feat: core instruments

web/src/lib/core/analyze.ts

@@ -0,0 +1,26 @@
+import type { PixelImage } from './types';
+
+export type ImageInfo = {
+	width: number;
+	height: number;
+	hasAlpha: boolean;
+	colorCount: number;
+};
+
+export function imageInfo(img: PixelImage): ImageInfo {
+	let hasAlpha = false;
+	const seen = new Set<number>();
+	for (let i = 0; i < img.data.length; i += 4) {
+		if (!hasAlpha && img.data[i + 3] !== 255) {
+			hasAlpha = true;
+		}
+		const key =
+			((img.data[i] << 24) |
+				(img.data[i + 1] << 16) |
+				(img.data[i + 2] << 8) |
+				img.data[i + 3]) >>>
+			0;
+		seen.add(key);
+	}
+	return { width: img.width, height: img.height, hasAlpha, colorCount: seen.size };
+}