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    926

    use num_traits::Zero;
    use std::io;
    use std::marker::PhantomData;
    use std::ops::{Deref, DerefMut, Index, IndexMut, Range};
    use std::path::Path;
    use std::slice::{Chunks, ChunksMut};

    use color::{ColorType, FromColor, Luma, LumaA, Rgb, Rgba, Bgr, Bgra};
    use flat::{FlatSamples, SampleLayout};
    use dynimage::save_buffer;
    use image::{GenericImage, GenericImageView};
    use traits::Primitive;
    use utils::expand_packed;

    /// A generalized pixel.
    ///
    /// A pixel object is usually not used standalone but as a view into an image buffer.
    pub trait Pixel: Copy + Clone {
        /// The underlying subpixel type.
        type Subpixel: Primitive;

        /// Returns the number of channels of this pixel type.
        fn channel_count() -> u8;

        /// Returns the components as a slice.
        fn channels(&self) -> &[Self::Subpixel];

        /// Returns the components as a mutable slice
        fn channels_mut(&mut self) -> &mut [Self::Subpixel];

        /// Returns a string that can help to interpret the meaning each channel
        /// See [gimp babl](http://gegl.org/babl/).
        fn color_model() -> &'static str;

        /// Returns the ColorType for this pixel format
        fn color_type() -> ColorType;

        /// Returns the channels of this pixel as a 4 tuple. If the pixel
        /// has less than 4 channels the remainder is filled with the maximum value
        ///
        /// TODO deprecate
        fn channels4(
            &self,
        ) -> (
            Self::Subpixel,
            Self::Subpixel,
            Self::Subpixel,
            Self::Subpixel,
        );

        /// Construct a pixel from the 4 channels a, b, c and d.
        /// If the pixel does not contain 4 channels the extra are ignored.
        ///
        /// TODO deprecate
        fn from_channels(
            a: Self::Subpixel,
            b: Self::Subpixel,
            c: Self::Subpixel,
            d: Self::Subpixel,
        ) -> Self;

        /// Returns a view into a slice.
        ///
        /// Note: The slice length is not checked on creation. Thus the caller has to ensure
        /// that the slice is long enough to present panics if the pixel is used later on.
        fn from_slice(slice: &[Self::Subpixel]) -> &Self;

        /// Returns mutable view into a mutable slice.
        ///
        /// Note: The slice length is not checked on creation. Thus the caller has to ensure
        /// that the slice is long enough to present panics if the pixel is used later on.
        fn from_slice_mut(slice: &mut [Self::Subpixel]) -> &mut Self;

        /// Convert this pixel to RGB
        fn to_rgb(&self) -> Rgb<Self::Subpixel>;

        /// Convert this pixel to RGB with an alpha channel
        fn to_rgba(&self) -> Rgba<Self::Subpixel>;

        /// Convert this pixel to luma
        fn to_luma(&self) -> Luma<Self::Subpixel>;

        /// Convert this pixel to luma with an alpha channel
        fn to_luma_alpha(&self) -> LumaA<Self::Subpixel>;

        /// Convert this pixel to BGR
        fn to_bgr(&self) -> Bgr<Self::Subpixel>;

        /// Convert this pixel to BGR with an alpha channel
        fn to_bgra(&self) -> Bgra<Self::Subpixel>;

        /// Apply the function ```f``` to each channel of this pixel.
        fn map<F>(&self, f: F) -> Self
        where
            F: FnMut(Self::Subpixel) -> Self::Subpixel;

        /// Apply the function ```f``` to each channel of this pixel.
        fn apply<F>(&mut self, f: F)
        where
            F: FnMut(Self::Subpixel) -> Self::Subpixel;

        /// Apply the function ```f``` to each channel except the alpha channel.
        /// Apply the function ```g``` to the alpha channel.
        fn map_with_alpha<F, G>(&self, f: F, g: G) -> Self
        where
            F: FnMut(Self::Subpixel) -> Self::Subpixel,
            G: FnMut(Self::Subpixel) -> Self::Subpixel;

