Added toImage method (#661)

CHANGELOG.md

@@ -21,6 +21,7 @@
  - Add assertion to make sure Draggables are safe to add
  - Add utility methods to the Anchor class to make it more "enum like"
  - Enable user-defined anchors
+ - Added `toImage` method for the `Sprite` class
 
 ## 1.0.0-rc6
  - Use `Offset` type directly in `JoystickAction.update` calculations

lib/image_composition.dart

@@ -39,6 +39,8 @@ class _Composed {
 }
 
 /// The [ImageComposition] allows for composing multiple images onto a single image.
+///
+/// **Note:** Composing images is a heavy async operation and should not be called on each [Game.render].
 class ImageComposition {
   /// The values that will be used to compose the image
   final List<_Composed> _composes = [];

lib/src/extensions/vector2.dart

@@ -15,6 +15,13 @@ extension Vector2Extension on Vector2 {
   /// Creates a [Point] from the [Vector2]
   Point toPoint() => Point(x, y);
 
+  /// A rectangle constructor operator.
+  ///
+  /// Combines two [Vector2]s to form a Rect whose top-left coordinate is the
+  /// point given by adding this vector, the left-hand-side operand,
+  /// to the origin, and whose size is the right-hand-side operand.
+  Rect operator &(Vector2 size) => toPositionedRect(size);
+
   /// Creates a [Rect] starting from [x, y] and having the size of the
   /// argument [Vector2]
   Rect toPositionedRect(Vector2 size) => Rect.fromLTWH(x, y, size.x, size.y);

lib/src/sprite.dart

@@ -1,5 +1,6 @@
 import 'dart:ui';
 
+import '../image_composition.dart';
 import 'anchor.dart';
 import 'extensions/offset.dart';
 import 'extensions/vector2.dart';
@@ -76,4 +77,13 @@ class Sprite {
 
     canvas.drawImageRect(image, src, drawRect, drawPaint);
   }
+
+  /// Return a new Image based on the [src] of the Sprite.
+  ///
+  /// **Note:** This is a heavy async operation and should not be called on each [Game.render].
+  Future<Image> toImage() async {
+    final composition = ImageComposition()
+      ..add(image, Vector2.zero(), source: src);
+    return composition.compose();
+  }
 }