LCL-GTK2: Paint a form with one color also after scrolling. Issue #16183, patch from Joeny Ang.

git-svn-id: trunk@64167 -

lcl/interfaces/gtk2/gtk2proc.inc

@@ -7575,7 +7575,7 @@ function CreateFormContents(AForm: TCustomForm;
   var FormWidget: Pointer; AWidgetInfo: PWidgetInfo = nil): Pointer;
 var
   ScrolledWidget, ClientAreaWidget: PGtkWidget;
-  WindowStyle: PGtkStyle;
+//  WindowStyle: PGtkStyle;
   Adjustment: PGtkAdjustment;
 begin
   // Create the VBox. We need that to place controls outside
@@ -7592,8 +7592,10 @@ begin
   gtk_widget_show(ScrolledWidget);
 
   ClientAreaWidget := gtk_layout_new(nil, nil);
-  WindowStyle := GetStyle(lgsWindow);
-  gtk_widget_set_style(ClientAreaWidget, WindowStyle);
+  // issue #16183: not sure why the GtkLayout is given a GtkWindow style here,
+  // this prevents setting color to the GtkLayout
+//  WindowStyle := GetStyle(lgsWindow);
+//  gtk_widget_set_style(ClientAreaWidget, WindowStyle);
   //debugln('CreateFormContents Style=',GetStyleDebugReport(WindowStyle));
   gtk_container_add(PGtkContainer(ScrolledWidget), ClientAreaWidget);
 

lcl/interfaces/gtk2/gtk2widgetset.inc

@@ -2307,7 +2307,10 @@ begin
 
   if ChangeBGColor then
   begin
-    if (BGColor = clDefault) or (BGColor = clBtnFace) then
+    // setting bg color to nil will cancel previous calls to gtk_widget_modify_bg()
+    // cannot use nil on a GtkLayout (issue #16183)
+    if not GTK_IS_LAYOUT(AWidget) and
+      ((BGColor = clDefault) or (BGColor = clBtnFace)) then
       NewColor := nil
     else
     begin

lcl/interfaces/gtk2/gtk2wsforms.pp

@@ -863,8 +863,27 @@ begin
 end;
 
 class procedure TGtk2WSCustomForm.SetColor(const AWinControl: TWinControl);
+var
+  AScrolled: PGtkWidget;
+  AColor: TColor;
 begin
   TGtk2WSWinControl.SetColor(AWinControl);
+
+  // Forms: GtkWindow->GtkVBox->gtkScrolledWindow->GtkLayout
+  // we need to set the color of the GtkLayout so that the whole viewport
+  // will be filled (issue #16183)
+  AScrolled := g_object_get_data({%H-}PGObject(AWinControl.Handle), odnScrollArea);
+  if GTK_IS_SCROLLED_WINDOW(AScrolled) and
+    GTK_IS_LAYOUT({%H-}PGtkBin(AScrolled)^.child) then
+  begin
+    AColor := AWinControl.Color;
+    if AColor = clDefault then
+      AColor := GetDefaultColor(AWinControl, dctBrush);
+    Gtk2WidgetSet.SetWidgetColor({%H-}PGtkBin(AScrolled)^.child,
+                                 clNone, AColor,
+                                 [GTK_STATE_NORMAL, GTK_STATE_ACTIVE,
+                                  GTK_STATE_PRELIGHT, GTK_STATE_SELECTED]);
+  end;
 end;
 
 class procedure TGtk2WSCustomForm.SetRealPopupParent(
@@ -970,12 +989,20 @@ begin
 end;
 
 class procedure TGtk2WSScrollingWinControl.SetColor(const AWinControl: TWinControl);
+var
+  AColor: TColor;
 begin
   if not WSCheckHandleAllocated(AWinControl, 'SetColor')
   then Exit;
 
+  // ScrollingWinControl: GtkScrolledWindow->GtkLayout
+  // we need to set the color of the GtkLayout so that the whole viewport
+  // will be filled (issue #16183)
+  AColor := AWinControl.Color;
+  if AColor = clDefault then
+    AColor := GetDefaultColor(AWinControl, dctBrush);
   Gtk2WidgetSet.SetWidgetColor({%H-}PGtkBin(AWinControl.Handle)^.child,
-                               clNone, AWinControl.Color,
+                               clNone, AColor,
                                [GTK_STATE_NORMAL, GTK_STATE_ACTIVE,
                                 GTK_STATE_PRELIGHT, GTK_STATE_SELECTED]);
 end;

lcl/widgetset/wsforms.pp

@@ -50,6 +50,7 @@ type
   TWSScrollingWinControl = class(TWSWinControl)
   published
     // procedure ScrollBy is moved to TWSWinControl.
+    class function GetDefaultColor(const AControl: TControl; const ADefaultColorType: TDefaultColorType): TColor; override;
   end;
 
   { TWSScrollBox }
@@ -140,6 +141,19 @@ type
 
 implementation
 
+{ TWSScrollingWinControl }
+
+class function TWSScrollingWinControl.GetDefaultColor(const AControl: TControl;
+  const ADefaultColorType: TDefaultColorType): TColor;
+const
+  DefColors: array[TDefaultColorType] of TColor = (
+ { dctBrush } clForm,
+ { dctFont  } clBtnText
+  );
+begin
+  Result := DefColors[ADefaultColorType];
+end;
+
 { TWSCustomForm }
 
 class procedure TWSCustomForm.CloseModal(const ACustomForm: TCustomForm);