From a4503bccc006c750fc0861a98984a4fe89a5fc90 Mon Sep 17 00:00:00 2001
From: dmitry <dmitry@lazarus-ide.org>
Date: Sat, 29 Sep 2018 21:33:29 +0000
Subject: [PATCH] cocoa: additional control over cocoa window levels

git-svn-id: trunk@59185 -
---
 lcl/interfaces/cocoa/cocoaint.pas     | 13 ++++++++++
 lcl/interfaces/cocoa/cocoawindows.pas | 13 ++++++++++
 lcl/interfaces/cocoa/cocoawsforms.pas | 37 +++++++++++++++++++--------
 3 files changed, 52 insertions(+), 11 deletions(-)

diff --git a/lcl/interfaces/cocoa/cocoaint.pas b/lcl/interfaces/cocoa/cocoaint.pas
index 0fb5ed7c12..5a1eee617a 100644
--- a/lcl/interfaces/cocoa/cocoaint.pas
+++ b/lcl/interfaces/cocoa/cocoaint.pas
@@ -177,6 +177,7 @@ type
     procedure SetMainMenu(const AMenu: HMENU; const ALCLMenu: TMenu);
     function StartModal(awin: NSWindow; hasMenu: Boolean): Boolean;
     procedure EndModal(awin: NSWindow);
+    function isModalSession: Boolean;
 
     {todo:}
     function  DCGetPixel(CanvasHandle: HDC; X, Y: integer): TGraphicsColor; override;
@@ -580,11 +581,19 @@ end;
 function TCocoaWidgetSet.StartModal(awin: NSWindow; hasMenu: Boolean): Boolean;
 var
   sess : NSModalSession;
+  lvl : NSInteger;
 begin
   Result := false;
   if not Assigned(awin) then Exit;
+
+  lvl := awin.level;
+
   sess := NSApplication(NSApp).beginModalSessionForWindow(awin);
   if not Assigned(sess) then Exit;
+
+  // beginModalSession "configures" the modality and potentially is changing window level
+  awin.setLevel(lvl);
+
   if not Assigned(Modals) then Modals := TList.Create;
 
   // If a modal menu has it's menu, then SetMainMenu has already been called
@@ -619,6 +628,10 @@ begin
   Modals.Delete(Modals.Count-1);
 end;
 
+function TCocoaWidgetSet.isModalSession: Boolean;
+begin
+  Result := Assigned(Modals) and (Modals.Count > 0);
+end;
 
 initialization
 //  {$I Cocoaimages.lrs}
diff --git a/lcl/interfaces/cocoa/cocoawindows.pas b/lcl/interfaces/cocoa/cocoawindows.pas
index c76b7a57b3..c1ce41b9fd 100644
--- a/lcl/interfaces/cocoa/cocoawindows.pas
+++ b/lcl/interfaces/cocoa/cocoawindows.pas
@@ -138,6 +138,7 @@ type
     procedure windowDidExitFullScreen(notification: NSNotification); message 'windowDidExitFullScreen:';
   public
     callback: IWindowCallback;
+    keepWinLevel : NSInteger;
     //LCLForm: TCustomForm;
     procedure dealloc; override;
     function acceptsFirstResponder: Boolean; override;
@@ -758,6 +759,18 @@ end;
 
 procedure TCocoaWindow.windowDidBecomeKey(notification: NSNotification);
 begin
+  // forcing to keep the level as all other LCL windows
+  // Modal windows tend to "restore" their elevated level
+  // And that doesn't work for modal windows that are "Showing" other windows
+
+  // Another approach is to set elevated levels for windows, shown during modal session
+  // That requires to revoke the elevated level from windows on closing a window session
+  // This might be the way to go, if FormStyle (such as fsStayOnTop) would come
+  // in conflict with modality
+  if level <> keepWinLevel then begin
+    setLevel(keepWinLevel);
+  end;
+
   if Assigned(callback) then
     callback.Activate;
 end;
diff --git a/lcl/interfaces/cocoa/cocoawsforms.pas b/lcl/interfaces/cocoa/cocoawsforms.pas
index ce77eea660..3dbab16d10 100644
--- a/lcl/interfaces/cocoa/cocoawsforms.pas
+++ b/lcl/interfaces/cocoa/cocoawsforms.pas
@@ -170,6 +170,7 @@ type
 
 procedure ArrangeTabOrder(const AWinControl: TWinControl);
 function HWNDToForm(AFormHandle: HWND): TCustomForm;
+procedure WindowSetFormStyle(win: NSWindow; AFormStyle: TFormStyle);
 
 implementation
 
@@ -210,6 +211,25 @@ begin
     Result := AForm.BorderStyle;
 end;
 
+procedure WindowSetFormStyle(win: NSWindow; AFormStyle: TFormStyle);
+var
+  lvl : NSInteger;
+begin
+  if not (AFormStyle in [fsNormal, fsMDIChild, fsMDIForm]) then
+  begin
+    lvl := FormStyleToWindowLevel[AFormStyle];
+    win.setHidesOnDeactivate(FormStyleToHideOnDeactivate[AFormStyle]);
+  end
+  else
+  begin
+    lvl := 0;
+    win.setHidesOnDeactivate(false);
+  end;
+  win.setLevel(lvl);
+  if win.isKindOfClass(TCocoaWindow) then
+    TCocoaWindow(win).keepWinLevel := lvl;
+end;
+
 { TCocoaWSHintWindow }
 
 class function TCocoaWSHintWindow.CreateHandle(const AWinControl: TWinControl;
@@ -323,6 +343,9 @@ begin
     ACustForm.SetFocusedControl(ACustForm.ActiveControl);
 
     IsActivating:=False;
+
+    if CocoaWidgetSet.isModalSession then
+      NSView(ACustForm.Handle).window.orderFront(nil);
   end;
 end;
 
@@ -580,12 +603,8 @@ begin
     UpdateWindowIcons(win, GetDesigningBorderStyle(Form), Form.BorderIcons);
     // For safety, it is better to not apply any setLevel & similar if the form is just a standard style
     // see issue http://bugs.freepascal.org/view.php?id=28473
-    if not (Form.FormStyle in [fsNormal, fsMDIChild, fsMDIForm])
-      and not (csDesigning in AWinControl.ComponentState) then
-    begin
-      win.setLevel(FormStyleToWindowLevel[Form.FormStyle]);
-      win.setHidesOnDeactivate(FormStyleToHideOnDeactivate[Form.FormStyle]);
-    end;
+    if not (csDesigning in AWinControl.ComponentState) then
+      WindowSetFormStyle(win, Form.FormStyle);
     win.enableCursorRects;
 
     TCocoaWindow(win).callback := cb;
@@ -831,11 +850,7 @@ begin
   if AForm.HandleAllocated and not (csDesigning in AForm.ComponentState) then
   begin
     win := TCocoaWindowContent(AForm.Handle).lclOwnWindow;
-    if Assigned(win) then
-    begin
-      win.setLevel(FormStyleToWindowLevel[AFormStyle]);
-      win.setHidesOnDeactivate(FormStyleToHideOnDeactivate[AFormStyle]);
-    end;
+    WindowSetFormStyle(win, AFormStyle);
   end;
 end;