Bullets: a symbol the text font lacks falls back to a font that has it

Circled-number lists (circleNumDbPlain) and character bullets whose glyph
isn't in the paragraph's font were drawn as missing-glyph boxes (numbers)
or always from Inter (characters). Both now go through the usual font
fallback, as PowerPoint draws them.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

crates/render/src/lib.rs

@@ -248,7 +248,7 @@ pub fn needs_filters(pres: &Presentation, slide: &Slide) -> bool {
                 return;
             }
             let (e, _) = resolve::effects(&rctx, s);
-            if e.is_some_and(|e| !e.is_empty()) {
+            if e.is_some_and(|e| !e.is_empty()) || text_has_effects(&rctx, s) {
                 any = true;
             }
         });
@@ -261,6 +261,20 @@ pub fn needs_filters(pres: &Presentation, slide: &Slide) -> bool {
     any
 }
 
+/// Does the shape's text have a shadow or glow (on a run, in its list style, or in the master's
+/// text styles it inherits)? Such text is blurred, which needs filters.
+fn text_has_effects(rctx: &Ctx, s: &Shape) -> bool {
+    use deckcraft_model::text::{ListStyle, RunProps};
+    let fx = |r: &RunProps| r.shadow.as_ref().is_some_and(|s| !s.inner) || r.glow.as_ref().is_some_and(|g| g.radius > 0.0);
+    let styled = |l: &ListStyle| l.levels.iter().flatten().any(|lv| fx(&lv.run));
+    let Some(t) = &s.text else { return false };
+    t.paragraphs.iter().any(|p| p.runs.iter().any(|r| fx(&r.props)) || fx(&p.end_props))
+        || styled(&t.list_style)
+        || styled(&rctx.master.title_style)
+        || styled(&rctx.master.body_style)
+        || styled(&rctx.master.other_style)
+}
+
 /// Render slide `index` at `opts.scale` pixels per point. A panic inside the renderer becomes a
 /// blank image (logged), never a crash.
 pub fn render_slide(pres: &Presentation, index: usize, opts: &RenderOpts) -> Image {
@@ -1124,6 +1138,15 @@ pub fn draw_layout_with(ctx: &mut RenderContext, l: &deckcraft_text::TextLayout,
     for d in l.decos.iter().filter(|d| d.behind) {
         deco(ctx, d);
     }
+    // Text shadows, then glows, under all the text.
+    for pass in [TextEffect::Shadow, TextEffect::Glow] {
+        for run in &l.runs {
+            let ps = para(run.para);
+            if ps.visible && ps.opacity > 0.001 {
+                text_effect(ctx, run, pass, m * Affine::translate(ps.offset), ps.opacity);
+            }
+        }
+    }
     for run in &l.runs {
         if (run.alpha <= 0.0 || run.color.a == 0) && run.outline.is_none() {
             continue;
@@ -1176,6 +1199,49 @@ fn line_bounds(li: &deckcraft_text::LineInfo) -> Option<Rect> {
     (r.is_finite() && r.width() > 0.0 && r.height() > 0.0).then_some(r)
 }
 
