Fix for negative spacing

src/composables/useNegativeSpacing.ts

@@ -0,0 +1,21 @@
+import type { Sprite } from '@/types/sprites';
+import { getMaxDimensions } from './useSprites';
+
+/**
+ * Calculate negative spacing to add to top-left of cells.
+ * Uses half the available space so spacing is equal on all sides.
+ */
+export function calculateNegativeSpacing(sprites: Sprite[], enabled: boolean): number {
+  if (!enabled || sprites.length === 0) return 0;
+
+  const { maxWidth, maxHeight } = getMaxDimensions(sprites);
+  const minWidth = Math.min(...sprites.map(s => s.width));
+  const minHeight = Math.min(...sprites.map(s => s.height));
+
+  // Available space is the gap between cell size and smallest sprite
+  const availableWidth = maxWidth - minWidth;
+  const availableHeight = maxHeight - minHeight;
+
+  // Use half to balance spacing equally on all sides
+  return Math.floor(Math.min(availableWidth, availableHeight) / 2);
+}