2 small fixes

[Dmitri]

Recently I got many user reports about EOutOfResources happened at arbitrary time. Deep investigation showed that this exception is raised on GDIError. The error was returned by GDI in attempt to set size of a bitmap to very very large value (some million pixels). This bitmap is used in VCL Styles engine (StyleAPI.inc), and its size was suggested by TVclStyleScrollBarsHook hook established in VirtualTrees.pas.
I'm not sure why Delphi is silent about this problem, but it's clear that not all code branches in TVclStyleScrollBarsHook.GetHorzScrollBarSliderRect and TVclStyleScrollBarsHook.GetVertScrollBarSliderRect assign values to the returning result, leaving TRect unintialized if scrollbar is not visible or not enabled.

Fix is below:

 

function TVclStyleScrollBarsHook.GetHorzScrollBarSliderRect: TRect;
var
  P: TPoint;
  BarInfo: TScrollBarInfo;
begin
  if FHorzScrollBarWindow.Visible and FHorzScrollBarWindow.Enabled then
  begin
...

  end

+  else

+   Result := TRect.Empty;

end;

 

 

function TVclStyleScrollBarsHook.GetVertScrollBarSliderRect: TRect;

var
  P: TPoint;
  BarInfo: TScrollBarInfo;
begin
  if FVertScrollBarWindow.Visible and FVertScrollBarWindow.Enabled then
  begin
...

  end

+  else

+   Result := TRect.Empty;

end;

 

[Joachim Marder]

Thanks Dmitri, I've just committed your patch.

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[Dmitri]

Seems with this patch I broke compatibilty with earlier versions of Delphi. TRect.Empty is available only in recent Delphi libraries, while earlier ones do not have this method. Perhaps Result := Rect(0, 0, 0, 0) will be more appropriate.
BTW, what's the lowest supported/maintained version of Delphi? 7?

 

[Joachim Marder]

I noticed that and adapted your code before the commit.

We currently support Delphi 7 and higher. But I would like to make a (stable) branch for Delphi 7-2007 and in the trunk I would like to drop support for non-Unicode versions of Delphi.

2014-05-08 11:28 GMT+02:00 Dmitri <ddmi...@gmail.com>:

Seems with this patch I broke compatibilty with earlier versions of Delphi. TRect.Empty is available only in recent Delphi libraries, while earlier ones do not have this method. Perhaps Result := Rect(0, 0, 0, 0) will be more appropriate.
BTW, what's the lowest supported/maintained version of Delphi? 7?

 

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