commit d30e4aa0af9d21f8b58ccd04f63f529ffcaf6add
Author:     ManoloFLTK <41016272+ManoloFLTK@users.noreply.github.com>
AuthorDate: Tue Mar 12 17:29:29 2024 +0100
Commit:     ManoloFLTK <41016272+ManoloFLTK@users.noreply.github.com>
CommitDate: Tue Mar 12 17:29:29 2024 +0100

    Fix use of FLTK_SCALING_FACTOR under macOS

 src/Fl_Screen_Driver.cxx | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git src/Fl_Screen_Driver.cxx src/Fl_Screen_Driver.cxx
index f975195..2956b7b 100644
--- src/Fl_Screen_Driver.cxx
+++ src/Fl_Screen_Driver.cxx
@@ -564,7 +564,12 @@ void Fl_Screen_Driver::use_startup_scale_factor()
   if ((p = fl_getenv("FLTK_SCALING_FACTOR"))) {
     float factor = 1;
     sscanf(p, "%f", &factor);
-    for (int i = 0; i < s_count; i++)  scale(i, factor * scale(i));
+    if (rescalable() == SYSTEMWIDE_APP_SCALING) {
+      float new_val = factor * scale(0);
+      for (int i = 0; i < s_count; i++)  scale(i, new_val);
+    } else {
+      for (int i = 0; i < s_count; i++)  scale(i, factor * scale(i));
+    }
   }
 }