add grid functions for getting references or optional values

crates/servicepoint/src/byte_grid.rs

@@ -1,3 +1,4 @@
+use crate::grid::RefGrid;
 use crate::{DataRef, Grid};
 
 /// A 2D grid of bytes
@@ -42,6 +43,10 @@ impl ByteGrid {
         }
     }
 
+    fn is_position_valid(&self, x: isize, y: isize) -> bool {
+        x > 0 && x < self.width as isize && y > 0 && y < self.height as isize
+    }
+
     fn check_indexes(&self, x: usize, y: usize) {
         assert!(
             x < self.width,
@@ -54,6 +59,11 @@ impl ByteGrid {
             self.height
         );
     }
+
+    pub fn get_mut(&mut self, x: usize, y: usize) -> &mut u8 {
+        self.check_indexes(x, y);
+        &mut self.data[x + y * self.width]
+    }
 }
 
 impl Grid<u8> for ByteGrid {
@@ -91,6 +101,22 @@ impl Grid<u8> for ByteGrid {
         self.data[x + y * self.width]
     }
 
+    fn get_optional(&self, x: isize, y: isize) -> Option<u8> {
+        if self.is_position_valid(x, y) {
+            Some(self.get(x as usize, y as usize))
+        } else {
+            None
+        }
+    }
+
+    fn set_optional(&mut self, x: isize, y: isize, value: u8) -> Option<u8> {
+        if self.is_position_valid(x, y) {
+            Some(self.set(x as usize, y as usize, value))
+        } else {
+            None
+        }
+    }
+
     fn fill(&mut self, value: u8) {
         self.data.fill(value);
     }
@@ -123,6 +149,34 @@ impl From<ByteGrid> for Vec<u8> {
     }
 }
 
+impl RefGrid<u8> for ByteGrid {
+    fn get_ref(&self, x: usize, y: usize) -> &u8 {
+        self.check_indexes(x, y);
+        &self.data[x + y * self.width]
+    }
+
+    fn get_ref_optional(&self, x: isize, y: isize) -> Option<&u8> {
+        if self.is_position_valid(x, y) {
+            Some(&self.data[x as usize + y as usize * self.width])
+        } else {
+            None
+        }
+    }
+
+    fn get_ref_mut(&mut self, x: usize, y: usize) -> &mut u8 {
+        self.check_indexes(x, y);
+        &mut self.data[x + y * self.width]
+    }
+
+    fn get_ref_mut_optional(&mut self, x: isize, y: isize) -> Option<&mut u8> {
+        if self.is_position_valid(x, y) {
+            Some(&mut self.data[x as usize + y as usize * self.width])
+        } else {
+            None
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use crate::{ByteGrid, DataRef, Grid};

crates/servicepoint/src/grid.rs

@@ -51,3 +51,46 @@ pub trait Grid<T> {
     /// the height in y-direction
     fn height(&self) -> usize;
 }
+
+/// A grid that can return cells as references.
+pub trait RefGrid<T> {
+    /// Get a reference to the current value at the specified position
+    ///
+    /// # Arguments
+    ///
+    /// * `x` and `y`: position of the cell
+    ///
+    /// # Panics
+    ///
+    /// When accessing `x` or `y` out of bounds.
+    fn get_ref(&self, x: usize, y: usize) -> &T;
+
+    /// Get a reference to the current value at the specified position if the position is in bounds.
+    ///
+    /// # Arguments
+    ///
+    /// * `x` and `y`: position of the cell
+    ///
+    /// returns: Reference to cell or None
+    fn get_ref_optional(&self, x: isize, y: isize) -> Option<&T>;
+
+    /// Get a mutable reference to the current value at the specified position
+    ///
+    /// # Arguments
+    ///
+    /// * `x` and `y`: position of the cell
+    ///
+    /// # Panics
+    ///
+    /// When accessing `x` or `y` out of bounds.
+    fn get_ref_mut(&mut self, x: usize, y: usize) -> &mut T;
+
+    /// Get a mutable reference to the current value at the specified position if position is in bounds.
+    ///
+    /// # Arguments
+    ///
+    /// * `x` and `y`: position of the cell
+    ///
+    /// returns: Reference to cell or None
+    fn get_ref_mut_optional(&mut self, x: isize, y: isize) -> Option<&mut T>;
+}

crates/servicepoint/src/lib.rs

@@ -8,7 +8,7 @@ pub use crate::command::{Brightness, Command, Offset, Origin};
 pub use crate::compression_code::CompressionCode;
 pub use crate::connection::Connection;
 pub use crate::data_ref::DataRef;
-pub use crate::grid::Grid;
+pub use crate::grid::{Grid, RefGrid};
 pub use crate::packet::{Header, Packet, Payload};
 pub use crate::pixel_grid::PixelGrid;
 

crates/servicepoint/src/pixel_grid.rs

@@ -60,6 +60,10 @@ impl PixelGrid {
         }
     }
 
+    fn is_position_valid(&self, x: isize, y: isize) -> bool {
+        x > 0 && x < self.width as isize && y > 0 && y < self.height as isize
+    }
+
     fn check_indexes(&self, x: usize, y: usize) {
         assert!(
             x < self.width,
@@ -96,6 +100,27 @@ impl Grid<bool> for PixelGrid {
         self.bit_vec.get(x + y * self.width)
     }
 
+    fn get_optional(&self, x: isize, y: isize) -> Option<bool> {
+        if self.is_position_valid(x, y) {
+            Some(self.get(x as usize, y as usize))
+        } else {
+            None
+        }
+    }
+
+    fn set_optional(
+        &mut self,
+        x: isize,
+        y: isize,
+        value: bool,
+    ) -> Option<bool> {
+        if self.is_position_valid(x, y) {
+            Some(self.set(x as usize, y as usize, value))
+        } else {
+            None
+        }
+    }
+
     /// Sets the state of all pixels in the `PixelGrid`.
     ///
     /// # Arguments