first commit

common/resources/client/ui/interactions/utils/restrict-resizable-within-boundary.ts

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+import {InteractableRect} from '../interactable-event';
+
+export function restrictResizableWithinBoundary(
+  rect: InteractableRect,
+  boundaryRect: InteractableRect
+) {
+  const boundedRect = {...rect};
+
+  // restrict to left edge of boundary
+  boundedRect.left = Math.max(0, boundedRect.left);
+  // compensate width when left is bounded
+  const leftRestriction = boundedRect.left - rect.left;
+  if (leftRestriction > 0) {
+    boundedRect.width -= leftRestriction;
+  }
+
+  // restrict to top edge of boundary
+  boundedRect.top = Math.max(0, boundedRect.top);
+  // compensate height when top is bounded
+  const topRestriction = boundedRect.top - rect.top;
+  if (topRestriction > 0) {
+    boundedRect.height -= topRestriction;
+  }
+
+  // restrict to right edge of boundary
+  boundedRect.width = Math.min(
+    boundedRect.width,
+    boundaryRect.width - boundedRect.left
+  );
+
+  // restrict to bottom edge of boundary
+  boundedRect.height = Math.min(
+    boundedRect.height,
+    boundaryRect.height - boundedRect.top
+  );
+
+  return boundedRect;
+}