优化

src/labelRenderer.ts

@@ -252,6 +252,8 @@ export interface RenderLabelOptions {
   /** 输出格式，默认 png */
   imageFormat?: 'png' | 'jpeg';
   jpegQuality?: number;
+  /** 为 false 时不裁剪到画布边界（用于拖动浮层完整显示元素） */
+  clipToCanvas?: boolean;
 }
 
 /** 离屏渲染标签为 PNG data URL */
@@ -269,6 +271,7 @@ export async function renderLabelToDataUrl(options: RenderLabelOptions): Promise
     scale: scaleOption = 16,
     imageFormat = 'png',
     jpegQuality = 0.92,
+    clipToCanvas = true,
   } = options;
 
   const scale = scaleOption;
@@ -295,9 +298,11 @@ export async function renderLabelToDataUrl(options: RenderLabelOptions): Promise
   }
 
   ctx.save();
-  ctx.beginPath();
-  ctx.rect(0, 0, canvas.width, canvas.height);
-  ctx.clip();
+  if (clipToCanvas) {
+    ctx.beginPath();
+    ctx.rect(0, 0, canvas.width, canvas.height);
+    ctx.clip();
+  }
 
   for (const elem of elements) {
     const ex = Math.round(elem.x * scale);