        /// Apply the function ```f``` to each channel except the alpha channel.
        /// Apply the function ```g``` to the alpha channel. Works in-place.
        fn apply_with_alpha<F, G>(&mut self, f: F, g: G)
        where
            F: FnMut(Self::Subpixel) -> Self::Subpixel,
            G: FnMut(Self::Subpixel) -> Self::Subpixel;

        /// Apply the function ```f``` to each channel of this pixel and
        /// ```other``` pairwise.
        fn map2<F>(&self, other: &Self, f: F) -> Self
        where
            F: FnMut(Self::Subpixel, Self::Subpixel) -> Self::Subpixel;

        /// Apply the function ```f``` to each channel of this pixel and
        /// ```other``` pairwise. Works in-place.
        fn apply2<F>(&mut self, other: &Self, f: F)
        where
            F: FnMut(Self::Subpixel, Self::Subpixel) -> Self::Subpixel;

        /// Invert this pixel
        fn invert(&mut self);

        /// Blend the color of a given pixel into ourself, taking into account alpha channels
        fn blend(&mut self, other: &Self);
    }

    /// Iterate over pixel refs.
    pub struct Pixels<'a, P: Pixel + 'a>
    where
        P::Subpixel: 'a,
    {
        chunks: Chunks<'a, P::Subpixel>,
    }

    impl<'a, P: Pixel + 'a> Iterator for Pixels<'a, P>
    where
        P::Subpixel: 'a,
    {
        type Item = &'a P;

        #[inline(always)]
        fn next(&mut self) -> Option<&'a P> {
            self.chunks.next().map(|v| <P as Pixel>::from_slice(v))
        }
    }

    impl<'a, P: Pixel + 'a> ExactSizeIterator for Pixels<'a, P>
    where
        P::Subpixel: 'a,
    {
        fn len(&self) -> usize {
            self.chunks.len()
        }
    }

    impl<'a, P: Pixel + 'a> DoubleEndedIterator for Pixels<'a, P>
    where
        P::Subpixel: 'a,
    {
        #[inline(always)]
        fn next_back(&mut self) -> Option<&'a P> {
            self.chunks.next_back().map(|v| <P as Pixel>::from_slice(v))
        }
    }

    /// Iterate over mutable pixel refs.
    pub struct PixelsMut<'a, P: Pixel + 'a>
    where
        P::Subpixel: 'a,
    {
        chunks: ChunksMut<'a, P::Subpixel>,
    }

    impl<'a, P: Pixel + 'a> Iterator for PixelsMut<'a, P>
    where
        P::Subpixel: 'a,
    {
        type Item = &'a mut P;

        #[inline(always)]
        fn next(&mut self) -> Option<&'a mut P> {
            self.chunks.next().map(|v| <P as Pixel>::from_slice_mut(v))
        }
    }

    impl<'a, P: Pixel + 'a> ExactSizeIterator for PixelsMut<'a, P>
    where
        P::Subpixel: 'a,
    {
        fn len(&self) -> usize {
            self.chunks.len()
        }
    }

    impl<'a, P: Pixel + 'a> DoubleEndedIterator for PixelsMut<'a, P>
    where
        P::Subpixel: 'a,
    {
        #[inline(always)]
        fn next_back(&mut self) -> Option<&'a mut P> {
            self.chunks
                .next_back()
                .map(|v| <P as Pixel>::from_slice_mut(v))
        }
    }

    /// Enumerate the pixels of an image.
    pub struct EnumeratePixels<'a, P: Pixel + 'a>
    where
        <P as Pixel>::Subpixel: 'a,
    {
        pixels: Pixels<'a, P>,
        x: u32,
        y: u32,
        width: u32,
    }

    impl<'a, P: Pixel + 'a> Iterator for EnumeratePixels<'a, P>
    where
        P::Subpixel: 'a,
    {
        type Item = (u32, u32, &'a P);

