Added brush grid snapping

src/helpers/shared.js

@@ -23,3 +23,14 @@ export function fromEntries(iterable) {
 export function isStreamStopped(stream) {
   return stream.getTracks().reduce((a, b) => a && b, { mute: true });
 }
+
+export function roundTo(x, to) {
+  return Math.round(x / to) * to;
+}
+
+export function snapPositionToGrid(position, gridSize) {
+  return {
+    x: roundTo(position.x, gridSize.x),
+    y: roundTo(position.y, gridSize.y),
+  };
+}