Merge pull request #79 from image-rs/data-shader

Allow bytes to be bound as input/output planes

Author: 197g

canvas/src/frame.rs

@@ -4,7 +4,7 @@ use alloc::borrow::ToOwned;
 use alloc::vec::Vec;
 
 use image_texel::image::{
-    AtomicImage, AtomicImageRef, CellImage, CellImageRef, Image, ImageMut, ImageRef,
+    data, AtomicImage, AtomicImageRef, CellImage, CellImageRef, Image, ImageMut, ImageRef,
 };
 use image_texel::texels::U8;
 
@@ -36,6 +36,24 @@ pub struct Plane {
     inner: Image<PlaneBytes>,
 }
 
+/// A reference to bytes containing data of a single plane.
+///
+/// This can be created from a [`Plane`] but also by validating an arbitrary slice of bytes against
+/// some of the known layouts. These layouts can be partially defined by the user.
+///
+/// The common use for values is to pass an outside buffer to [`ConverterRun::
+pub struct PlaneDataRef<'data> {
+    pub(crate) inner: data::DataRef<'data, PlaneBytes>,
+}
+
+/// A reference to mutable bytes containing data of a single plane.
+///
+/// This can be created from a [`Plane`] but also by validating an arbitrary slice of bytes against
+/// some of the known layouts. These layouts can be partially defined by the user.
+pub struct PlaneDataMut<'data> {
+    pub(crate) inner: data::DataMut<'data, PlaneBytes>,
+}
+
 /// Represents a single matrix like layer of an image.
 ///
 /// Created from [`Canvas::plane`].
@@ -645,3 +663,51 @@ impl From<ArcCanvas> for RcCanvas {
         RcCanvas { inner: out }
     }
 }
+
+impl<'lt> From<&'lt Plane> for PlaneDataRef<'lt> {
+    fn from(plane: &'_ Plane) -> PlaneDataRef<'_> {
+        PlaneDataRef {
+            inner: plane.inner.as_ref().into_cloned_layout().into_data(),
+        }
+    }
+}
+
+impl<'lt> From<&'lt mut Plane> for PlaneDataMut<'lt> {
+    fn from(plane: &'_ mut Plane) -> PlaneDataMut<'_> {
+        PlaneDataMut {
+            inner: plane.inner.as_mut().into_cloned_layout().into_data(),
+        }
+    }
+}
+
+impl<'data> PlaneDataRef<'data> {
+    /// Create plane data from bytes and a layout.
+    ///
+    /// This returns `Some` if the data is long enough for the layout, and `None` otherwise.
+    /// Extraneous data is ignored.
+    pub fn new(data: &'data [u8], layout: PlaneBytes) -> Result<Self, LayoutError> {
+        let err = LayoutError::length_required(
+            data.len()..image_texel::layout::Layout::byte_len(&layout),
+        );
+
+        let inner = data::DataRef::with_layout_at(data, layout, 0).ok_or(err)?;
+
+        Ok(PlaneDataRef { inner })
+    }
+}
+
+impl<'data> PlaneDataMut<'data> {
+    /// Create mutable plane data from bytes and a layout.
+    ///
+    /// This returns `Some` if the data is long enough for the layout, and `None` otherwise.
+    /// Extraneous data is ignored.
+    pub fn new(data: &'data mut [u8], layout: PlaneBytes) -> Result<Self, LayoutError> {
+        let err = LayoutError::length_required(
+            data.len()..image_texel::layout::Layout::byte_len(&layout),
+        );
+
+        let inner = data::DataMut::with_layout_at(data, layout, 0).ok_or(err)?;
+
+        Ok(PlaneDataMut { inner })
+    }
+}

canvas/src/layout.rs

@@ -405,6 +405,7 @@ enum LayoutErrorInner {
     StrideError,
     NoChannelIndex(ColorChannel),
     ValidationError(u32),
+    LengthRequired { actual: usize, expected: usize },
 }
 
 impl Texel {
@@ -1229,6 +1230,15 @@ impl LayoutError {
         inner: LayoutErrorInner::NoModel,
     };
 
+    pub(crate) fn length_required(bytes: core::ops::Range<usize>) -> Self {
+        LayoutError {
+            inner: LayoutErrorInner::LengthRequired {
+                actual: bytes.start,
+                expected: bytes.end,
+            },
+        }
+    }
+
     fn validation(num: u32) -> Self {
         LayoutError {
             inner: LayoutErrorInner::ValidationError(num),

canvas/src/lib.rs

@@ -85,7 +85,8 @@ pub use self::shader::{ConversionError, Converter, ConverterPlaneHandle, Convert
 pub mod canvas {
     pub use crate::frame::{
         ArcCanvas, BytePlaneAtomics, BytePlaneCells, BytePlaneMut, BytePlaneRef,
-        BytePlaneRef as BytePlane, ChannelsMut, ChannelsRef, PlaneMut, PlaneRef, RcCanvas,
+        BytePlaneRef as BytePlane, ChannelsMut, ChannelsRef, PlaneDataMut, PlaneDataRef, PlaneMut,
+        PlaneRef, RcCanvas,
     };
 }