- Refactored support of no_std

- Added step in GitHub Action to check compilation for no_std.

.github/workflows/check_and_test.yaml

@@ -38,3 +38,7 @@ jobs:
         run: |
           cargo check --features rayon
           cargo test --features rayon
+
+      - name: Check compilation for no_std
+        run: |
+          cargo build --no-default-features --features=no_std

CHANGELOG.md

@@ -1,3 +1,11 @@
+## [Unreleased] - ReleaseDate
+
+### Added
+
+- Added support of `no_std` environment ([#58](https://github.com/Cykooz/fast_image_resize/issues/58)).
+  To use the crate in a such environment you must disable
+  default features and enabled the `no_std` feature.
+
 ## [5.5.0] - 2026-01-02
 
 ### Added

Cargo.lock

@@ -580,7 +580,6 @@ dependencies = [
  "fast_image_resize",
  "image",
  "itertools 0.14.0",
- "libm",
  "libvips",
  "nix",
  "num-traits",
@@ -1080,6 +1079,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "071dfc062690e90b734c0b2273ce72ad0ffa95f0c74596bc250dcfd960262841"
 dependencies = [
  "autocfg",
+ "libm",
 ]
 
 [[package]]

Cargo.toml

@@ -28,13 +28,17 @@ document-features = { version = "0.2.12", optional = true }
 image = { version = "0.25.6", optional = true, default-features = false }
 bytemuck = { version = "1.24", optional = true }
 rayon = { version = "1.11", optional = true }
-libm = "0.2.15"
 
 
 [features]
-# default = ["std"]
-## Whether or not to depend on the Rust `std`
+default = ["std"]
+## It must be enabled to use the crate in `std` environment.
 std = ["thiserror/std", "num-traits/std", "dep:document-features"]
+## This feature must be enabled to use the crate in `no_std` environment.
+## To prevent conflicts with the `std` feature it is not used for
+## conditional compilation. It just installs additional dependencies
+## or activates some features of existing dependencies.
+no_std = ["num-traits/libm"]
 ## Enable this feature to implement traits [IntoImageView](crate::IntoImageView) and
 ## [IntoImageViewMut](crate::IntoImageViewMut) for the
 ## [DynamicImage](https://docs.rs/image/latest/image/enum.DynamicImage.html)
@@ -44,10 +48,10 @@ std = ["thiserror/std", "num-traits/std", "dep:document-features"]
 image = ["std", "dep:image", "dep:bytemuck"]
 ## Enable this feature to implement traits [bytemuck::Pod] and
 ## [bytemuck::Zeroable] for the `Pixel` type.
-bytemuck = ["std", "dep:bytemuck"]
+bytemuck = ["dep:bytemuck"]
 ## This feature enables image processing in the ` rayon ` thread pool.
 rayon = ["std", "dep:rayon", "resize/rayon", "image/rayon"]
-for_testing = ["image", "image/png", "bytemuck"]
+for_testing = ["std", "image", "image/png", "bytemuck"]
 only_u8x4 = []  # This can be used to experiment with the crate's code.
 
 

README.md

@@ -49,6 +49,16 @@ that converts images from sRGB or gamma 2.2 into linear colorspace and back.
 You should enable `"rayon"` feature to turn on image processing in
 [rayon](https://docs.rs/rayon/latest/rayon/) thread pool.
 
+## Use in a `no_std` environment
+
+To use the crate in a `no_std` environment you must disable
+default features and enabled the `no_std` feature:
+
+```toml
+[dependencies]
+fast_image_resize = { version = "5.6", default-features = false, features = ["no_std"] }
+```
+
 ## Some benchmarks in single-threaded mode for x86_64
 
 _All benchmarks:_

src/alpha/f32x2/avx2.rs

@@ -1,10 +1,9 @@
 use core::arch::x86_64::*;
 
+use super::sse4;
 use crate::pixels::F32x2;
 use crate::{ImageView, ImageViewMut};
 
-use super::sse4;
-
 #[target_feature(enable = "avx2")]
 pub(crate) unsafe fn multiply_alpha(
     src_view: &impl ImageView<Pixel = F32x2>,

src/alpha/f32x2/mod.rs

@@ -1,9 +1,8 @@
+use super::AlphaMulDiv;
 use crate::cpu_extensions::CpuExtensions;
 use crate::pixels::F32x2;
 use crate::{ImageError, ImageView, ImageViewMut};
 
-use super::AlphaMulDiv;
-
 #[cfg(target_arch = "x86_64")]
 mod avx2;
 mod native;

src/alpha/f32x2/sse4.rs

@@ -1,10 +1,9 @@
 use core::arch::x86_64::*;
 
+use super::native;
 use crate::pixels::F32x2;
 use crate::{ImageView, ImageViewMut};
 