        #[inline(always)]
        fn next(&mut self) -> Option<(u32, u32, &'a P)> {
            if self.x >= self.width {
                self.x = 0;
                self.y += 1;
            }
            let (x, y) = (self.x, self.y);
            self.x += 1;
            match self.pixels.next() {
                None => None,
                Some(p) => Some((x, y, p)),
            }
        }
    }

    impl<'a, P: Pixel + 'a> ExactSizeIterator for EnumeratePixels<'a, P>
    where
        P::Subpixel: 'a,
    {
        fn len(&self) -> usize {
            self.pixels.len()
        }
    }

    /// Enumerate the pixels of an image.
    pub struct EnumeratePixelsMut<'a, P: Pixel + 'a>
    where
        <P as Pixel>::Subpixel: 'a,
    {
        pixels: PixelsMut<'a, P>,
        x: u32,
        y: u32,
        width: u32,
    }

    impl<'a, P: Pixel + 'a> Iterator for EnumeratePixelsMut<'a, P>
    where
        P::Subpixel: 'a,
    {
        type Item = (u32, u32, &'a mut P);

        #[inline(always)]
        fn next(&mut self) -> Option<(u32, u32, &'a mut P)> {
            if self.x >= self.width {
                self.x = 0;
                self.y += 1;
            }
            let (x, y) = (self.x, self.y);
            self.x += 1;
            match self.pixels.next() {
                None => None,
                Some(p) => Some((x, y, p)),
            }
        }
    }

    impl<'a, P: Pixel + 'a> ExactSizeIterator for EnumeratePixelsMut<'a, P>
    where
        P::Subpixel: 'a,
    {
        fn len(&self) -> usize {
            self.pixels.len()
        }
    }

    /// Generic image buffer
    #[derive(Debug)]
    pub struct ImageBuffer<P: Pixel, Container> {
        width: u32,
        height: u32,
        _phantom: PhantomData<P>,
        data: Container,
    }

    // generic implementation, shared along all image buffers
    impl<P, Container> ImageBuffer<P, Container>
    where
        P: Pixel + 'static,
        P::Subpixel: 'static,
        Container: Deref<Target = [P::Subpixel]>,
    {
        /// Contructs a buffer from a generic container
        /// (for example a `Vec` or a slice)
        ///
        /// Returns `None` if the container is not big enough (including when the image dimensions
        /// necessitate an allocation of more bytes than supported by the container).
        pub fn from_raw(width: u32, height: u32, buf: Container) -> Option<ImageBuffer<P, Container>> {
            if Self::check_image_fits(width, height, buf.len()) {
                Some(ImageBuffer {
                    data: buf,
                    width,
                    height,
                    _phantom: PhantomData,
                })
            } else {
                None
            }
        }

        /// Returns the underlying raw buffer
        pub fn into_raw(self) -> Container {
            self.data
        }

        /// The width and height of this image.
        pub fn dimensions(&self) -> (u32, u32) {
            (self.width, self.height)
        }

        /// The width of this image.
        pub fn width(&self) -> u32 {
            self.width
        }

        /// The height of this image.
        pub fn height(&self) -> u32 {
            self.height
        }

        /// Returns an iterator over the pixels of this image.
        pub fn pixels(&self) -> Pixels<P> {
            Pixels {
                chunks: self.data.chunks(<P as Pixel>::channel_count() as usize),
            }
        }

        /// Enumerates over the pixels of the image.
        /// The iterator yields the coordinates of each pixel
        /// along with a reference to them.
        pub fn enumerate_pixels(&self) -> EnumeratePixels<P> {
            EnumeratePixels {
                pixels: self.pixels(),
                x: 0,
                y: 0,
                width: self.width,
            }
        }

