoffset, y + self.yoffset, pixel)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::io;
+    use std::path::Path;
+
+    use super::{
+        load_rect, ColorType, GenericImage, GenericImageView, ImageDecoder, ImageFormat,
+        ImageResult,
+    };
+    use crate::color::Rgba;
+    use crate::math::Rect;
+    use crate::{GrayImage, ImageBuffer};
+
+    #[test]
+    #[allow(deprecated)]
+    /// Test that alpha blending works as expected
+    fn test_image_alpha_blending() {
+        let mut target = ImageBuffer::new(1, 1);
+        target.put_pixel(0, 0, Rgba([255u8, 0, 0, 255]));
+        assert!(*target.get_pixel(0, 0) == Rgba([255, 0, 0, 255]));
+        target.blend_pixel(0, 0, Rgba([0, 255, 0, 255]));
+        assert!(*target.get_pixel(0, 0) == Rgba([0, 255, 0, 255]));
+
+        // Blending an alpha channel onto a solid background
+        target.blend_pixel(0, 0, Rgba([255, 0, 0, 127]));
+        assert!(*target.get_pixel(0, 0) == Rgba([127, 127, 0, 255]));
+
+        // Blending two alpha channels
+        target.put_pixel(0, 0, Rgba([0, 255, 0, 127]));
+        target.blend_pixel(0, 0, Rgba([255, 0, 0, 127]));
+        assert!(*target.get_pixel(0, 0) == Rgba([169, 85, 0, 190]));
+    }
+
+    #[test]
+    fn test_in_bounds() {
+        let mut target = ImageBuffer::new(2, 2);
+        target.put_pixel(0, 0, Rgba([255u8, 0, 0, 255]));
+
+        assert!(target.in_bounds(0, 0));
+        assert!(target.in_bounds(1, 0));
+        assert!(target.in_bounds(0, 1));
+        assert!(target.in_bounds(1, 1));
+
+        assert!(!target.in_bounds(2, 0));
+        assert!(!target.in_bounds(0, 2));
+        assert!(!target.in_bounds(2, 2));
+    }
+
+    #[test]
+    fn test_can_subimage_clone_nonmut() {
+        let mut source = ImageBuffer::new(3, 3);
+        source.put_pixel(1, 1, Rgba([255u8, 0, 0, 255]));
+
+        // A non-mutable copy of the source image
+        let source = source.clone();
+
+        // Clone a view into non-mutable to a separate buffer
+        let cloned = source.view(1, 1, 1, 1).to_image();
+
+        assert!(cloned.get_pixel(0, 0) == source.get_pixel(1, 1));
+    }
+
+    #[test]
+    fn test_can_nest_views() {
+        let mut source = ImageBuffer::from_pixel(3, 3, Rgba([255u8, 0, 0, 255]));
+
+        {
+            let mut sub1 = source.sub_image(0, 0, 2, 2);
+            let mut sub2 = sub1.sub_image(1, 1, 1, 1);
+            sub2.put_pixel(0, 0, Rgba([0, 0, 0, 0]));
+        }
+
+        assert_eq!(*source.get_pixel(1, 1), Rgba([0, 0, 0, 0]));
+
+        let view1 = source.view(0, 0, 2, 2);
+        assert_eq!(*source.get_pixel(1, 1), view1.get_pixel(1, 1));
+
+        let view2 = view1.view(1, 1, 1, 1);
+        assert_eq!(*source.get_pixel(1, 1), view2.get_pixel(0, 0));
+    }
+
+    #[test]
+    #[should_panic]
+    fn test_view_out_of_bounds() {
+        let source = ImageBuffer::from_pixel(3, 3, Rgba([255u8, 0, 0, 255]));
+        source.view(1, 1, 3, 3);
+    }
+
+    #[test]
+    #[should_panic]
+    fn test_view_coordinates_out_of_bounds() {
+        let source = ImageBuffer::from_pixel(3, 3, Rgba([255u8, 0, 0, 255]));
+        source.view(3, 3, 3, 3);
+    }
+
+    #[test]
+    #[should_panic]
+    fn test_view_width_out_of_bounds() {
+        let source = ImageBuffer::from_pixel(3, 3, Rgba([255u8, 0, 0, 255]));
+        source.view(1, 1, 3, 2);
+    }
+
+    #[test]
+    #[should_panic]
+    fn test_view_height_out_of_bounds() {
+        let source = ImageBuffer::from_pixel(3, 3, Rgba([255u8, 0, 0, 255]));
+        source.view(1, 1, 2, 3);
+    }
+
+    #[test]
+    #[should_panic]
+    fn test_view_x_out_of_bounds() {
+        let source = ImageBuffer::from_pixel(3, 3, Rgba([255u8, 0, 0, 255]));
+        source.view(3, 1, 3, 3);
+    }
+
+    #[test]
+    #[should_panic]
+    fn test_view_y_out_of_bounds() {
+        let source = ImageBuffer::from_pixel(3, 3, Rgba([255u8, 0, 0, 255]));
+        source.view(1, 3, 3, 3);
+    }
+
+    #[test]
+    fn test_view_in_bounds() {
+        let source = ImageBuffer::from_pixel(3, 3, Rgba([255u8, 0, 0, 255]));
+        source.view(0, 0, 3, 3);
+        source.view(1, 1, 2, 2);
+        source.view(2, 2, 0, 0);
+    }
+
+    #[test]
+    fn test_copy_sub_image() {
+        let source = ImageBuffer::from_pixel(3, 3, Rgba([255u8, 0, 0, 255]));
+        let view = source.view(0, 0, 3, 3);
