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TrackControl overflow problem

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Aaron Koolen View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Aaron Koolen Quote  Post ReplyReply Direct Link To This Post Topic: TrackControl overflow problem
    Posted: 20 June 2010 at 11:17pm
Hi there.
I was getting strange behaviour with my TrackControl where the slider would jump to the end of my time line range when I reached a certain position. I tracked the issue down to an overflow in the CXTPTrackControlHeader OnMoveSlider (~line 180) method.



int fromPosition = m_ptStartDrag.x * (pControl->GetTimeLineMax() - pControl->GetTimeLineMin()) / rcSliderArea.Width();
int toPosition = pt.x * (pControl->GetTimeLineMax() - pControl->GetTimeLineMin()) / rcSliderArea.Width();
int delta = toPosition - fromPosition;


With large timelines, as I had, the initial multiplication overflowed into negative. The fromPosition and toPosition can actually be removed and the delta performed before the multiplication and division. Even better would be to divide first, as I don't think the difference in rounding would matter. I have made the change in my code and all is working well.

As an aside to this, I would suggest that CXTPTrackControl handled unsigned.

Aaron

Product: Xtreme ToolkitPro v13.3.0 (MFC)
Platform: Windows XP (32bit) - SP 3
Language: Visual C++ 6
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Oleg View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Oleg Quote  Post ReplyReply Direct Link To This Post Posted: 21 June 2010 at 9:24am
Thanks, replaced to


     int fromPosition = MulDiv(m_ptStartDrag.x, (pControl->GetTimeLineMax() - pControl->GetTimeLineMin()), rcSliderArea.Width());
     int toPosition = MulDiv(pt.x, (pControl->GetTimeLineMax() - pControl->GetTimeLineMin()), rcSliderArea.Width());
Oleg, Support Team
CODEJOCK SOFTWARE SOLUTIONS
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Aaron Koolen View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Aaron Koolen Quote  Post ReplyReply Direct Link To This Post Posted: 21 June 2010 at 5:49pm
No problem. I also found a couple of other places where the same thing occurs.

XTPrackPaintManager::DrawTrackHeader, around line 305.
XTPTrackHeader::OnLButtonDown, around line 418.

Both of those perform out of range multiplications.

Cheers
Aaron

Product: Xtreme ToolkitPro v13.3.0 (MFC)
Platform: Windows XP (32bit) - SP 3
Language: Visual C++ 6
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Oleg View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Oleg Quote  Post ReplyReply Direct Link To This Post Posted: 23 June 2010 at 5:02am
Thanks, replaced also.
Oleg, Support Team
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