From 8c39979848e1251043b65f1ceaf5ea9b4be2ac23 Mon Sep 17 00:00:00 2001
From: 21pages <sunboeasy@gmail.com>
Date: Tue, 18 Jun 2024 19:37:15 +0800
Subject: [PATCH] fix get mac display scale, find screen from display id
 (#8401)

---
 src/platform/macos.mm | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/platform/macos.mm b/src/platform/macos.mm
index bce2a6b5b..0f963b97f 100644
--- a/src/platform/macos.mm
+++ b/src/platform/macos.mm
@@ -109,17 +109,17 @@ extern "C" bool MacCheckAdminAuthorization() {
     return Elevate(NULL, NULL);
 }
 
+// https://gist.github.com/briankc/025415e25900750f402235dbf1b74e42
 extern "C" float BackingScaleFactor(uint32_t display) {
-    NSScreen* s = [NSScreen mainScreen];
-    if (s) return [s backingScaleFactor];
-    /* on my mini mac, display==2, but only 1 screen
-    display -= 1;
     NSArray<NSScreen *> *screens = [NSScreen screens];
-    if (display >= 0 && display < [screens count]) {
-        NSScreen* s = [screens objectAtIndex:display];
-        if (s) return [s backingScaleFactor];
+    for (NSScreen *screen in screens) {
+        NSDictionary *deviceDescription = [screen deviceDescription];
+        NSNumber *screenNumber = [deviceDescription objectForKey:@"NSScreenNumber"];
+        CGDirectDisplayID screenDisplayID = [screenNumber unsignedIntValue];
+        if (screenDisplayID == display) {
+            return [screen backingScaleFactor];
+        }
     }
-    */
     return 1;
 }