Merge pull request #1951

crates/render/src/stroke.rs

@@ -6,6 +6,14 @@ use super::{
     pdf_layers, peniko, vello_cpu,
 };
 
+/// `stroke` as round dots `weight` wide, one every `2 × weight`. Kurbo's stroker drops
+/// zero-length dashes, so each dot is a dash a hair long, centred where the zero-length dash
+/// would be (so the path's ends get dots too).
+pub(crate) fn dotted(stroke: kurbo::Stroke, weight: f64) -> kurbo::Stroke {
+    let dot = weight * 1e-3;
+    stroke.with_dashes(dot / 2.0, [dot, weight * 2.0 - dot]).with_caps(kurbo::Cap::Round)
+}
+
 impl Renderer {
     pub(crate) fn draw_stroke(&mut self, ctx: &mut RenderContext, f: &Frame, it: &Item, bp: &BezPath, xf: Affine) {
         self.draw_stroke_painted(ctx, f, it, bp, xf);
@@ -37,9 +45,7 @@ impl Renderer {
             StrokeType::Dashed { pattern } if StrokeType::expandable_dashes(pattern, length) => {
                 stroke = stroke.with_dashes(0.0, pattern.iter().copied())
             }
-            StrokeType::Dotted if StrokeType::expandable_dashes(&[0.0, st.weight * 2.0], length) => {
-                stroke = stroke.with_dashes(0.0, [0.0, st.weight * 2.0]).with_caps(kurbo::Cap::Round)
-            }
+            StrokeType::Dotted if StrokeType::expandable_dashes(&[0.0, st.weight * 2.0], length) => stroke = dotted(stroke, st.weight),
             _ => {}
         }
         ctx.set_transform(f.view * xf);

crates/render/src/tests.rs

@@ -695,3 +695,37 @@ fn inline_objects_are_painted_under_the_text() {
         (a.y as u32..b.y as u32).flat_map(|y| (a.x as u32..b.x as u32).map(move |x| (x, y))).filter(|&(x, y)| image.pixel(x, y)[0] < 100).count();
     assert!(dark > 20, "the line's glyphs show over the box: {dark} dark pixels");
 }
+
+#[test]
+fn dotted_strokes_draw_every_dot() {
+    // A 4 pt dotted line 96 pt long: dots every 8 pt, 13 of them.
+    let mut d = Document::new(&NewDocument::default());
+    let lid = d.default_layer();
+    let id = designcraft_doc::ItemId(d.alloc());
+    let path = designcraft_geom::shapes::line(designcraft_geom::Point::new(100.0, 400.0), designcraft_geom::Point::new(196.0, 400.0));
+    let mut line = Item::new(id, lid, designcraft_doc::Shape::GraphicLine, path);
+    line.stroke = designcraft_doc::Stroke {
+        swatch: designcraft_color::swatch::BLACK.into(),
+        weight: 4.0,
+        kind: designcraft_doc::StrokeType::Dotted,
+        ..Default::default()
+    };
+    d.insert_item(SpreadRef::Doc(0), line, None).unwrap();
+    let cache = Cache::new();
+    let mut r = Renderer::new();
+    r.threads = 0;
+    let img = r.render_page(&d, &cache, 0, 1.0, false, &RenderOptions::default()).unwrap();
+    for i in 0..13 {
+        let x = 100 + i * 8;
+        assert!(img.pixel(x, 400)[0] < 128, "dot {i} at x={x}: {:?}", img.pixel(x, 400));
+        if i < 12 {
+            assert_eq!(img.pixel(x + 4, 400), [255, 255, 255, 255], "gap after dot {i}");
+        }
+    }
+    // Table and paragraph rules: one round dot per period.
+    let stroke = text::cell_stroke(&designcraft_doc::StrokeType::Dotted, 4.0, 96.0);
+    let edge = kurbo::Line::new((0.0, 0.0), (96.0, 0.0));
+    let outline = kurbo::stroke(kurbo::Shape::path_elements(&edge, 0.01), &stroke, &kurbo::StrokeOpts::default(), 0.01);
+    let dots = outline.elements().iter().filter(|e| matches!(e, kurbo::PathEl::MoveTo(_))).count();
+    assert_eq!(dots, 13);
+}

crates/render/src/text.rs

@@ -613,9 +613,7 @@ pub(crate) fn cell_stroke(kind: &designcraft_doc::StrokeType, weight: f64, lengt
         StrokeType::Dashed { pattern } if StrokeType::expandable_dashes(pattern, length) => {
             st.with_caps(kurbo::Cap::Butt).with_dashes(0.0, pattern.iter().copied())
         }
-        StrokeType::Dotted if StrokeType::expandable_dashes(&[0.0, weight * 2.0], length) => {
-            st.with_dashes(0.0, [0.0, weight * 2.0]).with_caps(kurbo::Cap::Round)
-        }
+        StrokeType::Dotted if StrokeType::expandable_dashes(&[0.0, weight * 2.0], length) => super::stroke::dotted(st, weight),
         _ => st,
     }
 }