1 files changed, 93 insertions, 0 deletions
diff --git a/libhitomezashi/src/pixel_buffer.rs b/libhitomezashi/src/pixel_buffer.rs
new file mode 100644
index 0000000..b151906
--- /dev/null
+++ b/libhitomezashi/src/pixel_buffer.rs
@@ -0,0 +1,93 @@
+use bitvec::prelude::*;
+use std::fmt;
+use std::ops::{Index, IndexMut};
+
+/// 2D buffer of monochrome (white/black i.e. true/false) pixels
+pub struct PixelBuffer {
+    buffer: BitVec,
+    pub width: usize,
+    pub height: usize,
+}
+
+impl PixelBuffer {
+    pub fn new(width: usize, height: usize) -> Self {
+        let mut buffer = BitVec::with_capacity(width * height);
+        buffer.resize(width * height, false);
+        PixelBuffer {
+            buffer,
+            width,
+            height,
+        }
+    }
+    pub fn fill_rect(&mut self, x: usize, y: usize, width: usize, height: usize) {
+        for i in x..(x + width) {
+            for j in y..(y + height) {
+                self[i].set(j, true);
+            }
+        }
+    }
+}
+
+impl Index<usize> for PixelBuffer {
+    type Output = BitSlice;
+
+    fn index(&self, column: usize) -> &Self::Output {
+        &self.buffer[(column * self.height)..((column + 1) * self.height)]
+    }
+}
+
+impl IndexMut<usize> for PixelBuffer {
+    fn index_mut(&mut self, column: usize) -> &mut Self::Output {
+        &mut self.buffer[(column * self.height)..((column + 1) * self.height)]
+    }
+}
+
+impl fmt::Display for PixelBuffer {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let mut result = String::new();
+        for y in 0..self.height {
+            for x in 0..self.width {
+                result.push(if self[x][y] { '1' } else { '0' })
+            }
+            result.push('\n')
+        }
+        write!(f, "{}", result)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn access_default() {
+        let pixel_buffer = PixelBuffer::new(2, 3);
+        assert!(pixel_buffer[0][0] == false);
+    }
+    #[test]
+    fn mutate() {
+        let mut pixel_buffer = PixelBuffer::new(2, 3);
+        pixel_buffer[1].set(2, true);
+        assert!(pixel_buffer[1][2] == true);
+    }
+    #[test]
+    #[should_panic]
+    fn access_out_of_bounds() {
+        let pixel_buffer = PixelBuffer::new(10, 20);
+        assert!(pixel_buffer[10][0] == false);
+    }
+    #[test]
+    fn print() {
+        let mut pixel_buffer = PixelBuffer::new(3, 3);
+        pixel_buffer[1].set(1, true);
+        let result = format!("{}", pixel_buffer);
+        assert!(result == "000\n010\n000\n");
+    }
+    #[test]
+    fn rect() {
+        let mut pixel_buffer = PixelBuffer::new(5, 3);
+        pixel_buffer.fill_rect(1, 0, 2, 2);
+        let result = format!("{}", pixel_buffer);
+        assert!(result == "01100\n01100\n00000\n");
+    }
+}