        /// Gets a reference to the pixel at location `(x, y)`
        ///
        /// # Panics
        ///
        /// Panics if `(x, y)` is out of the bounds `(width, height)`.
        pub fn get_pixel(&self, x: u32, y: u32) -> &P {
            match self.pixel_indices(x, y) {
                None => panic!("Image index {:?} out of bounds {:?}", (x, y), (self.width, self.height)),
                Some(pixel_indices) => <P as Pixel>::from_slice(&self.data[pixel_indices]),
            }
        }

        /// Test that the image fits inside the buffer.
        ///
        /// Verifies that the maximum image of pixels inside the bounds is smaller than the provided
        /// length. Note that as a corrolary we also have that the index calculation of pixels inside
        /// the bounds will not overflow.
        fn check_image_fits(width: u32, height: u32, len: usize) -> bool {
            let checked_len = Self::image_buffer_len(width, height);
            checked_len.map(|min_len| min_len <= len).unwrap_or(false)
        }

        fn image_buffer_len(width: u32, height: u32) -> Option<usize> {
            Some(<P as Pixel>::channel_count() as usize)
                .and_then(|size| size.checked_mul(width as usize))
                .and_then(|size| size.checked_mul(height as usize))
        }

        #[inline(always)]
        fn pixel_indices(&self, x: u32, y: u32) -> Option<Range<usize>> {
            if x >= self.width || y >= self.height {
                return None
            }

            Some(self.pixel_indices_unchecked(x, y))
        }

        #[inline(always)]
        fn pixel_indices_unchecked(&self, x: u32, y: u32) -> Range<usize> {
            let no_channels = <P as Pixel>::channel_count() as usize;
            // If in bounds, this can't overflow as we have tested that at construction!
            let min_index = (y as usize*self.width as usize + x as usize)*no_channels;
            min_index..min_index+no_channels
        }

        /// Get the format of the buffer when viewed as a matrix of samples.
        pub fn sample_layout(&self) -> SampleLayout {
            // None of these can overflow, as all our memory is addressable.
            SampleLayout::row_major_packed(<P as Pixel>::channel_count(), self.width, self.height)
        }

        /// Return the raw sample buffer with its stride an dimension information.
        ///
        /// The returned buffer is guaranteed to be well formed in all cases. It is layed out by
        /// colors, width then height, meaning `channel_stride <= width_stride <= height_stride`. All
        /// strides are in numbers of elements but those are mostly `u8` in which case the strides are
        /// also byte strides.
        pub fn into_flat_samples(self) -> FlatSamples<Container>
            where Container: AsRef<[P::Subpixel]>
        {
            // None of these can overflow, as all our memory is addressable.
            let layout = self.sample_layout();
            FlatSamples {
                samples: self.data,
                layout,
                color_hint: Some(P::color_type()),
            }
        }

        /// Return a view on the raw sample buffer.
        ///
        /// See `flattened` for more details.
        pub fn as_flat_samples(&self) -> FlatSamples<&[P::Subpixel]>
            where Container: AsRef<[P::Subpixel]>
        {
            let layout = self.sample_layout();
            FlatSamples {
                samples: self.data.as_ref(),
                layout,
                color_hint: Some(P::color_type()),
            }
        }
    }

    impl<P, Container> ImageBuffer<P, Container>
    where
        P: Pixel + 'static,
        P::Subpixel: 'static,
        Container: Deref<Target = [P::Subpixel]> + DerefMut,
    {
        /// Returns an iterator over the mutable pixels of this image.
        pub fn pixels_mut(&mut self) -> PixelsMut<P> {
            PixelsMut {
                chunks: self.data.chunks_mut(<P as Pixel>::channel_count() as usize),
            }
        }

        /// Enumerates over the pixels of the image.
        /// The iterator yields the coordinates of each pixel
        /// along with a mutable reference to them.
        pub fn enumerate_pixels_mut(&mut self) -> EnumeratePixelsMut<P> {
            let width = self.width;
            EnumeratePixelsMut {
                pixels: self.pixels_mut(),
                x: 0,
                y: 0,
                width,
            }
        }

