text: Allow small shear when displaying device text

core/src/display_object/edit_text.rs

@@ -2672,7 +2672,12 @@ impl<'gc> TDisplayObject<'gc> for EditText<'gc> {
 
         fn is_transform_positive_scale_only(context: &mut RenderContext) -> bool {
             let Matrix { a, b, c, d, .. } = context.transform_stack.transform().matrix;
-            b == 0.0 && c == 0.0 && a > 0.0 && d > 0.0
+            // Flash does allow small shear. The following value is higher than
+            // expected due to the fact that the final calculated shear differs
+            // between Flash and Ruffle, and using a precise value would hide
+            // some objects that should otherwise be shown.
+            const ALLOWED_SHEAR: f32 = 0.006;
+            b.abs() < ALLOWED_SHEAR && c.abs() < ALLOWED_SHEAR && a > 0.0 && d > 0.0
         }
 
         // EditText is not rendered if device font is used

tests/tests/swfs/visual/edittext/edittext_device_transform_small_rotation/test.as

@@ -0,0 +1,35 @@
+Stage.scaleMode = "noScale";
+
+function renderField(mc, x, y, w, h, r) {
+    var tf = mc.createTextField(
+            "field_" + x + "_" + y,
+            mc.getNextHighestDepth(),
+            0, 0, 1, 1);
+    tf._x = x;
+    tf._y = y;
+    tf._width = w;
+    tf._height = h;
+    tf._rotation = r;
+    tf.borderColor = 0xFF00FF;
+    tf.backgroundColor = 0x0000FF;
+    tf.border = true;
+    tf.background = false;
+    tf.embedFonts = false;
+}
+
+renderField(_root, 10, 10, 10, 10, 0);
+renderField(_root, 30, 10, 10, 10, 0.0001);
+renderField(_root, 50, 10, 10, 10, 0.001);
+renderField(_root, 10, 30, 10, 10, 0.01);
+renderField(_root, 30, 30, 10, 10, 0.2);
+renderField(_root, 50, 30, 10, 10, 0.3);
+
+var mc = _root.createEmptyMovieClip("inner", _root.getNextHighestDepth());
+mc._rotation = 0.1;
+mc._x = 0;
+mc._y = 35;
+renderField(mc, 10, 10, 10, 10, 0);
+renderField(mc, 30, 10, 10, 10, 0.0001);
+renderField(mc, 50, 10, 10, 10, 0.001);
+renderField(mc, 10, 30, 10, 10, 0.01);
+renderField(mc, 30, 30, 10, 10, 0.2);

tests/tests/swfs/visual/edittext/edittext_device_transform_small_rotation/test.toml

@@ -0,0 +1,8 @@
+num_ticks = 1
+
+[image_comparisons."output"]
+trigger = 1
+max_outliers = 11
+
+[player_options]
+with_renderer = { optional = false, sample_count = 4 }

tests/tests/swfs/visual/edittext/edittext_device_transform_small_shear/test.as

@@ -0,0 +1,89 @@
+Stage.scaleMode = "noScale";
+
+var nextX = 10;
+var nextY = 30;
+
+function renderField(mc, a, b, c, d) {
+    var x = nextX;
+    var y = nextY;
+    var mc2 = mc.createEmptyMovieClip("mc_" + x + "_" + y, mc.getNextHighestDepth());
+    mc2.transform.matrix = new flash.geom.Matrix(a, b, c, d, x, y);
+
+    var tf = mc2.createTextField(
+            "field_" + x + "_" + y,
+            mc2.getNextHighestDepth(),
+            0, 0, 5, 5);
+    tf.borderColor = 0xFF00FF;
+    tf.backgroundColor = 0x0000FF;
+    tf.border = true;
+    tf.background = false;
+    tf.embedFonts = false;
+
+    var tf = mc2.createTextField(
+            "field_" + x + "_" + y + "_2",
+            mc2.getNextHighestDepth(),
+            7, 0, 8, 5);
+    tf.borderColor = 0xFF00FF;
+    tf.backgroundColor = 0x0000FF;
+    tf.border = true;
+    tf.background = false;
+    tf.embedFonts = false;
+
+    var tf = mc2.createTextField(
+            "field_" + x + "_" + y + "_3",
+            mc2.getNextHighestDepth(),
+            0, 7, 15, 8);
+    tf.borderColor = 0xFF00FF;
+    tf.backgroundColor = 0x0000FF;
+    tf.border = true;
+    tf.background = false;
+    tf.embedFonts = false;
+
+    nextX += 40;
+}
+
+renderField(_root, 1, 0, 0, 1);
+renderField(_root, 1, 0.00488281273, 0, 1);
+renderField(_root, 1, 0, 0.00488281273, 1);
+renderField(_root, 1, 0.00488281273, 0.00488281273, 1);
+
+nextX = 10;
+nextY = 50;
+
+renderField(_root, 1, 0, 0, 1);
+renderField(_root, 1, -0.00488281273, 0, 1);
+renderField(_root, 1, 0, -0.00488281273, 1);
+renderField(_root, 1, -0.00488281273, -0.00488281273, 1);
+
+nextX = 10;
+nextY = 70;
+
+renderField(_root, 2, 0, 0, 2);
+renderField(_root, 2, 0.00488281273, 0, 2);
+renderField(_root, 2, 0, 0.00488281273, 2);
+renderField(_root, 2, 0.00488281273, 0.00488281273, 2);
+
+nextX = 10;
+nextY = 120;
+
+renderField(_root, 2, 0, 0, 2);
+renderField(_root, 2, -0.00488281273, 0, 2);
+renderField(_root, 2, 0, -0.00488281273, 2);
+renderField(_root, 2, -0.00488281273, -0.00488281273, 2);
+
+nextX = 10;
+nextY = 170;
+
+var mc = _root.createEmptyMovieClip("outer", _root.getNextHighestDepth());
+mc.transform.matrix = new flash.geom.Matrix(1, 500.001, 0, 1, nextX, nextY);
+var mc2 = mc.createEmptyMovieClip("inner", mc.getNextHighestDepth());
+mc2.transform.matrix = new flash.geom.Matrix(1, -500, 0, 1, 0, 0);
+var tf = mc2.createTextField(
+        "field_inner",
+        mc2.getNextHighestDepth(),
+        0, 0, 10, 10);
+tf.borderColor = 0xFF00FF;
+tf.backgroundColor = 0x0000FF;
+tf.border = true;
+tf.background = false;
+tf.embedFonts = false;

tests/tests/swfs/visual/edittext/edittext_device_transform_small_shear/test.toml

@@ -0,0 +1,8 @@
+num_ticks = 1
+
+[image_comparisons."output"]
+trigger = 1
+max_outliers = 50
+
+[player_options]
+with_renderer = { optional = false, sample_count = 4 }