feat: add win.getBackgroundColor() for macOS (#21448)

thanks @vbennich - great work on this 🌟

docs/api/browser-window.md

@@ -1019,6 +1019,11 @@ console.log(win.getBounds())
 
 Returns [`Rectangle`](structures/rectangle.md) - The `bounds` of the window as `Object`.
 
+#### `win.getBackgroundColor()`
+
+Returns `String` - Gets the background color of the window. See [Setting
+`backgroundColor`](#setting-backgroundcolor).
+
 #### `win.setContentBounds(bounds[, animate])`
 
 * `bounds` [Rectangle](structures/rectangle.md)

shell/browser/api/atom_api_browser_view.h

@@ -56,7 +56,6 @@ class BrowserView : public gin_helper::TrackableObject<BrowserView>,
   void SetBounds(const gfx::Rect& bounds);
   gfx::Rect GetBounds();
   void SetBackgroundColor(const std::string& color_name);
-
   v8::Local<v8::Value> GetWebContents();
 
   v8::Global<v8::Value> web_contents_;

shell/browser/api/atom_api_top_level_window.cc

@@ -620,6 +620,10 @@ void TopLevelWindow::SetBackgroundColor(const std::string& color_name) {
   window_->SetBackgroundColor(color);
 }
 
+std::string TopLevelWindow::GetBackgroundColor() {
+  return ToRGBHex(window_->GetBackgroundColor());
+}
+
 void TopLevelWindow::SetHasShadow(bool has_shadow) {
   window_->SetHasShadow(has_shadow);
 }
@@ -1145,6 +1149,7 @@ void TopLevelWindow::BuildPrototype(v8::Isolate* isolate,
       .SetMethod("setKiosk", &TopLevelWindow::SetKiosk)
       .SetMethod("isKiosk", &TopLevelWindow::IsKiosk)
       .SetMethod("setBackgroundColor", &TopLevelWindow::SetBackgroundColor)
+      .SetMethod("getBackgroundColor", &TopLevelWindow::GetBackgroundColor)
       .SetMethod("setHasShadow", &TopLevelWindow::SetHasShadow)
       .SetMethod("hasShadow", &TopLevelWindow::HasShadow)
       .SetMethod("setOpacity", &TopLevelWindow::SetOpacity)

shell/browser/api/atom_api_top_level_window.h

@@ -155,6 +155,7 @@ class TopLevelWindow : public gin_helper::TrackableObject<TopLevelWindow>,
   void SetKiosk(bool kiosk);
   bool IsKiosk();
   virtual void SetBackgroundColor(const std::string& color_name);
+  std::string GetBackgroundColor();
   void SetHasShadow(bool has_shadow);
   bool HasShadow();
   void SetOpacity(const double opacity);

shell/browser/native_window.h

@@ -149,6 +149,7 @@ class NativeWindow : public base::SupportsUserData,
   virtual void SetKiosk(bool kiosk) = 0;
   virtual bool IsKiosk() = 0;
   virtual void SetBackgroundColor(SkColor color) = 0;
+  virtual SkColor GetBackgroundColor() = 0;
   virtual void SetHasShadow(bool has_shadow) = 0;
   virtual bool HasShadow() = 0;
   virtual void SetOpacity(const double opacity) = 0;

shell/browser/native_window_mac.h

@@ -93,6 +93,7 @@ class NativeWindowMac : public NativeWindow {
   void SetKiosk(bool kiosk) override;
   bool IsKiosk() override;
   void SetBackgroundColor(SkColor color) override;
+  SkColor GetBackgroundColor() override;
   void SetHasShadow(bool has_shadow) override;
   bool HasShadow() override;
   void SetOpacity(const double opacity) override;

shell/browser/native_window_mac.mm

@@ -1102,6 +1102,11 @@ void NativeWindowMac::SetBackgroundColor(SkColor color) {
   [[[window_ contentView] layer] setBackgroundColor:cgcolor];
 }
 
+SkColor NativeWindowMac::GetBackgroundColor() {
+  return skia::CGColorRefToSkColor(
+      [[[window_ contentView] layer] backgroundColor]);
+}
+
 void NativeWindowMac::SetHasShadow(bool has_shadow) {
   [window_ setHasShadow:has_shadow];
 }

shell/browser/native_window_views.cc

@@ -903,6 +903,10 @@ bool NativeWindowViews::IsKiosk() {
   return IsFullscreen();
 }
 
+SkColor NativeWindowViews::GetBackgroundColor() {
+  return root_view_->background()->get_color();
+}
+
 void NativeWindowViews::SetBackgroundColor(SkColor background_color) {
   // web views' background color.
   root_view_->SetBackground(views::CreateSolidBackground(background_color));

shell/browser/native_window_views.h

@@ -66,6 +66,7 @@ class NativeWindowViews : public NativeWindow,
   gfx::Rect GetContentBounds() override;
   gfx::Size GetContentSize() override;
   gfx::Rect GetNormalBounds() override;
+  SkColor GetBackgroundColor() override;
   void SetContentSizeConstraints(
       const extensions::SizeConstraints& size_constraints) override;
   void SetResizable(bool resizable) override;

spec-main/api-browser-window-spec.ts

@@ -834,6 +834,29 @@ describe('BrowserWindow module', () => {
       })
     })
 
+    describe('BrowserWindow.getBackgroundColor()', () => {
+      it('returns default value if no backgroundColor is set', () => {
+        w.destroy()
+        w = new BrowserWindow({})
+        expect(w.getBackgroundColor()).to.equal('#FFFFFF')
+      })
+      it('returns correct value if backgroundColor is set', () => {
+        const backgroundColor = '#BBAAFF'
+        w.destroy()
+        w = new BrowserWindow({
+          backgroundColor: backgroundColor
+        })
+        expect(w.getBackgroundColor()).to.equal(backgroundColor)
+      })
+      it('returns correct value from setBackgroundColor()', () => {
+        const backgroundColor = '#AABBFF'
+        w.destroy()
+        w = new BrowserWindow({})
+        w.setBackgroundColor(backgroundColor)
+        expect(w.getBackgroundColor()).to.equal(backgroundColor)
+      })
+    })
+
     describe(`BrowserWindow.getNormalBounds()`, () => {
       describe(`Normal state`, () => {
         it(`checks normal bounds after resize`, (done) => {