-use super::native;
-
 #[target_feature(enable = "sse4.1")]
 pub(crate) unsafe fn multiply_alpha(
     src_view: &impl ImageView<Pixel = F32x2>,

src/alpha/f32x4/avx2.rs

@@ -1,10 +1,9 @@
 use core::arch::x86_64::*;
 
+use super::native;
 use crate::pixels::F32x4;
 use crate::{ImageView, ImageViewMut};
 
-use super::native;
-
 #[target_feature(enable = "avx2")]
 pub(crate) unsafe fn multiply_alpha(
     src_view: &impl ImageView<Pixel = F32x4>,

src/alpha/f32x4/mod.rs

@@ -1,9 +1,8 @@
+use super::AlphaMulDiv;
 use crate::cpu_extensions::CpuExtensions;
 use crate::pixels::F32x4;
 use crate::{ImageError, ImageView, ImageViewMut};
 
-use super::AlphaMulDiv;
-
 #[cfg(target_arch = "x86_64")]
 mod avx2;
 mod native;

src/alpha/f32x4/sse4.rs

@@ -1,10 +1,9 @@
 use core::arch::x86_64::*;
 
+use super::native;
 use crate::pixels::F32x4;
 use crate::{ImageView, ImageViewMut};
 
-use super::native;
-
 #[target_feature(enable = "sse4.1")]
 pub(crate) unsafe fn multiply_alpha(
     src_view: &impl ImageView<Pixel = F32x4>,

src/alpha/u16x2/mod.rs

@@ -1,8 +1,7 @@
+use super::AlphaMulDiv;
 use crate::pixels::U16x2;
 use crate::{CpuExtensions, ImageError, ImageView, ImageViewMut};
 
-use super::AlphaMulDiv;
-
 #[cfg(target_arch = "x86_64")]
 mod avx2;
 mod native;

src/alpha/u16x2/neon.rs

@@ -1,10 +1,8 @@
 use core::arch::aarch64::*;
 
-use crate::neon_utils;
-use crate::pixels::U16x2;
-use crate::{ImageView, ImageViewMut};
-
 use super::native;
+use crate::pixels::U16x2;
+use crate::{neon_utils, ImageView, ImageViewMut};
 
 #[target_feature(enable = "neon")]
 pub(crate) unsafe fn multiply_alpha(

src/alpha/u16x2/wasm32.rs

@@ -1,11 +1,10 @@
 use core::arch::wasm32::*;
 
+use super::native;
 use crate::pixels::U16x2;
 use crate::utils::foreach_with_pre_reading;
 use crate::{ImageView, ImageViewMut};
 
-use super::native;
-
 pub(crate) unsafe fn multiply_alpha(
     src_view: &impl ImageView<Pixel = U16x2>,
     dst_view: &mut impl ImageViewMut<Pixel = U16x2>,

src/alpha/u16x4/mod.rs

@@ -1,8 +1,7 @@
+use super::AlphaMulDiv;
 use crate::pixels::U16x4;
 use crate::{CpuExtensions, ImageError, ImageView, ImageViewMut};
 
-use super::AlphaMulDiv;
-
 #[cfg(target_arch = "x86_64")]
 mod avx2;
 mod native;

src/alpha/u16x4/neon.rs

@@ -1,11 +1,9 @@
 use core::arch::aarch64::*;
 
-use crate::neon_utils;
+use super::native;
 use crate::pixels::U16x4;
 use crate::utils::foreach_with_pre_reading;
-use crate::{ImageView, ImageViewMut};
-
-use super::native;
+use crate::{neon_utils, ImageView, ImageViewMut};
 
 #[target_feature(enable = "neon")]
 pub(crate) unsafe fn multiply_alpha(

src/alpha/u16x4/sse4.rs

@@ -1,11 +1,10 @@
 use core::arch::x86_64::*;
 
+use super::native;
 use crate::pixels::U16x4;
 use crate::utils::foreach_with_pre_reading;
 use crate::{ImageView, ImageViewMut};
 
-use super::native;
-
 #[target_feature(enable = "sse4.1")]
 pub(crate) unsafe fn multiply_alpha(
     src_view: &impl ImageView<Pixel = U16x4>,

src/alpha/u16x4/wasm32.rs

@@ -1,11 +1,10 @@
 use core::arch::wasm32::*;
 
+use super::native;
 use crate::pixels::U16x4;
 use crate::utils::foreach_with_pre_reading;
 use crate::{ImageView, ImageViewMut};
 
-use super::native;
-
 pub(crate) unsafe fn multiply_alpha(
     src_view: &impl ImageView<Pixel = U16x4>,
     dst_view: &mut impl ImageViewMut<Pixel = U16x4>,

src/alpha/u8x2/avx2.rs

@@ -1,11 +1,10 @@
 use core::arch::x86_64::*;
 
