richmemo: prevent win32 scrolling on changing text attributes

git-svn-id: https://svn.code.sf.net/p/lazarus-ccr/svn@5974 8e941d3f-bd1b-0410-a28a-d453659cc2b4

components/richmemo/richmemo.pas

@@ -864,7 +864,6 @@ var
   p : TFontParams;
   allowInternalChange: Boolean;
   fp : TFontParams;
-  h,v : integer;
 const
   AllFontStyles : TFontStyles = [fsBold, fsItalic, fsUnderline, fsStrikeOut];
 begin
@@ -872,8 +871,6 @@ begin
 
   if (ModifyMask = []) or (TextLength = 0) then Exit;
 
-  h:=Self.HorzScrollBar.Position;
-  v:=Self.VertScrollBar.Position;
   allowInternalChange:=(not (tmm_Styles in ModifyMask)) or (AddFontStyle+RemoveFontStyle=AllFontStyles);
 
   if allowInternalChange and (TWSCustomRichMemoClass(WidgetSetClass).isInternalChange(Self, ModifyMask)) then
@@ -886,8 +883,6 @@ begin
     Exit;
   end;
 
-  //todo: this is temporary workaround
-  //      the style changing should not be adjusting the scroll
   Lines.BeginUpdate;
   try
     // manually looping from text ranges and re-applying
@@ -912,10 +907,6 @@ begin
       inc(i, l);
     end;
   finally
-    // todo: this is a workaround.
-    //  getting position is necessary, so the cached values are refershed
-    if Self.HorzScrollBar.Position<>h then Self.HorzScrollBar.Position:=h;
-    if Self.VertScrollBar.Position<>v then Self.VertScrollBar.Position:=v;
     Lines.EndUpdate;
   end;
 end;

components/richmemo/win32/win32richmemo.pas

@@ -630,9 +630,11 @@ var
   OrigLen   : Integer;
   NeedLock  : Boolean;
   eventmask : Integer;
+  pt        : TPoint;
 begin
   if not Assigned(RichEditManager) or not Assigned(AWinControl) then Exit;
 
+  RichEditManager.GetScroll(AWinControl.Handle, pt);
   eventmask := RichEditManager.SetEventMask(AWinControl.Handle, 0);
   RichEditManager.GetSelection(AWinControl.Handle, OrigStart, OrigLen);
   
@@ -646,6 +648,7 @@ begin
   end else 
     RichEditManager.SetSelectedTextStyle(AWinControl.Handle, Params);
 
+  RichEditManager.SetScroll(AWinControl.Handle, pt);
   RichEditManager.SetEventMask(AWinControl.Handle, eventmask);
 end;
 
@@ -654,12 +657,15 @@ class function TWin32WSCustomRichMemo.GetTextAttributes(const AWinControl: TWinC
 var
   Orig      : TCHARRANGE;
   eventmask : LongWord;
+  pt        : TPoint;
 begin
   if not Assigned(RichEditManager) or not Assigned(AWinControl) then begin
     Result := false;
     Exit;
   end;
   InitFontParams(Params);
+
+  RichEditManager.GetScroll(AWinControl.Handle, pt);
   eventmask := RichEditManager.SetEventMask(AWinControl.Handle, 0);
 
   LockRedraw(TCustomRichMemo(AWinControl), AWinControl.Handle);
@@ -670,6 +676,7 @@ begin
   Result := RichEditManager.GetSelectedTextStyle(AWinControl.Handle, Params );
 
   RichEditManager.SetSelRange(AWinControl.Handle, Orig);
+  RichEditManager.SetScroll(AWinControl.Handle, pt);
   UnlockRedraw(TCustomRichMemo(AWinControl), AWinControl.Handle, false);
 
   RichEditManager.SetEventMask(AWinControl.Handle,eventmask);
@@ -689,8 +696,10 @@ var
   OrigLen   : Integer;
   eventmask : longword;
   NeedLock  : Boolean;
+  pt        : TPoint;
 begin
   eventmask := RichEditManager.SetEventMask(AWinControl.Handle, 0);
+  RichEditManager.GetScroll(AWinControl.Handle, pt);
   RichEditManager.GetSelection(AWinControl.Handle, OrigStart, OrigLen);
 
