1 files changed, 211 insertions, 0 deletions
diff --git a/apps/web/src/lib/graphics/definitions/polygon.ts b/apps/web/src/lib/graphics/definitions/polygon.ts
new file mode 100644
index 00000000..780c974c
--- /dev/null
+++ b/apps/web/src/lib/graphics/definitions/polygon.ts
@@ -0,0 +1,211 @@
+import type { ParamDefinition } from "@/lib/params";
+import { applyAlignedStroke } from "../stroke";
+import { STROKE_ALIGN_PARAM, type GraphicStrokeAlign } from "./shared";
+import type { GraphicDefinition } from "../types";
+
+interface Point {
+	x: number;
+	y: number;
+}
+
+interface PolygonParams {
+	fill: string;
+	stroke: string;
+	strokeWidth: number;
+	strokeAlign: GraphicStrokeAlign;
+	sides: number;
+	cornerRadius: number;
+}
+
+const POLYGON_PARAMS: ParamDefinition<keyof PolygonParams & string>[] = [
+	{
+		key: "fill",
+		label: "Fill",
+		type: "color",
+		default: "#ffffff",
+	},
+	{
+		key: "stroke",
+		label: "Color",
+		type: "color",
+		default: "#000000",
+		group: "stroke",
+	},
+	{
+		key: "strokeWidth",
+		label: "Width",
+		type: "number",
+		default: 0,
+		min: 0,
+		max: 64,
+		step: 1,
+		shortLabel: "W",
+		group: "stroke",
+	},
+	STROKE_ALIGN_PARAM,
+	{
+		key: "sides",
+		label: "Sides",
+		type: "number",
+		default: 5,
+		min: 3,
+		max: 12,
+		step: 1,
+		shortLabel: "S",
+	},
+	{
+		key: "cornerRadius",
+		label: "Corner radius",
+		type: "number",
+		default: 0,
+		min: 0,
+		max: 50,
+		step: 1,
+		shortLabel: "R",
+	},
+];
+
+function buildPolygonVertices({
+	centerX,
+	centerY,
+	radius,
+	sides,
+}: {
+	centerX: number;
+	centerY: number;
+	radius: number;
+	sides: number;
+}): Point[] {
+	return Array.from({ length: sides }, (_, index) => {
+		const angle = -Math.PI / 2 + (index * Math.PI * 2) / sides;
+		return {
+			x: centerX + Math.cos(angle) * radius,
+			y: centerY + Math.sin(angle) * radius,
+		};
+	});
+}
+
+function distance({ a, b }: { a: Point; b: Point }): number {
+	return Math.hypot(a.x - b.x, a.y - b.y);
+}
+
+function normalize(point: Point): Point {
+	const length = Math.hypot(point.x, point.y) || 1;
+	return {
+		x: point.x / length,
+		y: point.y / length,
+	};
+}
+
+function traceRoundedPolygonPath({
+	path,
+	vertices,
+	radius,
+}: {
+	path: Path2D;
+	vertices: Point[];
+	radius: number;
+}): void {
+	if (vertices.length < 3) {
+		return;
+	}
+
+	if (radius <= 0) {
+		path.moveTo(vertices[0].x, vertices[0].y);
+		for (let index = 1; index < vertices.length; index++) {
+			path.lineTo(vertices[index].x, vertices[index].y);
+		}
+		path.closePath();
+		return;
+	}
+
+	for (let index = 0; index < vertices.length; index++) {
+		const previous = vertices[(index - 1 + vertices.length) % vertices.length];
+		const current = vertices[index];
+		const next = vertices[(index + 1) % vertices.length];
+		const toPrevious = normalize({
+			x: previous.x - current.x,
+			y: previous.y - current.y,
+		});
+		const toNext = normalize({
+			x: next.x - current.x,
+			y: next.y - current.y,
+		});
+		const angle = Math.acos(
+			Math.max(-1, Math.min(1, toPrevious.x * toNext.x + toPrevious.y * toNext.y)),
+		);
+		const maxOffset =
+			Math.min(distance({ a: previous, b: current }), distance({ a: current, b: next })) / 2;
+		const tangentOffset = Math.min(radius / Math.tan(angle / 2), maxOffset);
+		const start = {
+			x: current.x + toPrevious.x * tangentOffset,
+			y: current.y + toPrevious.y * tangentOffset,
+		};
+		const end = {
+			x: current.x + toNext.x * tangentOffset,
+			y: current.y + toNext.y * tangentOffset,
+		};
+
+		if (index === 0) {
+			path.moveTo(start.x, start.y);
+		} else {
+			path.lineTo(start.x, start.y);
+		}
+
+		path.arcTo(
+			current.x,
+			current.y,
+			end.x,
+			end.y,
+			Math.min(radius, maxOffset),
+		);
+	}
+
+	path.closePath();
+}
+
+export const polygonGraphicDefinition: GraphicDefinition = {
+	id: "polygon",
+	name: "Polygon",
+	keywords: ["polygon", "triangle", "pentagon", "hexagon", "diamond"],
+	params: POLYGON_PARAMS,
+	render({ ctx, params, width, height }) {
+		const fill = String(params.fill ?? "#ffffff");
+		const stroke = String(params.stroke ?? "#000000");
+		const strokeWidth = Math.max(0, Number(params.strokeWidth ?? 0));
+		const strokeAlign = (params.strokeAlign ?? "center") as GraphicStrokeAlign;
+		const sides = Math.max(3, Math.min(12, Math.round(Number(params.sides ?? 5))));
+		const inset = strokeAlign === "center" ? strokeWidth / 2 : 0;
+		const radius = Math.max(1, Math.min(width, height) / 2 - inset);
+		const maxCornerRadius = radius * Math.sin(Math.PI / sides);
+		const cornerRadiusPercent = Math.max(0, Number(params.cornerRadius ?? 0));
+		const cornerRadius =
+			maxCornerRadius * Math.min(cornerRadiusPercent, 50) / 50;
+		const vertices = buildPolygonVertices({
+			centerX: width / 2,
+			centerY: height / 2,
+			radius,
+			sides,
+		});
+
+		ctx.clearRect(0, 0, width, height);
+		const path = new Path2D();
+		traceRoundedPolygonPath({
+			path,
+			vertices,
+			radius: cornerRadius,
+		});
+		ctx.fillStyle = fill;
+		ctx.fill(path);
+
+		if (strokeWidth > 0) {
+			applyAlignedStroke({
+				ctx,
+				path,
+				strokeWidth,
+				strokeAlign,
+				strokeColor: stroke,
+			});
+		}
+	},
+};