Vendor things

third-party/vendor/image/src/traits.rs

@@ -0,0 +1,370 @@
+//! This module provides useful traits that were deprecated in rust
+
+// Note copied from the stdlib under MIT license
+
+use num_traits::{Bounded, Num, NumCast};
+use std::ops::AddAssign;
+
+use crate::color::{ColorType, Luma, LumaA, Rgb, Rgba};
+
+/// Types which are safe to treat as an immutable byte slice in a pixel layout
+/// for image encoding.
+pub trait EncodableLayout: seals::EncodableLayout {
+    /// Get the bytes of this value.
+    fn as_bytes(&self) -> &[u8];
+}
+
+impl EncodableLayout for [u8] {
+    fn as_bytes(&self) -> &[u8] {
+        bytemuck::cast_slice(self)
+    }
+}
+
+impl EncodableLayout for [u16] {
+    fn as_bytes(&self) -> &[u8] {
+        bytemuck::cast_slice(self)
+    }
+}
+
+impl EncodableLayout for [f32] {
+    fn as_bytes(&self) -> &[u8] {
+        bytemuck::cast_slice(self)
+    }
+}
+
+/// The type of each channel in a pixel. For example, this can be `u8`, `u16`, `f32`.
+// TODO rename to `PixelComponent`? Split up into separate traits? Seal?
+pub trait Primitive: Copy + NumCast + Num + PartialOrd<Self> + Clone + Bounded {
+    /// The maximum value for this type of primitive within the context of color.
+    /// For floats, the maximum is `1.0`, whereas the integer types inherit their usual maximum values.
+    const DEFAULT_MAX_VALUE: Self;
+
+    /// The minimum value for this type of primitive within the context of color.
+    /// For floats, the minimum is `0.0`, whereas the integer types inherit their usual minimum values.
+    const DEFAULT_MIN_VALUE: Self;
+}
+
+macro_rules! declare_primitive {
+    ($base:ty: ($from:expr)..$to:expr) => {
+        impl Primitive for $base {
+            const DEFAULT_MAX_VALUE: Self = $to;
+            const DEFAULT_MIN_VALUE: Self = $from;
+        }
+    };
+}
+
+declare_primitive!(usize: (0)..Self::MAX);
+declare_primitive!(u8: (0)..Self::MAX);
+declare_primitive!(u16: (0)..Self::MAX);
+declare_primitive!(u32: (0)..Self::MAX);
+declare_primitive!(u64: (0)..Self::MAX);
+
+declare_primitive!(isize: (Self::MIN)..Self::MAX);
+declare_primitive!(i8: (Self::MIN)..Self::MAX);
+declare_primitive!(i16: (Self::MIN)..Self::MAX);
+declare_primitive!(i32: (Self::MIN)..Self::MAX);
+declare_primitive!(i64: (Self::MIN)..Self::MAX);
+declare_primitive!(f32: (0.0)..1.0);
+declare_primitive!(f64: (0.0)..1.0);
+
+/// An Enlargable::Larger value should be enough to calculate
+/// the sum (average) of a few hundred or thousand Enlargeable values.
+pub trait Enlargeable: Sized + Bounded + NumCast {
+    type Larger: Copy + NumCast + Num + PartialOrd<Self::Larger> + Clone + Bounded + AddAssign;
+
+    fn clamp_from(n: Self::Larger) -> Self {
+        if n > Self::max_value().to_larger() {
+            Self::max_value()
+        } else if n < Self::min_value().to_larger() {
+            Self::min_value()
+        } else {
+            NumCast::from(n).unwrap()
+        }
+    }
+
+    fn to_larger(self) -> Self::Larger {
+        NumCast::from(self).unwrap()
+    }
+}
+
+impl Enlargeable for u8 {
+    type Larger = u32;
+}
+impl Enlargeable for u16 {
+    type Larger = u32;
+}
+impl Enlargeable for u32 {
+    type Larger = u64;
+}
+impl Enlargeable for u64 {
+    type Larger = u128;
+}
+impl Enlargeable for usize {
+    // Note: On 32-bit architectures, u64 should be enough here.
+    type Larger = u128;
+}
+impl Enlargeable for i8 {
+    type Larger = i32;
+}
+impl Enlargeable for i16 {
+    type Larger = i32;
+}
+impl Enlargeable for i32 {
+    type Larger = i64;
+}
+impl Enlargeable for i64 {
+    type Larger = i128;
+}
+impl Enlargeable for isize {
+    // Note: On 32-bit architectures, i64 should be enough here.
+    type Larger = i128;
+}
+impl Enlargeable for f32 {
+    type Larger = f64;
+}
+impl Enlargeable for f64 {
+    type Larger = f64;
+}
+
+/// Linear interpolation without involving floating numbers.
