feat(art): dynamic avatar transformation

src/games/genshin/assets/avatar.ts

@@ -0,0 +1,85 @@
+import { createCanvas, loadImage } from "@napi-rs/canvas";
+import type { Canvas } from "@napi-rs/canvas";
+
+import {
+  applyFeatherToCanvas,
+  type Feather,
+} from "@/games/genshin/assets/feather";
+
+export type CharacterTransform = {
+  x: number;
+  y: number;
+  w: number;
+};
+
+function drawWithTransform(
+  canvas: Canvas,
+  image: Awaited<ReturnType<typeof loadImage>>,
+  transform: CharacterTransform,
+) {
+  const ctx = canvas.getContext("2d");
+  const drawWidth = transform.w * canvas.width;
+  const drawHeight = (image.height / image.width) * drawWidth;
+  const drawX = transform.x * canvas.width;
+  const drawY = transform.y * canvas.height;
+
+  ctx.drawImage(image, drawX, drawY, drawWidth, drawHeight);
+}
+
+function drawBuiltInFallback(
+  canvas: Canvas,
+  image: Awaited<ReturnType<typeof loadImage>>,
+) {
+  const ctx = canvas.getContext("2d");
+  const drawHeight = canvas.height * 1.3;
+  const drawWidth = drawHeight * (image.width / image.height);
+  const drawX = canvas.width * 0.5 - drawWidth / 2;
+  const drawY = canvas.height * 0.55 - drawHeight / 2;
+
+  ctx.drawImage(image, drawX, drawY, drawWidth, drawHeight);
+}
+
+function drawCustomFallback(
+  canvas: Canvas,
+  image: Awaited<ReturnType<typeof loadImage>>,
+) {
+  const ctx = canvas.getContext("2d");
+  const drawWidth = canvas.width;
+  const drawHeight = (image.height / image.width) * drawWidth;
+  const drawY = (canvas.height - drawHeight) / 2;
+
+  ctx.drawImage(image, 0, drawY, drawWidth, drawHeight);
+}
+
+export async function renderCharacterArtToCanvas(
+  input: ArrayBuffer,
+  {
+    stageWidth,
+    stageHeight,
+    transform,
+    passes = [[0, 0.3, 0, 0]],
+    isCustom = false,
+  }: {
+    stageWidth: number;
+    stageHeight: number;
+    transform?: CharacterTransform;
+    passes?: Feather[];
+    isCustom?: boolean;
+  },
+) {
+  const image = await loadImage(Buffer.from(input));
+  const preFeatherCanvas = createCanvas(stageWidth, stageHeight);
+
+  if (transform) drawWithTransform(preFeatherCanvas, image, transform);
+  else if (isCustom) drawCustomFallback(preFeatherCanvas, image);
+  else drawBuiltInFallback(preFeatherCanvas, image);
+
+  const finalCanvas = createCanvas(stageWidth, stageHeight);
+  finalCanvas.getContext("2d").drawImage(preFeatherCanvas, 0, 0);
+  applyFeatherToCanvas(finalCanvas, { passes });
+
+  return {
+    preFeatherCanvas,
+    finalCanvas,
+  };
+}

src/games/genshin/assets/background.tsx

@@ -1,4 +1,5 @@
 import { createCanvas, loadImage } from "@napi-rs/canvas";
+import type { Canvas } from "@napi-rs/canvas";
 import type { ImageData as CanvasImageData } from "@napi-rs/canvas";
 import { file } from "bun";
 
@@ -142,11 +143,13 @@ export async function generateBackground({
   width,
   height,
   element,
+  artCanvas,
   artSource,
 }: {
   width: number;
   height: number;
   element: string;
+  artCanvas?: Canvas;
   artSource?: ArrayBuffer;
 }) {
   const canvas = createCanvas(width * 1.2, height * 1.2);
@@ -154,24 +157,29 @@ export async function generateBackground({
 
   const elementColor = elementColors[element] ?? "#444444";
 
-  if (artSource) {
+  if (artCanvas || artSource) {
     try {
-      const art = await loadImage(artSource);
-      const artCanvas = createCanvas(art.width, art.height);
-      const artCtx = artCanvas.getContext("2d");
+      const sourceCanvas = artCanvas ?? createCanvas(1, 1);
 
