From 25189a79956f04a15efb24760bbae3d153461050 Mon Sep 17 00:00:00 2001
From: Tiga Wu <voygagaga@outlook.com>
Date: Wed, 20 Mar 2019 23:24:49 -0400
Subject: [PATCH 1/2] add option on macos to disallow highdpi

---
 src/os/macos.rs              |  9 +++++++++
 src/platform/macos/window.rs | 14 ++++++++++----
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/src/os/macos.rs b/src/os/macos.rs
index b9ea993b39..fcea7cc7f9 100644
--- a/src/os/macos.rs
+++ b/src/os/macos.rs
@@ -82,6 +82,7 @@ impl Default for ActivationPolicy {
 ///  - `with_titlebar_hidden`
 ///  - `with_titlebar_buttons_hidden`
 ///  - `with_fullsize_content_view`
+///  - `with_disallow_hidpi`
 pub trait WindowBuilderExt {
     /// Sets the activation policy for the window being built.
     fn with_activation_policy(self, activation_policy: ActivationPolicy) -> WindowBuilder;
@@ -99,6 +100,8 @@ pub trait WindowBuilderExt {
     fn with_fullsize_content_view(self, fullsize_content_view: bool) -> WindowBuilder;
     /// Build window with `resizeIncrements` property. Values must not be 0.
     fn with_resize_increments(self, increments: LogicalSize) -> WindowBuilder;
+    /// Disables hidpi.
+    fn with_disallow_hidpi(self, disallow_hidpi: bool) -> WindowBuilder;
 }
 
 impl WindowBuilderExt for WindowBuilder {
@@ -149,6 +152,12 @@ impl WindowBuilderExt for WindowBuilder {
         self.platform_specific.resize_increments = Some(increments.into());
         self
     }
+
+    #[inline]
+    fn with_disallow_hidpi(mut self, disallow_hidpi: bool) -> WindowBuilder {
+        self.platform_specific.disallow_hidpi = disallow_hidpi;
+        self
+    }
 }
 
 /// Additional methods on `MonitorId` that are specific to MacOS.
diff --git a/src/platform/macos/window.rs b/src/platform/macos/window.rs
index 4fc27328a3..eb51f524a3 100644
--- a/src/platform/macos/window.rs
+++ b/src/platform/macos/window.rs
@@ -539,6 +539,7 @@ pub struct PlatformSpecificWindowBuilderAttributes {
     pub titlebar_hidden: bool,
     pub titlebar_buttons_hidden: bool,
     pub fullsize_content_view: bool,
+    pub disallow_hidpi: bool,
     pub resize_increments: Option<LogicalSize>,
 }
 
@@ -715,7 +716,7 @@ impl Window2 {
                 return Err(OsError(format!("Couldn't create NSWindow")));
             },
         };
-        let (view, cursor) = match Window2::create_view(*window, Weak::clone(&shared)) {
+        let (view, cursor) = match Window2::create_view(*window, Weak::clone(&shared), &pl_attribs) {
             Some(view) => view,
             None => {
                 let _: () = unsafe { msg_send![autoreleasepool, drain] };
@@ -952,12 +953,17 @@ impl Window2 {
         }
     }
 
-    fn create_view(window: id, shared: Weak<Shared>) -> Option<(IdRef, Weak<Mutex<util::Cursor>>)> {
+    fn create_view(
+        window: id,
+        shared: Weak<Shared>,
+        pl_attribs: &PlatformSpecificWindowBuilderAttributes
+    ) -> Option<(IdRef, Weak<Mutex<util::Cursor>>)> {
         unsafe {
             let (view, cursor) = new_view(window, shared);
             view.non_nil().map(|view| {
-                view.setWantsBestResolutionOpenGLSurface_(YES);
-
+                if !pl_attribs.disallow_hidpi {
+                    view.setWantsBestResolutionOpenGLSurface_(YES);
+                }
                 // On Mojave, views automatically become layer-backed shortly after being added to
                 // a window. Changing the layer-backedness of a view breaks the association between
                 // the view and its associated OpenGL context. To work around this, on Mojave we

From 4a36f406a0eeadf3d4af9f746b8dd0d2781aeaf2 Mon Sep 17 00:00:00 2001
From: Tiga Wu <voygagaga@outlook.com>
Date: Wed, 20 Mar 2019 23:29:13 -0400
Subject: [PATCH 2/2] update CHANGELOG

---
 CHANGELOG.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8783afba1c..aaa5475a67 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,7 @@
 # Unreleased
 
 - On Windows, fix `CursorMoved(0, 0)` getting dispatched on window focus.
+- On macOS, add `WindowBuilderExt::with_disallow_hidpi` to have the option to turn off best resolution openGL surface
 
 # Version 0.19.0 (2019-03-06)