        /// Gets a reference to the mutable pixel at location `(x, y)`
        ///
        /// # Panics
        ///
        /// Panics if `(x, y)` is out of the bounds `(width, height)`.
        pub fn get_pixel_mut(&mut self, x: u32, y: u32) -> &mut P {
            match self.pixel_indices(x, y) {
                None => panic!("Image index {:?} out of bounds {:?}", (x, y), (self.width, self.height)),
                Some(pixel_indices) => <P as Pixel>::from_slice_mut(&mut self.data[pixel_indices]),
            }
        }

        /// Puts a pixel at location `(x, y)`
        ///
        /// # Panics
        ///
        /// Panics if `(x, y)` is out of the bounds `(width, height)`.
        pub fn put_pixel(&mut self, x: u32, y: u32, pixel: P) {
            *self.get_pixel_mut(x, y) = pixel
        }
    }

    impl<P, Container> ImageBuffer<P, Container>
    where
        P: Pixel<Subpixel = u8> + 'static,
        Container: Deref<Target = [u8]>,
    {
        /// Saves the buffer to a file at the path specified.
        ///
        /// The image format is derived from the file extension.
        /// Currently only jpeg and png files are supported.
        pub fn save<Q>(&self, path: Q) -> io::Result<()>
        where
            Q: AsRef<Path>,
        {
            // This is valid as the subpixel is u8.
            save_buffer(
                path,
                self,
                self.width(),
                self.height(),
                <P as Pixel>::color_type(),
            )
        }
    }

    impl<P, Container> Deref for ImageBuffer<P, Container>
    where
        P: Pixel + 'static,
        P::Subpixel: 'static,
        Container: Deref<Target = [P::Subpixel]>,
    {
        type Target = [P::Subpixel];

        fn deref(&self) -> &<Self as Deref>::Target {
            &*self.data
        }
    }

    impl<P, Container> DerefMut for ImageBuffer<P, Container>
    where
        P: Pixel + 'static,
        P::Subpixel: 'static,
        Container: Deref<Target = [P::Subpixel]> + DerefMut,
    {
        fn deref_mut(&mut self) -> &mut <Self as Deref>::Target {
            &mut *self.data
        }
    }

    impl<P, Container> Index<(u32, u32)> for ImageBuffer<P, Container>
    where
        P: Pixel + 'static,
        P::Subpixel: 'static,
        Container: Deref<Target = [P::Subpixel]>,
    {
        type Output = P;

        fn index(&self, (x, y): (u32, u32)) -> &P {
            self.get_pixel(x, y)
        }
    }

    impl<P, Container> IndexMut<(u32, u32)> for ImageBuffer<P, Container>
    where
        P: Pixel + 'static,
        P::Subpixel: 'static,
        Container: Deref<Target = [P::Subpixel]> + DerefMut,
    {
        fn index_mut(&mut self, (x, y): (u32, u32)) -> &mut P {
            self.get_pixel_mut(x, y)
        }
    }

    impl<P, Container> Clone for ImageBuffer<P, Container>
    where
        P: Pixel,
        Container: Deref<Target = [P::Subpixel]> + Clone,
    {
        fn clone(&self) -> ImageBuffer<P, Container> {
            ImageBuffer {
                data: self.data.clone(),
                width: self.width,
                height: self.height,
                _phantom: PhantomData,
            }
        }
    }

    impl<P, Container> GenericImageView for ImageBuffer<P, Container>
    where
        P: Pixel + 'static,
        Container: Deref<Target = [P::Subpixel]> + Deref,
        P::Subpixel: 'static,
    {
        type Pixel = P;
        type InnerImageView = Self;

        fn dimensions(&self) -> (u32, u32) {
            self.dimensions()
        }

        fn bounds(&self) -> (u32, u32, u32, u32) {
            (0, 0, self.width, self.height)
        }

        fn get_pixel(&self, x: u32, y: u32) -> P {
            *self.get_pixel(x, y)
        }