   NeedLock := (OrigStart <> TextStart) or (OrigLen <> TextLen);
@@ -703,6 +712,7 @@ begin
   end else
     RichEditManager.SetSelectedTextStyle(AWinControl.Handle, Params, True, AModifyMask);
 
+  RichEditManager.SetScroll(AWinControl.Handle, pt);
   RichEditManager.SetEventMask(AWinControl.Handle, eventmask);
 end;
 
@@ -743,12 +753,15 @@ class function TWin32WSCustomRichMemo.GetStyleRange(
 var
   Orig      : TCharRange;
   eventmask : longword;
+  pt  : TPoint;
 begin
   if not Assigned(RichEditManager) or not Assigned(AWinControl) then begin
     Result := false;
     Exit;
   end;
 
+  RichEditManager.GetScroll(AWinControl.Handle, pt);
+
   eventmask := RichEditManager.SetEventMask(AWinControl.Handle, 0);
   LockRedraw(TCustomRichMemo(AWinControl), AWinControl.Handle);
 
@@ -761,6 +774,7 @@ begin
   end;
   
   RichEditManager.SetSelRange(AWinControl.Handle, Orig);
+  RichEditManager.SetScroll(AWinControl.Handle, pt);
   UnlockRedraw(TCustomRichMemo(AWinControl), AWinControl.Handle, false);
   
   RichEditManager.SetEventMask(AWinControl.Handle, eventmask);
@@ -1460,10 +1474,10 @@ var
 begin
   if not Assigned(AWinControl) or not (AWinControl.HandleAllocated) or ((DeltaX=0) and (DeltaY=0)) then Exit;
 
-  Windows.SendMessage(AWinControl.Handle, EM_GETSCROLLPOS, 0, LPARAM(@pt));
+  RichEditManager.GetScroll(AWinControl.Handle, pt);
   dec(pt.x,DeltaX);
   dec(pt.y,Deltay);
-  Windows.SendMessage(AWinControl.Handle, EM_SETSCROLLPOS, 0, LPARAM(@pt));
+  RichEditManager.SetScroll(AWinControl.Handle, pt);
 end;
 
 // The function doesn't use Windows 7 (Vista?) animations. And should.

components/richmemo/win32/win32richmemoproc.pas

@@ -193,6 +193,9 @@ type
     class function Find(RichEditWnd: THandle; const ANiddle: WideString; const ASearch: TIntSearchOpt; var TextLen: Integer): Integer; virtual; overload;
     class function Find(RichEditWnd: THandle; const ANiddle: WideString; const ASearch: TIntSearchOpt): Integer; overload;
     class procedure GetParaRange(RichEditWnd: Handle; TextStart: integer; var para: TParaRange); virtual;
+
+    class procedure GetScroll(RichEditWnd: Handle; out pt: TPoint); virtual;
+    class procedure SetScroll(RichEditWnd: Handle; const pt: TPoint); virtual;
   end;
   TRichManagerClass = class of TRichEditManager;
                      
@@ -973,6 +976,16 @@ begin
   para.length:=toend;
 end;
 
+class procedure TRichEditManager.GetScroll(RichEditWnd: Handle; out pt: TPoint);
+begin
+  SendMessage(RichEditWnd, EM_GETSCROLLPOS, 0, LPARAM(@pt));
+end;
+
+class procedure TRichEditManager.SetScroll(RichEditWnd: Handle; const pt: TPoint);
+begin
+  SendMessage(RichEditWnd, EM_SETSCROLLPOS, 0, LPARAM(@pt));
+end;
+
 function WinInsertImageFromFile (const ARichMemo: TCustomRichMemo; APos: Integer;
    const FileNameUTF8: string;
    const AImgSize: TSize): Boolean;