+        let mut views = Vec::new();
+        views.push(view);
+        view.to_image();
+    }
+
+    #[test]
+    fn test_load_rect() {
+        struct MockDecoder {
+            scanline_number: u64,
+            scanline_bytes: u64,
+        }
+        impl<'a> ImageDecoder<'a> for MockDecoder {
+            type Reader = Box<dyn io::Read>;
+            fn dimensions(&self) -> (u32, u32) {
+                (5, 5)
+            }
+            fn color_type(&self) -> ColorType {
+                ColorType::L8
+            }
+            fn into_reader(self) -> ImageResult<Self::Reader> {
+                unimplemented!()
+            }
+            fn scanline_bytes(&self) -> u64 {
+                self.scanline_bytes
+            }
+        }
+
+        const DATA: [u8; 25] = [
+            0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
+            24,
+        ];
+
+        fn seek_scanline(m: &mut MockDecoder, n: u64) -> io::Result<()> {
+            m.scanline_number = n;
+            Ok(())
+        }
+        fn read_scanline(m: &mut MockDecoder, buf: &mut [u8]) -> io::Result<()> {
+            let bytes_read = m.scanline_number * m.scanline_bytes;
+            if bytes_read >= 25 {
+                return Ok(());
+            }
+
+            let len = m.scanline_bytes.min(25 - bytes_read);
+            buf[..(len as usize)].copy_from_slice(&DATA[(bytes_read as usize)..][..(len as usize)]);
+            m.scanline_number += 1;
+            Ok(())
+        }
+
+        for scanline_bytes in 1..30 {
+            let mut output = [0u8; 26];
+
+            load_rect(
+                0,
+                0,
+                5,
+                5,
+                &mut output,
+                |_| {},
+                &mut MockDecoder {
+                    scanline_number: 0,
+                    scanline_bytes,
+                },
+                seek_scanline,
+                read_scanline,
+            )
+            .unwrap();
+            assert_eq!(output[0..25], DATA);
+            assert_eq!(output[25], 0);
+
+            output = [0u8; 26];
+            load_rect(
+                3,
+                2,
+                1,
+                1,
+                &mut output,
+                |_| {},
+                &mut MockDecoder {
+                    scanline_number: 0,
+                    scanline_bytes,
+                },
+                seek_scanline,
+                read_scanline,
+            )
+            .unwrap();
+            assert_eq!(output[0..2], [13, 0]);
+
+            output = [0u8; 26];
+            load_rect(
+                3,
+                2,
+                2,
+                2,
+                &mut output,
+                |_| {},
+                &mut MockDecoder {
+                    scanline_number: 0,
+                    scanline_bytes,
+                },
+                seek_scanline,
+                read_scanline,
+            )
+            .unwrap();
+            assert_eq!(output[0..5], [13, 14, 18, 19, 0]);
+
+            output = [0u8; 26];
+            load_rect(
+                1,
+                1,
+                2,
+                4,
+                &mut output,
+                |_| {},
+                &mut MockDecoder {
+                    scanline_number: 0,
+                    scanline_bytes,
+                },
+                seek_scanline,
+                read_scanline,
+            )
+            .unwrap();
+            assert_eq!(output[0..9], [6, 7, 11, 12, 16, 17, 21, 22, 0]);
+        }
+    }
+
+    #[test]
+    fn test_load_rect_single_scanline() {
+        const DATA: [u8; 25] = [
+            0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
+            24,
+        ];
+
+        struct MockDecoder;
+        impl<'a> ImageDecoder<'a> for MockDecoder {
+            type Reader = Box<dyn io::Read>;
+            fn dimensions(&self) -> (u32, u32) {
+                (5, 5)
+            }
+            fn color_type(&self) -> ColorType {
+                ColorType::L8
+            }
+            fn into_reader(self) -> ImageResult<Self::Reader> {
+                unimplemented!()
+            }
+            fn scanline_bytes(&self) -> u64 {
+                25
+            }
+        }
+
+        // Ensure that seek scanline is called only once.