        /// Returns the pixel located at (x, y), ignoring bounds checking.
        #[inline(always)]
        unsafe fn unsafe_get_pixel(&self, x: u32, y: u32) -> P {
            let indices = self.pixel_indices_unchecked(x, y);
            *<P as Pixel>::from_slice(self.data.get_unchecked(indices))
        }

        fn inner(&self) -> &Self::InnerImageView {
            self
        }
    }

    impl<P, Container> GenericImage for ImageBuffer<P, Container>
    where
        P: Pixel + 'static,
        Container: Deref<Target = [P::Subpixel]> + DerefMut,
        P::Subpixel: 'static,
    {
        type InnerImage = Self;

        fn get_pixel_mut(&mut self, x: u32, y: u32) -> &mut P {
            self.get_pixel_mut(x, y)
        }

        fn put_pixel(&mut self, x: u32, y: u32, pixel: P) {
            *self.get_pixel_mut(x, y) = pixel
        }

        /// Puts a pixel at location (x, y), ignoring bounds checking.
        #[inline(always)]
        unsafe fn unsafe_put_pixel(&mut self, x: u32, y: u32, pixel: P) {
            let indices = self.pixel_indices_unchecked(x, y);
            let p = <P as Pixel>::from_slice_mut(self.data.get_unchecked_mut(indices));
            *p = pixel
        }

        /// Put a pixel at location (x, y), taking into account alpha channels
        ///
        /// DEPRECATED: This method will be removed. Blend the pixel directly instead.
        fn blend_pixel(&mut self, x: u32, y: u32, p: P) {
            self.get_pixel_mut(x, y).blend(&p)
        }

        fn inner_mut(&mut self) -> &mut Self::InnerImage {
            self
        }
    }

    // concrete implementation for `Vec`-backed buffers
    // TODO: I think that rustc does not "see" this impl any more: the impl with
    // Container meets the same requirements. At least, I got compile errors that
    // there is no such function as `into_vec`, whereas `into_raw` did work, and
    // `into_vec` is redundant anyway, because `into_raw` will give you the vector,
    // and it is more generic.
    impl<P: Pixel + 'static> ImageBuffer<P, Vec<P::Subpixel>>
    where
        P::Subpixel: 'static,
    {
        /// Creates a new image buffer based on a `Vec<P::Subpixel>`.
        ///
        /// # Panics
        ///
        /// Panics when the resulting image is larger the the maximum size of a vector.
        pub fn new(width: u32, height: u32) -> ImageBuffer<P, Vec<P::Subpixel>> {
            let size = Self::image_buffer_len(width, height)
                .expect("Buffer length in `ImageBuffer::new` overflows usize");
            ImageBuffer {
                data: vec![Zero::zero(); size],
                width,
                height,
                _phantom: PhantomData,
            }
        }

        /// Constructs a new ImageBuffer by copying a pixel
        ///
        /// # Panics
        ///
        /// Panics when the resulting image is larger the the maximum size of a vector.
        pub fn from_pixel(width: u32, height: u32, pixel: P) -> ImageBuffer<P, Vec<P::Subpixel>> {
            let mut buf = ImageBuffer::new(width, height);
            for p in buf.pixels_mut() {
                *p = pixel
            }
            buf
        }

        /// Constructs a new ImageBuffer by repeated application of the supplied function.
        ///
        /// The arguments to the function are the pixel's x and y coordinates.
        ///
        /// # Panics
        ///
        /// Panics when the resulting image is larger the the maximum size of a vector.
        pub fn from_fn<F>(width: u32, height: u32, mut f: F) -> ImageBuffer<P, Vec<P::Subpixel>>
        where
            F: FnMut(u32, u32) -> P,
        {
            let mut buf = ImageBuffer::new(width, height);
            for (x, y, p) in buf.enumerate_pixels_mut() {
                *p = f(x, y)
            }
            buf
        }

