Merge pull request #4791 from atom/nativeimage-as-nsimage

Convert NativeImage instances to OS-specific representations

atom/common/api/atom_api_native_image.cc

@@ -184,6 +184,8 @@ mate::ObjectTemplateBuilder NativeImage::GetObjectTemplateBuilder(
     template_.Reset(isolate, mate::ObjectTemplateBuilder(isolate)
         .SetMethod("toPng", &NativeImage::ToPNG)
         .SetMethod("toJpeg", &NativeImage::ToJPEG)
+        .SetMethod("getNativeHandle",
+          &NativeImage::GetNativeHandle)
         .SetMethod("toDataURL", &NativeImage::ToDataURL)
         .SetMethod("toDataUrl", &NativeImage::ToDataURL)  // deprecated.
         .SetMethod("isEmpty", &NativeImage::IsEmpty)
@@ -221,6 +223,23 @@ std::string NativeImage::ToDataURL() {
   return data_url;
 }
 
+v8::Local<v8::Value> NativeImage::GetNativeHandle(
+    v8::Isolate* isolate,
+    mate::Arguments* args) {
+void* ptr = NULL;
+#if defined(OS_MACOSX)
+  ptr = reinterpret_cast<void*>(image_.AsNSImage());
+#else
+  args->ThrowError();
+  return v8::Undefined(isolate);
+#endif
+
+  return node::Buffer::Copy(
+    isolate,
+    reinterpret_cast<char*>(ptr),
+    sizeof(void*)).ToLocalChecked();
+}
+
 bool NativeImage::IsEmpty() {
   return image_.IsEmpty();
 }

atom/common/api/atom_api_native_image.h

@@ -61,6 +61,9 @@ class NativeImage : public mate::Wrappable {
  private:
   v8::Local<v8::Value> ToPNG(v8::Isolate* isolate);
   v8::Local<v8::Value> ToJPEG(v8::Isolate* isolate, int quality);
+  v8::Local<v8::Value> GetNativeHandle(
+    v8::Isolate* isolate,
+    mate::Arguments* args);
   std::string ToDataURL();
   bool IsEmpty();
   gfx::Size GetSize();

docs/api/native-image.md

@@ -133,6 +133,12 @@ Returns a [Buffer][buffer] that contains the image's `JPEG` encoded data.
 
 Returns the data URL of the image.
 
+### `image.getNativeHandle()`
+
+Returns a pointer to an underlying native type (encoded as a [Buffer][buffer]) which can be used with native APIs. Note that in many cases, this pointer is a weak pointer to the underlying native image not a copy, so you _must_ ensure that the associated `nativeImage` instance is kept around.
+
+Returns a [Buffer][buffer] that represents a pointer to a native type - on OS X, this type is an NSImage object.
+
 ### `image.isEmpty()`
 
 Returns a boolean whether the image is empty.

spec/api-native-image-spec.js

@@ -34,5 +34,18 @@ describe('nativeImage module', () => {
       assert.equal(image.getSize().height, 190);
       assert.equal(image.getSize().width, 538);
     });
+
+    it('Gets an NSImage pointer on OS X', () => {
+      if (process.platform !== 'darwin') return;
+
+      const imagePath = `${path.join(__dirname, 'fixtures', 'api')}${path.sep}..${path.sep}${path.join('assets', 'logo.png')}`;
+      const image = nativeImage.createFromPath(imagePath);
+      const nsimage = image.getNativeHandle();
+
+      assert.equal(nsimage.length, 8);
+
+      // If all bytes are null, that's Bad
+      assert.equal(nsimage.reduce((acc,x) => acc || (x != 0), false), true);
+    });
   });
 });