+        let mut seeks = 0;
+        let seek_scanline = |_d: &mut MockDecoder, n: u64| -> io::Result<()> {
+            seeks += 1;
+            assert_eq!(n, 0);
+            assert_eq!(seeks, 1);
+            Ok(())
+        };
+
+        fn read_scanline(_m: &mut MockDecoder, buf: &mut [u8]) -> io::Result<()> {
+            buf.copy_from_slice(&DATA);
+            Ok(())
+        }
+
+        let mut output = [0; 26];
+        load_rect(
+            1,
+            1,
+            2,
+            4,
+            &mut output,
+            |_| {},
+            &mut MockDecoder,
+            seek_scanline,
+            read_scanline,
+        )
+        .unwrap();
+        assert_eq!(output[0..9], [6, 7, 11, 12, 16, 17, 21, 22, 0]);
+    }
+
+    #[test]
+    fn test_image_format_from_path() {
+        fn from_path(s: &str) -> ImageResult<ImageFormat> {
+            ImageFormat::from_path(Path::new(s))
+        }
+        assert_eq!(from_path("./a.jpg").unwrap(), ImageFormat::Jpeg);
+        assert_eq!(from_path("./a.jpeg").unwrap(), ImageFormat::Jpeg);
+        assert_eq!(from_path("./a.JPEG").unwrap(), ImageFormat::Jpeg);
+        assert_eq!(from_path("./a.pNg").unwrap(), ImageFormat::Png);
+        assert_eq!(from_path("./a.gif").unwrap(), ImageFormat::Gif);
+        assert_eq!(from_path("./a.webp").unwrap(), ImageFormat::WebP);
+        assert_eq!(from_path("./a.tiFF").unwrap(), ImageFormat::Tiff);
+        assert_eq!(from_path("./a.tif").unwrap(), ImageFormat::Tiff);
+        assert_eq!(from_path("./a.tga").unwrap(), ImageFormat::Tga);
+        assert_eq!(from_path("./a.dds").unwrap(), ImageFormat::Dds);
+        assert_eq!(from_path("./a.bmp").unwrap(), ImageFormat::Bmp);
+        assert_eq!(from_path("./a.Ico").unwrap(), ImageFormat::Ico);
+        assert_eq!(from_path("./a.hdr").unwrap(), ImageFormat::Hdr);
+        assert_eq!(from_path("./a.exr").unwrap(), ImageFormat::OpenExr);
+        assert_eq!(from_path("./a.pbm").unwrap(), ImageFormat::Pnm);
+        assert_eq!(from_path("./a.pAM").unwrap(), ImageFormat::Pnm);
+        assert_eq!(from_path("./a.Ppm").unwrap(), ImageFormat::Pnm);
+        assert_eq!(from_path("./a.pgm").unwrap(), ImageFormat::Pnm);
+        assert_eq!(from_path("./a.AViF").unwrap(), ImageFormat::Avif);
+        assert!(from_path("./a.txt").is_err());
+        assert!(from_path("./a").is_err());
+    }
+
+    #[test]
+    fn test_generic_image_copy_within_oob() {
+        let mut image: GrayImage = ImageBuffer::from_raw(4, 4, vec![0u8; 16]).unwrap();
+        assert!(!image.sub_image(0, 0, 4, 4).copy_within(
+            Rect {
+                x: 0,
+                y: 0,
+                width: 5,
+                height: 4
+            },
+            0,
+            0
+        ));
+        assert!(!image.sub_image(0, 0, 4, 4).copy_within(
+            Rect {
+                x: 0,
+                y: 0,
+                width: 4,
+                height: 5
+            },
+            0,
+            0
+        ));
+        assert!(!image.sub_image(0, 0, 4, 4).copy_within(
+            Rect {
+                x: 1,
+                y: 0,
+                width: 4,
+                height: 4
+            },
+            0,
+            0
+        ));
+        assert!(!image.sub_image(0, 0, 4, 4).copy_within(
+            Rect {
+                x: 0,
+                y: 0,
+                width: 4,
+                height: 4
+            },
+            1,
+            0
+        ));
+        assert!(!image.sub_image(0, 0, 4, 4).copy_within(
+            Rect {
+                x: 0,
+                y: 1,
+                width: 4,
+                height: 4
+            },
+            0,
+            0
+        ));
+        assert!(!image.sub_image(0, 0, 4, 4).copy_within(
+            Rect {
+                x: 0,
+                y: 0,
+                width: 4,
+                height: 4
+            },
+            0,
+            1
+        ));
+        assert!(!image.sub_image(0, 0, 4, 4).copy_within(
+            Rect {
+                x: 1,
+                y: 1,
+                width: 4,
+                height: 4
+            },
