improve:UI面板弹出

Ink Canvas/MainWindow_cs/MW_FloatingBarIcons.cs

@@ -49,6 +49,7 @@ namespace Ink_Canvas
             else
             {
                 HideSubPanels();
+                UpdateTwoFingerGestureBorderPosition();
                 AnimationsHelper.ShowWithSlideFromBottomAndFade(TwoFingerGestureBorder);
                 AnimationsHelper.ShowWithSlideFromBottomAndFade(BoardTwoFingerGestureBorder);
             }
@@ -1742,6 +1743,7 @@ namespace Ink_Canvas
             else
             {
                 HideSubPanels();
+                UpdateBorderToolsPosition();
                 AnimationsHelper.ShowWithSlideFromBottomAndFade(BorderTools);
                 AnimationsHelper.ShowWithSlideFromBottomAndFade(BoardBorderTools);
             }
@@ -2439,6 +2441,7 @@ namespace Ink_Canvas
                     else
                     {
                         HideSubPanels();
+                        UpdatePenPalettePosition();
                         AnimationsHelper.ShowWithSlideFromBottomAndFade(PenPalette);
                         AnimationsHelper.ShowWithSlideFromBottomAndFade(BoardPenPalette);
                     }
@@ -2548,6 +2551,7 @@ namespace Ink_Canvas
                 // 已是橡皮状态，再次点击才弹出/收起面板
                 if (EraserSizePanel.Visibility == Visibility.Collapsed)
                 {
+                    UpdateEraserSizePanelPosition();
                     AnimationsHelper.ShowWithSlideFromBottomAndFade(EraserSizePanel);
                     if (BoardEraserSizePanel != null)
                         AnimationsHelper.ShowWithSlideFromBottomAndFade(BoardEraserSizePanel);
@@ -2598,6 +2602,7 @@ namespace Ink_Canvas
                 // 已是橡皮状态，再次点击才弹出/收起面板
                 if (BoardEraserSizePanel != null && BoardEraserSizePanel.Visibility == Visibility.Collapsed)
                 {
+                    UpdateEraserSizePanelPosition();
                     AnimationsHelper.ShowWithSlideFromBottomAndFade(BoardEraserSizePanel);
                     AnimationsHelper.ShowWithSlideFromBottomAndFade(EraserSizePanel);
                 }
@@ -4209,6 +4214,101 @@ namespace Ink_Canvas
             }
         }
 
+        /// <summary>
+        /// 通用子面板位置更新方法：根据触发按钮的位置，动态调整子面板的水平位置，
+        /// 使面板水平中心对齐按钮中心。不改变面板大小，不改变上下边距。
+        /// </summary>
+        /// <param name="button">触发按钮元素</param>
+        /// <param name="panel">需要定位的子面板</param>
+        /// <param name="defaultPanelWidth">面板默认宽度（当无法从Margin计算时使用）</param>
+        private void UpdateSubPanelPosition(FrameworkElement button, FrameworkElement panel, double defaultPanelWidth)
+        {
+            try
+            {
+                if (button == null || panel == null) return;
+                if (!(panel.Parent is FrameworkElement panelContainer)) return;
+
+                var ancestor = StackPanelFloatingBar;
+                if (ancestor == null) return;
+
+                // 获取按钮中心的X坐标（相对于 StackPanelFloatingBar 坐标系）
+                var buttonTransform = button.TransformToAncestor(ancestor);
+                var buttonOrigin = buttonTransform.Transform(new Point(0, 0));
+                double buttonCenterX = buttonOrigin.X + button.ActualWidth / 2.0;
+
+                // 获取面板容器（零宽度Grid）的X坐标（相对于 StackPanelFloatingBar 坐标系）
+                var containerTransform = panelContainer.TransformToAncestor(ancestor);
+                var containerOrigin = containerTransform.Transform(new Point(0, 0));
+                double containerX = containerOrigin.X;
+
+                // 计算当前面板宽度（保持不变）：panelWidth = -Margin.Left - Margin.Right
+                double currentLeft = panel.Margin.Left;
+                double currentRight = panel.Margin.Right;
+                double panelWidth = -currentLeft - currentRight;
+                if (panelWidth <= 0) panelWidth = defaultPanelWidth;
+
+                // 计算新的左边距，使面板水平中心对齐按钮：
+                //   panel_center = containerX + newLeft + panelWidth/2 = buttonCenterX
+                //   => newLeft = buttonCenterX - containerX - panelWidth/2
+                double newLeft = buttonCenterX - containerX - panelWidth / 2.0;
+
+                // 保持面板宽度不变：-newLeft - newRight = panelWidth
+                //   => newRight = -panelWidth - newLeft
+                double newRight = -panelWidth - newLeft;
+
+                // 清除可能残留的 Margin 动画（HoldEnd 会阻止本地值生效）
+                panel.BeginAnimation(FrameworkElement.MarginProperty, null);
+
+                // 更新边距，仅调整Left/Right，保持Top/Bottom不变
+                var margin = panel.Margin;
+                panel.Margin = new Thickness(newLeft, margin.Top, newRight, margin.Bottom);
+            }
+            catch (Exception ex)
+            {
+                LogHelper.WriteLogToFile($"更新子面板位置失败: {ex.Message}", LogHelper.LogType.Error);
+            }
+        }
+
+        /// <summary>
+        /// 更新批注子面板（PenPalette）的弹出位置，使其水平中心对齐笔按钮。
+        /// </summary>
+        private void UpdatePenPalettePosition()
+        {
+            UpdateSubPanelPosition(Pen_Icon, PenPalette, 193);
+        }
+
+        /// <summary>
+        /// 更新工具面板（BorderTools）的弹出位置，使其水平中心对齐工具按钮。
+        /// </summary>
+        private void UpdateBorderToolsPosition()
+        {
+            UpdateSubPanelPosition(ToolsFloatingBarBtn, BorderTools, 119);
+        }
+
+        /// <summary>
+        /// 更新橡皮擦尺寸面板（EraserSizePanel）的弹出位置，使其水平中心对齐橡皮擦按钮。
+        /// </summary>
+        private void UpdateEraserSizePanelPosition()
+        {
+            UpdateSubPanelPosition(Eraser_Icon, EraserSizePanel, 120);
+        }
+
+        /// <summary>
+        /// 更新形状绘制面板（BorderDrawShape）的弹出位置，使其水平中心对齐形状按钮。
+        /// </summary>
+        private void UpdateBorderDrawShapePosition()
+        {
+            UpdateSubPanelPosition(ShapeDrawFloatingBarBtn, BorderDrawShape, 317);
+        }
+
+        /// <summary>
+        /// 更新手势面板（TwoFingerGestureBorder）的弹出位置，使其水平中心对齐手势按钮。
+        /// </summary>
+        private void UpdateTwoFingerGestureBorderPosition()
+        {
+            UpdateSubPanelPosition(EnableTwoFingerGestureBorder, TwoFingerGestureBorder, 119);
+        }
+
         /// <summary>
         /// 隐藏浮动栏高光显示
         /// </summary>