feat: add core tools - transfor, light, effects

web/src/lib/core/effects.ts

@@ -0,0 +1,24 @@
+import { clonePixelImage, createPixelImage, type PixelImage } from './types';
+
+export function vignette(img: PixelImage, strengthPercent: number): PixelImage {
+	const strength = Math.min(Math.max(strengthPercent, 0), 100) / 100;
+	if (strength === 0) return clonePixelImage(img);
+	const cx = (img.width - 1) / 2;
+	const cy = (img.height - 1) / 2;
+	const maxDist = Math.sqrt(cx * cx + cy * cy);
+	const out = createPixelImage(img.width, img.height);
+	for (let y = 0; y < img.height; y++) {
+		for (let x = 0; x < img.width; x++) {
+			const dx = x - cx;
+			const dy = y - cy;
+			const t = Math.sqrt(dx * dx + dy * dy) / maxDist;
+			const factor = 1 - strength * t * t;
+			const di = (y * img.width + x) * 4;
+			out.data[di] = img.data[di] * factor;
+			out.data[di + 1] = img.data[di + 1] * factor;
+			out.data[di + 2] = img.data[di + 2] * factor;
+			out.data[di + 3] = img.data[di + 3];
+		}
+	}
+	return out;
+}