        /// Creates an image buffer out of an existing buffer.
        /// Returns None if the buffer is not big enough.
        pub fn from_vec(
            width: u32,
            height: u32,
            buf: Vec<P::Subpixel>,
        ) -> Option<ImageBuffer<P, Vec<P::Subpixel>>> {
            ImageBuffer::from_raw(width, height, buf)
        }

        /// Consumes the image buffer and returns the underlying data
        /// as an owned buffer
        pub fn into_vec(self) -> Vec<P::Subpixel> {
            self.into_raw()
        }
    }

    /// Provides color conversions for whole image buffers.
    pub trait ConvertBuffer<T> {
        /// Converts `self` to a buffer of type T
        ///
        /// A generic implementation is provided to convert any image buffer to a image buffer
        /// based on a `Vec<T>`.
        fn convert(&self) -> T;
    }

    // concrete implementation Luma -> Rgba
    impl GrayImage {
        /// Expands a color palette by re-using the existing buffer.
        /// Assumes 8 bit per pixel. Uses an optionally transparent index to
        /// adjust it's alpha value accordingly.
        pub fn expand_palette(
            self,
            palette: &[(u8, u8, u8)],
            transparent_idx: Option<u8>,
        ) -> RgbaImage {
            let (width, height) = self.dimensions();
            let mut data = self.into_raw();
            let entries = data.len();
            data.resize(entries.checked_mul(4).unwrap(), 0);
            let mut buffer = ImageBuffer::from_vec(width, height, data).unwrap();
            expand_packed(&mut buffer, 4, 8, |idx, pixel| {
                let (r, g, b) = palette[idx as usize];
                let a = if let Some(t_idx) = transparent_idx {
                    if t_idx == idx {
                        0
                    } else {
                        255
                    }
                } else {
                    255
                };
                pixel[0] = r;
                pixel[1] = g;
                pixel[2] = b;
                pixel[3] = a;
            });
            buffer
        }
    }

    // TODO: Equality constraints are not yet supported in where clauses, when they
    // are, the T parameter should be removed in favor of ToType::Subpixel, which
    // will then be FromType::Subpixel.
    impl<'a, 'b, Container, FromType: Pixel + 'static, ToType: Pixel + 'static>
        ConvertBuffer<ImageBuffer<ToType, Vec<ToType::Subpixel>>> for ImageBuffer<FromType, Container>
    where
        Container: Deref<Target = [FromType::Subpixel]>,
        ToType: FromColor<FromType>,
        FromType::Subpixel: 'static,
        ToType::Subpixel: 'static,
    {
        fn convert(&self) -> ImageBuffer<ToType, Vec<ToType::Subpixel>> {
            let mut buffer: ImageBuffer<ToType, Vec<ToType::Subpixel>> =
                ImageBuffer::new(self.width, self.height);
            for (to, from) in buffer.pixels_mut().zip(self.pixels()) {
                to.from_color(from)
            }
            buffer
        }
    }

    /// Sendable Rgb image buffer
    pub type RgbImage = ImageBuffer<Rgb<u8>, Vec<u8>>;
    /// Sendable Rgb + alpha channel image buffer
    pub type RgbaImage = ImageBuffer<Rgba<u8>, Vec<u8>>;
    /// Sendable grayscale image buffer
    pub type GrayImage = ImageBuffer<Luma<u8>, Vec<u8>>;
    /// Sendable grayscale + alpha channel image buffer
    pub type GrayAlphaImage = ImageBuffer<LumaA<u8>, Vec<u8>>;
    /// Sendable Bgr image buffer
    pub type BgrImage = ImageBuffer<Bgr<u8>, Vec<u8>>;
    /// Sendable Bgr + alpha channel image buffer
    pub type BgraImage = ImageBuffer<Bgra<u8>, Vec<u8>>;

