[CLOSED] Code cleanup in gtk widgetsets

[lagprogramming]

The gtk2 and gtk3 widgetsets contain some useless result assignments. I have doubts they increase code readability.
Check out the following routines.

Code: Pascal  [Select][+][-]

1. function TGtk2WidgetSet.FillRgn(DC: HDC; RegionHnd: HRGN; hbr: HBRUSH): Bool;
2. var
3.   GtkDC: Integer;
4.   OldRgn: PGdkRegion;
5.   DevCtx: TGtkDeviceContext absolute DC;
6.   ARect: TRect;
7.   CRect : TGDKRectangle;
8.   hasClipping: Boolean;
9. begin
10.  
11.   Result := IsValidDC(DC) and IsValidGDIObject(hbr) and IsValidGDIObject(RegionHnd);
12.   if not Result then Exit;
13.   GtkDC := SaveDC(DC);
14.   if (DevCtx.ClipRegion <> nil) and (DevCtx.ClipRegion^.GDIRegionObject <> nil) then
15.     OldRgn := gdk_region_copy(DevCtx.ClipRegion^.GDIRegionObject)
16.   else
17.     OldRgn := nil;
18.   hasClipping := Assigned(OldRgn);
19.   try
20.     if SelectClipRGN(DC, RegionHnd) <> ERROR then
21.     begin
22.       gdk_region_get_clipbox({%H-}PGDIObject(RegionHnd)^.GDIRegionObject, @CRect);
23.       ARect := RectFromGdkRect(CRect);
24.       DevCtx.FillRect(ARect, hbr, True);
25.       // revert clip (whatever it is - null or valid region)
26.       SelectClipRGN(DC, {%H-}HRGN(OldRgn));
27.       Result := True;
28.     end;
29.   finally
30.     if hasClipping then
31.       gdk_region_destroy(OldRgn);
32.     RestoreDC(DC, GtkDC);
33.   end;
34. end;

Code: Pascal  [Select][+][-]

1. function TGtk3WidgetSet.SetForegroundWindow(hWnd: HWND): boolean;
2. var
3.   AWindow: TGtk3Window;
4. begin
5.   {$IFDEF GTK3DEBUGNOTIMPLEMENTED}
6.   // DebugLn('WARNING: TGtk3WidgetSet.SetForegroundWindow not implemented ...');
7.   {$ENDIF}
8.   if not IsValidHandle(HWnd) then
9.     exit(False);
10.   Result := wtWindow in TGtk3Widget(HWND).WidgetType;
11.   if Result then
12.   begin
13.     AWindow := TGtk3Window(HWND);
14.     if not AWindow.Visible then
15.       exit(False);
16.     // DebugLn('TGtk3WidgetSet.SetForegroundWindow ',dbgsName(AWindow.LCLObject));
17.     AWindow.Activate;
18.     Result := True;
19.   end;
20. end;
21.  

Code: Pascal  [Select][+][-]

1. function TGtk3WidgetSet.ShowWindow(hWnd: HWND; nCmdShow: Integer): Boolean;
2. begin
3.   {$IFDEF GTK3DEBUGNOTIMPLEMENTED}
4.   DebugLn('WARNING: TGtk3WidgetSet.ShowWindow not implemented ...');
5.   {$ENDIF}
6.   Result := IsValidHandle(Hwnd);
7.   if not result then exit;
8.   if TObject(hWnd) is TGtk3Window then
9.     Result:=TGtk3Window(hWnd).ShowState(nCmdShow)
10.   else
11.   begin
12.     TGtk3Widget(hWnd).Show;
13.     Result:=true;
14.   end;
15. end;

Notice the Result := True; lines. Result is already true when reaching those lines.

In addition, function TGtk3WidgetSet.GetKeyState starts with the following code:

Code: Pascal  [Select][+][-]

1. function TGtk3WidgetSet.GetKeyState(nVirtKey: Integer): Smallint;
2. const
3.   StateDown    = SmallInt($FF80);
4. var
5.   AKeyMap: PGdkKeymap;
6.   AModifiers: TGdkModifierType;
7. begin
8.   Result := 0;
9.  
10.   Result := 0;
11.  
12.   case nVirtKey of
13.     VK_LSHIFT:   nVirtKey := VK_SHIFT;
14.     VK_LCONTROL: nVirtKey := VK_CONTROL;
15.     VK_LMENU:    nVirtKey := VK_MENU;
16.   end;
17. ....

   
The following patch removes those three result:=true lines and also removes the duplicate Result:=0 line.

Code: Pascal  [Select][+][-]

1. diff --git a/lcl/interfaces/gtk2/gtk2winapi.inc b/lcl/interfaces/gtk2/gtk2winapi.inc
2. index 475afa4cfb..12d3426b61 100644
3. --- a/lcl/interfaces/gtk2/gtk2winapi.inc
4. +++ b/lcl/interfaces/gtk2/gtk2winapi.inc
5. @@ -3998,7 +3998,6 @@ var
6.    CRect : TGDKRectangle;
7.    hasClipping: Boolean;
8.  begin
9. -
10.    Result := IsValidDC(DC) and IsValidGDIObject(hbr) and IsValidGDIObject(RegionHnd);
11.    if not Result then Exit;
12.    GtkDC := SaveDC(DC);
13. @@ -4015,7 +4014,6 @@ begin
14.        DevCtx.FillRect(ARect, hbr, True);
15.        // revert clip (whatever it is - null or valid region)
16.        SelectClipRGN(DC, {%H-}HRGN(OldRgn));
17. -      Result := True;
18.      end;
19.    finally
20.      if hasClipping then
21. diff --git a/lcl/interfaces/gtk3/gtk3winapi.inc b/lcl/interfaces/gtk3/gtk3winapi.inc
22. index 54aa27f35e..ac00749898 100644
23. --- a/lcl/interfaces/gtk3/gtk3winapi.inc
24. +++ b/lcl/interfaces/gtk3/gtk3winapi.inc
25. @@ -2197,8 +2197,6 @@ var
26.  begin
27.    Result := 0;
28.  
29. -  Result := 0;
30. -
31.    case nVirtKey of
32.      VK_LSHIFT:   nVirtKey := VK_SHIFT;
33.      VK_LCONTROL: nVirtKey := VK_CONTROL;
34. @@ -3561,7 +3559,6 @@ begin
35.        exit(False);
36.      // DebugLn('TGtk3WidgetSet.SetForegroundWindow ',dbgsName(AWindow.LCLObject));
37.      AWindow.Activate;
38. -    Result := True;
39.    end;
40.  end;
41.  
42. @@ -3975,10 +3972,7 @@ begin
43.    if TObject(hWnd) is TGtk3Window then
44.      Result:=TGtk3Window(hWnd).ShowState(nCmdShow)
45.    else
46. -  begin
47.      TGtk3Widget(hWnd).Show;
48. -    Result:=true;
49. -  end;
50.  end;
51.  
52.  function TGtk3WidgetSet.StretchBlt(DestDC: HDC; X, Y, Width, Height: Integer;

[AlexTP]

Posted to https://gitlab.com/freepascal.org/lazarus/lazarus/-/issues/40489