-      artCtx.drawImage(art, 0, 0);
+      if (!artCanvas && artSource) {
+        const art = await loadImage(artSource);
+        sourceCanvas.width = art.width;
+        sourceCanvas.height = art.height;
+        sourceCanvas.getContext("2d").drawImage(art, 0, 0);
+      }
+
+      const artCtx = sourceCanvas.getContext("2d");
 
       const sliceX = Math.min(
-        Math.round(artCanvas.width * 0.9),
-        artCanvas.width - 3,
+        Math.round(sourceCanvas.width * 0.9),
+        sourceCanvas.width - 3,
       );
-      const sliceWidth = Math.min(3, artCanvas.width);
+      const sliceWidth = Math.min(3, sourceCanvas.width);
       const adaptiveSlice = artCtx.getImageData(
         Math.max(0, sliceX),
         0,
         sliceWidth,
-        artCanvas.height,
+        sourceCanvas.height,
       );
       const bands = buildAdaptiveBands(adaptiveSlice, elementColor);
       const gradient = ctx.createLinearGradient(

src/games/genshin/assets/feather.ts

@@ -1,6 +1,44 @@
 import { createCanvas, loadImage } from "@napi-rs/canvas";
+import type { Canvas } from "@napi-rs/canvas";
 
-type Feather = [number, number, number, number];
+export type Feather = [number, number, number, number];
+
+export function applyFeatherToCanvas(
+  canvas: Canvas,
+  {
+    passes,
+  }: {
+    passes: Feather[];
+  },
+) {
+  const ctx = canvas.getContext("2d");
+  const w = canvas.width;
+  const h = canvas.height;
+
+  const sides = [
+    [0, 0, 0, h],
+    [w, 0, 0, 0],
+    [0, h, 0, 0],
+    [0, 0, w, 0],
+  ];
+
+  for (const [top, right, bottom, left] of passes) {
+    [top, right, bottom, left].forEach((s, i) => {
+      if (!s) return;
+
+      const g = ctx.createLinearGradient(
+        ...(sides[i] as [number, number, number, number]),
+      );
+      g.addColorStop(0, "rgba(255,255,255,0)");
+      g.addColorStop(s, "rgba(255,255,255,1)");
+
+      ctx.globalCompositeOperation = "destination-in";
+      ctx.fillStyle = g;
+      ctx.fillRect(0, 0, w, h);
+      ctx.globalCompositeOperation = "source-over";
+    });
+  }
+}
 
 export async function featherImage(
   input: ArrayBuffer,
@@ -30,32 +68,7 @@ export async function featherImage(
 
   ctx.drawImage(img, sx, sy, cropW, cropH, 0, 0, cropW, cropH);
 
-  const w = cropW;
-  const h = cropH;
-
-  const sides = [
-    [0, 0, 0, h], // top
-    [w, 0, 0, 0], // right
-    [0, h, 0, 0], // bottom
-    [0, 0, w, 0], // left
-  ];
-
-  for (const [top, right, bottom, left] of passes) {
-    [top, right, bottom, left].forEach((s, i) => {
-      if (!s) return;
-
-      const g = ctx.createLinearGradient(
-        ...(sides[i] as [number, number, number, number]),
-      );
-      g.addColorStop(0, "rgba(255,255,255,0)");
-      g.addColorStop(s, "rgba(255,255,255,1)");
-
-      ctx.globalCompositeOperation = "destination-in";
-      ctx.fillStyle = g;
-      ctx.fillRect(0, 0, w, h);
-      ctx.globalCompositeOperation = "source-over";
-    });
-  }
+  applyFeatherToCanvas(canvas, { passes });
 
   return canvas.toBuffer("image/png");
 }

src/games/genshin/data/transform.ts

@@ -0,0 +1,41 @@
+export const TRANSFORM_CONSTANT = {
+  "10000005": "-0.016674353503593475,0.027102803738317905,1.2263671875000002,0",
+  "10000007": "-0.016674353503593475,0.027102803738317905,1.2263671875000002,0",
+  "10000117": "-0.3267884428741016,0.06140186915887837,1.605322265625,0",
+  "10000118": " -0.31077201576937885,0.05504672897196261,1.605322265625,0",
+} as const;
+
+// thanks stackoverflow
+type WS = " " | "\n" | "\t";
+
+type TrimLeft<S extends string> = S extends `${WS}${infer R}` ? TrimLeft<R> : S;
+type TrimRight<S extends string> = S extends `${infer R}${WS}`
+  ? TrimRight<R>
+  : S;
+type Trim<S extends string> = TrimLeft<TrimRight<S>>;
+
+type ParseTransform<S extends string> =
+  S extends `${infer X},${infer Y},${infer W},${string}`
+    ? {
+        readonly x: Trim<X> extends `${infer N extends number}` ? N : never;
+        readonly y: Trim<Y> extends `${infer N extends number}` ? N : never;
+        readonly w: Trim<W> extends `${infer N extends number}` ? N : never;
+      }
+    : never;
+
+type TransformMap<T extends Record<string, string>> = {
+  readonly [K in keyof T]: ParseTransform<T[K]>;
+};
+
+function makeTransformMap<
+  const T extends Record<string, `${string},${string},${string},${string}`>,
+>(obj: T): TransformMap<T> {
+  return Object.fromEntries(
+    Object.entries(obj).map(([key, value]) => {
+      const [x, y, w] = value.split(",").map(Number);
+      return [key, { x, y, w }];
+    }),
+  ) as TransformMap<T>;
+}
+
+export const TRANSFORM_MAP = makeTransformMap(TRANSFORM_CONSTANT);

