From 90a40a38a76024c35936f732f0828dccb993b9b7 Mon Sep 17 00:00:00 2001
From: Janus Weil <janus@gcc.gnu.org>
Date: Mon, 25 Jan 2021 19:35:26 +0100
Subject: [PATCH] Add new property DisplayInfo.RefreshRate (#1505)

* DisplayInfo: add a property 'RefreshRate' (#1443)
* Samples: show RefreshRate on DeviceInfoPage (#1443)
* Add documentation for DisplayInfo.RefreshRate (#1443)
* Add the logic to read the macos refresh rate
  Based on xamarin-macios issue: https://github.com/xamarin/xamarin-macios/issues/9958
  Copied code from: https://gist.github.com/chamons/1eae64a2e5e10cbaf18b140e92ec4ca3
* Try to guess the Hz, but fall back to 60
  This is not the most correct way, but is probably good enough. If there are any better ways in future, we can just add them in or replace this logic.

Co-authored-by: Matthew Leibowitz <mattleibow@live.com>
---
 Samples/Samples/View/DeviceInfoPage.xaml      |  1 +
 .../DeviceDisplay/DeviceDisplay.android.cs    |  7 +--
 .../DeviceDisplay/DeviceDisplay.ios.cs        |  3 +-
 .../DeviceDisplay/DeviceDisplay.macos.cs      | 13 ++++-
 .../DeviceDisplay/DeviceDisplay.shared.cs     |  2 +-
 .../DeviceDisplay/DeviceDisplay.uwp.cs        |  7 ++-
 Xamarin.Essentials/Platform/Platform.macos.cs | 52 +++++++++++++++++++
 .../Types/DisplayInfo.shared.cs               | 13 +++++
 .../xamarin-essentials-android.xml            |  2 +
 .../xamarin-essentials-ios.xml                |  2 +
 .../xamarin-essentials-macos.xml              |  2 +
 .../xamarin-essentials-tvos.xml               |  2 +
 .../xamarin-essentials-uwp.xml                |  2 +
 .../xamarin-essentials-watchos.xml            |  2 +
 .../en/FrameworksIndex/xamarin-essentials.xml |  2 +
 docs/en/Xamarin.Essentials/DisplayInfo.xml    | 48 +++++++++++++++++
 16 files changed, 153 insertions(+), 7 deletions(-)

diff --git a/Samples/Samples/View/DeviceInfoPage.xaml b/Samples/Samples/View/DeviceInfoPage.xaml
index a7ca78225..af212e140 100644
--- a/Samples/Samples/View/DeviceInfoPage.xaml
+++ b/Samples/Samples/View/DeviceInfoPage.xaml
@@ -29,6 +29,7 @@
                 <Label Text="{Binding ScreenMetrics.Density, StringFormat='Density: {0}'}" />
                 <Label Text="{Binding ScreenMetrics.Orientation, StringFormat='Orientation: {0}'}" />
                 <Label Text="{Binding ScreenMetrics.Rotation, StringFormat='Rotation: {0}'}" />
+                <Label Text="{Binding ScreenMetrics.RefreshRate, StringFormat='Refresh Rate: {0}'}" />
             </StackLayout>
         </ScrollView>
     </StackLayout>
diff --git a/Xamarin.Essentials/DeviceDisplay/DeviceDisplay.android.cs b/Xamarin.Essentials/DeviceDisplay/DeviceDisplay.android.cs
index d105fd5b1..e733b7db2 100644
--- a/Xamarin.Essentials/DeviceDisplay/DeviceDisplay.android.cs
+++ b/Xamarin.Essentials/DeviceDisplay/DeviceDisplay.android.cs
@@ -34,7 +34,7 @@ static bool PlatformKeepScreenOn
         static DisplayInfo GetMainDisplayInfo()
         {
             using var displayMetrics = new DisplayMetrics();
-            using var display = GetDefaultDisplay();
+            var display = GetDefaultDisplay();
             display?.GetRealMetrics(displayMetrics);
 
