electron · MarshallOfSound · Aug 24, 2017 · Aug 9, 2017 · Aug 9, 2017 · Aug 9, 2017
diff --git a/atom/browser/native_browser_view.cc b/atom/browser/native_browser_view.cc
@@ -2,6 +2,8 @@
 // Use of this source code is governed by the MIT license that can be
 // found in the LICENSE file.
 
+#include <vector>
+
 #include "atom/browser/native_browser_view.h"
 
 #include "atom/browser/api/atom_api_web_contents.h"

diff --git a/atom/browser/native_browser_view.h b/atom/browser/native_browser_view.h
@@ -5,6 +5,9 @@
 #ifndef ATOM_BROWSER_NATIVE_BROWSER_VIEW_H_
 #define ATOM_BROWSER_NATIVE_BROWSER_VIEW_H_
 
+#include <vector>
+
+#include "atom/common/draggable_region.h"
 #include "base/macros.h"
 #include "third_party/skia/include/core/SkColor.h"
 
@@ -38,6 +41,10 @@ class NativeBrowserView {
   virtual void SetBounds(const gfx::Rect& bounds) = 0;
   virtual void SetBackgroundColor(SkColor color) = 0;
 
+  // Called when the window needs to update its draggable region.
+  virtual void UpdateDraggableRegions(
+    const std::vector<gfx::Rect>& system_drag_exclude_areas) {}
+
  protected:
   explicit NativeBrowserView(
       brightray::InspectableWebContentsView* web_contents_view);

diff --git a/atom/browser/native_browser_view_mac.h b/atom/browser/native_browser_view_mac.h
@@ -6,8 +6,11 @@
 #define ATOM_BROWSER_NATIVE_BROWSER_VIEW_MAC_H_
 
 #import <Cocoa/Cocoa.h>
+#include <vector>
 
 #include "atom/browser/native_browser_view.h"
+#include "atom/common/draggable_region.h"
+#include "base/mac/scoped_nsobject.h"
 
 namespace atom {
 
@@ -20,6 +23,8 @@ class NativeBrowserViewMac : public NativeBrowserView {
   void SetAutoResizeFlags(uint8_t flags) override;
   void SetBounds(const gfx::Rect& bounds) override;
   void SetBackgroundColor(SkColor color) override;
+  void UpdateDraggableRegions(
+      const std::vector<gfx::Rect>& system_drag_exclude_areas) override;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(NativeBrowserViewMac);

diff --git a/atom/browser/native_browser_view_mac.mm b/atom/browser/native_browser_view_mac.mm
@@ -12,6 +12,101 @@
 const NSAutoresizingMaskOptions kDefaultAutoResizingMask =
     NSViewMaxXMargin | NSViewMinYMargin;
 
+@interface DragRegionView : NSView
+
+@property (assign) NSPoint initialLocation;
+
+@end
+
+@interface NSWindow ()
+- (void)performWindowDragWithEvent:(NSEvent *)event;
+@end
+
+@implementation DragRegionView
+
+- (BOOL)mouseDownCanMoveWindow
+{
+  return NO;
+}
+
+- (NSView *)hitTest:(NSPoint)aPoint
+{
+    // Pass-through events that don't hit one of the exclusion zones
+    for (NSView *exlusion_zones in [self subviews]) {
+      if ([exlusion_zones hitTest:aPoint])
+        return nil;
+    }
+
+    return self;
+}
+
+- (void)mouseDown:(NSEvent *)event
+{
+  if ([self.window respondsToSelector:@selector(performWindowDragWithEvent)]) {
+    [self.window performWindowDragWithEvent:event];
+    return;
+  }
+
+  self.initialLocation = [event locationInWindow];
+}
+
+- (void)mouseDragged:(NSEvent *)theEvent
+{
+  if ([self.window respondsToSelector:@selector(performWindowDragWithEvent)]) {
+    return;
+  }
+
+  NSPoint currentLocation = [NSEvent mouseLocation];
+  NSPoint newOrigin;
+
+  NSRect screenFrame = [[NSScreen mainScreen] frame];
+  NSRect windowFrame = [self.window frame];
+
+  newOrigin.x = currentLocation.x - self.initialLocation.x;
+  newOrigin.y = currentLocation.y - self.initialLocation.y;
+
+  // Don't let window get dragged up under the menu bar
+  if ((newOrigin.y + windowFrame.size.height) > (screenFrame.origin.y + screenFrame.size.height)) {
+    newOrigin.y = screenFrame.origin.y + (screenFrame.size.height - windowFrame.size.height);
+  }
+
+  // Move the window to the new location
+  [self.window setFrameOrigin:newOrigin];
+}
+
+// Debugging tips:
+// Uncomment the following four lines to color DragRegionView bright red
+// #ifdef DEBUG_DRAG_REGIONS
+// - (void)drawRect:(NSRect)aRect
+// {
+//     [[NSColor redColor] set];
+//     NSRectFill([self bounds]);
+// }
+// #endif
+
+@end
+
+@interface ExcludeDragRegionView : NSView
+@end
+
+@implementation ExcludeDragRegionView
+
+- (BOOL)mouseDownCanMoveWindow {
+  return NO;
+}
+
+// Debugging tips:
+// Uncomment the following four lines to color ExcludeDragRegionView bright red
+// #ifdef DEBUG_DRAG_REGIONS
+// - (void)drawRect:(NSRect)aRect
+// {
+//     [[NSColor greenColor] set];
+//     NSRectFill([self bounds]);
+// }
+// #endif
+
+@end
+
 namespace atom {
 
