chore: moved to a new branch to save space

libs/alpha_composite.js

@@ -0,0 +1,31 @@
+import sharp from "sharp";
+import path from "path";
+
+export default class AlphaComposite {
+
+  async process(filename, maskFilename, extractedDir) {
+    const image = sharp(path.join(extractedDir, filename))
+      .removeAlpha()
+    const imageMeta = await image.metadata()
+    const imageBuffer = await image.toBuffer()
+    const mask = await sharp(path.join(extractedDir, maskFilename))
+      .extractChannel("blue")
+      .resize(imageMeta.width, imageMeta.height)
+      .toBuffer();
+
+    return sharp(imageBuffer)
+      .joinChannel(mask)
+      .toBuffer()
+  }
+
+  async crop(buffer, rect) {
+    const left = rect.y
+    const top = rect.x
+    const width = rect.h
+    const height = rect.w
+    const rotate = rect.rotate === 0 ? -90 : 0
+    const newImage = await sharp(buffer).rotate(90).extract({ left: left, top: top, width: width, height: height }).resize(width, height).extract({ left: 0, top: 0, width: width, height: height }).toBuffer()
+    return await sharp(newImage).rotate(rotate).toBuffer()
+  }
+
+}