first commit

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

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+import {InteractableRect} from '../interactable-event';
+import {calcNewSizeFromAspectRatio} from './calc-new-size-from-aspect-ratio';
+
+export function centerWithinBoundary(
+  boundary: Omit<InteractableRect, 'angle'>,
+  aspectRatio: number | null = null
+): InteractableRect {
+  // set rect to the size of specified boundary
+  const rect: InteractableRect = {
+    width: boundary.width,
+    height: boundary.height,
+    top: 0,
+    left: 0,
+    angle: 0,
+  };
+  // maybe resize rect based on aspect ratio
+  if (aspectRatio) {
+    const newSize = calcNewSizeFromAspectRatio(
+      aspectRatio,
+      rect.width,
+      rect.height
+    );
+    rect.width = newSize.width;
+    rect.height = newSize.height;
+  }
+  // center the rect
+  rect.left = (boundary.width - rect.width) / 2;
+  rect.top = (boundary.height - rect.height) / 2;
+  return rect;
+}