add ability to load PixelGrid and BitVec

src/bit_vec.rs

@@ -10,6 +10,10 @@ impl BitVec {
         Self { data: vec!(0; size / 8) }
     }
 
+    pub fn load(data: &[u8]) -> BitVec {
+        Self { data: Vec::from(data) }
+    }
+
     pub fn set(&mut self, index: usize, value: bool) -> bool {
         let (byte_index, bit_mask) = self.get_indexes(index);
 

src/pixel_grid.rs

@@ -22,6 +22,17 @@ impl PixelGrid {
         Self::new(PIXEL_WIDTH as usize, PIXEL_HEIGHT as usize)
     }
 
+    pub fn load(width: usize, height: usize, data: &[u8]) -> Self {
+        assert_eq!(width % 8, 0);
+        assert_eq!(height % 8, 0);
+        assert_eq!(data.len(), height * width / 8);
+        Self {
+            width,
+            height,
+            bit_vec: BitVec::load(data),
+        }
+    }
+
     pub fn set(&mut self, x: usize, y: usize, value: bool) -> bool {
         self.bit_vec.set(x + y * self.width, value)
     }