[lazarus] Treeview scrollbars

[Mattias Gaertner]

On Sun, 21 Dec 2003 15:12:56 +0100  Micha Nelissen <micha at neli.hopto.org>
wrote:

> Hi,
> 
> On win32 treeviews always schow scrollbars, which is quite annoying 
> because they are not always necessary. I think I have found the problem: 
> the SCROLLINFO record passed when calling SetScrollInfo has the 
> following property:
> 
> ---
> The SetScrollInfo function performs range checking on the values 
> specified by the nPage and nPos members of the SCROLLINFO structure. The 
> nPage member must specify a value from 0 to nMax - nMin +1. The nPos 
> member must specify a value between nMin and nMax - max(nPage  - 1, 0). 
> If either value is beyond its range, the function sets it to a value 
> that is just within the range.
> ---
> 
> The lcl always passes nPage <= nMax, because GetMaxScrollLeft always 
> returns a value >= 0 and nMax is:
> 
> ScrollInfo.nMax := Max(1,GetMaxScrollLeft+integer(ScrollInfo.nPage));
> 
> But only when setting nPage > nMax ( == nPage = nMax+1 ) the scrollbar 
> will disappear. I have tried some fiddling around, but it didn't work as 
> I wanted, and I am not familiar with the code at all. Can someone make a 
> suggestion?

Not really a suggestion:
I implemented ssAutoHorizontal, ssAutoVertical, ssAutoBoth for TTreeView.


Mattias