             return new DisplayInfo(
@@ -42,7 +42,8 @@ static DisplayInfo GetMainDisplayInfo()
                 height: displayMetrics?.HeightPixels ?? 0,
                 density: displayMetrics?.Density ?? 0,
                 orientation: CalculateOrientation(),
-                rotation: CalculateRotation());
+                rotation: CalculateRotation(),
+                rate: display?.RefreshRate ?? 0);
         }
 
         static void StartScreenMetricsListeners()
@@ -66,7 +67,7 @@ static void OnScreenMetricsChanged()
 
         static DisplayRotation CalculateRotation()
         {
-            using var display = GetDefaultDisplay();
+            var display = GetDefaultDisplay();
 
             return display?.Rotation switch
             {
diff --git a/Xamarin.Essentials/DeviceDisplay/DeviceDisplay.ios.cs b/Xamarin.Essentials/DeviceDisplay/DeviceDisplay.ios.cs
index 5ef3de6b4..187b03b8d 100644
--- a/Xamarin.Essentials/DeviceDisplay/DeviceDisplay.ios.cs
+++ b/Xamarin.Essentials/DeviceDisplay/DeviceDisplay.ios.cs
@@ -23,7 +23,8 @@ static DisplayInfo GetMainDisplayInfo()
                 height: bounds.Height * scale,
                 density: scale,
                 orientation: CalculateOrientation(),
-                rotation: CalculateRotation());
+                rotation: CalculateRotation(),
+                rate: UIScreen.MainScreen.MaximumFramesPerSecond);
         }
 
         static void StartScreenMetricsListeners()
diff --git a/Xamarin.Essentials/DeviceDisplay/DeviceDisplay.macos.cs b/Xamarin.Essentials/DeviceDisplay/DeviceDisplay.macos.cs
index 35bbaf967..16c307c76 100644
--- a/Xamarin.Essentials/DeviceDisplay/DeviceDisplay.macos.cs
+++ b/Xamarin.Essentials/DeviceDisplay/DeviceDisplay.macos.cs
@@ -1,4 +1,5 @@
 using AppKit;
+using CoreVideo;
 using Foundation;
 
 namespace Xamarin.Essentials
@@ -38,12 +39,22 @@ static DisplayInfo GetMainDisplayInfo()
             var frame = mainScreen.Frame;
             var scale = mainScreen.BackingScaleFactor;
 
+            var mainDisplayId = CoreGraphicsInterop.MainDisplayId;
+
+            // try determine the refresh rate, but fall back to 60Hz
+            var refreshRate = CoreGraphicsInterop.GetRefreshRate(mainDisplayId);
+            if (refreshRate == 0)
+                refreshRate = CVDisplayLinkInterop.GetRefreshRate(mainDisplayId);
+            if (refreshRate == 0)
+                refreshRate = 60.0;
+
             return new DisplayInfo(
                 width: frame.Width,
                 height: frame.Height,
                 density: scale,
                 orientation: DisplayOrientation.Portrait,
-                rotation: DisplayRotation.Rotation0);
+                rotation: DisplayRotation.Rotation0,
+                rate: (float)refreshRate);
         }
 
         static void StartScreenMetricsListeners()
diff --git a/Xamarin.Essentials/DeviceDisplay/DeviceDisplay.shared.cs b/Xamarin.Essentials/DeviceDisplay/DeviceDisplay.shared.cs
index 7583ccac9..8b6f10876 100644
--- a/Xamarin.Essentials/DeviceDisplay/DeviceDisplay.shared.cs
+++ b/Xamarin.Essentials/DeviceDisplay/DeviceDisplay.shared.cs
@@ -17,7 +17,7 @@ public static bool KeepScreenOn
         public static DisplayInfo MainDisplayInfo => GetMainDisplayInfo();
 
         static void SetCurrent(DisplayInfo metrics) =>
-            currentMetrics = new DisplayInfo(metrics.Width, metrics.Height, metrics.Density, metrics.Orientation, metrics.Rotation);
+            currentMetrics = new DisplayInfo(metrics.Width, metrics.Height, metrics.Density, metrics.Orientation, metrics.Rotation, metrics.RefreshRate);
 
