diff --git a/src/plotcutter/contour.ts b/src/plotcutter/contour.ts
index 2e6490e..da07d22 100644
--- a/src/plotcutter/contour.ts
+++ b/src/plotcutter/contour.ts
@@ -38,17 +38,17 @@ export function getRoundedRectPoints(
   }
 
   // 左上角圆角（从顶部开始，顺时针）
-  for (let i = 0; i < segmentsPerCorner; i++) {
-    const angle = (Math.PI / 2) * (i / segmentsPerCorner);
+  for (let i = 0; i <= segmentsPerCorner; i++) {
+    const angle = (Math.PI / 2) * (i / segmentsPerCorner) - Math.PI;
     points.push([
-      r + r * Math.cos(angle - Math.PI / 2),
-      r + r * Math.sin(angle - Math.PI / 2)
+      r + r * Math.cos(angle),
+      r + r * Math.sin(angle)
     ]);
   }
 
   // 右上角圆角
-  for (let i = 0; i < segmentsPerCorner; i++) {
-    const angle = (Math.PI / 2) * (i / segmentsPerCorner);
+  for (let i = 0; i <= segmentsPerCorner; i++) {
+    const angle = (Math.PI / 2) * (i / segmentsPerCorner) - Math.PI/2;
     points.push([
       width - r + r * Math.cos(angle),
       r + r * Math.sin(angle)
@@ -56,8 +56,8 @@ export function getRoundedRectPoints(
   }
 
   // 右下角圆角
-  for (let i = 0; i < segmentsPerCorner; i++) {
-    const angle = (Math.PI / 2) * (i / segmentsPerCorner) + Math.PI / 2;
+  for (let i = 0; i <= segmentsPerCorner; i++) {
+    const angle = (Math.PI / 2) * (i / segmentsPerCorner);
     points.push([
       width - r + r * Math.cos(angle),
       height - r + r * Math.sin(angle)
@@ -65,8 +65,8 @@ export function getRoundedRectPoints(
   }
 
   // 左下角圆角
-  for (let i = 0; i < segmentsPerCorner; i++) {
-    const angle = (Math.PI / 2) * (i / segmentsPerCorner) + Math.PI;
+  for (let i = 0; i <= segmentsPerCorner; i++) {
+    const angle = (Math.PI / 2) * (i / segmentsPerCorner) + Math.PI/2;
     points.push([
       r + r * Math.cos(angle),
       height - r + r * Math.sin(angle)