+#[derive(Clone, Copy, PartialEq)]
+enum TextEffect {
+    Shadow,
+    Glow,
+}
+
+/// Draw `run`'s shadow or glow (if it has one) under its glyphs, placed by `m`.
+fn text_effect(ctx: &mut RenderContext, run: &deckcraft_text::GlyphRun, which: TextEffect, m: Affine, opacity: f64) {
+    let Some(fx) = run.effects else { return };
+    let k = run.size / run.face.upem.max(1.0);
+    let skew = if run.fake_italic { Affine::new([1.0, 0.0, -0.2, 1.0, 0.0, 0.0]) } else { Affine::IDENTITY };
+    let px = scale_of(m);
+    let (c, sigma, offset, grow) = match (which, fx.shadow, fx.glow) {
+        (TextEffect::Shadow, Some(s), _) => (s.color, s.blur * 0.5 * px, Vec2::new(s.dx, s.dy), 0.0),
+        // Measured on PowerPoint's export: a text glow of radius r is solid to about a third of r
+        // past the glyph's edge and fades out by about two thirds of r.
+        (TextEffect::Glow, _, Some((gc, r))) => (gc, r * 0.15 * px, Vec2::ZERO, r * 0.68),
+        _ => return,
+    };
+    let alpha = (c.a as f64 / 255.0) * opacity;
+    if alpha <= 0.0 {
+        return;
+    }
+    ctx.set_transform(Affine::IDENTITY);
+    ctx.push_layer(None, None, Some(alpha as f32), None, Some(blur(sigma)));
+    ctx.set_paint(color(c.with_alpha(255), 1.0));
+    for (gid, x, y) in &run.glyphs {
+        let path = glyph(&run.face, *gid);
+        if path.elements().is_empty() {
+            continue;
+        }
+        // The offset is in slide space: a shadow falls the same way whatever the text's rotation.
+        let at = pre_translate(m * Affine::translate((*x, *y)), offset * px) * skew * Affine::scale(k);
+        ctx.set_transform(at);
+        ctx.fill_path(&path);
+        if grow > 0.0 {
+            ctx.set_stroke(kurbo::Stroke::new(grow / k.max(1e-9)).with_join(kurbo::Join::Round));
+            ctx.stroke_path(&path);
+        }
+    }
+    ctx.pop_layer();
+}
+
 /// Draw glyph `gid` of `run` with its origin (on the baseline) mapped by `at`, faded by `opacity`.
 pub(crate) fn draw_glyph(ctx: &mut RenderContext, run: &deckcraft_text::GlyphRun, gid: u32, at: Affine, opacity: f64) {
     draw_glyph_with(ctx, run, gid, at, opacity, None);

crates/render/src/tests.rs

@@ -701,3 +701,52 @@ fn a_text_gradient_starts_over_on_every_line() {
         assert!(bottom(band) > 150, "line {band:?} ends at {}", bottom(band));
     }
 }
+
+/// A text box of big black "IIII" with `set` applied to its run.
+fn effect_text(set: impl Fn(&mut deckcraft_model::text::RunProps)) -> Presentation {
+    let mut sh = Shape { id: ShapeId(740), xfrm: Some(Xfrm::new(100.0, 100.0, 600.0, 300.0)), text_box: true, ..Default::default() };
+    let mut t = TextBody::from_text("IIII");
+    let props = &mut t.paragraphs[0].runs[0].props;
+    props.size = Some(100.0);
+    props.fill = Some(deckcraft_model::style::Fill::solid(ColorRef::rgb(deckcraft_color::Rgba::rgb(0, 0, 0))));
+    set(props);
+    sh.text = Some(t);
+    deck_with(vec![sh])
+}
+
+#[test]
+fn text_glow_and_shadow_are_drawn() {
+    let count = |img: &Image, f: &dyn Fn(&[u8; 4]) -> bool| img.pixels.as_chunks::<4>().0.iter().filter(|px| f(px)).count();
+    let green = |p: &[u8; 4]| p[1] > 150 && p[0] < 120 && p[2] < 120;
+    let plain = effect_text(|_| {});
+    assert!(!needs_filters(&plain, &plain.slides[0]));
+    let img = render_slide(&plain, 0, &RenderOpts { scale: 1.0, ..Default::default() });
+    assert_eq!(count(&img, &green), 0);
+    // Glow: a green halo hugging the letters, needing the blur filter.
+    let glow =
+        effect_text(|p| p.glow = Some(deckcraft_model::style::Glow { color: ColorRef::rgb(deckcraft_color::Rgba::rgb(0, 255, 0)), radius: 8.0 }));
+    assert!(needs_filters(&glow, &glow.slides[0]), "text glow blurs");
+    let img = render_slide(&glow, 0, &RenderOpts { scale: 1.0, threads: 4, ..Default::default() });
+    let halo = count(&img, &green);
+    assert!(halo > 300, "green halo pixels {halo}");
+    // Shadow: grey ink below and right of the letters, where the plain text has none.
+    let shadow = effect_text(|p| {
+        p.shadow = Some(deckcraft_model::style::Shadow {
+            color: ColorRef::rgb(deckcraft_color::Rgba { r: 0, g: 0, b: 0, a: 128 }),
+            blur: 2.0,
+            dist: 12.0,
+            dir: 45.0,
+            inner: false,
+            sx: 1.0,
+            sy: 1.0,
+            kx: 0.0,
+            ky: 0.0,
+            align: String::new(),
+            rotate_with_shape: false,
+        })
+    });
+    let img = render_slide(&shadow, 0, &RenderOpts { scale: 1.0, threads: 4, ..Default::default() });
+    let base = render_slide(&plain, 0, &RenderOpts { scale: 1.0, ..Default::default() });
+    let grey = |p: &[u8; 4]| p[0] > 60 && p[0] < 230 && p[0] == p[1] && p[1] == p[2];
+    assert!(count(&img, &grey) > count(&base, &grey) + 300, "a grey shadow appears");
+}

