From 97958d6ec19ce2059cff7de74039c70682708a6a Mon Sep 17 00:00:00 2001
From: Myriad-Dreamin <35292584+Myriad-Dreamin@users.noreply.github.com>
Date: Wed, 27 Nov 2024 19:27:55 +0800
Subject: [PATCH] fix: calculate bbox of text elements which have zero advance
 (#608)

---
 crates/conversion/vec2canvas/src/lib.rs      | 16 ++++++++++++----
 crates/conversion/vec2dom/src/svg_backend.rs | 14 +++++++++-----
 crates/reflexo/src/vector/ir/geom.rs         |  8 ++++++++
 3 files changed, 29 insertions(+), 9 deletions(-)

diff --git a/crates/conversion/vec2canvas/src/lib.rs b/crates/conversion/vec2canvas/src/lib.rs
index 18f099e3..7d8d29d2 100644
--- a/crates/conversion/vec2canvas/src/lib.rs
+++ b/crates/conversion/vec2canvas/src/lib.rs
@@ -219,12 +219,20 @@ impl<'m, 't, Feat: ExportFeature> RenderVm<'m> for CanvasRenderTask<'m, 't, Feat
             let upem = Scalar(font.units_per_em.0);
             let accender = Scalar(font.ascender.0) * upem;
 
+            // todo: glyphs like macron has zero width... why?
             let w = text.width();
 
-            CanvasBBox::Static(Box::new(Rect {
-                lo: Point::new(Scalar(0.), accender - upem),
-                hi: Point::new(w * upem / text.shape.size, accender),
-            }))
+            if text.shape.size.0 == 0. {
+                CanvasBBox::Static(Box::new(Rect {
+                    lo: Point::new(Scalar(0.), accender - upem),
+                    hi: Point::new(Scalar(0.), accender),
+                }))
+            } else {
+                CanvasBBox::Static(Box::new(Rect {
+                    lo: Point::new(Scalar(0.), accender - upem),
+                    hi: Point::new(w * upem / text.shape.size, accender),
+                }))
+            }
         };
         for style in &text.shape.styles {
             if let ir::PathStyle::Fill(fill) = style {
diff --git a/crates/conversion/vec2dom/src/svg_backend.rs b/crates/conversion/vec2dom/src/svg_backend.rs
index 65bd78a7..e0057b64 100644
--- a/crates/conversion/vec2dom/src/svg_backend.rs
+++ b/crates/conversion/vec2dom/src/svg_backend.rs
@@ -282,13 +282,17 @@ impl TypstElem {
         }
 
         let bbox = self.canvas.as_ref().unwrap().bbox_at(ts);
-        // web_sys::console::log_2(
-        //     &"bbox".into(),
-        //     &format!("{:?} -> {:?} & {:?}", self.f.as_svg_id("g"), bbox,
-        // viewport).into(), );
         let should_visible = bbox
-            .map(|new_rect| !new_rect.intersect(&viewport).is_empty())
+            .map(|new_rect| new_rect.intersect(&viewport).is_intersected())
             .unwrap_or(true);
+        // web_sys::console::log_2(
+        //     &"bbox".into(),
+        //     &format!(
+        //         "{:?} -> ({bbox:?} & {viewport:?}) = {should_visible}",
+        //         self.f.as_svg_id("g")
+        //     )
+        //     .into(),
+        // );
 
         if should_visible != self.is_svg_visible {
             let (x, y) = (&self.stub, &self.g);
diff --git a/crates/reflexo/src/vector/ir/geom.rs b/crates/reflexo/src/vector/ir/geom.rs
index abc073ec..4ce22864 100644
--- a/crates/reflexo/src/vector/ir/geom.rs
+++ b/crates/reflexo/src/vector/ir/geom.rs
@@ -362,10 +362,18 @@ impl Rect {
         }
     }
 
+    /// Returns whether the rectangle has no area.
     pub fn is_empty(&self) -> bool {
         self.lo.x >= self.hi.x || self.lo.y >= self.hi.y
     }
 
+    /// Returns whether the rectangle is not well constructed.
+    ///
+    /// Note: This is not the same as `is_empty`.
+    pub fn is_intersected(&self) -> bool {
+        self.lo.x <= self.hi.x || self.lo.y <= self.hi.y
+    }
+
     pub fn intersect(&self, other: &Self) -> Self {
         Self {
             lo: self.lo.max(&other.lo),