         public static event EventHandler<DisplayInfoChangedEventArgs> MainDisplayInfoChanged
         {
diff --git a/Xamarin.Essentials/DeviceDisplay/DeviceDisplay.uwp.cs b/Xamarin.Essentials/DeviceDisplay/DeviceDisplay.uwp.cs
index 328055374..2ee952f75 100644
--- a/Xamarin.Essentials/DeviceDisplay/DeviceDisplay.uwp.cs
+++ b/Xamarin.Essentials/DeviceDisplay/DeviceDisplay.uwp.cs
@@ -1,4 +1,5 @@
 using Windows.Graphics.Display;
+using Windows.Graphics.Display.Core;
 using Windows.System.Display;
 
 namespace Xamarin.Essentials
@@ -54,12 +55,16 @@ static DisplayInfo GetMainDisplayInfo(DisplayInformation di = null)
             var w = di.ScreenWidthInRawPixels;
             var h = di.ScreenHeightInRawPixels;
 
+            var hdi = HdmiDisplayInformation.GetForCurrentView();
+            var hdm = hdi?.GetCurrentDisplayMode();
+
             return new DisplayInfo(
                 width: perpendicular ? h : w,
                 height: perpendicular ? w : h,
                 density: di.LogicalDpi / 96.0,
                 orientation: CalculateOrientation(di),
-                rotation: rotation);
+                rotation: rotation,
+                rate: (float)(hdm?.RefreshRate ?? 0));
         }
 
         static void StartScreenMetricsListeners()
diff --git a/Xamarin.Essentials/Platform/Platform.macos.cs b/Xamarin.Essentials/Platform/Platform.macos.cs
index fbe0981d9..5f9781cda 100644
--- a/Xamarin.Essentials/Platform/Platform.macos.cs
+++ b/Xamarin.Essentials/Platform/Platform.macos.cs
@@ -2,6 +2,7 @@
 using System.Runtime.InteropServices;
 using AppKit;
 using CoreFoundation;
+using CoreVideo;
 using Foundation;
 using ObjCRuntime;
 
@@ -20,6 +21,57 @@ internal static NSWindow GetCurrentWindow(bool throwIfNull = true)
         }
     }
 
+    internal static class CoreGraphicsInterop
+    {
+        public static uint MainDisplayId => CGMainDisplayID();
+
+        [DllImport(Constants.CoreGraphicsLibrary)]
+        static extern IntPtr CGDisplayCopyDisplayMode(uint display);
+
+        [DllImport(Constants.CoreGraphicsLibrary)]
+        static extern void CGDisplayModeRelease(IntPtr mode);
+
+        [DllImport(Constants.CoreGraphicsLibrary)]
+        static extern double CGDisplayModeGetRefreshRate(IntPtr mode);
+
+        [DllImport(Constants.CoreGraphicsLibrary)]
+        static extern uint CGMainDisplayID();
+
+        public static double GetRefreshRate(uint display)
+        {
+            var mode = CGDisplayCopyDisplayMode(display);
+            if (mode == IntPtr.Zero)
+                return 0.0;
+
+            var refreshRate = CGDisplayModeGetRefreshRate(mode);
+
+            CGDisplayModeRelease(mode);
+
+            return refreshRate;
+        }
+    }
+
+    internal static class CVDisplayLinkInterop
+    {
+        [DllImport(Constants.CoreGraphicsLibrary)]
+        static extern int CVDisplayLinkCreateWithCGDisplay(uint display, out IntPtr handle);
+
+        public static double GetRefreshRate(uint display)
+        {
+            var result = CVDisplayLinkCreateWithCGDisplay(display, out var handle);
+            if (result != 0 || handle == IntPtr.Zero)
+                return 0.0;
+
+            using var dl = new CVDisplayLink(handle);
+
+            var period = dl.NominalOutputVideoRefreshPeriod;
+            if (((CVTimeFlags)period.Flags).HasFlag(CVTimeFlags.IsIndefinite) || period.TimeValue == 0)
+                return 0.0;
+
+            return period.TimeScale / (double)period.TimeValue;
+        }
+    }
+
     internal static class IOKit
     {
         const string IOKitLibrary = "/System/Library/Frameworks/IOKit.framework/IOKit";
diff --git a/Xamarin.Essentials/Types/DisplayInfo.shared.cs b/Xamarin.Essentials/Types/DisplayInfo.shared.cs
index 530657e39..6923f6865 100644
--- a/Xamarin.Essentials/Types/DisplayInfo.shared.cs
+++ b/Xamarin.Essentials/Types/DisplayInfo.shared.cs
@@ -12,6 +12,17 @@ public DisplayInfo(double width, double height, double density, DisplayOrientati
             Density = density;
             Orientation = orientation;
             Rotation = rotation;
+            RefreshRate = 0;
+        }
+
+        public DisplayInfo(double width, double height, double density, DisplayOrientation orientation, DisplayRotation rotation, float rate)
+        {
+            Width = width;
+            Height = height;
+            Density = density;
+            Orientation = orientation;
+            Rotation = rotation;
+            RefreshRate = rate;
         }
 