+use super::sse4;
 use crate::pixels::U8x2;
 use crate::utils::foreach_with_pre_reading;
 use crate::{simd_utils, ImageView, ImageViewMut};
 
-use super::sse4;
-
 #[target_feature(enable = "avx2")]
 pub(crate) unsafe fn multiply_alpha(
     src_view: &impl ImageView<Pixel = U8x2>,

src/alpha/u8x2/mod.rs

@@ -1,9 +1,8 @@
+use super::AlphaMulDiv;
 use crate::cpu_extensions::CpuExtensions;
 use crate::pixels::U8x2;
 use crate::{ImageError, ImageView, ImageViewMut};
 
-use super::AlphaMulDiv;
-
 #[cfg(target_arch = "x86_64")]
 mod avx2;
 mod native;

src/alpha/u8x2/neon.rs

@@ -1,11 +1,9 @@
 use core::arch::aarch64::*;
 
-use crate::neon_utils;
+use super::native;
 use crate::pixels::U8x2;
 use crate::utils::foreach_with_pre_reading;
-use crate::{ImageView, ImageViewMut};
-
-use super::native;
+use crate::{neon_utils, ImageView, ImageViewMut};
 
 #[target_feature(enable = "neon")]
 pub(crate) unsafe fn multiply_alpha(

src/alpha/u8x2/wasm32.rs

@@ -1,11 +1,10 @@
 use core::arch::wasm32::*;
 
+use super::native;
 use crate::pixels::U8x2;
 use crate::wasm32_utils::u16x8_mul_add_shr16;
 use crate::{ImageView, ImageViewMut};
 
-use super::native;
-
 pub(crate) unsafe fn multiply_alpha(
     src_view: &impl ImageView<Pixel = U8x2>,
     dst_view: &mut impl ImageViewMut<Pixel = U8x2>,

src/alpha/u8x4/avx2.rs

@@ -1,9 +1,9 @@
-use crate::pixels::U8x4;
-use crate::utils::foreach_with_pre_reading;
-use crate::{simd_utils, ImageView, ImageViewMut};
 use core::arch::x86_64::*;
 
 use super::sse4;
+use crate::pixels::U8x4;
+use crate::utils::foreach_with_pre_reading;
+use crate::{simd_utils, ImageView, ImageViewMut};
 
 #[target_feature(enable = "avx2")]
 pub(crate) unsafe fn multiply_alpha(

src/alpha/u8x4/neon.rs

@@ -1,11 +1,9 @@
 use core::arch::aarch64::*;
 
-use crate::neon_utils;
+use super::native;
 use crate::pixels::U8x4;
 use crate::utils::foreach_with_pre_reading;
-use crate::{ImageView, ImageViewMut};
-
-use super::native;
+use crate::{neon_utils, ImageView, ImageViewMut};
 
 #[target_feature(enable = "neon")]
 pub(crate) unsafe fn multiply_alpha(

src/alpha/u8x4/sse4.rs

@@ -1,11 +1,10 @@
 use core::arch::x86_64::*;
 
+use super::native;
 use crate::pixels::U8x4;
 use crate::utils::foreach_with_pre_reading;
 use crate::{ImageView, ImageViewMut};
 
-use super::native;
-
 #[target_feature(enable = "sse4.1")]
 pub(crate) unsafe fn multiply_alpha(
     src_view: &impl ImageView<Pixel = U8x4>,

src/alpha/u8x4/wasm32.rs

@@ -1,11 +1,10 @@
 use core::arch::wasm32::*;
 
+use super::native;
 use crate::pixels::U8x4;
 use crate::wasm32_utils::u16x8_mul_add_shr16;
 use crate::{ImageView, ImageViewMut};
 
-use super::native;
-
 pub(crate) unsafe fn multiply_alpha(
     src_view: &impl ImageView<Pixel = U8x4>,
     dst_view: &mut impl ImageViewMut<Pixel = U8x4>,

src/array_chunks.rs

@@ -1,6 +1,5 @@
 use core::array::IntoIter;
-use core::iter::Take;
-use core::iter::{FusedIterator, Iterator};
+use core::iter::{FusedIterator, Iterator, Take};
 use core::mem::MaybeUninit;
 
 /// An iterator over `N` elements of the iterator at a time.

src/color/mappers.rs

@@ -1,5 +1,6 @@
-#[cfg(not(feature = "std"))]
-use crate::float_ext::FloatExt;
+#[allow(unused_imports)]
+// It is used to implement floats in no_std
+use crate::compat::*;
 use crate::PixelComponentMapper;
 
 fn gamma_into_linear(input: f32) -> f32 {

src/color/mod.rs

@@ -1,12 +1,9 @@
 //! Functions and structs for working with colorspace and gamma.
-#[cfg(not(feature = "std"))]
-use alloc::boxed::Box;
 
 use num_traits::bounds::UpperBounded;
-#[cfg(not(feature = "std"))]
-use num_traits::float::FloatCore;
 use num_traits::Zero;
 
