From 6467a4ada01a1c45ade557dde7cb09b4a4f92e48 Mon Sep 17 00:00:00 2001
From: Manolo Gouy <Manolo>
Date: Mon, 5 Nov 2018 09:04:38 +0000
Subject: [PATCH] MacOS: fix support of Cairo under macOS 10.14 Mojave.

The cairo_test program would redraw the window vertically flipped after the window was
hidden or miniaturized when layer-backed windows were used.

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@13111 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
---
 FL/Fl.H            |  3 +++
 cairo/Fl_Cairo.cxx |  7 +++++++
 src/Fl_cocoa.mm    | 15 +++++++++++++--
 3 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/FL/Fl.H b/FL/Fl.H
index a8f1db765..03924b234 100644
--- a/FL/Fl.H
+++ b/FL/Fl.H
@@ -166,6 +166,9 @@ public: // should be private!
   static int compose_state; // used for dead keys (WIN32) or marked text (MacOS)
   static void call_screen_init(); // recompute screen number and dimensions
 #ifdef __APPLE__
+#  ifdef FLTK_HAVE_CAIRO
+      static bool using_cairo_context;
+#  endif
   static void reset_marked_text(); // resets marked text
   static void insertion_point_location(int x, int y, int height); // sets window coordinates & height of insertion point
 #endif
diff --git a/cairo/Fl_Cairo.cxx b/cairo/Fl_Cairo.cxx
index 6207d3c2e..6208272b2 100644
--- a/cairo/Fl_Cairo.cxx
+++ b/cairo/Fl_Cairo.cxx
@@ -34,6 +34,7 @@
 # elif defined(WIN32)
 #  include <cairo-win32.h>
 # elif defined(__APPLE_QUARTZ__)
+bool Fl::using_cairo_context = false;
 #  include <cairo-quartz.h>
 # else
 #  error Cairo is not supported on this platform.
@@ -78,9 +79,15 @@ cairo_t * Fl::cairo_make_current(Fl_Window* wi) {
     if (fl_gc==0) { // means remove current cc
 	Fl::cairo_cc(0); // destroy any previous cc
 	cairo_state_.window(0);
+#if defined(__APPLE_QUARTZ__)
+      Fl::using_cairo_context = false;
+#endif
 	return 0;
     }
 
+#if defined(__APPLE_QUARTZ__)
+  Fl::using_cairo_context = true;
+#endif
     // don't re-create a context if it's the same gc/window couple
     if (fl_gc==Fl::cairo_state_.gc() && fl_xid(wi) == (Window) Fl::cairo_state_.window())
 	return Fl::cairo_cc();
diff --git a/src/Fl_cocoa.mm b/src/Fl_cocoa.mm
index cd4060e78..36c67a2e0 100644
--- a/src/Fl_cocoa.mm
+++ b/src/Fl_cocoa.mm
@@ -36,9 +36,8 @@ extern "C" {
 #include <pthread.h>
 }
 
-
-#include <FL/Fl.H>
 #include <FL/x.H>
+#include <FL/Fl.H>
 #include <FL/Fl_Window.H>
 #include <FL/Fl_Tooltip.H>
 #include <FL/Fl_Printer.H>
@@ -2421,8 +2420,20 @@ static CGContextRef prepare_bitmap_for_layer(int w, int h ) {
   }
   if (window->damage()) {
     through_drawRect = YES;
+#ifdef FLTK_HAVE_CAIRO
+    CGFloat before_flush = CGContextGetCTM(layer_gc).d;
+    Fl::using_cairo_context = false;
+#endif
     i->flush();
     Fl_X::q_release_context();
+#ifdef FLTK_HAVE_CAIRO
+    if (Fl::using_cairo_context && CGContextGetCTM(layer_gc).d != before_flush ) {
+      // necessary for Cairo and layer-backed views
+      CGContextRestoreGState(layer_gc);
+      CGContextSaveGState(layer_gc);
+    }
+    Fl::using_cairo_context = false;
+#endif
     through_drawRect = NO;
     window->clear_damage();
     if (layer_gc) {