Don't skip first dash in dash pattern

src/stroke.rs

@@ -650,7 +650,7 @@ fn dash_impl<T: Iterator<Item = PathEl>>(
 ) -> DashIterator<T> {
     let mut dash_ix = 0;
     let mut dash_remaining = dash_offset;
-    let mut is_active = true;
+    let mut is_active = false;
     // Find place in dashes array for initial offset.
     while dash_remaining > 0.0 {
         let dash_len = dashes[dash_ix];
@@ -771,11 +771,11 @@ impl<'a, T: Iterator<Item = PathEl>> DashIterator<'a, T> {
             self.is_active = !self.is_active;
             self.t += t1 * (1.0 - self.t);
             self.seg_remaining -= self.dash_remaining;
+            self.dash_remaining = self.dashes[self.dash_ix];
             self.dash_ix += 1;
             if self.dash_ix == self.dashes.len() {
                 self.dash_ix = 0;
             }
-            self.dash_remaining = self.dashes[self.dash_ix];
         } else {
             if self.is_active {
                 let seg = self.current_seg.subsegment(self.t..1.0);
@@ -808,7 +808,9 @@ impl<'a, T: Iterator<Item = PathEl>> DashIterator<'a, T> {
 
 #[cfg(test)]
 mod tests {
-    use crate::{stroke, Cap::Butt, CubicBez, Join::Miter, Shape, Stroke};
+    use crate::{
+        dash, segments, stroke, Cap::Butt, CubicBez, Join::Miter, Line, PathSeg, Shape, Stroke
+    };
 
     // A degenerate stroke with a cusp at the endpoint.
     #[test]
@@ -858,4 +860,20 @@ mod tests {
             assert!(stroked.is_finite());
         }
     }
+
+    #[test]
+    fn dash_sequence() {
+        let shape = Line::new((0.0, 0.0), (21.0, 0.0));
+        let dashes = [1., 5., 2., 5.];
+        let expansion = [
+            PathSeg::Line(Line::new((0., 0.), (1., 0.))),
+            PathSeg::Line(Line::new((6., 0.), (8., 0.))),
+            PathSeg::Line(Line::new((13., 0.), (14., 0.))),
+            PathSeg::Line(Line::new((19., 0.), (21., 0.))),
+        ];
+        let iter = segments(dash(shape.path_elements(0.), 0., &dashes));
+        for (got, want) in iter.zip(expansion) {
+            assert_eq!(got, want);
+        }
+    }
 }