Render: moved type with mitred strokes redraws where its spikes reach

Follows #3461: character strokes' miter spikes reach past half the weight, which the redrawn area missed.

crates/doc/src/text.rs

@@ -1713,8 +1713,18 @@ impl TextObject {
     /// How far the characters' strokes paint past their glyphs, in document space: they scale
     /// with the type.
     pub fn char_stroke_outset(&self) -> f64 {
+        self.char_strokes(CharStyle::stroke_outset)
+    }
+    /// How far the characters' strokes can paint past their glyphs, their miter spikes and square
+    /// caps included ([`StrokeLayer::reach`]), in document space: what a change of the type must
+    /// redraw. The visual bounds take [`Self::char_stroke_outset`].
+    pub fn char_stroke_reach(&self) -> f64 {
+        self.char_strokes(|style| if style.has_stroke() { style.stroke_layer().reach() } else { 0.0 })
+    }
+    /// The farthest `outset` of the characters' styles, scaled with the type.
+    fn char_strokes(&self, outset: impl Fn(&CharStyle) -> f64) -> f64 {
         let k = crate::node::Scaling::factor(self.xf).unwrap_or(1.0);
-        self.runs.iter().map(|r| r.style.stroke_outset()).fold(0.0, f64::max) * k
+        self.runs.iter().map(|r| outset(&r.style)).fold(0.0, f64::max) * k
     }
     pub fn transform(&mut self, a: Affine) {
         self.xf = a * self.xf;

crates/render/src/fx.rs

@@ -489,11 +489,12 @@ fn cull_bounds_in(symbols: &SymbolBoxes, n: &Node, after_reshape: bool) -> Optio
 }
 
 /// The box of type `t`'s glyphs as laid out (its layout bounds, else laid out now), grown by its
-/// characters' strokes and by `outset`: on a path they stand above it and run past its ends, in an
-/// area they can hang past its frame, where its own box ([`Node::visual_bounds_with`]) doesn't.
+/// characters' strokes, miter spikes included, and by `outset`: on a path they stand above it and
+/// run past its ends, in an area they can hang past its frame, where its own box
+/// ([`Node::visual_bounds_with`]) doesn't.
 fn glyphs_box(t: &vectorcraft_doc::TextObject, outset: f64) -> Option<Rect> {
     let b = t.cached_bounds.unwrap_or_else(|| vectorcraft_text::layout(vectorcraft_text::FontDb::global(), t).bounds);
-    let o = outset.max(t.char_stroke_outset());
+    let o = outset.max(t.char_stroke_reach());
     (b.width() > 0.0 || b.height() > 0.0).then(|| t.xf.transform_rect_bbox(b).inflate(o, o))
 }
 

crates/render/src/tests_changed.rs

@@ -192,6 +192,28 @@ fn reshaping_the_path_of_type_on_a_path_changes_where_its_letters_were_and_are()
     redraw(&old, &new);
 }
 
+/// Stroked type with sharp corners: the miter spikes of its characters' strokes reach past half
+/// the weight, and change where they were and where they are.
+#[test]
+fn moving_type_with_mitred_strokes_changes_where_its_spikes_reach() {
+    let mut old = Document::new(110.0, 80.0);
+    let l = old.layers[0].id;
+    let style = vectorcraft_doc::text::CharStyle {
+        size: 30.0,
+        stroke: Paint::solid(Color::BLACK),
+        stroke_width: 10.0,
+        stroke_join: vectorcraft_doc::LineJoin::Miter,
+        stroke_miter_limit: 10.0,
+        ..Default::default()
+    };
+    let mut t = vectorcraft_doc::text::TextObject::point(Point::new(10.0, 50.0), "VAWV", style);
+    t.cached_bounds = Some(vectorcraft_text::layout(vectorcraft_text::FontDb::global(), &t).bounds);
+    let text = old.insert(Some(l), 0, Node::new(NodeId(0), NodeKind::Text(Box::new(t)))).unwrap();
+    let mut new = old.clone();
+    new.node_mut(text).unwrap().transform(Affine::translate((9.0, 7.0)), false);
+    redraw(&old, &new);
+}
+
 #[test]
 fn an_unchanged_document_changes_nothing_and_a_new_symbol_everything() {
     let (old, _) = document();