diff options
Diffstat (limited to 'components/script/dom/intersectionobserver.rs')
| -rw-r--r-- | components/script/dom/intersectionobserver.rs | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/components/script/dom/intersectionobserver.rs b/components/script/dom/intersectionobserver.rs index ec98116d3a4..6a6f9ce45eb 100644 --- a/components/script/dom/intersectionobserver.rs +++ b/components/script/dom/intersectionobserver.rs @@ -524,11 +524,10 @@ impl IntersectionObserver { // Step 9 // > Let targetArea be targetRect’s area. - let target_area = target_rect.size.width.0 * target_rect.size.height.0; - // Step 10 // > Let intersectionArea be intersectionRect’s area. - let intersection_area = intersection_rect.size.width.0 * intersection_rect.size.height.0; + // These steps are folded in Step 12, rewriting (w1 * h1) / (w2 * h2) as (w1 / w2) * (h1 / h2) + // to avoid multiplication overflows. // Step 11 // > Let isIntersecting be true if targetRect and rootBounds intersect or are edge-adjacent, @@ -545,9 +544,12 @@ impl IntersectionObserver { // Step 12 // > If targetArea is non-zero, let intersectionRatio be intersectionArea divided by targetArea. // > Otherwise, let intersectionRatio be 1 if isIntersecting is true, or 0 if isIntersecting is false. - let intersection_ratio = match target_area { - 0 => is_intersecting.into(), - _ => (intersection_area as f64) / (target_area as f64), + let intersection_ratio = if target_rect.size.width.0 == 0 || target_rect.size.height.0 == 0 + { + is_intersecting.into() + } else { + (intersection_rect.size.width.0 as f64 / target_rect.size.width.0 as f64) * + (intersection_rect.size.height.0 as f64 / target_rect.size.height.0 as f64) }; // Step 13 |