avm1: Implement Matrix.deltaTransformPoint

core/src/avm1/globals/matrix.rs

@@ -358,6 +358,23 @@ fn transform_point<'gc>(
     Ok(object.into())
 }
 
+fn delta_transform_point<'gc>(
+    activation: &mut Activation<'_, 'gc, '_>,
+    this: Object<'gc>,
+    args: &[Value<'gc>],
+) -> Result<Value<'gc>, Error<'gc>> {
+    let matrix = object_to_matrix(this, activation)?;
+    let point = value_to_point(
+        args.get(0).unwrap_or(&Value::Undefined).to_owned(),
+        activation,
+    )?;
+
+    let x = point.0 * matrix.a as f64 + point.1 * matrix.c as f64;
+    let y = point.0 * matrix.b as f64 + point.1 * matrix.d as f64;
+    let object = point_to_object((x, y), activation)?;
+    Ok(object.into())
+}
+
 fn to_string<'gc>(
     activation: &mut Activation<'_, 'gc, '_>,
     this: Object<'gc>,
@@ -481,5 +498,13 @@ pub fn create_proto<'gc>(
         Some(fn_proto),
     );
 
+    object.force_set_function(
+        "deltaTransformPoint",
+        delta_transform_point,
+        gc_context,
+        EnumSet::empty(),
+        Some(fn_proto),
+    );
+
     object.into()
 }

core/tests/swfs/avm1/matrix/output.txt

@@ -160,3 +160,14 @@ false
 (x=18, y=23)
 
 
+/// deltaTransformPoint
+// matrix = new Matrix(2, 3, 5, 7, 11, 13);
+(a=2, b=3, c=5, d=7, tx=11, ty=13)
+
+// matrix.deltaTransformPoint();
+(x=NaN, y=NaN)
+
+// matrix.deltaTransformPoint(new Point(1, 1));
+(x=7, y=10)
+
+