Panic hardening of ab-glyph (#64)

* Panic hardening of ab-glyph
PolyMeilex · Jul 2, 2024 · 83b5673 · 83b5673
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,4 +1,5 @@
 ## [Unreleased]
+- Panic hardening of ab-glyph (#64)
 
 ## 0.10.0
 - Bump sctk to 0.19

diff --git a/src/title/ab_glyph_renderer.rs b/src/title/ab_glyph_renderer.rs
@@ -96,20 +96,26 @@ impl AbGlyphTitleText {
                 let top = bounds.min.y as u32;
                 outline.draw(|x, y, c| {
                     // `ab_glyph` may return values greater than 1.0, but they are defined to be
-                    // same as 1.0. For our purposes, we need to contrain this value.
+                    // same as 1.0. For our purposes, we need to constrain this value.
                     let c = c.min(1.0);
 
                     // offset the index by 1, so it is in the center of the pixmap
                     let p_idx = (top + y + 1) * width + (left + x + 1);
-                    let old_alpha_u8 = pixels[p_idx as usize].alpha();
+                    let Some(pixel) = pixels.get_mut(p_idx as usize) else {
+                        log::warn!("Ignoring out of range pixel (pixel id: {p_idx}");
+                        return;
+                    };
+
+                    let old_alpha_u8 = pixel.alpha();
+
                     let new_alpha = c + (old_alpha_u8 as f32 / 255.0);
                     if let Some(px) = PremultipliedColorU8::from_rgba(
                         (self.color.red() * new_alpha * 255.0) as _,
                         (self.color.green() * new_alpha * 255.0) as _,
                         (self.color.blue() * new_alpha * 255.0) as _,
                         (new_alpha * 255.0) as _,
                     ) {
-                        pixels[p_idx as usize] = px;
+                        *pixel = px;
                     }
                 })
             }