fix(webview2): scale native bounds for fractional DPI

ui/views/wv2_view.py

@@ -152,19 +152,32 @@ class WebView2View(QtWidgets.QWidget):
     # ---------- 几何同步 ----------
     def _dpr(self):
         try:
-            d = self.dpr()
+            d = float(self.devicePixelRatioF())
             return d if d > 0 else 1.0
         except Exception:
             return 1.0
 
+    @staticmethod
+    def _physical_bounds(x, y, width, height, dpr):
+        """按矩形边界换算物理像素，避免分数 DPR 产生相邻白缝。"""
+        def pixel(value):
+            scaled = value * dpr
+            return int(scaled + 0.5) if scaled >= 0 else int(scaled - 0.5)
+
+        left = pixel(x)
+        top = pixel(y)
+        right = pixel(x + width)
+        bottom = pixel(y + height)
+        return left, top, max(1, right - left), max(1, bottom - top)
+
     def sync_bounds(self):
         if not self.isVisible() or not self._session.child_hwnd:
             return
         top = self.window()
         p = self.mapTo(top, QtCore.QPoint(0, 0))
         d = self._dpr()
-        L, T = p.x() * d, p.y() * d
-        W, H = max(1, self.width() * d), max(1, self.height() * d)
+        L, T, W, H = self._physical_bounds(
+            p.x(), p.y(), self.width(), self.height(), d)
         # 去重：值没变就不发跨进程 COM（移动窗口时避免主线程被 WebView2 阻塞 → 整窗黑屏）
         # 注：旧版 resize hold（放大时钳制旧尺寸→露白边）已移除 ——
         #     拖动黑边的真凶是假异步 JS 泵（已修真异步），高频 SetBounds 实测 Chromium 完全跟得上；