Multihead fullscreen broken on macOS

[fltk]

Multihead fullscreen broken on macOS

[CendioOssman]

Suggested fix:

diff -up fltk-1.3.5/src/Fl_cocoa.mm.multihead fltk-1.3.5/src/Fl_cocoa.mm
--- fltk-1.3.5/src/Fl_cocoa.mm.multihead	2020-01-21 13:46:18.640982691 +0100
+++ fltk-1.3.5/src/Fl_cocoa.mm	2020-01-21 13:49:00.267671569 +0100
@@ -3100,8 +3100,31 @@ void Fl_Window::fullscreen_x() {
     [i->xid setStyleMask:NSBorderlessWindowMask]; //10.6
 #endif
     [i->xid setLevel:NSStatusWindowLevel];
-    int X,Y,W,H;
-    Fl::screen_xywh(X, Y, W, H, x(), y(), w(), h());
+
+    int top, bottom, left, right;
+    int sx, sy, sw, sh, X, Y, W, H;
+
+    top = fullscreen_screen_top;
+    bottom = fullscreen_screen_bottom;
+    left = fullscreen_screen_left;
+    right = fullscreen_screen_right;
+
+    if ((top < 0) || (bottom < 0) || (left < 0) || (right < 0)) {
+      top = Fl::screen_num(x(), y(), w(), h());
+      bottom = top;
+      left = top;
+      right = top;
+    }
+
+    Fl::screen_xywh(sx, sy, sw, sh, top);
+    Y = sy;
+    Fl::screen_xywh(sx, sy, sw, sh, bottom);
+    H = sy + sh - Y;
+    Fl::screen_xywh(sx, sy, sw, sh, left);
+    X = sx;
+    Fl::screen_xywh(sx, sy, sw, sh, right);
+    W = sx + sw - X;
+
     resize(X, Y, W, H);
   }
   Fl::handle(FL_FULLSCREEN, this);

This is for 1.3.5 but the principle should apply to master as well.

[ManoloFLTK]

Thanks for the patch.
Committed to the 1.4 branch. [Branch 1.3 is no longer updated].
Please, close issue if you confirm it's OK.

[CendioOssman]

I'm afraid I don't have a test setup for 1.4. But your commit looks fine, so let's just close this issue. :)