commit b8b280527041710b69e7dd18d721089698abb227
Author:     ManoloFLTK <41016272+ManoloFLTK@users.noreply.github.com>
AuthorDate: Mon Aug 17 17:21:44 2020 +0200
Commit:     ManoloFLTK <41016272+ManoloFLTK@users.noreply.github.com>
CommitDate: Mon Aug 17 17:21:53 2020 +0200

    Make recent changes to support macOS 11.0 "Big Sur" active with 11.0 only.
    
    An optimisation used for drawing to windows is not possible under 11.0.
    This commits reinstalls it under macOS 10.14 and 10.15.

 src/Fl_cocoa.mm | 39 ++++++++++++++++++++++++++-------------
 1 file changed, 26 insertions(+), 13 deletions(-)

diff --git src/Fl_cocoa.mm src/Fl_cocoa.mm
index d6da12b..899f35d 100644
--- src/Fl_cocoa.mm
+++ src/Fl_cocoa.mm
@@ -559,7 +559,7 @@ void Fl_Cocoa_Screen_Driver::breakMacEventLoop()
 #endif
 - (BOOL)did_view_resolution_change;
 #if MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_14
-- (void)create_aux_bitmap:(BOOL)retina;
+- (void)create_aux_bitmap:(CGContextRef)gc retina:(BOOL)r;
 - (void)reset_aux_bitmap;
 #endif
 @end
@@ -2182,12 +2182,19 @@ static FLTextInputContext* fltextinputcontext_instance = nil;
   return NO;
 }
 #if MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_14
-- (void)create_aux_bitmap:(BOOL)retina {
-  int W = [self frame].size.width, H = [self frame].size.height;
-  if (retina) { W *= 2; H *= 2; }
-  static CGColorSpaceRef cspace = CGColorSpaceCreateDeviceRGB();
-  aux_bitmap = CGBitmapContextCreate(NULL, W, H, 8, 0, cspace, kCGImageAlphaPremultipliedFirst);
-  if (retina) CGContextScaleCTM(aux_bitmap, 2, 2);
+- (void)create_aux_bitmap:(CGContextRef)gc retina:(BOOL)r {
+  if (!gc || fl_mac_os_version >= 110000) {
+    // bitmap context-related functions (e.g., CGBitmapContextGetBytesPerRow) can't be used here with macOS 11.0 "Big Sur"
+    static CGColorSpaceRef cspace = CGColorSpaceCreateDeviceRGB();
+    int W = [self frame].size.width, H = [self frame].size.height;
+    if (r) { W *= 2; H *= 2; }
+    aux_bitmap = CGBitmapContextCreate(NULL, W, H, 8, 0, cspace, kCGImageAlphaPremultipliedFirst);
+  } else {
+    aux_bitmap = CGBitmapContextCreate(NULL, CGBitmapContextGetWidth(gc), CGBitmapContextGetHeight(gc),
+                                       CGBitmapContextGetBitsPerComponent(gc), CGBitmapContextGetBytesPerRow(gc),
+                                       CGBitmapContextGetColorSpace(gc), CGBitmapContextGetBitmapInfo(gc));
+  }
+  if (r) CGContextScaleCTM(aux_bitmap, 2, 2);
 }
 - (void)reset_aux_bitmap {
   CGContextRelease(aux_bitmap);
@@ -2241,20 +2248,26 @@ static FLTextInputContext* fltextinputcontext_instance = nil;
     window->clear_damage(FL_DAMAGE_ALL);
   }
 #if MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_14
-  if (views_use_CA && !aux_bitmap && !window->as_gl_window()) [self create_aux_bitmap:d->mapped_to_retina()];
+  CGContextRef destination = NULL;
+  if (views_use_CA) {
+    destination = [[NSGraphicsContext currentContext] CGContext];
+    if (!aux_bitmap && !window->as_gl_window()) [self create_aux_bitmap:destination retina:d->mapped_to_retina()];
+  }
 #endif
   through_drawRect = YES;
   if (window->damage()) d->Fl_Window_Driver::flush();
 #if MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_14
-  if (views_use_CA) {
-    CGContextRef destination = [[NSGraphicsContext currentContext] CGContext];
-    if (destination) { // can be NULL with gl_start/gl_finish
+  if (destination) { // can be NULL with gl_start/gl_finish
+    if (fl_mac_os_version < 110000 && CGBitmapContextGetBytesPerRow(aux_bitmap) == CGBitmapContextGetBytesPerRow(destination)) {
+      memcpy(CGBitmapContextGetData(destination), CGBitmapContextGetData(aux_bitmap),
+             CGBitmapContextGetHeight(aux_bitmap) * CGBitmapContextGetBytesPerRow(aux_bitmap));
+    } else {
       CGImageRef img = CGBitmapContextCreateImage(aux_bitmap);
       CGContextDrawImage(destination, [self frame], img);
       CGImageRelease(img);
     }
-    Fl_Cocoa_Window_Driver::q_release_context();
-    }
+  }
+  Fl_Cocoa_Window_Driver::q_release_context();
 #endif
   if (!through_Fl_X_flush) window->clear_damage();
   through_drawRect = NO;