add png compression to save space

compressImage.js

@@ -0,0 +1,27 @@
+import fs from 'fs/promises';
+import UPNG from 'upng-js';
+
+const countUniqueColors = (data) => {
+  const uniqueColors = new Set();
+  for (let i = 0; i < data.length; i += 4) {
+    uniqueColors.add(`${data[i]},${data[i + 1]},${data[i + 2]},${data[i + 3]}`);
+    if (uniqueColors.size > 256) {
+      return uniqueColors.size;
+    }
+  }
+  return uniqueColors.size;
+};
+
+export async function compressPng (filePath) {
+  const buffer = await fs.readFile(filePath);
+  const arrayBuffer = buffer.buffer.slice(buffer.byteOffset, buffer.byteOffset + buffer.byteLength);
+  const img = UPNG.decode(arrayBuffer);
+  const rgba = new Uint8Array(img.data);
+  const frameData = new Uint8Array(img.width * img.height * 4);
+  frameData.set(rgba.subarray(0, frameData.length));
+  const cnum = countUniqueColors(rgba) <= 256 ? 256 : 0;
+  const optimizedArrayBuffer = UPNG.encode([frameData.buffer], img.width, img.height, cnum, img.depth);
+  const optimizedBuffer = Buffer.from(optimizedArrayBuffer);
+  await fs.writeFile(filePath, optimizedBuffer);
+  return filePath;
+};

imageGenerator.js

@@ -2,12 +2,13 @@ import path from "path";
 import { mkdir, writeFile } from "fs/promises";
 import { fileURLToPath } from "url";
 import { callOllama } from "./ollamaClient.js";
+import { compressPng } from "./compressPng.js";
 
 const __dirname = path.dirname(fileURLToPath(import.meta.url));
 const COMFYUI_URL = process.env.COMFYUI_URL || "http://localhost:8188";
 
 // Drawing style prefix
-const STYLE_PREFIX = `a high-contrast, black and white pen and ink drawing, hand-drawn sketch aesthetic, very low detail, visible loose linework, expressive simple hatching for shadows, quick conceptual sketch, subtle color accent`;
+const STYLE_PREFIX = `a high-contrast, black and white pen and ink drawing, hand-drawn sketch aesthetic, very low detail, extremely minimal, visible loose linework, expressive simple hatching for shadows, quick conceptual sketch, subtle color accent`;
 
 // 1. Generate engineered visual prompt
 async function generateVisualPrompt(flavor) {
@@ -181,6 +182,9 @@ async function generateImageViaComfyUI(prompt, filename) {
 
     console.log("Downloading image...");
     const filepath = await downloadImage(comfyFilename, filename);
+
+    console.log("Compressing PNG...");
+    await compressPng(filepath);
     return filepath;
 
   } catch (err) {

package-lock.json

@@ -10,7 +10,8 @@
       "license": "SEE LICENSE IN README.md",
       "dependencies": {
         "dotenv": "^17.2.1",
-        "puppeteer": "^24.17.1"
+        "puppeteer": "^24.17.1",
+        "upng-js": "^2.1.0"
       },
       "devDependencies": {
         "@eslint/js": "^9.34.0",
@@ -1475,6 +1476,12 @@
         "node": ">= 14"
       }
     },
+    "node_modules/pako": {
+      "version": "1.0.11",
+      "resolved": "https://registry.npmjs.org/pako/-/pako-1.0.11.tgz",
+      "integrity": "sha512-4hLB8Py4zZce5s4yd9XzopqwVv/yGNhV1Bl8NTmCq1763HeK2+EwVTv+leGeL13Dnh2wfbqowVPXCIO0z4taYw==",
+      "license": "(MIT AND Zlib)"
+    },
     "node_modules/parent-module": {
       "version": "1.0.1",
       "resolved": "https://registry.npmjs.org/parent-module/-/parent-module-1.0.1.tgz",
@@ -1871,6 +1878,15 @@
       "license": "MIT",
       "optional": true
     },
+    "node_modules/upng-js": {
+      "version": "2.1.0",
+      "resolved": "https://registry.npmjs.org/upng-js/-/upng-js-2.1.0.tgz",
+      "integrity": "sha512-d3xzZzpMP64YkjP5pr8gNyvBt7dLk/uGI67EctzDuVp4lCZyVMo0aJO6l/VDlgbInJYDY6cnClLoBp29eKWI6g==",
+      "license": "MIT",
+      "dependencies": {
+        "pako": "^1.0.5"
+      }
+    },
     "node_modules/uri-js": {
       "version": "4.4.1",
       "resolved": "https://registry.npmjs.org/uri-js/-/uri-js-4.4.1.tgz",

package.json

@@ -13,7 +13,8 @@
   "description": "",
   "dependencies": {
     "dotenv": "^17.2.1",
-    "puppeteer": "^24.17.1"
+    "puppeteer": "^24.17.1",
+    "upng-js": "^2.1.0"
   },
   "devDependencies": {
     "@eslint/js": "^9.34.0",