Revert "Try using pixelmatch for testing"

This reverts commit 2cb6a0a.

Author: davepagurek

package-lock.json

@@ -52,7 +52,6 @@
     "i18next-browser-languagedetector": "^4.0.1",
     "lint-staged": "^15.1.0",
     "msw": "^2.6.3",
-    "pixelmatch": "^6.0.0",
     "rollup": "^4.9.6",
     "rollup-plugin-string": "^3.0.0",
     "rollup-plugin-visualizer": "^5.12.0",

package.json

@@ -1,6 +1,5 @@
 import p5 from '../../../src/app.js';
 import { server } from '@vitest/browser/context'
-import pixelmatch from 'pixelmatch'
 import { THRESHOLD, DIFFERENCE, ERODE } from '../../../src/core/constants.js';
 const { readFile, writeFile } = server.commands
 
@@ -105,22 +104,39 @@ export async function checkMatch(actual, expected, p5) {
     );
   }
 
-  const diffData = actual.drawingContext.createImageData(actual.width, actual.height);
-  const diffCount = pixelmatch(
-    actual.drawingContext.getImageData(0, 0, actual.width, actual.height).data,
-    expected.drawingContext.getImageData(0, 0, actual.width, actual.height).data,
-    diffData.data,
-    actual.width,
-    actual.height,
-    { threshold: 0.4 }
-  );
+  const expectedWithBg = p5.createGraphics(expected.width, expected.height);
+  expectedWithBg.pixelDensity(1);
+  expectedWithBg.background(BG);
+  expectedWithBg.image(expected, 0, 0);
 
   const cnv = p5.createGraphics(actual.width, actual.height);
-  cnv.drawingContext.putImageData(diffData, 0, 0)
-  const diff = cnv.get()
+  cnv.pixelDensity(1);
+  cnv.background(BG);
+  cnv.image(actual, 0, 0);
+  cnv.blendMode(DIFFERENCE);
+  cnv.image(expectedWithBg, 0, 0);
+  for (let i = 0; i < shiftThreshold; i++) {
+    cnv.filter(ERODE, false);
+  }
+  const diff = cnv.get();
   cnv.remove();
+  diff.loadPixels();
+  expectedWithBg.remove();
+
+  let ok = true;
+  for (let i = 0; i < diff.pixels.length; i += 4) {
+    let diffSum = 0;
+    for (let off = 0; off < 3; off++) {
+      diffSum += diff.pixels[i+off]
+    }
+    diffSum /= 3;
+    if (diffSum > COLOR_THRESHOLD) {
+      ok = false;
+      break;
+    }
+  }
 
-  return { ok: diffCount === 0, diff };
+  return { ok, diff };
 }
 
 /**