lcl: various TControlScrollBar, TScollingWinControl fixes:

- fix scrollbar visibility when AutoScroll = False, scrollbars must appear if visible = True and range > page (with help of patch of Sven Barth, issue #0014279)
  - fix class definition (no need to handle writing of properties using stored modifier - fpc bug was fixed long ago)

git-svn-id: trunk@21501 -

lcl/forms.pp

@@ -91,7 +91,7 @@ type
     FPage: TScrollBarInc;
     FPosition: Integer;
     FRange: Integer;
-    FSmooth : Boolean;
+    FSmooth: Boolean;
     FVisible: Boolean;
     FOldScrollInfo: TScrollInfo;
     FOldScrollInfoValid: Boolean;
@@ -108,8 +108,6 @@ type
     function GetSmooth: Boolean; virtual;
     function GetVisible: Boolean; virtual;
     function HandleAllocated: boolean; virtual;
-    function SmoothIsStored: boolean; virtual;
-    function VisibleIsStored: boolean; virtual;
     procedure AutoCalcRange; virtual;
     procedure ControlUpdateScrollBars; virtual;
     procedure ScrollHandler(var Message: TLMScroll);
@@ -134,17 +132,16 @@ type
     function ScrollPos: Integer; virtual;
     property Kind: TScrollBarKind read FKind;
     function GetOtherScrollBar: TControlScrollBar;
-    property Size: integer read GetSize write SetSize stored false;
+    property Size: integer read GetSize write SetSize stored False;
   published
     property Increment: TScrollBarInc read GetIncrement write SetIncrement default 8;
     property Page: TScrollBarInc read GetPage write SetPage default 80;
-    property Smooth : Boolean read GetSmooth write SetSmooth stored SmoothIsStored;
+    property Smooth: Boolean read GetSmooth write SetSmooth default False;
     property Position: Integer read GetPosition write SetPosition default 0;
     property Range: Integer read GetRange write SetRange default 0;
-    property Visible: Boolean read GetVisible write SetVisible stored VisibleIsStored;
+    property Visible: Boolean read GetVisible write SetVisible default True;
   end;
 
-
   { TScrollingWinControl }
 
   TScrollingWinControl = class(TCustomControl)

lcl/include/controlscrollbar.inc

@@ -91,11 +91,6 @@ begin
   end;
 end;
 
-function TControlScrollBar.SmoothIsStored: boolean;
-begin
-  Result := FSmooth;
-end;
-
 function TControlScrollBar.GetIncrement: TScrollBarInc;
 begin
   Result := FIncrement;
@@ -171,11 +166,6 @@ begin
   ControlUpdateScrollBars;
 end;
 
-function TControlScrollBar.VisibleIsStored: boolean;
-begin
-  Result := FVisible;
-end;
-
 function TControlScrollBar.GetSize: integer;
 var
   KindID: integer;
@@ -211,7 +201,7 @@ end;
 
 procedure TControlScrollBar.SetSize(const AValue: integer);
 begin
-  raise EScrollBar.Create('[TControlScrollBar.SetPage] Size is readonly');
+  raise EScrollBar.Create('[TControlScrollBar.SetSize] Size is readonly');
 end;
 
 procedure TControlScrollBar.SetVisible(const Value: Boolean);
@@ -300,6 +290,7 @@ end;
 procedure TControlScrollBar.UpdateScrollBar;
 var
   ScrollInfo: TScrollInfo;
+  NewVisible: Boolean;
 begin
   if HandleAllocated and (FControl is TScrollingWinControl) then
   begin
@@ -317,10 +308,11 @@ begin
       FOldScrollInfoValid := True;
       SetScrollInfo(FControl.Handle, IntfBarKind[Kind], ScrollInfo, FVisible);
     end;
-    if FOldHandleVisible <> FVisible then
+    NewVisible := Visible and (ScrollInfo.nMax - ScrollInfo.nPage > 0);
+    if FOldHandleVisible <> NewVisible then
     begin
-      FOldHandleVisible := FVisible;
-      ShowScrollBar(FControl.Handle, IntfBarKind[Kind], FVisible);
+      FOldHandleVisible := NewVisible;
+      ShowScrollBar(FControl.Handle, IntfBarKind[Kind], NewVisible);
     end;
     {$IFDEF VerboseScrollingWinControl}
     if DebugCondition then
@@ -427,8 +419,9 @@ begin
   FIncrement := 8;
   FPosition := 0;
   FRange := 0;
-  FSmooth := false;
-  FVisible := false;
+  FSmooth := False;
+  FVisible := True;
+  FOldHandleVisible := True;
 end;
 
 procedure TControlScrollBar.Assign(Source: TPersistent);

lcl/include/scrollingwincontrol.inc

@@ -139,7 +139,7 @@ function TScrollingWinControl.ComputeScrollbars: Boolean;
     CurMax: Integer;
     OldVisible: Boolean;
   begin
-    OldVisible:=p_Bar.FVisible;
+    OldVisible := p_Bar.FVisible;
     if p_Bar.Kind = sbVertical then
       CurMax := ClientHeight
     else
@@ -157,7 +157,7 @@ function TScrollingWinControl.ComputeScrollbars: Boolean;
 var
   NewPage: Integer;
 begin
-  Result := false;
+  Result := False;
   // page
   NewPage := Max(1,Min(ClientWidth - 1, High(HorzScrollbar.FPage)));
   if NewPage <> HorzScrollbar.FPage then
@@ -190,20 +190,9 @@ begin
   FIsUpdating := True;
   try
     if AutoScroll then
-    begin
       ComputeScrollbars; // page, autorange, visible
-      FVertScrollbar.UpdateScrollbar;
-      FHorzScrollbar.UpdateScrollbar;
-    end
-    else
-    begin
-      // If AutoScroll is false, then the scrollbars are always invisible
-      if HandleAllocated then
-      begin
-        ShowScrollBar(Handle, SB_HORZ, False);
-        ShowScrollBar(Handle, SB_VERT, False);
-      end;
-    end;
+    FVertScrollbar.UpdateScrollbar;
+    FHorzScrollbar.UpdateScrollbar;
   finally
     FIsUpdating := False;
   end;