src/games/genshin/index.ts

@@ -606,7 +606,8 @@ export function card(app: App) {
                       `https://enka.network/api/profile/${username}/hoyos/${buildHash}/builds/`,
                     )
                       .then(throwNotOk)
-                      .then((r) => r.json())) as Promise<
+                      .then((r) => r.json())
+                ).finally(() => log`Enka data loaded`) as Promise<
                   Record<
                     string,
                     {

src/games/genshin/render/character.tsx

@@ -4,6 +4,7 @@ import { EquipType } from "enka.ts";
 import { ImageResponse } from "takumi-js/response";
 
 import { font, iconFont, sansFont } from "@/assets/fonts";
+import { renderCharacterArtToCanvas } from "@/games/genshin/assets/avatar";
 import { generateBackground } from "@/games/genshin/assets/background";
 import { ConstsSvg } from "@/games/genshin/assets/consts";
 import { featherImage } from "@/games/genshin/assets/feather";
@@ -17,6 +18,7 @@ import { assets, getAvatar } from "@/games/genshin/data/assets";
 import { buildDisplayRows } from "@/games/genshin/data/rows";
 import type { RollSummary } from "@/games/genshin/data/substat";
 import { buildRollSummary } from "@/games/genshin/data/substat";
+import { TRANSFORM_MAP } from "@/games/genshin/data/transform";
 import type {
   AvatarStore,
   EnkaAffixes,
@@ -171,28 +173,69 @@ export async function CharacterPage({
   const avatarArtPath =
     (char.costumeId && avatar.Costumes?.[char.costumeId].Art) ||
     avatar.SideIconName.replace("AvatarIcon_Side", "Gacha_AvatarImg");
+  const fontSize = 30.466 * (height / 1024);
+  const leftStageWidth = Math.round(30.4 * fontSize);
+  const leftStageHeight = Math.round(height);
+  const defaultTransform = customImage
+    ? undefined
+    : TRANSFORM_MAP[`${char.avatar.avatarId}` as keyof typeof TRANSFORM_MAP];
   const artBytesRes = customImage
     ? fetch(customImage).then((r) => r.arrayBuffer())
     : assets.load(avatarArtPath);
-  const featherAvatar = (buf: ArrayBuffer) =>
-    featherImage(buf, {
-      passes: [[0, 0.3, 0, 0]],
-      ratio: 1024 / 1124,
-    });
+  let avatarCanvasRes: Promise<
+    Awaited<ReturnType<typeof renderCharacterArtToCanvas>>
+  > | null = null;
+  const getAvatarCanvas = () =>
+    (avatarCanvasRes ??= artBytesRes.then((buf) =>
+      renderCharacterArtToCanvas(buf, {
+        stageWidth: leftStageWidth,
+        stageHeight: leftStageHeight,
+        transform: defaultTransform,
+        isCustom: !!customImage,
+      }),
+    ));
   const avatarRes = customImage
-    ? artBytesRes.then(featherAvatar)
-    : assets.fnCache(`${avatarArtPath}-avatar`, async () =>
-        featherAvatar(await artBytesRes),
+    ? getAvatarCanvas().then(({ finalCanvas }) =>
+        finalCanvas.toBuffer("image/png"),
+      )
+    : assets.fnCache(
+        `${avatarArtPath}-avatar-${leftStageWidth}x${leftStageHeight}`,
+        async () => (await getAvatarCanvas()).finalCanvas.toBuffer("image/png"),
       );
-  const backgroundRes = adaptiveColor
-    ? artBytesRes.then((artSource) =>
+  const backgroundAccentRes = adaptiveColor
+    ? getAvatarCanvas().then(({ preFeatherCanvas }) =>
         generateBackground({
-          artSource,
+          artCanvas: preFeatherCanvas,
           element: avatar.Element,
           width: 1218,
           height: 508,
-        }),
+        }).then((r) => r.accent),
       )
+    : generateBackground({
+        element: avatar.Element,
+        width: 1218,
+        height: 508,
+      }).then((r) => r.accent);
+  const backgroundRes = adaptiveColor
+    ? customImage
+      ? getAvatarCanvas().then(({ preFeatherCanvas }) =>
+          generateBackground({
+            artCanvas: preFeatherCanvas,
+            element: avatar.Element,
+            width: 1218,
+            height: 508,
+          }).then((r) => r.canvas.toBuffer("image/webp")),
+        )
+      : assets.fnCache(
+          `bg-${avatar.Element}-${avatarArtPath}-${leftStageWidth}x${leftStageHeight}-1218x508`,
+          async () =>
+            generateBackground({
+              artCanvas: (await getAvatarCanvas()).preFeatherCanvas,
+              element: avatar.Element,
+              width: 1218,
+              height: 508,
+            }).then((r) => r.canvas.toBuffer("image/webp")),
+        )
     : assets.fnCache(`bg-${avatar.Element}`, async () =>
         generateBackground({
           element: avatar.Element,
@@ -229,15 +272,7 @@ export async function CharacterPage({
         ),
       })),
     avatarRes.then((data) => ({ src: "/avatar", data })),
-    backgroundRes.then((data) => ({
-      src: `/bg-${avatar.Element}`,
-      data:
-        data instanceof Buffer || data instanceof ArrayBuffer
-          ? data
-          : (
-              data as Awaited<ReturnType<typeof generateBackground>>
-            ).canvas.toBuffer("image/webp"),
-    })),
+    backgroundRes.then((data) => ({ src: `/bg-${avatar.Element}`, data })),
   ] satisfies Promise<{ src: string; data: ArrayBuffer | Buffer }>[]);
 