         public double Width { get; }
@@ -24,6 +35,8 @@ public DisplayInfo(double width, double height, double density, DisplayOrientati
 
         public DisplayRotation Rotation { get; }
 
+        public float RefreshRate { get; }
+
         public static bool operator ==(DisplayInfo left, DisplayInfo right) =>
             left.Equals(right);
 
diff --git a/docs/en/FrameworksIndex/xamarin-essentials-android.xml b/docs/en/FrameworksIndex/xamarin-essentials-android.xml
index 746c36beb..0e0d2bf0e 100644
--- a/docs/en/FrameworksIndex/xamarin-essentials-android.xml
+++ b/docs/en/FrameworksIndex/xamarin-essentials-android.xml
@@ -313,6 +313,7 @@
     </Type>
     <Type Name="Xamarin.Essentials.DisplayInfo" Id="T:Xamarin.Essentials.DisplayInfo">
       <Member Id="M:Xamarin.Essentials.DisplayInfo.#ctor(System.Double,System.Double,System.Double,Xamarin.Essentials.DisplayOrientation,Xamarin.Essentials.DisplayRotation)" />
+      <Member Id="M:Xamarin.Essentials.DisplayInfo.#ctor(System.Double,System.Double,System.Double,Xamarin.Essentials.DisplayOrientation,Xamarin.Essentials.DisplayRotation,System.Single)" />
       <Member Id="M:Xamarin.Essentials.DisplayInfo.Equals(System.Object)" />
       <Member Id="M:Xamarin.Essentials.DisplayInfo.Equals(Xamarin.Essentials.DisplayInfo)" />
       <Member Id="M:Xamarin.Essentials.DisplayInfo.GetHashCode" />
@@ -322,6 +323,7 @@
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Density" />
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Height" />
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Orientation" />
+      <Member Id="P:Xamarin.Essentials.DisplayInfo.RefreshRate" />
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Rotation" />
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Width" />
     </Type>
diff --git a/docs/en/FrameworksIndex/xamarin-essentials-ios.xml b/docs/en/FrameworksIndex/xamarin-essentials-ios.xml
index c0584570f..c7b363f56 100644
--- a/docs/en/FrameworksIndex/xamarin-essentials-ios.xml
+++ b/docs/en/FrameworksIndex/xamarin-essentials-ios.xml
@@ -301,6 +301,7 @@
     </Type>
     <Type Name="Xamarin.Essentials.DisplayInfo" Id="T:Xamarin.Essentials.DisplayInfo">
       <Member Id="M:Xamarin.Essentials.DisplayInfo.#ctor(System.Double,System.Double,System.Double,Xamarin.Essentials.DisplayOrientation,Xamarin.Essentials.DisplayRotation)" />
+      <Member Id="M:Xamarin.Essentials.DisplayInfo.#ctor(System.Double,System.Double,System.Double,Xamarin.Essentials.DisplayOrientation,Xamarin.Essentials.DisplayRotation,System.Single)" />
       <Member Id="M:Xamarin.Essentials.DisplayInfo.Equals(System.Object)" />
       <Member Id="M:Xamarin.Essentials.DisplayInfo.Equals(Xamarin.Essentials.DisplayInfo)" />
       <Member Id="M:Xamarin.Essentials.DisplayInfo.GetHashCode" />
@@ -310,6 +311,7 @@
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Density" />
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Height" />
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Orientation" />
+      <Member Id="P:Xamarin.Essentials.DisplayInfo.RefreshRate" />
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Rotation" />
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Width" />
     </Type>
diff --git a/docs/en/FrameworksIndex/xamarin-essentials-macos.xml b/docs/en/FrameworksIndex/xamarin-essentials-macos.xml
index eae1ab7d7..d1551f48f 100644
--- a/docs/en/FrameworksIndex/xamarin-essentials-macos.xml
+++ b/docs/en/FrameworksIndex/xamarin-essentials-macos.xml