+use crate::compat::*;
 use crate::pixels::{
     GetCount, InnerPixel, IntoPixelComponent, PixelComponent, PixelType, U16x2, U16x3, U16x4, U8x2,
     U8x3, U8x4, Values, U16, U8,

src/compat/mod.rs

@@ -0,0 +1,16 @@
+//! This module is used as compatability layer to support `std` and `no_std`.
+
+cfg_if::cfg_if! {
+    if #[cfg(feature = "std")] {
+        pub use std::boxed::Box;
+        pub use std::{vec, vec::Vec};
+        pub use std::borrow::ToOwned;
+    } else {
+        pub use alloc::boxed::Box;
+        pub use alloc::{vec, vec::Vec};
+        pub use alloc::borrow::ToOwned;
+
+        // `no_std` feature must be enabled
+        pub use num_traits::Float;
+    }
+}

src/convolution/f32x2/mod.rs

@@ -1,10 +1,9 @@
+use super::{Coefficients, Convolution};
 use crate::convolution::vertical_f32::vert_convolution_f32;
 use crate::cpu_extensions::CpuExtensions;
 use crate::pixels::F32x2;
 use crate::{ImageView, ImageViewMut};
 
-use super::{Coefficients, Convolution};
-
 #[cfg(target_arch = "x86_64")]
 mod avx2;
 mod native;

src/convolution/f32x3/mod.rs

@@ -1,10 +1,9 @@
+use super::{Coefficients, Convolution};
 use crate::convolution::vertical_f32::vert_convolution_f32;
 use crate::cpu_extensions::CpuExtensions;
 use crate::pixels::F32x3;
 use crate::{ImageView, ImageViewMut};
 
-use super::{Coefficients, Convolution};
-
 #[cfg(target_arch = "x86_64")]
 mod avx2;
 mod native;

src/convolution/f32x4/mod.rs

@@ -1,10 +1,9 @@
+use super::{Coefficients, Convolution};
 use crate::convolution::vertical_f32::vert_convolution_f32;
 use crate::cpu_extensions::CpuExtensions;
 use crate::pixels::F32x4;
 use crate::{ImageView, ImageViewMut};
 
-use super::{Coefficients, Convolution};
-
 #[cfg(target_arch = "x86_64")]
 mod avx2;
 mod native;

src/convolution/filters.rs

@@ -1,11 +1,11 @@
 use core::f64::consts::PI;
 use core::fmt::{Debug, Formatter};
-#[cfg(not(feature = "std"))]
-use num_traits::float::FloatCore;
+
 use thiserror::Error;
 
-#[cfg(not(feature = "std"))]
-use crate::float_ext::FloatExt;
+#[allow(unused_imports)]
+// It is used to implement floats in no_std
+use crate::compat::*;
 
 type FilterFn = fn(f64) -> f64;
 

src/convolution/i32x1/native.rs

@@ -1,10 +1,10 @@
+#[allow(unused_imports)]
+// It is used to implement floats in no_std
+use crate::compat::*;
 use crate::convolution::Coefficients;
 use crate::pixels::I32;
 use crate::{ImageView, ImageViewMut};
 
-#[cfg(not(feature = "std"))]
-use num_traits::float::FloatCore;
-
 pub(crate) fn horiz_convolution(
     src_view: &impl ImageView<Pixel = I32>,
     dst_view: &mut impl ImageViewMut<Pixel = I32>,

src/convolution/mod.rs

@@ -1,14 +1,9 @@
-#[cfg(not(feature = "std"))]
-use alloc::vec::Vec;
-
 pub use filters::*;
 
+use crate::compat::*;
 use crate::pixels::InnerPixel;
 use crate::{CpuExtensions, ImageView, ImageViewMut};
 
-#[cfg(not(feature = "std"))]
-use num_traits::float::FloatCore;
-
 #[macro_use]
 mod macros;
 

src/convolution/optimisations.rs

@@ -1,12 +1,6 @@
-#[cfg(not(feature = "std"))]
-use alloc::borrow::ToOwned;
-#[cfg(not(feature = "std"))]
-use alloc::vec::Vec;
-
-#[cfg(not(feature = "std"))]
-use num_traits::float::FloatCore;
-
+use crate::compat::*;
 use crate::convolution::Coefficients;
+
 // This code is based on C-implementation from Pillow-SIMD package for Python
 // https://github.com/uploadcare/pillow-simd
 
