Fix 0pt strokes (#923)

src/export/render.rs

@@ -402,28 +402,33 @@ fn render_shape(
         miter_limit,
     }) = &shape.stroke
     {
-        let dash = dash_pattern.as_ref().and_then(|pattern| {
-            // tiny-skia only allows dash patterns with an even number of elements,
-            // while pdf allows any number.
-            let len = if pattern.array.len() % 2 == 1 {
-                pattern.array.len() * 2
-            } else {
-                pattern.array.len()
-            };
-            let dash_array =
-                pattern.array.iter().map(|l| l.to_f32()).cycle().take(len).collect();
+        let width = thickness.to_f32();
 
-            sk::StrokeDash::new(dash_array, pattern.phase.to_f32())
-        });
-        let paint = paint.into();
-        let stroke = sk::Stroke {
-            width: thickness.to_f32(),
-            line_cap: line_cap.into(),
-            line_join: line_join.into(),
-            dash,
-            miter_limit: miter_limit.0 as f32,
-        };
-        canvas.stroke_path(&path, &paint, &stroke, ts, mask);
+        // Don't draw zero-pt stroke.
+        if width > 0.0 {
+            let dash = dash_pattern.as_ref().and_then(|pattern| {
+                // tiny-skia only allows dash patterns with an even number of elements,
+                // while pdf allows any number.
+                let len = if pattern.array.len() % 2 == 1 {
+                    pattern.array.len() * 2
+                } else {
+                    pattern.array.len()
+                };
+                let dash_array =
+                    pattern.array.iter().map(|l| l.to_f32()).cycle().take(len).collect();
+
+                sk::StrokeDash::new(dash_array, pattern.phase.to_f32())
+            });
+            let paint = paint.into();
+            let stroke = sk::Stroke {
+                width,
+                line_cap: line_cap.into(),
+                line_join: line_join.into(),
+                dash,
+                miter_limit: miter_limit.0 as f32,
+            };
+            canvas.stroke_path(&path, &paint, &stroke, ts, mask);
+        }
     }
 
     Some(())

tests/typ/visualize/stroke.typ

@@ -69,3 +69,36 @@
 
 // Error: 29-55 expected "solid", "dotted", "densely-dotted", "loosely-dotted", "dashed", "densely-dashed", "loosely-dashed", "dashdotted", "densely-dashdotted", "loosely-dashdotted", array, dictionary, dash pattern, or none
 #line(length: 60pt, stroke: (color: red, dash: "dash"))
+
+---
+// 0pt strokes must function exactly like 'none' strokes and not draw anything
+#rect(width: 10pt, height: 10pt, stroke: none)
+#rect(width: 10pt, height: 10pt, stroke: 0pt)
+
+#rect(width: 10pt, height: 10pt, stroke: none, fill: blue)
+#rect(width: 10pt, height: 10pt, stroke: 0pt + red, fill: blue)
+
+#line(length: 30pt, stroke: 0pt)
+#line(length: 30pt, stroke: (color: red, thickness: 0pt, dash: ("dot", 1pt)))
+
+#table(columns: 2, stroke: none)[A][B]
+#table(columns: 2, stroke: 0pt)[A][B]
+
+#path(
+    fill: red,
+    stroke: none,
+    closed: true,
+    ((0%, 0%), (4%, -4%)),
+    ((50%, 50%), (4%, -4%)),
+    ((0%, 50%), (4%, 4%)),
+    ((50%, 0%), (4%, 4%)),
+)
+#path(
+    fill: red,
+    stroke: 0pt,
+    closed: true,
+    ((0%, 0%), (4%, -4%)),
+    ((50%, 50%), (4%, -4%)),
+    ((0%, 50%), (4%, 4%)),
+    ((50%, 0%), (4%, 4%)),
+)