make comments disappear when pasting over them, but not when placing single tiles

src/marble_engine/grid.rs

@@ -23,6 +23,35 @@ pub struct ResizeDeltas {
 	pub y_neg: usize,
 }
 
+impl ResizeDeltas {
+	pub fn new(
+		margin: usize,
+		(width, height): (usize, usize),
+		pos: Pos,
+		(new_width, new_height): (usize, usize),
+	) -> Self {
+		let margin = margin as PosInt;
+		let width = width as PosInt;
+		let height = height as PosInt;
+		let new_width = new_width as PosInt;
+		let new_height = new_height as PosInt;
+		Self {
+			x_pos: if (pos.x + margin + new_width) > width {
+				pos.x + margin + new_width - width
+			} else {
+				0
+			} as usize,
+			x_neg: if pos.x < margin { margin - pos.x } else { 0 } as usize,
+			y_pos: if (pos.y + margin + new_height) > height {
+				pos.y + margin + new_height - height
+			} else {
+				0
+			} as usize,
+			y_neg: if pos.y < margin { margin - pos.y } else { 0 } as usize,
+		}
+	}
+}
+
 impl Grid {
 	pub fn parse(source: &str) -> Self {
 		let mut rows = Vec::new();
@@ -185,6 +214,10 @@ impl Grid {
 		self.height
 	}
 
+	pub fn size(&self) -> (usize, usize) {
+		(self.width, self.height)
+	}
+
 	pub fn get_marbles(&self) -> Vec<Pos> {
 		let mut out = Vec::new();
 		for y in 0..self.height {