@@ -256,6 +250,7 @@ macro_rules! try_process_in_threads_v {
 mod tests {
     use super::*;
     use crate::convolution::Bound;
+
     fn get_coefficients(value: f64) -> Coefficients {
         Coefficients {
             values: vec![value],

src/convolution/u16x1/neon.rs

@@ -1,10 +1,8 @@
 use core::arch::aarch64::*;
 
 use crate::convolution::optimisations::{CoefficientsI32Chunk, Normalizer32};
-
-use crate::neon_utils;
 use crate::pixels::U16;
-use crate::{ImageView, ImageViewMut};
+use crate::{neon_utils, ImageView, ImageViewMut};
 
 #[inline]
 pub(crate) fn horiz_convolution(

src/convolution/u16x1/wasm32.rs

@@ -2,8 +2,7 @@ use core::arch::wasm32::*;
 
 use crate::convolution::optimisations::Normalizer32;
 use crate::pixels::U16;
-use crate::wasm32_utils;
-use crate::{ImageView, ImageViewMut};
+use crate::{wasm32_utils, ImageView, ImageViewMut};
 
 #[inline]
 pub(crate) fn horiz_convolution(

src/convolution/u16x2/neon.rs

@@ -1,9 +1,8 @@
 use core::arch::aarch64::*;
 
 use crate::convolution::optimisations::{CoefficientsI32Chunk, Normalizer32};
-use crate::neon_utils;
 use crate::pixels::U16x2;
-use crate::{ImageView, ImageViewMut};
+use crate::{neon_utils, ImageView, ImageViewMut};
 
 #[inline]
 pub(crate) fn horiz_convolution(

src/convolution/u16x2/wasm32.rs

@@ -2,8 +2,7 @@ use core::arch::wasm32::*;
 
 use crate::convolution::optimisations::Normalizer32;
 use crate::pixels::U16x2;
-use crate::wasm32_utils;
-use crate::{ImageView, ImageViewMut};
+use crate::{wasm32_utils, ImageView, ImageViewMut};
 
 #[inline]
 pub(crate) fn horiz_convolution(

src/convolution/u16x3/neon.rs

@@ -1,9 +1,8 @@
 use core::arch::aarch64::*;
 
 use crate::convolution::optimisations::{CoefficientsI32Chunk, Normalizer32};
-use crate::neon_utils;
 use crate::pixels::U16x3;
-use crate::{ImageView, ImageViewMut};
+use crate::{neon_utils, ImageView, ImageViewMut};
 
 #[inline]
 pub(crate) fn horiz_convolution(

src/convolution/u16x3/wasm32.rs

@@ -2,8 +2,7 @@ use core::arch::wasm32::*;
 
 use crate::convolution::optimisations::Normalizer32;
 use crate::pixels::U16x3;
-use crate::wasm32_utils;
-use crate::{ImageView, ImageViewMut};
+use crate::{wasm32_utils, ImageView, ImageViewMut};
 
 #[inline]
 pub(crate) fn horiz_convolution(

src/convolution/u16x4/neon.rs

@@ -1,9 +1,8 @@
 use core::arch::aarch64::*;
 
 use crate::convolution::optimisations::{CoefficientsI32Chunk, Normalizer32};
-use crate::neon_utils;
 use crate::pixels::U16x4;
-use crate::{ImageView, ImageViewMut};
+use crate::{neon_utils, ImageView, ImageViewMut};
 
 #[inline]
 pub(crate) fn horiz_convolution(

src/convolution/u16x4/wasm32.rs

@@ -2,8 +2,7 @@ use core::arch::wasm32::*;
 
 use crate::convolution::optimisations::Normalizer32;
 use crate::pixels::U16x4;
-use crate::wasm32_utils;
-use crate::{ImageView, ImageViewMut};
+use crate::{wasm32_utils, ImageView, ImageViewMut};
 
 #[inline]
 pub(crate) fn horiz_convolution(

src/convolution/u8x1/avx2.rs

@@ -1,7 +1,6 @@
-#[cfg(not(feature = "std"))]
-use alloc::borrow::ToOwned;
 use core::arch::x86_64::*;
 
+use crate::compat::*;
 use crate::convolution::optimisations::Normalizer16;
 use crate::pixels::U8;
 use crate::{simd_utils, ImageView, ImageViewMut};

src/convolution/u8x1/neon.rs

@@ -1,9 +1,8 @@
 use core::arch::aarch64::*;
 
 use crate::convolution::optimisations::Normalizer16;
-use crate::neon_utils;
 use crate::pixels::U8;
-use crate::{ImageView, ImageViewMut};
+use crate::{neon_utils, ImageView, ImageViewMut};
 
 #[inline]
 pub(crate) fn horiz_convolution(

src/convolution/u8x1/sse4.rs

@@ -1,7 +1,6 @@
-#[cfg(not(feature = "std"))]
-use alloc::borrow::ToOwned;
 use core::arch::x86_64::*;
 