@@ -300,6 +300,7 @@
     </Type>
     <Type Name="Xamarin.Essentials.DisplayInfo" Id="T:Xamarin.Essentials.DisplayInfo">
       <Member Id="M:Xamarin.Essentials.DisplayInfo.#ctor(System.Double,System.Double,System.Double,Xamarin.Essentials.DisplayOrientation,Xamarin.Essentials.DisplayRotation)" />
+      <Member Id="M:Xamarin.Essentials.DisplayInfo.#ctor(System.Double,System.Double,System.Double,Xamarin.Essentials.DisplayOrientation,Xamarin.Essentials.DisplayRotation,System.Single)" />
       <Member Id="M:Xamarin.Essentials.DisplayInfo.Equals(System.Object)" />
       <Member Id="M:Xamarin.Essentials.DisplayInfo.Equals(Xamarin.Essentials.DisplayInfo)" />
       <Member Id="M:Xamarin.Essentials.DisplayInfo.GetHashCode" />
@@ -309,6 +310,7 @@
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Density" />
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Height" />
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Orientation" />
+      <Member Id="P:Xamarin.Essentials.DisplayInfo.RefreshRate" />
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Rotation" />
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Width" />
     </Type>
diff --git a/docs/en/FrameworksIndex/xamarin-essentials-tvos.xml b/docs/en/FrameworksIndex/xamarin-essentials-tvos.xml
index ef3980cc1..52bcc3694 100644
--- a/docs/en/FrameworksIndex/xamarin-essentials-tvos.xml
+++ b/docs/en/FrameworksIndex/xamarin-essentials-tvos.xml
@@ -300,6 +300,7 @@
     </Type>
     <Type Name="Xamarin.Essentials.DisplayInfo" Id="T:Xamarin.Essentials.DisplayInfo">
       <Member Id="M:Xamarin.Essentials.DisplayInfo.#ctor(System.Double,System.Double,System.Double,Xamarin.Essentials.DisplayOrientation,Xamarin.Essentials.DisplayRotation)" />
+      <Member Id="M:Xamarin.Essentials.DisplayInfo.#ctor(System.Double,System.Double,System.Double,Xamarin.Essentials.DisplayOrientation,Xamarin.Essentials.DisplayRotation,System.Single)" />
       <Member Id="M:Xamarin.Essentials.DisplayInfo.Equals(System.Object)" />
       <Member Id="M:Xamarin.Essentials.DisplayInfo.Equals(Xamarin.Essentials.DisplayInfo)" />
       <Member Id="M:Xamarin.Essentials.DisplayInfo.GetHashCode" />
@@ -309,6 +310,7 @@
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Density" />
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Height" />
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Orientation" />
+      <Member Id="P:Xamarin.Essentials.DisplayInfo.RefreshRate" />
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Rotation" />
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Width" />
     </Type>
diff --git a/docs/en/FrameworksIndex/xamarin-essentials-uwp.xml b/docs/en/FrameworksIndex/xamarin-essentials-uwp.xml
index 5f35c2432..f88a606d2 100644
--- a/docs/en/FrameworksIndex/xamarin-essentials-uwp.xml
+++ b/docs/en/FrameworksIndex/xamarin-essentials-uwp.xml
@@ -302,6 +302,7 @@
     </Type>
     <Type Name="Xamarin.Essentials.DisplayInfo" Id="T:Xamarin.Essentials.DisplayInfo">
       <Member Id="M:Xamarin.Essentials.DisplayInfo.#ctor(System.Double,System.Double,System.Double,Xamarin.Essentials.DisplayOrientation,Xamarin.Essentials.DisplayRotation)" />
+      <Member Id="M:Xamarin.Essentials.DisplayInfo.#ctor(System.Double,System.Double,System.Double,Xamarin.Essentials.DisplayOrientation,Xamarin.Essentials.DisplayRotation,System.Single)" />
       <Member Id="M:Xamarin.Essentials.DisplayInfo.Equals(System.Object)" />
       <Member Id="M:Xamarin.Essentials.DisplayInfo.Equals(Xamarin.Essentials.DisplayInfo)" />