    #[cfg(test)]
    mod test {

        use super::{ImageBuffer, RgbImage};
        use color;
        #[cfg(feature = "benchmarks")]
        use test;

        #[test]
        /// Tests if image buffers from slices work
        fn slice_buffer() {
            let data = [0; 9];
            let buf: ImageBuffer<color::Luma<u8>, _> = ImageBuffer::from_raw(3, 3, &data[..]).unwrap();
            assert_eq!(&*buf, &data[..])
        }

        #[test]
        fn test_get_pixel() {
            let mut a: RgbImage = ImageBuffer::new(10, 10);
            {
                let b = a.get_mut(3 * 10).unwrap();
                *b = 255;
            }
            assert_eq!(a.get_pixel(0, 1)[0], 255)
        }

        #[test]
        fn test_mut_iter() {
            let mut a: RgbImage = ImageBuffer::new(10, 10);
            {
                let val = a.pixels_mut().next().unwrap();
                *val = color::Rgb([42, 0, 0]);
            }
            assert_eq!(a.data[0], 42)
        }

        #[bench]
        #[cfg(feature = "benchmarks")]
        fn bench_conversion(b: &mut test::Bencher) {
            use buffer::{ConvertBuffer, GrayImage, Pixel};
            let mut a: RgbImage = ImageBuffer::new(1000, 1000);
            for mut p in a.pixels_mut() {
                let rgb = p.channels_mut();
                rgb[0] = 255;
                rgb[1] = 23;
                rgb[2] = 42;
            }
            assert!(a.data[0] != 0);
            b.iter(|| {
                let b: GrayImage = a.convert();
                assert!(0 != b.data[0]);
                assert!(a.data[0] != b.data[0]);
                test::black_box(b);
            });
            b.bytes = 1000 * 1000 * 3
        }

        #[bench]
        #[cfg(feature = "benchmarks")]
        fn bench_image_access_row_by_row(b: &mut test::Bencher) {
            use buffer::{ImageBuffer, Pixel};

            let mut a: RgbImage = ImageBuffer::new(1000, 1000);
            for mut p in a.pixels_mut() {
                let rgb = p.channels_mut();
                rgb[0] = 255;
                rgb[1] = 23;
                rgb[2] = 42;
            }

            b.iter(move || {
                let image: &RgbImage = test::black_box(&a);
                let mut sum: usize = 0;
                for y in 0..1000 {
                    for x in 0..1000 {
                        let pixel = image.get_pixel(x, y);
                        sum = sum.wrapping_add(pixel[0] as usize);
                        sum = sum.wrapping_add(pixel[1] as usize);
                        sum = sum.wrapping_add(pixel[2] as usize);
                    }
                }
                test::black_box(sum)
            });

            b.bytes = 1000 * 1000 * 3;
        }

        #[bench]
        #[cfg(feature = "benchmarks")]
        fn bench_image_access_col_by_col(b: &mut test::Bencher) {
            use buffer::{ImageBuffer, Pixel};

            let mut a: RgbImage = ImageBuffer::new(1000, 1000);
            for mut p in a.pixels_mut() {
                let rgb = p.channels_mut();
                rgb[0] = 255;
                rgb[1] = 23;
                rgb[2] = 42;
            }

            b.iter(move || {
                let image: &RgbImage = test::black_box(&a);
                let mut sum: usize = 0;
                for x in 0..1000 {
                    for y in 0..1000 {
                        let pixel = image.get_pixel(x, y);
                        sum = sum.wrapping_add(pixel[0] as usize);
                        sum = sum.wrapping_add(pixel[1] as usize);
                        sum = sum.wrapping_add(pixel[2] as usize);
                    }
                }
                test::black_box(sum)
            });

            b.bytes = 1000 * 1000 * 3;
        }
    }

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