+use crate::compat::*;
 use crate::convolution::optimisations::Normalizer16;
 use crate::pixels::U8;
 use crate::{simd_utils, ImageView, ImageViewMut};

src/convolution/u8x1/wasm32.rs

@@ -2,8 +2,7 @@ use core::arch::wasm32::*;
 
 use crate::convolution::optimisations::Normalizer16;
 use crate::pixels::U8;
-use crate::wasm32_utils;
-use crate::{ImageView, ImageViewMut};
+use crate::{wasm32_utils, ImageView, ImageViewMut};
 
 #[inline]
 pub(crate) fn horiz_convolution(

src/convolution/u8x2/wasm32.rs

@@ -2,8 +2,7 @@ use core::arch::wasm32::*;
 
 use crate::convolution::optimisations::Normalizer16;
 use crate::pixels::U8x2;
-use crate::wasm32_utils;
-use crate::{ImageView, ImageViewMut};
+use crate::{wasm32_utils, ImageView, ImageViewMut};
 
 #[inline]
 pub(crate) fn horiz_convolution(

src/convolution/u8x3/neon.rs

@@ -1,9 +1,8 @@
 use core::arch::aarch64::*;
 
 use crate::convolution::optimisations::{CoefficientsI16Chunk, Normalizer16};
-use crate::neon_utils;
 use crate::pixels::U8x3;
-use crate::{ImageView, ImageViewMut};
+use crate::{neon_utils, ImageView, ImageViewMut};
 
 #[inline]
 pub(crate) fn horiz_convolution(

src/convolution/u8x3/wasm32.rs

@@ -3,8 +3,7 @@ use core::mem::transmute;
 
 use crate::convolution::optimisations::Normalizer16;
 use crate::pixels::U8x3;
-use crate::wasm32_utils;
-use crate::{ImageView, ImageViewMut};
+use crate::{wasm32_utils, ImageView, ImageViewMut};
 
 #[inline]
 pub(crate) fn horiz_convolution(

src/convolution/u8x4/neon.rs

@@ -1,9 +1,8 @@
 use core::arch::aarch64::*;
 
 use crate::convolution::optimisations::{CoefficientsI16Chunk, Normalizer16};
-use crate::neon_utils;
 use crate::pixels::U8x4;
-use crate::{ImageView, ImageViewMut};
+use crate::{neon_utils, ImageView, ImageViewMut};
 
 #[inline]
 pub(crate) fn horiz_convolution(

src/convolution/u8x4/wasm32.rs

@@ -3,8 +3,7 @@ use core::mem::transmute;
 
 use crate::convolution::optimisations::Normalizer16;
 use crate::pixels::U8x4;
-use crate::wasm32_utils;
-use crate::{ImageView, ImageViewMut};
+use crate::{wasm32_utils, ImageView, ImageViewMut};
 
 #[inline]
 pub(crate) fn horiz_convolution(

src/convolution/vertical_f32/avx2.rs

@@ -1,11 +1,10 @@
 use core::arch::x86_64::*;
 
+use super::native;
 use crate::convolution::{Coefficients, CoefficientsChunk};
 use crate::pixels::InnerPixel;
 use crate::{simd_utils, ImageView, ImageViewMut};
 
-use super::native;
-
 pub(crate) fn vert_convolution<T>(
     src_view: &impl ImageView<Pixel = T>,
     dst_view: &mut impl ImageViewMut<Pixel = T>,

src/convolution/vertical_f32/sse4.rs

@@ -1,11 +1,10 @@
 use core::arch::x86_64::*;
 
+use super::native;
 use crate::convolution::{Coefficients, CoefficientsChunk};
 use crate::pixels::InnerPixel;
 use crate::{simd_utils, ImageView, ImageViewMut};
 
-use super::native;
-
 pub(crate) fn vert_convolution<T>(
     src_view: &impl ImageView<Pixel = T>,
     dst_view: &mut impl ImageViewMut<Pixel = T>,

src/convolution/vertical_u16/neon.rs

@@ -1,13 +1,10 @@
-#[cfg(not(feature = "std"))]
-use alloc::{vec, vec::Vec};
-
 use core::arch::aarch64::*;
 use core::mem::transmute;
 
