WIP - add extractor, generate snippet_data

node_modules/@jimp/plugin-mask/src/index.js

@@ -0,0 +1,52 @@
+import { isNodePattern, throwError } from '@jimp/utils';
+
+/**
+ * Masks a source image on to this image using average pixel colour. A completely black pixel on the mask will turn a pixel in the image completely transparent.
+ * @param {Jimp} src the source Jimp instance
+ * @param {number} x the horizontal position to blit the image
+ * @param {number} y the vertical position to blit the image
+ * @param {function(Error, Jimp)} cb (optional) a callback for when complete
+ * @returns {Jimp} this for chaining of methods
+ */
+export default () => ({
+  mask(src, x = 0, y = 0, cb) {
+    if (!(src instanceof this.constructor)) {
+      return throwError.call(this, 'The source must be a Jimp image', cb);
+    }
+
+    if (typeof x !== 'number' || typeof y !== 'number') {
+      return throwError.call(this, 'x and y must be numbers', cb);
+    }
+
+    // round input
+    x = Math.round(x);
+    y = Math.round(y);
+
+    const w = this.bitmap.width;
+    const h = this.bitmap.height;
+    const baseImage = this;
+
+    src.scanQuiet(0, 0, src.bitmap.width, src.bitmap.height, function(
+      sx,
+      sy,
+      idx
+    ) {
+      const destX = x + sx;
+      const destY = y + sy;
+
+      if (destX >= 0 && destY >= 0 && destX < w && destY < h) {
+        const dstIdx = baseImage.getPixelIndex(destX, destY);
+        const { data } = this.bitmap;
+        const avg = (data[idx + 0] + data[idx + 1] + data[idx + 2]) / 3;
+
+        baseImage.bitmap.data[dstIdx + 3] *= avg / 255;
+      }
+    });
+
+    if (isNodePattern(cb)) {
+      cb.call(this, null, this);
+    }
+
+    return this;
+  }
+});