refactor!: Extract TextRendererFactory (#2680)

This is part of my ongoing effort to simplify the text rendering
pipeline.
My ultimate goal is to:
* get rid of renders
* rename formatters to renderers
* make the interface complies to both
All details are specified here:
#2663

As a first step to break down that huge PR, this extracts
TextRendererFactory in preparation of getting rid of TextRenderer
entirely.

This is technically a breaking change but should have no effect for
users, unless you they have a custom Renderer *and* are using the
registry (which I honestly doubt). But if you are:
* just import TextRendererFactory and use the createDefault method from
there instead

packages/flame/lib/src/components/text_component.dart

@@ -1,8 +1,7 @@
 import 'dart:ui';
 
 import 'package:flame/components.dart';
-import 'package:flame/src/text/elements/text_element.dart';
-import 'package:flame/src/text/text_renderer.dart';
+import 'package:flame/text.dart';
 import 'package:flutter/painting.dart';
 import 'package:meta/meta.dart';
 
@@ -19,7 +18,7 @@ class TextComponent<T extends TextRenderer> extends PositionComponent {
     super.priority,
     super.key,
   })  : _text = text ?? '',
-        _textRenderer = textRenderer ?? TextRenderer.createDefault<T>() {
+        _textRenderer = textRenderer ?? TextRendererFactory.createDefault<T>() {
     updateBounds();
   }
 

packages/flame/lib/src/text/text_renderer.dart

@@ -41,25 +41,4 @@ class TextRenderer<T extends TextFormatter> {
   }) {
     format(text).render(canvas, position, anchor: anchor);
   }
-
-  /// A registry containing default providers for every [TextRenderer] subclass;
-  /// used by [createDefault] to create default parameter values.
-  ///
-  /// If you add a new [TextRenderer] child, you can register it by adding it,
-  /// together with a provider lambda, to this map.
-  static Map<Type, TextRenderer Function()> defaultRenderersRegistry = {
-    TextRenderer: TextPaint.new,
-    TextPaint: TextPaint.new,
-  };
-
-  /// Given a generic type [T], creates a default renderer of that type.
-  static T createDefault<T extends TextRenderer>() {
-    final creator = defaultRenderersRegistry[T];
-    if (creator != null) {
-      return creator() as T;
-    } else {
-      throw 'Unknown implementation of TextRenderer: $T. Please register it '
-          'under [defaultRenderersRegistry].';
-    }
-  }
 }

packages/flame/lib/src/text/text_renderer_factory.dart

@@ -0,0 +1,24 @@
+import 'package:flame/text.dart';
+
+class TextRendererFactory {
+  /// A registry containing default providers for every [TextRenderer] subclass;
+  /// used by [createDefault] to create default parameter values.
+  ///
+  /// If you add a new [TextRenderer] child, you can register it by adding it,
+  /// together with a provider lambda, to this map.
+  static Map<Type, TextRenderer Function()> defaultRegistry = {
+    TextRenderer: TextPaint.new,
+    TextPaint: TextPaint.new,
+  };
+
+  /// Given a generic type [T], creates a default renderer of that type.
+  static T createDefault<T extends TextRenderer>() {
+    final creator = defaultRegistry[T];
+    if (creator != null) {
+      return creator() as T;
+    } else {
+      throw 'Unknown implementation of TextRenderer: $T. Please register it '
+          'under [TextRendererFactory.defaultRegistry].';
+    }
+  }
+}

packages/flame/lib/text.dart

@@ -34,3 +34,4 @@ export 'src/text/styles/flame_text_style.dart' show FlameTextStyle;
 export 'src/text/styles/style.dart' show Style;
 export 'src/text/text_paint.dart' show TextPaint;
 export 'src/text/text_renderer.dart' show TextRenderer;
+export 'src/text/text_renderer_factory.dart' show TextRendererFactory;

packages/flame/test/text/text_renderer_test.dart

@@ -6,11 +6,11 @@ import 'package:test/test.dart';
 void main() {
   group('TextRenderer', () {
     test('createDefault', () {
-      final tp = TextRenderer.createDefault<TextPaint>();
+      final tp = TextRendererFactory.createDefault<TextPaint>();
       expect(tp, isNotNull);
       expect(tp, isA<TextPaint>());
 
-      final tr = TextRenderer.createDefault();
+      final tr = TextRendererFactory.createDefault();
       expect(tr, isNotNull);
       expect(tr, isA<TextRenderer>());
     });
@@ -24,7 +24,7 @@ void main() {
     });
 
     test('custom renderer', () {
-      TextRenderer.defaultRenderersRegistry[_CustomTextRenderer] =
+      TextRendererFactory.defaultRegistry[_CustomTextRenderer] =
           _CustomTextRenderer.new;
       final tc = TextComponent<_CustomTextRenderer>(text: 'foo');
       expect(tc.textRenderer, isA<_CustomTextRenderer>());