Move the place where we divide rotation center by resolution into the VM. Also revert the method of putting data into storage to the one that was convoluted but working

package.json

@@ -34,6 +34,7 @@
     "babel-loader": "^7.0.0",
     "babel-preset-es2015": "^6.24.1",
     "buffer-loader": "0.0.1",
+    "canvas-toBlob": "1.0.0",
     "copy-webpack-plugin": "4.2.1",
     "decode-html": "2.0.0",
     "escape-html": "1.0.3",

src/virtual-machine.js

@@ -2,6 +2,7 @@ const TextEncoder = require('text-encoding').TextEncoder;
 const EventEmitter = require('events');
 const JSZip = require('jszip');
 
+const Buffer = require('buffer').Buffer;
 const centralDispatch = require('./dispatch/central-dispatch');
 const ExtensionManager = require('./extension-support/extension-manager');
 const log = require('./util/log');
@@ -17,6 +18,7 @@ const Variable = require('./engine/variable');
 const {loadCostume} = require('./import/load-costume.js');
 const {loadSound} = require('./import/load-sound.js');
 const {serializeSounds, serializeCostumes} = require('./serialization/serialize-assets');
+require('canvas-toBlob');
 
 const RESERVED_NAMES = ['_mouse_', '_stage_', '_edge_', '_myself_', '_random_'];
 
@@ -554,7 +556,7 @@ class VirtualMachine extends EventEmitter {
             return this.runtime.storage.get(id).decodeText();
         } else if (format === this.runtime.storage.DataFormat.PNG ||
                 format === this.runtime.storage.DataFormat.JPG) {
-            return this.runtime.storage.get(id).encodeDataURI('image/png');
+            return this.runtime.storage.get(id).encodeDataURI();
         }
         log.error(`Unhandled format: ${this.runtime.storage.get(id).dataFormat}`);
         return null;
@@ -562,16 +564,17 @@ class VirtualMachine extends EventEmitter {
 
     /**
      * Update a costume with the given bitmap
-     * @param {int} costumeIndex - the index of the costume to be updated.
+     * @param {!int} costumeIndex - the index of the costume to be updated.
-     * @param {ImageData} bitmap - new bitmap for the renderer.
+     * @param {!ImageData} bitmap - new bitmap for the renderer.
-     * @param {number} rotationCenterX x of point about which the costume rotates, relative to its upper left corner
+     * @param {!number} rotationCenterX x of point about which the costume rotates, relative to its upper left corner
-     * @param {number} rotationCenterY y of point about which the costume rotates, relative to its upper left corner
+     * @param {!number} rotationCenterY y of point about which the costume rotates, relative to its upper left corner
-     * @param {number} bitmapResolution 1 for bitmaps that have 1 pixel per unit of stage,
+     * @param {!number} bitmapResolution 1 for bitmaps that have 1 pixel per unit of stage,
      *     2 for double-resolution bitmaps
      */
     updateBitmap (costumeIndex, bitmap, rotationCenterX, rotationCenterY, bitmapResolution) {
         const costume = this.editingTarget.getCostumes()[costumeIndex];
-        if (costume && this.runtime && this.runtime.renderer) {
+        if (!(costume && this.runtime && this.runtime.renderer)) return;
+
         costume.rotationCenterX = rotationCenterX;
         costume.rotationCenterY = rotationCenterY;
 
@@ -582,21 +585,33 @@ class VirtualMachine extends EventEmitter {
         const context = canvas.getContext('2d');
         context.putImageData(bitmap, 0, 0);
         
+        // Divide by resolution because the renderer's definition of the rotation center
+        // is the rotation center divided by the bitmap resolution
         this.runtime.renderer.updateBitmapSkin(
-                costume.skinId, canvas, bitmapResolution, [rotationCenterX, rotationCenterY]);
+            costume.skinId,
-        }
+            canvas,
+            bitmapResolution,
+            [rotationCenterX / bitmapResolution, rotationCenterY / bitmapResolution]
+        );
 
+        // @todo there should be a better way to get from ImageData to a decodable storage format
+        canvas.toBlob(blob => {
+            const reader = new FileReader();
+            reader.addEventListener('loadend', () => {
                 const storage = this.runtime.storage;
                 costume.assetId = storage.builtinHelper.cache(
                     storage.AssetType.ImageBitmap,
                     storage.DataFormat.PNG,
-            bitmap.data
+                    Buffer.from(reader.result)
                 );
                 costume.dataFormat = storage.DataFormat.PNG;
                 costume.bitmapResolution = bitmapResolution;
-        // costume.size = [bitmap.width, bitmap.height];
+                costume.size = [bitmap.width, bitmap.height];
-        // costume.md5 = `${costume.assetId}.${costume.dataFormat}`;
+                costume.md5 = `${costume.assetId}.${costume.dataFormat}`;
                 this.emitTargetsUpdate();
+            });
+            reader.readAsArrayBuffer(blob);
+        });
     }
 
     /**