feat(core): add slider dom (#613)

packages/core/src/dom/utils/index.ts

@@ -1,4 +1,5 @@
 export type { StateAttrMap } from '../../core/ui/types';
 export { applyElementProps } from './element-props';
 export { logMissingFeature } from './log';
+export { getPercentFromPointerEvent } from './pointer';
 export { applyStateDataAttrs, getStateDataAttrs } from './state-data-attrs';

packages/core/src/dom/utils/pointer.ts

@@ -0,0 +1,21 @@
+import { clamp } from '@videojs/utils/number';
+
+/** Convert a pointer event position to a 0–100 percent along an element's rect. */
+export function getPercentFromPointerEvent(
+  event: { clientX: number; clientY: number },
+  rect: DOMRect,
+  orientation: 'horizontal' | 'vertical',
+  isRTL: boolean
+): number {
+  let ratio: number;
+
+  if (orientation === 'vertical') {
+    ratio = 1 - (event.clientY - rect.top) / rect.height;
+  } else if (isRTL) {
+    ratio = (rect.right - event.clientX) / rect.width;
+  } else {
+    ratio = (event.clientX - rect.left) / rect.width;
+  }
+
+  return clamp(ratio * 100, 0, 100);
+}