crates/text/src/lib.rs

@@ -57,6 +57,25 @@ pub struct GlyphRun {
     /// Alpha of the fill (0–1).
     pub alpha: f64,
     pub gradient: Option<deckcraft_model::style::Gradient>,
+    /// Shadow and glow behind the glyphs (`a:rPr/a:effectLst`).
+    pub effects: Option<RunEffects>,
+}
+
+/// A text run's shadow and glow, colours resolved.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub struct RunEffects {
+    pub shadow: Option<TextShadow>,
+    /// Glow colour (with its alpha) and radius in points.
+    pub glow: Option<(Rgba, f64)>,
+}
+
+/// An outer shadow: colour (with its alpha), blur radius and offset in points.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub struct TextShadow {
+    pub color: Rgba,
+    pub blur: f64,
+    pub dx: f64,
+    pub dy: f64,
 }
 
 impl std::fmt::Debug for GlyphRun {
@@ -174,6 +193,7 @@ struct Style {
     outline: Option<(Rgba, f64)>,
     link: bool,
     gradient: Option<deckcraft_model::style::Gradient>,
+    effects: Option<RunEffects>,
     /// "Regular", "Bold"… for the slot and fallback faces.
     style_name: &'static str,
     /// BCP 47 language (`a:rPr/@lang`), for shaping.
@@ -288,6 +308,7 @@ fn make_style(ctx: &Ctx, r: &RunProps, scale: f64, prompt: Option<Rgba>) -> Styl
         outline,
         link: r.link.is_some(),
         gradient,
+        effects: run_effects(ctx, r, scale),
         style_name: style_name(bold, italic),
         lang: r.lang.clone().filter(|l| !l.is_empty()),
         ea,
@@ -471,9 +492,7 @@ fn shape_para(ctx: &Ctx, shape: &Shape, body: &TextBody, pi: usize, scale: f64,
                 st.baseline = 0.0;
                 // Symbol fonts (Wingdings) aren't available: map common private-use bullets.
                 let ch = map_symbol_bullet(char, props.bullet_font.as_deref());
-                if !st.face.covers(ch.chars().next().unwrap_or('•')) {
-                    st.face = db.face("Inter", "Regular");
-                }
+                bullet_face(db, &mut st, &ch);
                 Some((ch, st))
             }
             Some(Bullet::AutoNum { scheme, start_at }) => {
@@ -483,8 +502,10 @@ fn shape_para(ctx: &Ctx, shape: &Shape, body: &TextBody, pi: usize, scale: f64,
                 }
                 rp.size = Some(lead.size.unwrap_or(18.0) * props.bullet_size.unwrap_or(1.0));
                 rp.underline = None;
-                let st = make_style(ctx, &rp, scale, opts.prompt_color);
-                Some((autonum(scheme, start_at.saturating_sub(1).saturating_add(number.unwrap_or(1))), st))
+                let mut st = make_style(ctx, &rp, scale, opts.prompt_color);
+                let label = autonum(scheme, start_at.saturating_sub(1).saturating_add(number.unwrap_or(1)));
+                bullet_face(db, &mut st, &label);
+                Some((label, st))
             }
             _ => None,
         }
@@ -492,8 +513,27 @@ fn shape_para(ctx: &Ctx, shape: &Shape, body: &TextBody, pi: usize, scale: f64,
     ParaShaped { cells, styles, faces, props, lead_size, lead_face, bullet, level: para.level, rtl }
 }
 
