avm1: Correct `TextFormat` properties coercion

core/src/avm1/globals/text_format.rs

@@ -88,8 +88,7 @@ fn set_size<'gc>(
 ) -> Result<(), Error<'gc>> {
     text_format.size = match value {
         Value::Undefined | Value::Null => None,
-        // TODO: round up
+        value => Some(round_to_i32(value.coerce_to_f64(activation)?).into()),
-        value => Some(value.coerce_to_i32(activation)?.into()),
     };
     Ok(())
 }
@@ -233,7 +232,7 @@ fn set_align<'gc>(
             "center" => Some(swf::TextAlign::Center),
             "right" => Some(swf::TextAlign::Right),
             "justify" => Some(swf::TextAlign::Justify),
-            _ => None,
+            _ => return Ok(()),
         },
     };
     Ok(())
@@ -256,8 +255,7 @@ fn set_left_margin<'gc>(
 ) -> Result<(), Error<'gc>> {
     text_format.left_margin = match value {
         Value::Undefined | Value::Null => None,
-        // TODO: round up
+        value => Some(round_to_i32(value.coerce_to_f64(activation)?.max(0.0)).into()),
-        value => Some(value.coerce_to_i32(activation)?.into()),
     };
     Ok(())
 }
@@ -279,8 +277,7 @@ fn set_right_margin<'gc>(
 ) -> Result<(), Error<'gc>> {
     text_format.right_margin = match value {
         Value::Undefined | Value::Null => None,
-        // TODO: round up
+        value => Some(round_to_i32(value.coerce_to_f64(activation)?.max(0.0)).into()),
-        value => Some(value.coerce_to_i32(activation)?.into()),
     };
     Ok(())
 }
@@ -299,8 +296,7 @@ fn set_indent<'gc>(
 ) -> Result<(), Error<'gc>> {
     text_format.indent = match value {
         Value::Undefined | Value::Null => None,
-        // TODO: round up
+        value => Some(round_to_i32(value.coerce_to_f64(activation)?).into()),
-        value => Some(value.coerce_to_i32(activation)?.into()),
     };
     Ok(())
 }
@@ -319,8 +315,7 @@ fn set_leading<'gc>(
 ) -> Result<(), Error<'gc>> {
     text_format.leading = match value {
         Value::Undefined | Value::Null => None,
-        // TODO: round up
+        value => Some(round_to_i32(value.coerce_to_f64(activation)?).into()),
-        value => Some(value.coerce_to_i32(activation)?.into()),
     };
     Ok(())
 }
@@ -342,8 +337,7 @@ fn set_block_indent<'gc>(
 ) -> Result<(), Error<'gc>> {
     text_format.block_indent = match value {
         Value::Undefined | Value::Null => None,
-        // TODO: round up
+        value => Some(round_to_i32(value.coerce_to_f64(activation)?).into()),
-        value => Some(value.coerce_to_i32(activation)?.into()),
     };
     Ok(())
 }
@@ -376,8 +370,7 @@ fn set_tab_stops<'gc>(
             let tab_stops: Result<Vec<_>, Error<'gc>> = (0..length)
                 .map(|i| {
                     let element = object.get_element(activation, i);
-                    // TODO: round up
+                    Ok(round_to_i32(element.coerce_to_f64(activation)?).into())
-                    Ok(element.coerce_to_i32(activation)?.into())
                 })
                 .collect();
             Some(tab_stops?)
@@ -551,3 +544,23 @@ pub fn create_proto<'gc>(
     define_properties_on(PROTO_DECLS, gc_context, object, fn_proto);
     text_format.into()
 }
+
+/// Implements the IEEE-754 "Round to nearest, ties to even" rounding rule.
+/// (e.g., both 1.5 and 2.5 will round to 2).
+/// This is the rounding method used by Flash for the above coercions.
+/// Although this is easy to do on most architectures, Rust provides no standard
+/// way to round in this manner (`f64::round` always rounds away from zero).
+/// For more info and the below code snippet, see: https://github.com/rust-lang/rust/issues/55107
+/// This also clamps out-of-range values and NaN to `i32::MIN`.
+/// TODO: Investigate using SSE/wasm intrinsics for this.
+fn round_to_i32(x: f64) -> i32 {
+    let k = 1.0 / f64::EPSILON;
+    let a = x.abs();
+    let out = if a < k { ((a + k) - k).copysign(x) } else { x };
+    // Values outside of i32 range get clamped to i32::MIN.
+    if out.is_finite() && out >= i32::MIN.into() && out <= i32::MAX.into() {
+        out as i32
+    } else {
+        i32::MIN
+    }
+}

tests/tests/regression_tests.rs

@@ -324,6 +324,7 @@ swf_tests! {
     (textfield_background_color, "avm1/textfield_background_color", 1),
     (textfield_border_color, "avm1/textfield_border_color", 1),
     (textfield_variable, "avm1/textfield_variable", 8),
+    (text_format, "avm1/text_format", 1),
     (error, "avm1/error", 1),
     (color_transform, "avm1/color_transform", 1),
     (with, "avm1/with", 1),