+pub trait Lerp: Bounded + NumCast {
+    type Ratio: Primitive;
+
+    fn lerp(a: Self, b: Self, ratio: Self::Ratio) -> Self {
+        let a = <Self::Ratio as NumCast>::from(a).unwrap();
+        let b = <Self::Ratio as NumCast>::from(b).unwrap();
+
+        let res = a + (b - a) * ratio;
+
+        if res > NumCast::from(Self::max_value()).unwrap() {
+            Self::max_value()
+        } else if res < NumCast::from(0).unwrap() {
+            NumCast::from(0).unwrap()
+        } else {
+            NumCast::from(res).unwrap()
+        }
+    }
+}
+
+impl Lerp for u8 {
+    type Ratio = f32;
+}
+
+impl Lerp for u16 {
+    type Ratio = f32;
+}
+
+impl Lerp for u32 {
+    type Ratio = f64;
+}
+
+impl Lerp for f32 {
+    type Ratio = f32;
+
+    fn lerp(a: Self, b: Self, ratio: Self::Ratio) -> Self {
+        a + (b - a) * ratio
+    }
+}
+
+/// The pixel with an associated `ColorType`.
+/// Not all possible pixels represent one of the predefined `ColorType`s.
+pub trait PixelWithColorType: Pixel + self::private::SealedPixelWithColorType {
+    /// This pixel has the format of one of the predefined `ColorType`s,
+    /// such as `Rgb8`, `La16` or `Rgba32F`.
+    /// This is needed for automatically detecting
+    /// a color format when saving an image as a file.
+    const COLOR_TYPE: ColorType;
+}
+
+impl PixelWithColorType for Rgb<u8> {
+    const COLOR_TYPE: ColorType = ColorType::Rgb8;
+}
+impl PixelWithColorType for Rgb<u16> {
+    const COLOR_TYPE: ColorType = ColorType::Rgb16;
+}
+impl PixelWithColorType for Rgb<f32> {
+    const COLOR_TYPE: ColorType = ColorType::Rgb32F;
+}
+
+impl PixelWithColorType for Rgba<u8> {
+    const COLOR_TYPE: ColorType = ColorType::Rgba8;
+}
+impl PixelWithColorType for Rgba<u16> {
+    const COLOR_TYPE: ColorType = ColorType::Rgba16;
+}
+impl PixelWithColorType for Rgba<f32> {
+    const COLOR_TYPE: ColorType = ColorType::Rgba32F;
+}
+
+impl PixelWithColorType for Luma<u8> {
+    const COLOR_TYPE: ColorType = ColorType::L8;
+}
+impl PixelWithColorType for Luma<u16> {
+    const COLOR_TYPE: ColorType = ColorType::L16;
+}
+impl PixelWithColorType for LumaA<u8> {
+    const COLOR_TYPE: ColorType = ColorType::La8;
+}
+impl PixelWithColorType for LumaA<u16> {
+    const COLOR_TYPE: ColorType = ColorType::La16;
+}
+
+/// Prevents down-stream users from implementing the `Primitive` trait
+mod private {
+    use crate::color::*;
+
+    pub trait SealedPixelWithColorType {}
+    impl SealedPixelWithColorType for Rgb<u8> {}
+    impl SealedPixelWithColorType for Rgb<u16> {}
+    impl SealedPixelWithColorType for Rgb<f32> {}
+
+    impl SealedPixelWithColorType for Rgba<u8> {}
+    impl SealedPixelWithColorType for Rgba<u16> {}
+    impl SealedPixelWithColorType for Rgba<f32> {}
+
+    impl SealedPixelWithColorType for Luma<u8> {}
+    impl SealedPixelWithColorType for LumaA<u8> {}
+
+    impl SealedPixelWithColorType for Luma<u16> {}
+    impl SealedPixelWithColorType for LumaA<u16> {}
+}
+
+/// 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 scalar type that is used to store each channel in this pixel.
+    type Subpixel: Primitive;
+
+    /// The number of channels of this pixel type.
+    const 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];
+
+    /// A string that can help to interpret the meaning each channel
+    /// See [gimp babl](http://gegl.org/babl/).
+    const COLOR_MODEL: &'static str;
+
+    /// 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
+    #[deprecated(since = "0.24.0", note = "Use `channels()` or `channels_mut()`")]
+    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.
+    #[deprecated(
+        since = "0.24.0",
+        note = "Use the constructor of the pixel, for example `Rgba([r,g,b,a])` or `Pixel::from_slice`"
+    )]
+    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 prevent 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 prevent 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>;
+
+    /// 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 except the alpha channel.
+    fn map_without_alpha<F>(&self, f: F) -> Self
+    where
+        F: FnMut(Self::Subpixel) -> Self::Subpixel,
+    {
+        let mut this = *self;
+        this.apply_with_alpha(f, |x| x);
+        this
+    }
+
+    /// Apply the function ```f``` to each channel except the alpha channel.
+    /// Works in place.
+    fn apply_without_alpha<F>(&mut self, f: F)
+    where
+        F: FnMut(Self::Subpixel) -> Self::Subpixel,
+    {
+        self.apply_with_alpha(f, |x| x);
+    }
+
+    /// 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);
+}
+
+/// Private module for supertraits of sealed traits.
+mod seals {
+    pub trait EncodableLayout {}
+
+    impl EncodableLayout for [u8] {}
+    impl EncodableLayout for [u16] {}
+    impl EncodableLayout for [f32] {}
+}