角度

src/qelmt/arc.rs

@@ -4,6 +4,18 @@ use dxf::entities::LwPolyline;
 use hex_color::HexColor;
 use simple_xml_builder::XMLElement;
 
+fn normalize_angle(angle: f64) -> f64 {
+    let mut norm = angle % 360.0;
+    if norm < 0.0 {
+        norm += 360.0;
+    }
+    norm
+}
+
+fn qet_start_angle(angle: f64) -> f64 {
+    normalize_angle(270.0 - angle)
+}
+
 #[derive(Debug)]
 pub struct Arc {
     //need to brush up on my Rust scoping rules, isn't there a way to make this pub to just the module?
@@ -74,7 +86,7 @@ impl Arc {
             y: -arc.center.y - arc.radius,
             height: arc.radius * 2.0,
             width: arc.radius * 2.0,
-            start: if start_angle < 0.0 { -start_angle } else { start_angle },
+            start: qet_start_angle(normalize_angle(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
@@ -275,18 +287,8 @@ impl Arc {
             (start_y_qet - center_y_qet).atan2(start.0 - center_x).to_degrees();
         let mut end_angle = (end_y_qet - center_y_qet).atan2(end.0 - center_x).to_degrees();
 
-        let normalize = |mut angle: f64| {
+        start_angle = normalize_angle(start_angle);
-            while angle < 0.0 {
+        end_angle = normalize_angle(end_angle);
-                angle += 360.0;
-            }
-            while angle >= 360.0 {
-                angle -= 360.0;
-            }
-            angle
-        };
-
-        start_angle = normalize(start_angle);
-        end_angle = normalize(end_angle);
 
         let ccw_sweep = (end_angle - start_angle).rem_euclid(360.0);
         let cw_sweep = (start_angle - end_angle).rem_euclid(360.0);
@@ -305,6 +307,8 @@ impl Arc {
             return Err("Arc sweep too small".into());
         }
 
+        let start_angle = qet_start_angle(start_angle);
+
         Ok(Arc {
             x: center_x - radius,
             y: center_y_qet - radius,