From 17a7db57389c3b87bca31b0d7b120d66175ff237 Mon Sep 17 00:00:00 2001
From: Jeremy Rose <nornagon@nornagon.net>
Date: Fri, 2 Oct 2020 16:14:04 -0700
Subject: [PATCH] fix: nativeImage.crop().toBitmap() returning garbage

---
 shell/common/api/electron_api_native_image.cc | 21 ++++++++++++-------
 spec/api-native-image-spec.js                 |  6 ++++++
 2 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/shell/common/api/electron_api_native_image.cc b/shell/common/api/electron_api_native_image.cc
index cd2faa86fcb22..8159d0a062616 100644
--- a/shell/common/api/electron_api_native_image.cc
+++ b/shell/common/api/electron_api_native_image.cc
@@ -180,13 +180,20 @@ v8::Local<v8::Value> NativeImage::ToBitmap(gin::Arguments* args) {
 
   const SkBitmap bitmap =
       image_.AsImageSkia().GetRepresentation(scale_factor).GetBitmap();
-  SkPixelRef* ref = bitmap.pixelRef();
-  if (!ref)
-    return node::Buffer::New(args->isolate(), 0).ToLocalChecked();
-  return node::Buffer::Copy(args->isolate(),
-                            reinterpret_cast<const char*>(ref->pixels()),
-                            bitmap.computeByteSize())
-      .ToLocalChecked();
+
+  SkImageInfo info =
+      SkImageInfo::MakeN32Premul(bitmap.width(), bitmap.height());
+
+  auto array_buffer =
+      v8::ArrayBuffer::New(args->isolate(), info.computeMinByteSize());
+  auto backing_store = array_buffer->GetBackingStore();
+  if (bitmap.readPixels(info, backing_store->Data(), info.minRowBytes(), 0,
+                        0)) {
+    return node::Buffer::New(args->isolate(), array_buffer, 0,
+                             info.computeMinByteSize())
+        .ToLocalChecked();
+  }
+  return node::Buffer::New(args->isolate(), 0).ToLocalChecked();
 }
 
 v8::Local<v8::Value> NativeImage::ToJPEG(v8::Isolate* isolate, int quality) {
diff --git a/spec/api-native-image-spec.js b/spec/api-native-image-spec.js
index ae5ef33de6a92..8ef1964a0289c 100644
--- a/spec/api-native-image-spec.js
+++ b/spec/api-native-image-spec.js
@@ -498,6 +498,12 @@ describe('nativeImage module', () => {
       expect(cropB.getSize()).to.deep.equal({ width: 25, height: 64 });
       expect(cropA.toPNG().equals(cropB.toPNG())).to.be.false();
     });
+
+    it('toBitmap() returns a buffer of the right size', () => {
+      const image = nativeImage.createFromPath(path.join(__dirname, 'fixtures', 'assets', 'logo.png'));
+      const crop = image.crop({ width: 25, height: 64, x: 0, y: 0 });
+      expect(crop.toBitmap().length).to.equal(25 * 64 * 4);
+    });
   });
 
   describe('getAspectRatio()', () => {