refactor(editor): extract drag handle widget (#9415)

2026-07-18 10:36:22 +08:00 · 2024-12-29 06:51:48 +00:00
parent b96a03b283
commit cec4a4b2c0
47 changed files with 277 additions and 92 deletions
@@ -0,0 +1,30 @@
+export function autoScroll(
+  viewportElement: HTMLElement,
+  y: number,
+  threshold = 50
+): boolean {
+  const { scrollHeight, clientHeight, scrollTop } = viewportElement;
+  let _scrollTop = scrollTop;
+  const max = scrollHeight - clientHeight;
+
+  let d = 0;
+  let flag = false;
+
+  if (Math.ceil(scrollTop) < max && clientHeight - y < threshold) {
+    // ↓
+    d = threshold - (clientHeight - y);
+    flag = Math.ceil(_scrollTop) < max;
+  } else if (scrollTop > 0 && y < threshold) {
+    // ↑
+    d = y - threshold;
+    flag = _scrollTop > 0;
+  }
+
+  _scrollTop += d * 0.25;
+
+  if (flag && scrollTop !== _scrollTop) {
+    viewportElement.scrollTop = _scrollTop;
+    return true;
+  }
+  return false;
+}