From c5790e39dc4c83b03b10b3b3b8758e7f0428015b Mon Sep 17 00:00:00 2001
From: Kevin Sawicki <kevinsawicki@gmail.com>
Date: Wed, 26 Oct 2016 12:12:12 +0900
Subject: [PATCH] Add support for zooming to content size

---
 atom/browser/native_window_mac.h  |  4 +++
 atom/browser/native_window_mac.mm | 49 +++++++++++++++++++++++++++++++
 atom/common/options_switches.cc   |  3 ++
 atom/common/options_switches.h    |  1 +
 4 files changed, 57 insertions(+)

diff --git a/atom/browser/native_window_mac.h b/atom/browser/native_window_mac.h
index 339e10e853c..6bd2c69ed4d 100644
--- a/atom/browser/native_window_mac.h
+++ b/atom/browser/native_window_mac.h
@@ -117,6 +117,8 @@ class NativeWindowMac : public NativeWindow,
   };
   TitleBarStyle title_bar_style() const { return title_bar_style_; }
 
+  bool zoom_to_content_size() const { return zoom_to_content_size_; }
+
  protected:
   // Return a vector of non-draggable regions that fill a window of size
   // |width| by |height|, but leave gaps where the window should be draggable.
@@ -155,6 +157,8 @@ class NativeWindowMac : public NativeWindow,
 
   bool is_kiosk_;
 
+  bool zoom_to_content_size_;
+
   NSInteger attention_request_id_;  // identifier from requestUserAttention
 
   // The presentation options before entering kiosk mode.
diff --git a/atom/browser/native_window_mac.mm b/atom/browser/native_window_mac.mm
index 42157f93f9d..69dd29b4f0b 100644
--- a/atom/browser/native_window_mac.mm
+++ b/atom/browser/native_window_mac.mm
@@ -102,6 +102,52 @@ bool ScopedDisableResize::disable_resize_ = false;
    }
 }
 
+// Called when the user clicks the zoom button or selects it from the Window
+// menu) to determine the "standard size" of the window.
+- (NSRect)windowWillUseStandardFrame:(NSWindow*)window
+                        defaultFrame:(NSRect)frame {
+  if (!shell_->zoom_to_content_size())
+    return frame;
+
+  // If the shift key is down, maximize.
+  if ([[NSApp currentEvent] modifierFlags] & NSShiftKeyMask)
+    return frame;
+
+  // To prevent strange results on portrait displays, the basic minimum zoomed
+  // width is the larger of: 60% of available width, 60% of available height
+  // (bounded by available width).
+  const CGFloat kProportion = 0.6;
+  CGFloat zoomedWidth =
+      std::max(kProportion * NSWidth(frame),
+               std::min(kProportion * NSHeight(frame), NSWidth(frame)));
+
+  content::WebContents* web_contents = shell_->web_contents();
+  if (web_contents) {
+    // If the intrinsic width is bigger, then make it the zoomed width.
+    const int kScrollbarWidth = 16;  // TODO(viettrungluu): ugh.
+    CGFloat intrinsicWidth = static_cast<CGFloat>(
+        web_contents->GetPreferredSize().width() + kScrollbarWidth);
+    zoomedWidth = std::max(zoomedWidth,
+                           std::min(intrinsicWidth, NSWidth(frame)));
+  }
+
+  // Never shrink from the current size on zoom (see above).
+  NSRect currentFrame = [shell_->GetNativeWindow() frame];
+  zoomedWidth = std::max(zoomedWidth, NSWidth(currentFrame));
+
+  // |frame| determines our maximum extents. We need to set the origin of the
+  // frame -- and only move it left if necessary.
+  if (currentFrame.origin.x + zoomedWidth > NSMaxX(frame))
+    frame.origin.x = NSMaxX(frame) - zoomedWidth;
+  else
+    frame.origin.x = currentFrame.origin.x;
+
+  // Set the width. Don't touch y or height.
+  frame.size.width = zoomedWidth;
+
+  return frame;
+}
+
 - (void)windowDidBecomeMain:(NSNotification*)notification {
   content::WebContents* web_contents = shell_->web_contents();
   if (!web_contents)
@@ -584,6 +630,7 @@ NativeWindowMac::NativeWindowMac(
     NativeWindow* parent)
     : NativeWindow(web_contents, options, parent),
       is_kiosk_(false),
+      zoom_to_content_size_(false),
       attention_request_id_(0),
       title_bar_style_(NORMAL) {
   int width = 800, height = 600;
@@ -706,6 +753,8 @@ NativeWindowMac::NativeWindowMac(
   if (!has_frame() || !use_content_size)
     SetSize(gfx::Size(width, height));
 
+  options.Get(options::kZoomToContentSize, &zoom_to_content_size_);
+
   // Enable the NSView to accept first mouse event.
   bool acceptsFirstMouse = false;
   options.Get(options::kAcceptFirstMouse, &acceptsFirstMouse);
diff --git a/atom/common/options_switches.cc b/atom/common/options_switches.cc
index 00b2c8c0268..eab2cf8145e 100644
--- a/atom/common/options_switches.cc
+++ b/atom/common/options_switches.cc
@@ -45,6 +45,9 @@ const char kAcceptFirstMouse[] = "acceptFirstMouse";
 // Whether window size should include window frame.
 const char kUseContentSize[] = "useContentSize";
 
+// Whether window zoom should be to content size.
+const char kZoomToContentSize[] = "zoomToContentSize";
+
 // The requested title bar style for the window
 const char kTitleBarStyle[] = "titleBarStyle";
 
diff --git a/atom/common/options_switches.h b/atom/common/options_switches.h
index 345329524b7..fcd98550b0a 100644
--- a/atom/common/options_switches.h
+++ b/atom/common/options_switches.h
@@ -34,6 +34,7 @@ extern const char kKiosk[];
 extern const char kAlwaysOnTop[];
 extern const char kAcceptFirstMouse[];
 extern const char kUseContentSize[];
+extern const char kZoomToContentSize[];
 extern const char kTitleBarStyle[];
 extern const char kAutoHideMenuBar[];
 extern const char kEnableLargerThanScreen[];