Re: Minor artefact with CScrollWindowImpl...

Hi Philippe,

Thank you for pointing this out. Your solution is what should be there, so
I will add it to the WTL code.

Thanks,
Nenad




On Sat, Jun 2, 2012 at 9:28 AM, Philippe <[email protected]> wrote:

> **
>
>
> Hi Nenad,
>
> I have controls derived from 'CScrollWindowImpl<MyControl, CFSBWindow>'
> and particularly a DataGrid.
> I noticed that when I turned my mouse's wheel (even if I dont need to
> scroll) some parts of my control were flickering.
> So I checked the atlscrl.h file's code, more precisely CScrollImpl and the
> OnMouseWheel handler (line #491 for the latest version of WTL) and found
> this:
>
> if(m_sizeAll.cy > m_sizeClient.cy)
> {
> for(int i = 0; i < zTotal; i += WHEEL_DELTA)
> {
> pT->DoScroll(SB_VERT, nScrollCode, (int&)m_ptOffset.y, m_sizeAll.cy,
> m_sizePage.cy, m_sizeLine.cy);
> pT->UpdateWindow();
> }
> }
> else // can't scroll vertically, scroll horizontally
> {
> for(int i = 0; i < zTotal; i += WHEEL_DELTA)
> {
> pT->DoScroll(SB_HORZ, nScrollCode, (int&)m_ptOffset.x, m_sizeAll.cx,
> m_sizePage.cx, m_sizeLine.cx);
> pT->UpdateWindow();
> }
> }
>
> This code means that if the mouse's wheel is turned then
> if(m_sizeAll.cy > m_sizeClient.cy)
> it will scroll vertically and update (repaint) the client rect of the
> control
> else
> it will scroll horizontally and update (repaint) the client rect of the
> control
>
> Which is by the way a very good idea.
>
> But before scrolling horizontally (and update the window) we have to check
> if it is necessary and it is necessary only
> if(m_sizeAll.cx > m_sizeClient.cx) as there's no reason to scroll
> horizontally if the control width is not larger than the client width ;o)
>
> I modified it like this:
>
> if(m_sizeAll.cy > m_sizeClient.cy)
> {
> for(int i = 0; i < zTotal; i += WHEEL_DELTA)
> {
> pT->DoScroll(SB_VERT, nScrollCode, (int&)m_ptOffset.y, m_sizeAll.cy,
> m_sizePage.cy, m_sizeLine.cy);
> pT->UpdateWindow();
> }
> }
> else // can't scroll vertically, scroll horizontally
> {
> if(m_sizeAll.cx > m_sizeClient.cx)
> {
> for(int i = 0; i < zTotal; i += WHEEL_DELTA)
> {
> pT->DoScroll(SB_HORZ, nScrollCode, (int&)m_ptOffset.x, m_sizeAll.cx,
> m_sizePage.cx, m_sizeLine.cx);
> pT->UpdateWindow();
> }
> }
> }
>
> and everything is perfect with my Grid, no more flickering!
>
> I know it's a minor problem but this flickering was so annoying so I hope
> it helps.
> Long live WTL and all the best to you and the WTL team.
>
> Philippe Marechal
>
>  
>


[Non-text portions of this message have been removed]



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