1 files changed, 12 insertions, 1 deletions

diff --git a/src/bitmap.rs b/src/bitmap.rs
index ff41cb8..ffc0258 100644
--- a/src/bitmap.rs
+++ b/src/bitmap.rs
@@ -13,7 +13,7 @@ pub struct Pixmap<T> {
     pub data: Vec<T>,
 }
 
-#[derive(Copy, Clone, Debug, Hash, PartialEq, Eq)]
+#[derive(Default, Copy, Clone, Debug, Hash, PartialEq, Eq)]
 pub struct MapPoint {
     pub x: u32,
     pub y: u32,
@@ -111,6 +111,17 @@ impl MapPoint {
     }
 
     #[inline]
+    pub fn reduce(self, c: u32) -> MapPoint {
+        if c == 0 {
+            panic!("reduce MapPoint by zero")
+        }
+        MapPoint {
+            x: self.x / c,
+            y: self.y / c,
+        }
+    }
+
+    #[inline]
     pub fn mirror_about(self, line: u32, axis: Axis) -> MapPoint {
         let MapPoint { x, y } = self;
         match axis {