core: Fix avm2 button bounding box when using scroll rects

core/src/display_object.rs

@@ -1153,7 +1153,7 @@ pub trait TDisplayObject<'gc>:
     /// the overall AABB.
     fn bounds_with_transform(&self, matrix: &Matrix) -> Rectangle<Twips> {
         // A scroll rect completely overrides an object's bounds,
-        // and can even the bounding box to be larger than the actual content
+        // and can even grow the bounding box to be larger than the actual content
         if let Some(scroll_rect) = self.scroll_rect() {
             return *matrix
                 * Rectangle {

core/src/display_object/avm2_button.rs

@@ -620,8 +620,17 @@ impl<'gc> TDisplayObject<'gc> for Avm2Button<'gc> {
     }
 
     fn bounds_with_transform(&self, matrix: &Matrix) -> Rectangle<Twips> {
-        // [NA]: The diff between this and the base impl is a lack of scroll_rect.
+        // A scroll rect completely overrides an object's bounds,
-        // Intentional, or bug?
+        // and can even grow the bounding box to be larger than the actual content
+        if let Some(scroll_rect) = self.scroll_rect() {
+            return *matrix
+                * Rectangle {
+                    x_min: Twips::ZERO,
+                    y_min: Twips::ZERO,
+                    x_max: scroll_rect.width(),
+                    y_max: scroll_rect.height(),
+                };
+        }
 
         // Get self bounds
         let mut bounds = *matrix * self.self_bounds();

tests/tests/swfs/visual/avm2_button_scroll_rect/output.txt

@@ -0,0 +1,2 @@
+frame 1: (x=0, y=0, w=100, h=100)
+frame 2: (x=0, y=0, w=100, h=100)

tests/tests/swfs/visual/avm2_button_scroll_rect/test.toml

@@ -0,0 +1,8 @@
+num_ticks = 3
+
+[image_comparisons.output]
+tolerance = 0
+
+[player_options]
+# Visual test will test the render bounds, whereas output test does the "normal" bounds
+with_renderer = { optional = true, sample_count = 1 }