   log`Image resources loaded\n${resources.map((r) => `- ${r.src} ${(r.data.byteLength / 1000).toFixed(2)}Kb`).join("\n")}`;
@@ -272,7 +307,7 @@ export async function CharacterPage({
       <SubstatDisplay
         substat={rollSummary}
         element={avatar.Element}
-        accent={((await backgroundRes) as { accent: string }).accent}
+        accent={await backgroundAccentRes}
       >
         <div
           tw={`flex relative text-white rounded-[.5em] overflow-hidden aspect-[1218/508] h-[${height}px]`}
@@ -284,21 +319,14 @@ export async function CharacterPage({
               tw="w-full h-full object-cover"
             />
           </div>
+          <div tw="absolute top-0 bottom-0 left-0 w-[30.4em]"></div>
           <div
             tw="absolute top-0 bottom-0 left-0 w-[30.4em] p-[1.6em] flex flex-col"
             style={{
               textShadow: "0 .08em .1em black,0 .1em .3em rgba(0,0,0,.4)",
             }}
           >
-            <img
-              src="/avatar"
-              alt="char"
-              tw="absolute h-full aspect-[1024/1124] left-[50%] top-[55%] max-w-none"
-              style={{
-                transform: "translate(-50%, -50%) scale(1.3)",
-                transformOrigin: "50% 50%",
-              }}
-            />
+            <img src="/avatar" alt="char" tw="absolute inset-0 w-full h-full" />
             <div tw="flex absolute top-0 left-0 bottom-0 right-0">
               <img src="shade" alt="shade" tw="opacity-40" />
             </div>
@@ -399,10 +427,13 @@ export async function CharacterPage({
                   </div>
                 );
               })}
-              <div tw="text-[0.9em] -mb-[1.3em] mt-[1.3em] right-[.8em] opacity-70">
-                {" "}
-                {artSource}
-              </div>
+              {/* artSource */}
+              {artSource && (
+                <div tw="text-[0.9em] -mb-[1.3em] mt-[1.3em] right-[.8em] opacity-70">
+                  {" "}
+                  {artSource}
+                </div>
+              )}
             </div>
             {/* caption */}
             {caption && (
@@ -698,7 +729,7 @@ function SubstatDisplay({
           {substat.map((s) => (
             <div
               key={s.id}
-              tw="mr-[1.2em] flex gap-[.2em] items-center whitespace-nowrap"
+              tw="mr-[1.65em] flex gap-[.2em] items-center whitespace-nowrap"
             >
               <div tw="ml-[.2em] mb-[.1em] text-[.75em] flex flex-col items-center font-[Open_Sans]">
                 {s.efficiency}