解决圆弧镜像的问题

src/qelmt/arc.rs

@@ -18,27 +18,56 @@ pub struct Arc {
 
 impl From<&entities::Arc> for Arc {
     fn from(arc: &entities::Arc) -> Self {
-        let temp_angle = if arc.start_angle > arc.end_angle {
-            (360.0 - arc.start_angle) + arc.end_angle
+
+        let is_mirror = arc.normal.z < 0.0;
+
+        let (start_angle, angle_span) = if is_mirror {
+            // 镜像变换：角度关于Y轴对称，即 θ -> 180° - θ
+            // 同时交换起始和结束角度以保持正确的绘制方向
+            let mirrored_start = 180.0 - arc.end_angle;
+            let mirrored_end = 180.0 - arc.start_angle;
+            
+            // 标准化角度到0-360度范围
+            let norm_start = if mirrored_start < 0.0 { 
+                mirrored_start + 360.0 
+            } else { 
+                mirrored_start 
+            };
+            let norm_end = if mirrored_end < 0.0 { 
+                mirrored_end + 360.0 
+            } else { 
+                mirrored_end 
+            };
+            
+            // 计算角度跨度
+            let span = if norm_end >= norm_start {
+                norm_end - norm_start
+            } else {
+                (360.0 - norm_start) + norm_end
+            };
+            
+            (norm_start, span)
         } else {
-            arc.end_angle - arc.start_angle
+            // 正常情况：直接使用原始角度
+            let span = if arc.end_angle >= arc.start_angle {
+                arc.end_angle - arc.start_angle
+            } else {
+                (360.0 - arc.start_angle) + arc.end_angle
+            };
+            (arc.start_angle, span)
         };
 
         Arc {
-            x: arc.center.x - arc.radius,
+            x: if is_mirror {
+                -arc.center.x - arc.radius
+            } else {
+                arc.center.x - arc.radius
+            },
             y: -arc.center.y - arc.radius,
             height: arc.radius * 2.0,
             width: arc.radius * 2.0,
-            start: if arc.start_angle < 0.0 {
-                -arc.start_angle
-            } else {
-                arc.start_angle
-            },
-            angle: if temp_angle < 0.0 {
-                -temp_angle
-            } else {
-                temp_angle
-            },
+            start: if start_angle < 0.0 { -start_angle } else { start_angle },
+            angle: if angle_span < 0.0 { -angle_span } else { angle_span },
 
             //in the original code antialias is always set to false...I'm guessing for performance
             //reasons...I'm trying to think if there is a time we might want to turn it on?

src/qelmt/ellipse.rs

@@ -41,8 +41,8 @@ impl From<&entities::Ellipse> for Ellipse {
         Ellipse {
             x: ellipse.center.x - ellipse.major_axis.x,
             y: -ellipse.center.y - ellipse.major_axis.x * ellipse.minor_axis_ratio,
-            height: ellipse.major_axis.x * 2.0,
-            width: ellipse.major_axis.x * 2.0 * ellipse.minor_axis_ratio,
+            width: ellipse.major_axis.x * 2.0,
+            height: ellipse.major_axis.x * 2.0 * ellipse.minor_axis_ratio,
 
             //in the original code antialias is always set to false...I'm guessing for performance
             //reasons...I'm trying to think if there is a time we might want to turn it on?