Utils example

tools/utils/args.js

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+const args = process.argv.splice(2).reduce((x,y) => {
+  const bits = y.split('=');
+  const name = bits[0].replace('--', '');
+  const val = bits[1];
+
+  x[name] = val;
+  return x;
+}, {});
+
+module.exports = {
+  args
+};

tools/utils/file.js

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+const path = require('path');
+const fs = require('fs');
+
+const mkdirp = dir => {
+  const resolved = path.resolve(dir);
+  const resolvedDir = path.dirname(resolved);
+  const bits = resolvedDir.split(path.sep);
+  let running = '';
+
+  bits.forEach(bit => {
+    running += bit;
+    if(!fs.existsSync(running)) fs.mkdirSync(running);
+    running += path.sep;
+  });
+}
+
+module.exports = {
+  mkdirp
+}

tools/utils/image.js

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+const { PNG } = require("pngjs");
+const path = require('path');
+const fs = require('fs');
+
+/**
+ * Loads an image into memory.
+ * @param image Image to load
+ * @returns A promise that resolves to the loaded image.
+ */
+const imageLoad = (image) => new Promise(resolve => {
+  fs.createReadStream(image)
+    .pipe(new PNG({ filterType: 4 }))
+    .on("parsed", function () {
+      // Normalize
+      const pixels = [];
+      for(let y = 0; y < this.height; y++) {
+        for(let x = 0; x < this.width; x++) {
+          const idx = (this.width * y + x) << 2;
+          const r = this.data[idx];
+          const g = this.data[idx + 1];
+          const b = this.data[idx + 2];
+          const a = this.data[idx + 3];
+
+          pixels.push({ r, g, b, a });
+        }
+      }
+      resolve({ pixels, width: this.width, height: this.height });
+    })
+  ;
+});
+
+/**
+ * Writes an image to an output file.
+ * @param image Image to write.
+ * @param file File to write to.
+ * @returns A promise that, when resolved, has saved the image.
+ */
+const imageWrite = (image, file) => new Promise(resolve => {
+  const png = new PNG({ width: image.width, height: image.height });
+  png.width = image.width;
+  png.height = image.height;
+  
+  for(let y = 0; y < image.height; y++) {
+    for(let x = 0; x < image.width; x++) {
+      const i = (image.width * y + x);
+      const idx = i << 2;
+
+      const pixel = image.pixels[i];
+      png.data[idx] = pixel.r;
+      png.data[idx + 1] = pixel.g;
+      png.data[idx + 2] = pixel.b;
+      png.data[idx + 3] = pixel.a;
+    }
+  }
+
+  png.pack().pipe(fs.createWriteStream(file))
+    .on('close', () => resolve(true))
+  ;
+});
+
+/**
+ * Creates a blank image
+ * @param width Width of the image.
+ * @param height Height of the image.
+ * @param fill Optional pixel to fill with, defaults to 0,0,0,0
+ * @returns The newly created image.
+ */
+const imageCreate = (width, height, pixel) => {
+  if(!pixel || !pixel.r) pixel = { r:0, g:0, b:0, a:0 };
+  const pixels = [];
+  for(let i = 0; i < width * height; i++) pixels.push({ ...pixel });
+  return { pixels, width, height };
+}
+
+/**
+ * Copies an area of a source image into a target image.
+ * @param target Target image to copy into.
+ * @param source Source image to copy from.
+ * @param tx Target X position to copy into
+ * @param ty Target Y position to copy into
+ * @param sub Optional source area to use, defined as { x, y, width, height }.
+ */
+const imageCopy = (target, source, tx, ty, sub) => {
+  if(!sub) sub = { x: 0, y: 0, width: source.width, height: source.height };
+
+  for(let x = sub.x; x < sub.x+sub.width; x++) {
+    for(let y = sub.y; y < sub.y+sub.height; y++) {
+      let absX = x - sub.x + tx;
+      let absY = y - sub.y + ty;
+      if(absX > target.width || absY > target.height) continue;
+      let ti = absY * target.width + absX;
+      let si = y * source.width + x;
+      target.pixels[ti] = { ...source.pixels[si] };
+    }
+  }
+}
+
+module.exports = {
+  imageWrite,
+  imageCreate,
+  imageLoad,
+  imageCopy
+}