+            0,
+            0
+        ));
+    }
+
+    #[test]
+    fn test_generic_image_copy_within_tl() {
+        let data = &[
+            00, 01, 02, 03, 04, 05, 06, 07, 08, 09, 10, 11, 12, 13, 14, 15,
+        ];
+        let expected = [
+            00, 01, 02, 03, 04, 00, 01, 02, 08, 04, 05, 06, 12, 08, 09, 10,
+        ];
+        let mut image: GrayImage = ImageBuffer::from_raw(4, 4, Vec::from(&data[..])).unwrap();
+        assert!(image.sub_image(0, 0, 4, 4).copy_within(
+            Rect {
+                x: 0,
+                y: 0,
+                width: 3,
+                height: 3
+            },
+            1,
+            1
+        ));
+        assert_eq!(&image.into_raw(), &expected);
+    }
+
+    #[test]
+    fn test_generic_image_copy_within_tr() {
+        let data = &[
+            00, 01, 02, 03, 04, 05, 06, 07, 08, 09, 10, 11, 12, 13, 14, 15,
+        ];
+        let expected = [
+            00, 01, 02, 03, 01, 02, 03, 07, 05, 06, 07, 11, 09, 10, 11, 15,
+        ];
+        let mut image: GrayImage = ImageBuffer::from_raw(4, 4, Vec::from(&data[..])).unwrap();
+        assert!(image.sub_image(0, 0, 4, 4).copy_within(
+            Rect {
+                x: 1,
+                y: 0,
+                width: 3,
+                height: 3
+            },
+            0,
+            1
+        ));
+        assert_eq!(&image.into_raw(), &expected);
+    }
+
+    #[test]
+    fn test_generic_image_copy_within_bl() {
+        let data = &[
+            00, 01, 02, 03, 04, 05, 06, 07, 08, 09, 10, 11, 12, 13, 14, 15,
+        ];
+        let expected = [
+            00, 04, 05, 06, 04, 08, 09, 10, 08, 12, 13, 14, 12, 13, 14, 15,
+        ];
+        let mut image: GrayImage = ImageBuffer::from_raw(4, 4, Vec::from(&data[..])).unwrap();
+        assert!(image.sub_image(0, 0, 4, 4).copy_within(
+            Rect {
+                x: 0,
+                y: 1,
+                width: 3,
+                height: 3
+            },
+            1,
+            0
+        ));
+        assert_eq!(&image.into_raw(), &expected);
+    }
+
+    #[test]
+    fn test_generic_image_copy_within_br() {
+        let data = &[
+            00, 01, 02, 03, 04, 05, 06, 07, 08, 09, 10, 11, 12, 13, 14, 15,
+        ];
+        let expected = [
+            05, 06, 07, 03, 09, 10, 11, 07, 13, 14, 15, 11, 12, 13, 14, 15,
+        ];
+        let mut image: GrayImage = ImageBuffer::from_raw(4, 4, Vec::from(&data[..])).unwrap();
+        assert!(image.sub_image(0, 0, 4, 4).copy_within(
+            Rect {
+                x: 1,
+                y: 1,
+                width: 3,
+                height: 3
+            },
+            0,
+            0
+        ));
+        assert_eq!(&image.into_raw(), &expected);
+    }
+
+    #[test]
+    fn image_formats_are_recognized() {
+        use ImageFormat::*;
+        const ALL_FORMATS: &'static [ImageFormat] = &[
+            Avif, Png, Jpeg, Gif, WebP, Pnm, Tiff, Tga, Dds, Bmp, Ico, Hdr, Farbfeld, OpenExr,
+        ];
+        for &format in ALL_FORMATS {
+            let mut file = Path::new("file.nothing").to_owned();
+            for ext in format.extensions_str() {
+                assert!(file.set_extension(ext));
+                match ImageFormat::from_path(&file) {
+                    Err(_) => panic!("Path {} not recognized as {:?}", file.display(), format),
+                    Ok(result) => assert_eq!(format, result),
+                }
+            }
+        }
+    }
+
+    #[test]
+    fn total_bytes_overflow() {
+        struct D;
+        impl<'a> ImageDecoder<'a> for D {
+            type Reader = std::io::Cursor<Vec<u8>>;
+            fn color_type(&self) -> ColorType {
+                ColorType::Rgb8
+            }
+            fn dimensions(&self) -> (u32, u32) {
+                (0xffffffff, 0xffffffff)
+            }
+            fn into_reader(self) -> ImageResult<Self::Reader> {
+                unreachable!()
+            }
+        }
+        assert_eq!(D.total_bytes(), u64::max_value());
+
+        let v: ImageResult<Vec<u8>> = super::decoder_to_vec(D);
+        assert!(v.is_err());
+    }
+}