feat : add image generator

lib/overview-image.test.ts

@@ -2,8 +2,13 @@ import { describe, expect, it } from "vitest";
 
 import {
   accentGradient,
+  detectThemeColorsFromPixels,
+  elementGlowColor,
+  elementGradientColors,
+  elementOrder,
   normalizeHex,
   overviewFileName,
+  overviewBlendModes,
   weaponTypeIconPath,
 } from "@/lib/overview-image";
 
@@ -42,10 +47,37 @@ describe("overview image generator", () => {
     expect(weaponTypeIconPath(null)).toBeNull();
   });
 
+  it("maps every element to gradient and fixed glow colors", () => {
+    for (const element of elementOrder) {
+      const [start, end] = elementGradientColors(element);
+      expect(normalizeHex(start)).toBe(start);
+      expect(normalizeHex(end)).toBe(end);
+      expect(normalizeHex(elementGlowColor(element))).toBe(
+        elementGlowColor(element),
+      );
+    }
+    expect(elementGradientColors("Unknown")).toEqual(["#FFFFFF", "#FFFFFF"]);
+    expect(elementGlowColor(null)).toBe("#FFFFFF");
+  });
+
   it("creates a safe PNG filename", () => {
     expect(overviewFileName("Traveler / Pyro", "Main DPS")).toBe(
       "overview-Traveler-Pyro-main-dps.png",
     );
   });
 
+  it("supports every Tailwind blend mode and detects top and bottom themes", () => {
+    expect(overviewBlendModes.map((mode) => mode.value)).toHaveLength(18);
+    const pixels = new Uint8ClampedArray([
+      255, 0, 0, 255, 255, 0, 0, 255,
+      255, 255, 0, 255, 255, 255, 0, 255,
+      0, 0, 255, 255, 0, 0, 255, 255,
+      0, 255, 255, 255, 0, 255, 255, 255,
+    ]);
+    expect(detectThemeColorsFromPixels(pixels, 2, 4)).toEqual({
+      top: ["#FF0000", "#FFFF00"],
+      bottom: ["#0000FF", "#00FFFF"],
+    });
+  });
+
 });