4 files changed, 61 insertions, 2 deletions

diff --git a/src/app.rs b/src/app.rs
index 3e7ac0f..d8a6132 100644
--- a/src/app.rs
+++ b/src/app.rs
@@ -257,6 +257,40 @@ impl<'ctx> AppState<'ctx> {
         }
     }
 
+    pub fn repeat_last_paint(&mut self, target: MapPoint) {
+        self.commit_operation();
+        if let Some(ModifyRecord::Paint(records)) = self
+            .undo_stack
+            .operations
+            .iter()
+            .rev()
+            .find(|&o| matches!(o, ModifyRecord::Paint(_)))
+        {
+            dbg!(target);
+            // find center of paint cluster
+            let centroid: MapPoint = records
+                .iter()
+                .fold(MapPoint { x: 0, y: 0 }, |acc, x| acc + x.point)
+                .reduce(records.len() as u32);
+            dbg!(centroid);
+            // re-center cluster around target
+            let centered_op = records
+                .iter()
+                .map(|x| PaintRecord {
+                    point: x.point + target - centroid,
+                    ..*x
+                })
+                .collect::<Vec<_>>();
+            let mut ud = Vec::new();
+            for r in &centered_op {
+                let p = r.point;
+                let v = r.new;
+                ud.push(PaintRecord::new(p, self.pixmap.set(p, v), v));
+            }
+            self.undo_stack.push(ModifyRecord::Paint(ud));
+        }
+    }
+
     pub fn zoom_in(&mut self, p: (i32, i32)) {
         // attempt to center around cursor
         if let Some(p) = self.idx_at_coord(p) {
@@ -774,6 +808,11 @@ impl<'ctx> AppState<'ctx> {
                                         let cursor = (mouse.x(), mouse.y());
                                         self.zoom_out(cursor);
                                     }
+                                    Keycode::Period => {
+                                        if let Some(contact) = self.idx_at_coord(self.mouse) {
+                                            self.repeat_last_paint(contact.into());
+                                        }
+                                    }
                                     // brush ops
                                     Keycode::Q => self.brush.shrink(),
                                     Keycode::E => self.brush.grow(),
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 {
diff --git a/src/lisp/prelude.rs b/src/lisp/prelude.rs
index dddce5f..ce3f97b 100644
--- a/src/lisp/prelude.rs
+++ b/src/lisp/prelude.rs
@@ -536,6 +536,15 @@ pub fn new_env() -> Result<Environment, LispError> {
         ]))
     });
 
+    primitive!(env, Arity::Exact(0), "active-color", |_, app| {
+        Ok(LispExpr::BoolLit(app.active_color))
+    });
+
+    primitive!(env, Arity::Exact(1), "set-active-color!", |args, app| {
+        app.active_color = args[0].cast_bool();
+        Ok(LispExpr::Unit)
+    });
+
     primitive!(env, Arity::Exact(2), "range", |args, _| {
         if type_match!(
             args,
diff --git a/src/undo.rs b/src/undo.rs
index 5effd79..f6c41ce 100644
--- a/src/undo.rs
+++ b/src/undo.rs
@@ -27,7 +27,7 @@ pub enum OpKind {
 
 #[derive(Debug)]
 pub struct UndoStack<T> {
-    operations: Vec<T>,
+    pub operations: Vec<T>,
     position: Option<u32>,
 }