 NativeBrowserViewMac::NativeBrowserViewMac(
@@ -51,6 +146,59 @@
   view.layer.backgroundColor = skia::CGColorCreateFromSkColor(color);
 }
 
+void NativeBrowserViewMac::UpdateDraggableRegions(
+    const std::vector<gfx::Rect>& system_drag_exclude_areas) {
+  NSView* webView = GetInspectableWebContentsView()->GetNativeView();
+
+  NSInteger superViewHeight = NSHeight([webView.superview bounds]);
+  NSInteger webViewHeight = NSHeight([webView bounds]);
+  NSInteger webViewWidth = NSWidth([webView bounds]);
+  NSInteger webViewX = NSMinX([webView frame]);
+  NSInteger webViewY = 0;
+
+  // Apple's NSViews have their coordinate system originate at the bottom left,
+  // meaning that we need to be a bit smarter when it comes to calculating our
+  // current top offset
+  if (webViewHeight > superViewHeight) {
+    webViewY = std::abs(webViewHeight - superViewHeight - (std::abs(NSMinY([webView frame]))));
+  } else {
+    webViewY = superViewHeight - NSMaxY([webView frame]);
+  }
+
+  // Remove all DraggableRegionViews that are added last time.
+  // Note that [webView subviews] returns the view's mutable internal array and
+  // it should be copied to avoid mutating the original array while enumerating
+  // it.
+  base::scoped_nsobject<NSArray> subviews([[webView subviews] copy]);
+  for (NSView* subview in subviews.get())
+    if ([subview isKindOfClass:[DragRegionView class]])
+      [subview removeFromSuperview];
+
+  // Create one giant NSView that is draggable.
+  base::scoped_nsobject<NSView> dragRegion(
+        [[DragRegionView alloc] initWithFrame:NSZeroRect]);
+    [dragRegion setFrame:NSMakeRect(0,
+                                    0,
+                                    webViewWidth,
+                                    webViewHeight)];
+
+  // Then, on top of that, add "exclusion zones"
+  for (auto iter = system_drag_exclude_areas.begin();
+       iter != system_drag_exclude_areas.end();
+       ++iter) {
+    base::scoped_nsobject<NSView> controlRegion(
+        [[ExcludeDragRegionView alloc] initWithFrame:NSZeroRect]);
+    [controlRegion setFrame:NSMakeRect(iter->x() - webViewX,
+                                       webViewHeight - iter->bottom() + webViewY,
+                                       iter->width(),
+                                       iter->height())];
+    [dragRegion addSubview:controlRegion];
+  }
+
+  // Add the DragRegion to the WebView
+  [webView addSubview:dragRegion];
+}
+
 // static
 NativeBrowserView* NativeBrowserView::Create(
     brightray::InspectableWebContentsView* web_contents_view) {

diff --git a/atom/browser/native_window_mac.h b/atom/browser/native_window_mac.h
@@ -154,7 +154,7 @@ class NativeWindowMac : public NativeWindow,
   void UninstallView();
 
   // Install the drag view, which will cover the whole window and decides
-  // whehter we can drag.
+  // whether we can drag.
   void UpdateDraggableRegionViews(const std::vector<DraggableRegion>& regions);
 
   void RegisterInputEventObserver(content::RenderViewHost* host);

diff --git a/atom/browser/native_window_mac.mm b/atom/browser/native_window_mac.mm
@@ -1767,6 +1767,10 @@ static bool FromV8(v8::Isolate* isolate, v8::Handle<v8::Value> val,
   std::vector<gfx::Rect> system_drag_exclude_areas =
       CalculateNonDraggableRegions(regions, webViewWidth, webViewHeight);
 
+  if (browser_view_) {
+    browser_view_->UpdateDraggableRegions(system_drag_exclude_areas);
+  }
+
   // Create and add a ControlRegionView for each region that needs to be
   // excluded from the dragging.
   for (std::vector<gfx::Rect>::const_iterator iter =