       <Member Id="M:Xamarin.Essentials.DisplayInfo.GetHashCode" />
@@ -311,6 +312,7 @@
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Density" />
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Height" />
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Orientation" />
+      <Member Id="P:Xamarin.Essentials.DisplayInfo.RefreshRate" />
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Rotation" />
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Width" />
     </Type>
diff --git a/docs/en/FrameworksIndex/xamarin-essentials-watchos.xml b/docs/en/FrameworksIndex/xamarin-essentials-watchos.xml
index 09956fcb5..4395536f4 100644
--- a/docs/en/FrameworksIndex/xamarin-essentials-watchos.xml
+++ b/docs/en/FrameworksIndex/xamarin-essentials-watchos.xml
@@ -300,6 +300,7 @@
     </Type>
     <Type Name="Xamarin.Essentials.DisplayInfo" Id="T:Xamarin.Essentials.DisplayInfo">
       <Member Id="M:Xamarin.Essentials.DisplayInfo.#ctor(System.Double,System.Double,System.Double,Xamarin.Essentials.DisplayOrientation,Xamarin.Essentials.DisplayRotation)" />
+      <Member Id="M:Xamarin.Essentials.DisplayInfo.#ctor(System.Double,System.Double,System.Double,Xamarin.Essentials.DisplayOrientation,Xamarin.Essentials.DisplayRotation,System.Single)" />
       <Member Id="M:Xamarin.Essentials.DisplayInfo.Equals(System.Object)" />
       <Member Id="M:Xamarin.Essentials.DisplayInfo.Equals(Xamarin.Essentials.DisplayInfo)" />
       <Member Id="M:Xamarin.Essentials.DisplayInfo.GetHashCode" />
@@ -309,6 +310,7 @@
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Density" />
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Height" />
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Orientation" />
+      <Member Id="P:Xamarin.Essentials.DisplayInfo.RefreshRate" />
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Rotation" />
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Width" />
     </Type>
diff --git a/docs/en/FrameworksIndex/xamarin-essentials.xml b/docs/en/FrameworksIndex/xamarin-essentials.xml
index 9c369ce18..64676849b 100644
--- a/docs/en/FrameworksIndex/xamarin-essentials.xml
+++ b/docs/en/FrameworksIndex/xamarin-essentials.xml
@@ -299,6 +299,7 @@
     </Type>
     <Type Name="Xamarin.Essentials.DisplayInfo" Id="T:Xamarin.Essentials.DisplayInfo">
       <Member Id="M:Xamarin.Essentials.DisplayInfo.#ctor(System.Double,System.Double,System.Double,Xamarin.Essentials.DisplayOrientation,Xamarin.Essentials.DisplayRotation)" />
+      <Member Id="M:Xamarin.Essentials.DisplayInfo.#ctor(System.Double,System.Double,System.Double,Xamarin.Essentials.DisplayOrientation,Xamarin.Essentials.DisplayRotation,System.Single)" />
       <Member Id="M:Xamarin.Essentials.DisplayInfo.Equals(System.Object)" />
       <Member Id="M:Xamarin.Essentials.DisplayInfo.Equals(Xamarin.Essentials.DisplayInfo)" />
       <Member Id="M:Xamarin.Essentials.DisplayInfo.GetHashCode" />
@@ -308,6 +309,7 @@
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Density" />
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Height" />
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Orientation" />
+      <Member Id="P:Xamarin.Essentials.DisplayInfo.RefreshRate" />
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Rotation" />
       <Member Id="P:Xamarin.Essentials.DisplayInfo.Width" />
     </Type>
diff --git a/docs/en/Xamarin.Essentials/DisplayInfo.xml b/docs/en/Xamarin.Essentials/DisplayInfo.xml
index f8f76aae3..03df2d624 100644
