1 files changed, 63 insertions, 3 deletions
diff --git a/evc/src/frame.rs b/evc/src/frame.rs
index 8e90832..1c18620 100644
--- a/evc/src/frame.rs
+++ b/evc/src/frame.rs
@@ -1,8 +1,11 @@
-use crate::pixel::Pixel;
-
+use crate::{pixel::Pixel, ser::Source};
+use std::{
+    io,
+    ops::{Index, IndexMut},
+};
 
 pub struct Frame {
-    size: (usize, usize),
+    pub size: (usize, usize),
     buffer: Vec<Vec<Pixel>>,
 }
 
@@ -15,4 +18,61 @@ impl Frame {
                 .collect(),
         }
     }
+    pub fn read(source: &mut impl Source, size: (usize, usize)) -> io::Result<Self> {
+        let mut frame = Frame::new(size);
+        for x in 0..size.0 {
+            for y in 0..size.1 {
+                let pixel = source.get::<Pixel>()?;
+                frame[(x, y)] = pixel;
+            }
+        }
+        Ok(frame)
+    }
+}
+
+impl Index<(usize, usize)> for Frame {
+    type Output = Pixel;
+    fn index(&self, (x, y): (usize, usize)) -> &Self::Output {
+        &self.buffer[x][y]
+    }
+}
+impl IndexMut<(usize, usize)> for Frame {
+    fn index_mut(&mut self, (x, y): (usize, usize)) -> &mut Self::Output {
+        &mut self.buffer[x][y]
+    }
+}
+
+pub struct View<'a> {
+    frame: &'a Frame,
+    offset: (usize, usize),
+    size: (usize, usize),
+}
+
+impl<'a> View<'a> {
+    pub fn new(frame: &'a Frame, offset: (usize, usize), size: (usize, usize)) -> Self {
+        Self {
+            frame,
+            offset,
+            size,
+        }
+    }
+    pub fn diff(&self, rhs: &Self) -> f64 {
+        assert_eq!(self.size, rhs.size);
+        let mut acc = 0.0;
+        for x in 0..self.size.0 {
+            for y in 0..self.size.1 {
+                let a = self[(x, y)];
+                let b = rhs[(x, y)];
+                acc += Pixel::distance(a, b);
+            }
+        }
+        acc
+    }
+}
+
+impl Index<(usize, usize)> for View<'_> {
+    type Output = Pixel;
+    fn index(&self, (x, y): (usize, usize)) -> &Self::Output {
+        &self.frame[(x + self.offset.0, y + self.offset.1)]
+    }
 }