+/// A face that draws the bullet `label` when the bullet's own can't (circled numbers ①, arrows
+/// and other symbols missing from the text font), by the usual fallback.
+fn bullet_face(db: &FontDb, st: &mut Style, label: &str) {
+    let chars: Vec<char> = label.chars().collect();
+    if !chars.is_empty() && !deckcraft_fonts::covers_cluster(&st.face, &chars) {
+        st.face = db.cascade(&chars, std::slice::from_ref(&st.face), st.style_name);
+    }
+}
+
 /// Shape a logical paragraph into cells: bidi levels, per-grapheme faces, items of one level,
 /// script, face and shaping style, each shaped with the whole paragraph as context.
+/// A run's outer shadow and glow (inner shadows aren't drawn on text), at the layout's `scale`.
+fn run_effects(ctx: &Ctx, r: &RunProps, scale: f64) -> Option<RunEffects> {
+    let shadow = r.shadow.as_ref().filter(|s| !s.inner).map(|s| {
+        let a = s.dir.to_radians();
+        TextShadow { color: ctx.color(&s.color, None), blur: s.blur.max(0.0) * scale, dx: a.cos() * s.dist * scale, dy: a.sin() * s.dist * scale }
+    });
+    let glow = r.glow.as_ref().filter(|g| g.radius > 0.0).map(|g| (ctx.color(&g.color, None), g.radius * scale));
+    (shadow.is_some() || glow.is_some()).then_some(RunEffects { shadow, glow })
+}
+
 fn shape_cells(ctx: &Ctx, text: &str, char_style: &[usize], styles: &[Style], faces: &mut Vec<Arc<FontFace>>, rtl: bool) -> Vec<Cell> {
     let db = FontDb::global();
     let chars: Vec<char> = text.chars().collect();
@@ -1231,6 +1271,7 @@ fn layout_scaled(ctx: &Ctx, shape: &Shape, body: &TextBody, bp: &BodyProps, opts
                 link: false,
                 alpha: st.alpha,
                 gradient: None,
+                effects: None,
             });
         }
         // Group visually consecutive cells by (style, face).
@@ -1264,6 +1305,7 @@ fn layout_scaled(ctx: &Ctx, shape: &Shape, body: &TextBody, bp: &BodyProps, opts
                     link: st.link,
                     alpha: st.alpha,
                     gradient: st.gradient.clone(),
+                    effects: st.effects,
                 });
                 cur_key = key;
             }

crates/text/src/tests.rs

@@ -602,3 +602,25 @@ fn emoji_take_a_colour_face_when_one_is_installed() {
         assert!(l.runs.iter().filter(|r| r.cells.iter().all(|(_, c)| c.is_ascii())).all(|r| !r.face.is_color()), "the letters keep a text face");
     }
 }
+
+#[test]
+fn a_bullet_the_text_font_lacks_falls_back_to_a_face_that_has_it() {
+    // circleNumDbPlain numbers ①②…: the text font usually has no circled digits; PowerPoint draws
+    // them from a fallback font instead of a missing-glyph box. Skipped when no installed or
+    // bundled face has ①.
+    let db = FontDb::global();
+    if !db.cascade(&['①'], &[], "Regular").covers('①') {
+        return;
+    }
+    let (p, mut sh) = setup("One\nTwo", 600.0, 300.0);
+    for para in &mut sh.text.as_mut().unwrap().paragraphs {
+        para.props.bullet = Some(Bullet::AutoNum { scheme: "circleNumDbPlain".into(), start_at: 1 });
+    }
+    let l = lay(&p, &sh, 600.0, 300.0);
+    let bullets: Vec<_> = l.runs.iter().filter(|r| r.cells.is_empty()).collect();
+    assert_eq!(bullets.len(), 2);
+    for b in bullets {
+        assert!(b.face.covers('①'), "drawn with {}, which lacks the circled digit", b.face.family);
+        assert!(b.glyphs.iter().all(|g| g.0 != 0), "no missing-glyph box");
+    }
+}