--- a/docs/en/Xamarin.Essentials/DisplayInfo.xml
+++ b/docs/en/Xamarin.Essentials/DisplayInfo.xml
@@ -50,6 +50,34 @@
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
+    <Member MemberName=".ctor">
+      <MemberSignature Language="C#" Value="public DisplayInfo (double width, double height, double density, Xamarin.Essentials.DisplayOrientation orientation, Xamarin.Essentials.DisplayRotation rotation, float rate);" />
+      <MemberSignature Language="ILAsm" Value=".method public hidebysig specialname rtspecialname instance void .ctor(float64 width, float64 height, float64 density, valuetype Xamarin.Essentials.DisplayOrientation orientation, valuetype Xamarin.Essentials.DisplayRotation rotation, float32 rate) cil managed" />
+      <MemberSignature Language="DocId" Value="M:Xamarin.Essentials.DisplayInfo.#ctor(System.Double,System.Double,System.Double,Xamarin.Essentials.DisplayOrientation,Xamarin.Essentials.DisplayRotation,System.Single)" />
+      <MemberType>Constructor</MemberType>
+      <AssemblyInfo>
+        <AssemblyName>Xamarin.Essentials</AssemblyName>
+        <AssemblyVersion>1.0.0.0</AssemblyVersion>
+      </AssemblyInfo>
+      <Parameters>
+        <Parameter Name="width" Type="System.Double" />
+        <Parameter Name="height" Type="System.Double" />
+        <Parameter Name="density" Type="System.Double" />
+        <Parameter Name="orientation" Type="Xamarin.Essentials.DisplayOrientation" />
+        <Parameter Name="rotation" Type="Xamarin.Essentials.DisplayRotation" />
+        <Parameter Name="rate" Type="System.Single" />
+      </Parameters>
+      <Docs>
+        <param name="width">The width of the display</param>
+        <param name="height">The height of the display</param>
+        <param name="density">The screen density</param>
+        <param name="orientation">The current orientation</param>
+        <param name="rotation">The rotation of the device.</param>
+        <param name="rate">The refresh rate of the display.</param>
+        <summary>Main constructor for Display Information</summary>
+        <remarks>To be added.</remarks>
+      </Docs>
+    </Member>
     <Member MemberName="Density">
       <MemberSignature Language="C#" Value="public double Density { get; }" />
       <MemberSignature Language="ILAsm" Value=".property instance float64 Density" />
@@ -222,6 +250,26 @@
         <remarks></remarks>
       </Docs>
     </Member>
+    <Member MemberName="RefreshRate">
+      <MemberSignature Language="C#" Value="public float RefreshRate { get; }" />
+      <MemberSignature Language="ILAsm" Value=".property instance float32 RefreshRate" />
+      <MemberSignature Language="DocId" Value="P:Xamarin.Essentials.DisplayInfo.RefreshRate" />
+      <MemberType>Property</MemberType>
+      <AssemblyInfo>
+        <AssemblyName>Xamarin.Essentials</AssemblyName>
+        <AssemblyVersion>1.0.0.0</AssemblyVersion>
+      </AssemblyInfo>
+      <ReturnValue>
+        <ReturnType>System.Single</ReturnType>
+      </ReturnValue>
+      <Docs>
+        <summary>Gets the refresh rate of the display.</summary>
+        <value>The refresh rate in Hz.</value>
+        <remarks>
+          <para></para>
+        </remarks>
+      </Docs>
+    </Member>
     <Member MemberName="Rotation">
       <MemberSignature Language="C#" Value="public Xamarin.Essentials.DisplayRotation Rotation { get; }" />
       <MemberSignature Language="ILAsm" Value=".property instance valuetype Xamarin.Essentials.DisplayRotation Rotation" />