fix(wp7-02): normalize generated image dimensions

2026-08-04 17:19:41 +08:00
parent 9d6f4ac24b
commit ae725a2d01
11 changed files with 153 additions and 17 deletions
@@ -0,0 +1,74 @@
+import sharp from "sharp";
+
+const productDimensions = Object.freeze({
+  "3:4": Object.freeze({ pixelHeight: 1440, pixelWidth: 1080 }),
+  "1:1": Object.freeze({ pixelHeight: 1080, pixelWidth: 1080 }),
+  "4:3": Object.freeze({ pixelHeight: 1080, pixelWidth: 1440 }),
+  "9:16": Object.freeze({ pixelHeight: 1920, pixelWidth: 1080 }),
+});
+
+const gptImageRequestSizes = Object.freeze({
+  "3:4": "1056x1408",
+  "1:1": "1088x1088",
+  "4:3": "1408x1056",
+  "9:16": "1008x1792",
+});
+
+const allowedMimeTypes = new Set(["image/jpeg", "image/png", "image/webp"]);
+const maximumInputBytes = 20 * 1024 * 1024;
+
+function assertRatio(ratio) {
+  if (!(ratio in productDimensions)) throw new Error("image_output_ratio_unsupported");
+  return ratio;
+}
+
+export function productDimensionsForRatio(ratio) {
+  return { ...productDimensions[assertRatio(ratio)] };
+}
+
+export function gptImageRequestSizeForRatio(ratio) {
+  return gptImageRequestSizes[assertRatio(ratio)];
+}
+
+export async function normalizeImageOutputToRatio(input) {
+  const ratio = assertRatio(input?.ratio);
+  if (!Buffer.isBuffer(input?.bytes) || input.bytes.length === 0 || input.bytes.length > maximumInputBytes
+    || !allowedMimeTypes.has(input?.mimeType)) {
+    throw new Error("image_output_media_invalid");
+  }
+  const target = productDimensions[ratio];
+  if (input.pixelWidth === target.pixelWidth && input.pixelHeight === target.pixelHeight) {
+    return {
+      bytes: Buffer.from(input.bytes),
+      mimeType: input.mimeType,
+      normalized: false,
+      ...target,
+      upstreamPixelHeight: input.pixelHeight,
+      upstreamPixelWidth: input.pixelWidth,
+    };
+  }
+
+  const image = sharp(input.bytes, { failOn: "error", limitInputPixels: 40_000_000 });
+  const metadata = await image.metadata();
+  if (!metadata.width || !metadata.height) throw new Error("image_output_dimensions_missing");
+  const requestedRatio = target.pixelWidth / target.pixelHeight;
+  const upstreamRatio = metadata.width / metadata.height;
+  if (Math.abs(upstreamRatio - requestedRatio) / requestedRatio > 0.02) {
+    throw new Error("image_output_aspect_ratio_mismatch");
+  }
+  const { data, info } = await image
+    .resize(target.pixelWidth, target.pixelHeight, { fit: "fill", kernel: sharp.kernel.lanczos3 })
+    .png({ compressionLevel: 9 })
+    .toBuffer({ resolveWithObject: true });
+  if (info.width !== target.pixelWidth || info.height !== target.pixelHeight || info.format !== "png") {
+    throw new Error("image_output_normalization_failed");
+  }
+  return {
+    bytes: data,
+    mimeType: "image/png",
+    normalized: true,
+    ...target,
+    upstreamPixelHeight: metadata.height,
+    upstreamPixelWidth: metadata.width,
+  };
+}