feat: add overlay layout options

- add configurable overlay sizing and anchors

- support non-capturing overlays and focus handles

- demonstrate overlay options in Example

src/Example/Program.cs

@@ -21,6 +21,7 @@ var statusText = new Text();
 var loader = new Loader(textMeasurer) { Message = "运行中" };
 using var loaderCancellation = new CancellationTokenSource();
 var input = new TinyTUI.Components.Input(textMeasurer) { Prompt = "请输入: " };
+IOverlayHandle? tipHandle = null;
 
 input.OnChanged = value => UpdateStatus(statusText, value, textMeasurer, renderer);
 input.OnSubmitted = value =>
@@ -29,15 +30,46 @@ input.OnSubmitted = value =>
     {
         case "/help":
             AddEvent(eventsText, "Overlay: help opened");
-            runtime.ShowOverlay(new HelpOverlay(runtime, textMeasurer));
+            runtime.ShowOverlay(
+                new HelpOverlay(runtime, textMeasurer),
+                new OverlayOptions
+                {
+                    Width = OverlaySize.Percent(45),
+                    MinWidth = 42,
+                    Anchor = OverlayAnchor.TopRight,
+                    Margin = new OverlayMargin(1),
+                });
+            break;
+        case "/tip":
+            tipHandle?.Hide();
+            tipHandle = runtime.ShowOverlay(
+                new TipOverlay(textMeasurer),
+                OverlayOptions.NonCapturingTooltip());
+            AddEvent(eventsText, "Overlay: non-capturing tip opened");
             break;
         case "/select":
             AddEvent(eventsText, "Overlay: select opened");
-            runtime.ShowOverlay(new SelectOverlay(runtime, message => AddEvent(eventsText, message), textMeasurer));
+            runtime.ShowOverlay(
+                new SelectOverlay(runtime, message => AddEvent(eventsText, message), textMeasurer),
+                new OverlayOptions
+                {
+                    Width = 34,
+                    Anchor = OverlayAnchor.LeftCenter,
+                    Margin = new OverlayMargin(1),
+                    MaxHeight = 9,
+                });
             break;
         case "/edit":
             AddEvent(eventsText, "Overlay: editor opened");
-            runtime.ShowOverlay(new EditorOverlay(runtime, message => AddEvent(eventsText, message), textMeasurer));
+            runtime.ShowOverlay(
+                new EditorOverlay(runtime, message => AddEvent(eventsText, message), textMeasurer),
+                new OverlayOptions
+                {
+                    Width = OverlaySize.Percent(70),
+                    MinWidth = 52,
+                    Anchor = OverlayAnchor.BottomCenter,
+                    Margin = new OverlayMargin(1),
+                });
             break;
         case "":
             AddEvent(eventsText, "Submitted empty input");
@@ -62,6 +94,7 @@ AddAll(
         "操作说明\n" +
         "- 输入文本后 Enter 提交\n" +
         "- /help 打开帮助弹层\n" +
+        "- /tip 打开不抢焦点的右上角提示\n" +
         "- /select 打开可交互选择列表\n" +
         "- /edit 打开需要焦点的多行编辑器\n" +
         "- Esc 退出"),
@@ -169,6 +202,21 @@ file sealed class HelpOverlay(ITuiRuntime runtime, ITextMeasurer textMeasurer) :
     }
 }
 
+file sealed class TipOverlay(ITextMeasurer textMeasurer) : IComponent
+{
+    private readonly Box _box = new(
+        new Text(
+            "这是 non-capturing overlay\n" +
+            "打开后输入框仍然接收键盘输入\n" +
+            "再次输入 /tip 会替换当前提示"),
+        textMeasurer)
+    {
+        Title = "Tip",
+    };
+
+    public IReadOnlyList<string> Render(int width) => _box.Render(width);
+}
+
 file sealed class SelectOverlay : IInputComponent
 {
     private readonly ITuiRuntime _runtime;