+use crate::compat::*;
 use crate::convolution::optimisations::{CoefficientsI32Chunk, Normalizer32};
-use crate::neon_utils;
 use crate::pixels::InnerPixel;
-use crate::{ImageView, ImageViewMut};
+use crate::{neon_utils, ImageView, ImageViewMut};
 
 pub(crate) fn vert_convolution<T>(
     src_view: &impl ImageView<Pixel = T>,

src/convolution/vertical_u16/wasm32.rs

@@ -3,8 +3,7 @@ use core::arch::wasm32::*;
 use crate::convolution::optimisations::{CoefficientsI32Chunk, Normalizer32};
 use crate::convolution::vertical_u16::native::convolution_by_u16;
 use crate::pixels::InnerPixel;
-use crate::wasm32_utils;
-use crate::{ImageView, ImageViewMut};
+use crate::{wasm32_utils, ImageView, ImageViewMut};
 
 pub(crate) fn vert_convolution<T: InnerPixel<Component = u16>>(
     src_view: &impl ImageView<Pixel = T>,

src/convolution/vertical_u8/neon.rs

@@ -1,13 +1,10 @@
-#[cfg(not(feature = "std"))]
-use alloc::{vec, vec::Vec};
-
 use core::arch::aarch64::*;
 use core::mem::transmute;
 
+use crate::compat::*;
 use crate::convolution::optimisations::{CoefficientsI16Chunk, Normalizer16};
-use crate::neon_utils;
 use crate::pixels::InnerPixel;
-use crate::{ImageView, ImageViewMut};
+use crate::{neon_utils, ImageView, ImageViewMut};
 
 pub(crate) fn vert_convolution<T>(
     src_view: &impl ImageView<Pixel = T>,

src/convolution/vertical_u8/wasm32.rs

@@ -3,8 +3,7 @@ use core::arch::wasm32::*;
 use crate::convolution::optimisations::{CoefficientsI16Chunk, Normalizer16};
 use crate::convolution::vertical_u8::native;
 use crate::pixels::InnerPixel;
-use crate::wasm32_utils;
-use crate::{ImageView, ImageViewMut};
+use crate::{wasm32_utils, ImageView, ImageViewMut};
 
 #[inline]
 pub(crate) fn vert_convolution<T: InnerPixel<Component = u8>>(

src/float_ext.rs

@@ -1,43 +0,0 @@
-pub trait FloatExt {
-    fn sin(self) -> Self;
-    fn cos(self) -> Self;
-    fn sqrt(self) -> Self;
-    fn exp(self) -> Self;
-    fn powf(self, exp: Self) -> Self;
-}
-
-impl FloatExt for f32 {
-    fn sin(self) -> Self {
-        libm::sinf(self)
-    }
-    fn cos(self) -> Self {
-        libm::cosf(self)
-    }
-    fn sqrt(self) -> Self {
-        libm::sqrtf(self)
-    }
-    fn exp(self) -> Self {
-        libm::expf(self)
-    }
-    fn powf(self, exp: f32) -> Self {
-        libm::powf(self, exp)
-    }
-}
-
-impl FloatExt for f64 {
-    fn sin(self) -> Self {
-        libm::sin(self)
-    }
-    fn cos(self) -> Self {
-        libm::cos(self)
-    }
-    fn sqrt(self) -> Self {
-        libm::sqrt(self)
-    }
-    fn exp(self) -> Self {
-        libm::exp(self)
-    }
-    fn powf(self, exp: f64) -> Self {
-        libm::pow(self, exp)
-    }
-}

src/image_view.rs

@@ -1,14 +1,10 @@
-#[cfg(not(feature = "std"))]
-use alloc::vec::Vec;
 use core::num::NonZeroU32;
 
+use crate::compat::*;
 use crate::images::{TypedCroppedImage, TypedCroppedImageMut, UnsafeImageMut};
 use crate::pixels::InnerPixel;
 use crate::{ArrayChunks, ImageError, PixelTrait, PixelType};
 
-#[cfg(not(feature = "std"))]
-use num_traits::float::FloatCore;
-
 /// A trait for getting access to image data.
 ///
 /// # Safety

src/images/image.rs

@@ -1,6 +1,4 @@
-#[cfg(not(feature = "std"))]
-use alloc::{vec, vec::Vec};
-
+use crate::compat::*;
 use crate::images::{BufferContainer, TypedImage, TypedImageRef};
 use crate::pixels::InnerPixel;
 use crate::{

src/images/image_crate.rs

@@ -1,14 +1,16 @@
 use core::ops::DerefMut;
 
-use crate::image_view::try_pixel_type;
-use crate::images::{TypedImage, TypedImageRef};
-use crate::{ImageView, ImageViewMut, IntoImageView, IntoImageViewMut, PixelTrait, PixelType};
 use bytemuck::cast_slice_mut;
 use image::{
     DynamicImage, GrayAlphaImage, GrayImage, ImageBuffer, Luma, LumaA, Rgb, Rgb32FImage, RgbImage,
     Rgba, Rgba32FImage, RgbaImage,
 };
 
