dimensions operator impls, pad image if it's too small

bingus/src/img/image.rs

@@ -1,6 +1,7 @@
 use std::{
     convert::Infallible,
-    ops::{Deref, DerefMut},
+    iter::once,
+    ops::{Add, Deref, DerefMut, Div, Mul, Sub},
 };
 
 pub use image::*;
@@ -25,15 +26,96 @@ where
     }
 }
 
+#[cfg_attr(debug_assertions, derive(Debug))]
 pub struct Dimensions {
     pub width: u32,
     pub height: u32,
 }
 
+impl Div<Dimensions> for Dimensions {
+    type Output = Dimensions;
+    fn div(self, rhs: Dimensions) -> Self::Output {
+        Dimensions {
+            width: self.width / rhs.width,
+            height: self.height / rhs.height,
+        }
+    }
+}
+
+impl Div<u32> for Dimensions {
+    type Output = Dimensions;
+    fn div(self, rhs: u32) -> Self::Output {
+        Dimensions {
+            width: self.width / rhs,
+            height: self.height / rhs,
+        }
+    }
+}
+
+impl Mul<Dimensions> for Dimensions {
+    type Output = Dimensions;
+    fn mul(self, rhs: Dimensions) -> Self::Output {
+        Dimensions {
+            width: self.width * rhs.width,
+            height: self.height * rhs.height,
+        }
+    }
+}
+
+impl Mul<u32> for Dimensions {
+    type Output = Dimensions;
+    fn mul(self, rhs: u32) -> Self::Output {
+        Dimensions {
+            width: self.width * rhs,
+            height: self.height * rhs,
+        }
+    }
+}
+
+impl Add<Dimensions> for Dimensions {
+    type Output = Dimensions;
+    fn add(self, rhs: Dimensions) -> Self::Output {
+        Dimensions {
+            width: self.width + rhs.width,
+            height: self.height + rhs.height,
+        }
+    }
+}
+
+impl Add<u32> for Dimensions {
+    type Output = Dimensions;
+    fn add(self, rhs: u32) -> Self::Output {
+        Dimensions {
+            width: self.width + rhs,
+            height: self.height + rhs,
+        }
+    }
+}
+
+impl Sub<Dimensions> for Dimensions {
+    type Output = Dimensions;
+    fn sub(self, rhs: Dimensions) -> Self::Output {
+        Dimensions {
+            width: self.width - rhs.width,
+            height: self.height - rhs.height,
+        }
+    }
+}
+
+impl Sub<u32> for Dimensions {
+    type Output = Dimensions;
+    fn sub(self, rhs: u32) -> Self::Output {
+        Dimensions {
+            width: self.width - rhs,
+            height: self.height - rhs,
+        }
+    }
+}
+
 impl<P: Pixel> TryFromDataBytes for ImageBuffer<P, Vec<P::Subpixel>>
 where
     Vec<P::Subpixel>: Deref<Target = [P::Subpixel]>,
-    P::Subpixel: ToBytes + FromBytes,
+    P::Subpixel: ToBytes + FromBytes + Zero,
     <P::Subpixel as FromBytes>::Bytes: for<'a> TryFrom<&'a [u8]>,
 {
     type Error = Infallible;
@@ -50,6 +132,7 @@ where
             format.width,
             format.height,
             match crop {
+                // TODO: separate outer crop from inner crop
                 crate::Crop::End => bytes
                     .chunks_exact(P::Subpixel::zero().to_ne_bytes().as_ref().len())
                     .map(|p| {
@@ -60,6 +143,10 @@ where
                             },
                         )
                     })
+                    .chain(once(P::Subpixel::zero()).cycle())
+                    .take(
+                        format.width as usize * format.height as usize * P::CHANNEL_COUNT as usize,
+                    )
                     .collect::<Vec<P::Subpixel>>(),
                 crate::Crop::Start => bytes
                     .rchunks_exact(P::Subpixel::zero().to_ne_bytes().as_ref().len())
@@ -71,6 +158,10 @@ where
                             },
                         )
                     })
+                    .chain(once(P::Subpixel::zero()).cycle())
+                    .take(
+                        format.width as usize * format.height as usize * P::CHANNEL_COUNT as usize,
+                    )
                     .collect::<Vec<P::Subpixel>>(),
             },
         )