From b06d33b66e70453451bc5eb5ade9164defea4849 Mon Sep 17 00:00:00 2001
From: Akshay <nerdy@peppe.rs>
Date: Sun, 28 Mar 2021 09:51:41 +0530
Subject: implement flood fill; new fill brush

---
 src/bitmap.rs | 37 +++++++++++++++++++++++++++++--------
 1 file changed, 29 insertions(+), 8 deletions(-)

(limited to 'src/bitmap.rs')

diff --git a/src/bitmap.rs b/src/bitmap.rs
index c7e8fd4..41af745 100644
--- a/src/bitmap.rs
+++ b/src/bitmap.rs
@@ -54,8 +54,8 @@ impl Add for MapPoint {
     type Output = Self;
     fn add(self, rhs: Self) -> Self::Output {
         MapPoint {
-            x: self.x + rhs.x,
-            y: self.y + rhs.y,
+            x: self.x.saturating_add(rhs.x),
+            y: self.y.saturating_add(rhs.y),
         }
     }
 }
@@ -64,8 +64,8 @@ impl Sub for MapPoint {
     type Output = Self;
     fn sub(self, rhs: Self) -> Self::Output {
         MapPoint {
-            x: self.x - rhs.x,
-            y: self.y - rhs.y,
+            x: self.x.saturating_sub(rhs.x),
+            y: self.y.saturating_sub(rhs.y),
         }
     }
 }
@@ -102,7 +102,7 @@ impl MapPoint {
 
 impl<T> Pixmap<T>
 where
-    T: Copy + Clone + Default,
+    T: Copy + Clone + Default + PartialEq,
 {
     pub fn new(width: u32, height: u32) -> Self {
         let data = vec![Default::default(); (width * height) as usize];
@@ -121,7 +121,7 @@ where
         }
     }
 
-    pub fn is_inside<P: Into<MapPoint>>(&self, pt: P) -> bool {
+    pub fn contains<P: Into<MapPoint>>(&self, pt: P) -> bool {
         let MapPoint { x, y } = pt.into();
         x < self.width && y < self.height
     }
@@ -181,7 +181,7 @@ where
         circle
             .into_iter()
             .flat_map(|pt| MapPoint::try_from(pt))
-            .filter(|&pt| self.is_inside(pt))
+            .filter(|&pt| self.contains(pt))
             .collect()
     }
 
@@ -226,9 +226,30 @@ where
         coordinates
             .into_iter()
             .flat_map(|pt| MapPoint::try_from(pt))
-            .filter(|&pt| self.is_inside(pt))
+            .filter(|&pt| self.contains(pt))
             .collect()
     }
+
+    pub fn flood_fill(
+        &mut self,
+        start: MapPoint,
+        target: T,
+        replacement: T,
+        pts: &mut Vec<MapPoint>,
+    ) {
+        if !self.contains(start) || self.get(start) != target || self.get(start) == replacement {
+            return;
+        } else {
+            pts.push(start);
+            self.set(start, replacement);
+            for (x, y) in [(1, 0), (0, 1), (-1, 0), (0, -1)].iter() {
+                let dir = MapPoint::try_from((start.x as i64 - x, start.y as i64 + y));
+                if let Ok(pt) = dir {
+                    self.flood_fill(pt, target, replacement, pts);
+                }
+            }
+        }
+    }
 }
 
 impl Pixmap<bool> {
-- 
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