+use crate::compat::*;
+use crate::image_view::try_pixel_type;
+use crate::images::{TypedImage, TypedImageRef};
+use crate::{ImageView, ImageViewMut, IntoImageView, IntoImageViewMut, PixelTrait, PixelType};
+
 impl IntoImageView for DynamicImage {
     fn pixel_type(&self) -> Option<PixelType> {
         match self {

src/images/mod.rs

@@ -1,6 +1,4 @@
 //! Contains different types of images and wrappers for them.
-#[cfg(not(feature = "std"))]
-use alloc::vec::Vec;
 use core::fmt::Debug;
 
 pub use cropped_image::*;
@@ -9,6 +7,8 @@ pub use typed_cropped_image::*;
 pub use typed_image::*;
 pub(crate) use unsafe_image::UnsafeImageMut;
 
+use crate::compat::*;
+
 mod cropped_image;
 mod image;
 mod typed_cropped_image;

src/images/typed_cropped_image.rs

@@ -1,7 +1,6 @@
-#[cfg(not(feature = "std"))]
-use alloc::vec::Vec;
 use core::num::NonZeroU32;
 
+use crate::compat::*;
 use crate::images::{View, ViewMut};
 use crate::{CropBoxError, ImageView, ImageViewMut};
 

src/images/typed_image.rs

@@ -1,15 +1,11 @@
-#[cfg(not(feature = "std"))]
-use alloc::{vec, vec::Vec};
 use core::fmt::Debug;
 use core::num::NonZeroU32;
 
+use crate::compat::*;
 use crate::images::BufferContainer;
 use crate::pixels::InnerPixel;
 use crate::{ImageBufferError, ImageView, ImageViewMut, InvalidPixelsSize};
 
-#[cfg(not(feature = "std"))]
-use num_traits::float::FloatCore;
-
 /// Generic reference to image data that provides [ImageView].
 #[derive(Debug)]
 pub struct TypedImageRef<'a, P> {

src/images/unsafe_image.rs

@@ -1,8 +1,7 @@
-#[cfg(not(feature = "std"))]
-use alloc::vec::Vec;
 use core::marker::PhantomData;
 use core::num::NonZeroU32;
 
+use crate::compat::*;
 use crate::{ArrayChunks, ImageView, ImageViewMut};
 
 #[derive(Copy)]

src/lib.rs

@@ -1,12 +1,17 @@
-#![cfg_attr(not(feature = "std"), no_std)]
+#![no_std]
 #![doc = include_str!("../README.md")]
 
 //!
 //! ## Feature flags
 #![cfg_attr(feature = "std", doc = document_features::document_features!())]
 
-#[cfg(not(feature = "std"))]
-extern crate alloc;
+cfg_if::cfg_if! {
+    if #[cfg(feature = "std")] {
+        extern crate std;
+    } else {
+        extern crate alloc;
+    }
+}
 
 pub use alpha::errors::*;
 pub use array_chunks::*;
@@ -27,6 +32,8 @@ use crate::alpha::AlphaMulDiv;
 #[macro_use]
 mod utils;
 
+mod compat;
+
 mod alpha;
 mod array_chunks;
 mod change_components_type;
@@ -35,7 +42,6 @@ mod convolution;
 mod cpu_extensions;
 mod crop_box;
 mod errors;
-mod float_ext;
 mod image_view;
 pub mod images;
 mod mul_div;

src/pixels.rs

@@ -4,8 +4,9 @@ use core::marker::PhantomData;
 use core::mem::size_of;
 use core::slice;
 
-#[cfg(not(feature = "std"))]
-use num_traits::float::FloatCore;
+#[allow(unused_imports)]
+// It is used to implement floats in no_std
+use crate::compat::*;
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 #[non_exhaustive]

src/resizer.rs

@@ -1,6 +1,4 @@
-#[cfg(not(feature = "std"))]
-use alloc::vec::Vec;
-
+use crate::compat::*;
 use crate::convolution::{self, FilterType};
 use crate::crop_box::CroppedSrcImageView;
 use crate::image_view::{try_pixel_type, ImageView, ImageViewMut, IntoImageView, IntoImageViewMut};
@@ -10,9 +8,6 @@ use crate::{
     CpuExtensions, CropBox, DifferentDimensionsError, MulDiv, PixelTrait, PixelType, ResizeError,
 };
 
-#[cfg(not(feature = "std"))]
-use num_traits::float::FloatCore;
-
 #[derive(Debug, Clone, Copy, Eq, PartialEq)]
 #[non_exhaustive]
 pub enum ResizeAlg {

src/testing.rs

@@ -1,4 +1,7 @@
-use std::cell::RefCell;
+use core::cell::RefCell;
+use std::string::{String, ToString};
+use std::thread_local;
+use std::vec::Vec;
 
 thread_local!(static TEST_LOGS: RefCell<Vec<String>> = const { RefCell::new(Vec::new()) });