fix: [#2421] Match Screenshot AA with Screen

CHANGELOG.md

@@ -20,6 +20,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 ### Fixed
 
+- Fixed issue where screenshots from `ex.Engine.screenshot()` did not match the smoothing set on the engine.
 - Fixed incorrect event type returned when `ex.Actor.on('postupdate', (event) => {...})`.
 - Fixed issue where using numerous `ex.Text` instances would cause Excalibur to crash webgl by implementing a global font cache.
 - Fixed issue where child entities did not inherit the scene from their parent

src/engine/Engine.ts

@@ -1461,6 +1461,7 @@ O|===|* >________________>\n\
       screenshot.width = finalWidth;
       screenshot.height = finalHeight;
       const ctx = screenshot.getContext('2d');
+      ctx.imageSmoothingEnabled = this.screen.antialiasing;
       ctx.drawImage(this.canvas, 0, 0, finalWidth, finalHeight);
 
       const result = new Image();

src/spec/EngineSpec.ts

@@ -1,7 +1,6 @@
 import * as ex from '@excalibur';
 import { TestUtils } from './util/TestUtils';
 import { ExcaliburAsyncMatchers, ExcaliburMatchers } from 'excalibur-jasmine';
-import { Engine } from '@excalibur';
 
 /**
  *
@@ -722,6 +721,36 @@ describe('The engine', () => {
     await expectAsync(hidpiImage).toEqualImage(flushWebGLCanvasTo2D(engine.canvas));
   });
 
+  it('can screen shot and match the anti-aliasing with a half pixel when pixelRatio != 1.0', async () => {
+    const engine = TestUtils.engine({
+      width: 200,
+      height: 200,
+      pixelRatio: 1.2,
+      suppressHiDPIScaling: false,
+      antialiasing: false,
+      snapToPixel: false
+    }, []);
+    const clock = engine.clock as ex.TestClock;
+    const img = new ex.ImageSource('src/spec/images/EngineSpec/sprite.png');
+    await img.load();
+    const actor = new ex.Actor({
+      x: 40.5,
+      y: 40.0,
+      scale: ex.vec(2, 2)
+    });
+    actor.graphics.use(img.toSprite());
+    engine.add(actor);
+    TestUtils.runToReady(engine);
+
+    clock.step(1);
+    const screenShotPromise = engine.screenshot();
+    clock.step(1);
+
+    const image = await screenShotPromise;
+
+    await expectAsync(image).toEqualImage('src/spec/images/EngineSpec/screenshot.png', 1.0);
+  });
+
   describe('lifecycle overrides', () => {
     let engine: ex.Engine;
     beforeEach(() => {