feat: Added ndarray to image

ndarray-image/src/lib.rs

@@ -1,4 +1,8 @@
 type Result<T, E = ndarray::ShapeError> = core::result::Result<T, E>;
+fn shape_error() -> ndarray::ShapeError {
+    ndarray::ShapeError::from_kind(ndarray::ErrorKind::IncompatibleShape)
+}
+
 mod rgb8 {
     use super::Result;
     pub(super) fn image_as_ndarray(image: &image::RgbImage) -> Result<ndarray::ArrayView3<u8>> {
@@ -11,6 +15,18 @@ mod rgb8 {
         let data = image.into_raw();
         ndarray::Array3::from_shape_vec((height as usize, width as usize, 3), data)
     }
+    pub(super) fn ndarray_to_image(array: &ndarray::ArrayView3<u8>) -> Result<image::RgbImage> {
+        let (height, width, channels) = array.dim();
+        let data = array.as_slice().ok_or_else(super::shape_error)?;
+        if channels != 3 {
+            return Err(super::shape_error());
+        }
+        Ok(
+            image::RgbImage::from_raw(width as u32, height as u32, data.to_vec()).ok_or(
+                ndarray::ShapeError::from_kind(ndarray::ErrorKind::IncompatibleShape),
+            )?,
+        )
+    }
 }
 
 mod rgba8 {
@@ -25,6 +41,18 @@ mod rgba8 {
         let data = image.into_raw();
         ndarray::Array3::from_shape_vec((height as usize, width as usize, 4), data)
     }
+    pub(super) fn ndarray_to_image(array: &ndarray::ArrayView3<u8>) -> Result<image::RgbaImage> {
+        let (height, width, channels) = array.dim();
+        let data = array.as_slice().ok_or_else(super::shape_error)?;
+        if channels != 4 {
+            return Err(super::shape_error());
+        }
+        Ok(
+            image::RgbaImage::from_raw(width as u32, height as u32, data.to_vec()).ok_or(
+                ndarray::ShapeError::from_kind(ndarray::ErrorKind::IncompatibleShape),
+            )?,
+        )
+    }
 }
 
 mod gray8 {
@@ -39,6 +67,15 @@ mod gray8 {
         let data = image.into_raw();
         ndarray::Array2::from_shape_vec((height as usize, width as usize), data)
     }
+    pub(super) fn ndarray_to_image(array: &ndarray::ArrayView2<u8>) -> Result<image::GrayImage> {
+        let (height, width) = array.dim();
+        let data = array.as_slice().ok_or_else(super::shape_error)?;
+        Ok(
+            image::GrayImage::from_raw(width as u32, height as u32, data.to_vec()).ok_or(
+                ndarray::ShapeError::from_kind(ndarray::ErrorKind::IncompatibleShape),
+            )?,
+        )
+    }
 }
 
 mod gray_alpha8 {
@@ -55,6 +92,20 @@ mod gray_alpha8 {
         let data = image.into_raw();
         ndarray::Array3::from_shape_vec((height as usize, width as usize, 2), data)
     }
+    pub(super) fn ndarray_to_image(
+        array: &ndarray::ArrayView3<u8>,
+    ) -> Result<image::GrayAlphaImage> {
+        let (height, width, channels) = array.dim();
+        let data = array.as_slice().ok_or_else(super::shape_error)?;
+        if channels != 2 {
+            return Err(super::shape_error());
+        }
+        Ok(
+            image::GrayAlphaImage::from_raw(width as u32, height as u32, data.to_vec()).ok_or(
+                ndarray::ShapeError::from_kind(ndarray::ErrorKind::IncompatibleShape),
+            )?,
+        )
+    }
 }
 
 mod dynamic_image {
@@ -95,6 +146,34 @@ pub trait ImageToNdarray {
     fn into_ndarray(self) -> Result<Self::OwnedOutput>;
 }
 
+pub trait NdarrayToImage<ImageOutput> {
+    fn to_image(&self) -> Result<ImageOutput>;
+}
+
+impl NdarrayToImage<image::RgbImage> for ndarray::ArrayView3<'_, u8> {
+    fn to_image(&self) -> Result<image::RgbImage> {
+        rgb8::ndarray_to_image(self)
+    }
+}
+
+impl NdarrayToImage<image::RgbaImage> for ndarray::ArrayView3<'_, u8> {
+    fn to_image(&self) -> Result<image::RgbaImage> {
+        rgba8::ndarray_to_image(self)
+    }
+}
+
+impl NdarrayToImage<image::GrayImage> for ndarray::ArrayView2<'_, u8> {
+    fn to_image(&self) -> Result<image::GrayImage> {
+        gray8::ndarray_to_image(self)
+    }
+}
+
+impl NdarrayToImage<image::GrayAlphaImage> for ndarray::ArrayView3<'_, u8> {
+    fn to_image(&self) -> Result<image::GrayAlphaImage> {
+        gray_alpha8::ndarray_to_image(self)
+    }
+}
+
 impl ImageToNdarray for image::RgbImage {
     type OwnedOutput = ndarray::Array3<u8>;
     type RefOutput<'a> = ndarray::ArrayView3<'a, u8>;