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flc.net
Joined: 21 Jun 2005
Posts: 89
Location: Switzerland
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 Posted: Mon Oct 03, 2005 9:23 am Post subject: Selected Row and Pinned Columns |
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Hello Support
I have a VT with a lot of Rows and Columns. Some Column are "Pinned". When I navigate through the Rows with the Up/Down Keys or with the Mouse a flickering effect occurs. It seems that VT draws first the not-pinned columns and afterwards the pinned columns.
Thanks and best Regards
Giuseppe |
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Infralution
Joined: 28 Feb 2005
Posts: 5027
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| Posted: Tue Oct 04, 2005 5:50 am Post subject: |
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The pinned columns are drawn on a separate "pinned panel" control. This is so that if there is an active editor control in an unpinned control it will slide underneath the pinned columns when scrolled horizontally.
Unfortunately this means that the drawing is not all done in a single paint event which can result in a the two paint events being perceptable when scrolling. On our (not very fast) test machine running our License Tracker application (with a lot of columns and rows) this is barely noticeable - ie you have to look pretty hard to see the effect.
How bad is the flicker you are seeing? Can you see the same effect when using our Dataset Browser sample?
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flc.net
Joined: 21 Jun 2005
Posts: 89
Location: Switzerland
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| Posted: Tue Oct 04, 2005 8:42 am Post subject: |
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Hello Support
The flicker on the Dataset Browser is ok, when the Form is not maximized.
After maximizing the Form, the ficker is good visible.
On our App it's flicker a little bit more.
Giuseppe |
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Infralution
Joined: 28 Feb 2005
Posts: 5027
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| Posted: Tue Oct 04, 2005 10:26 pm Post subject: |
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On our test machine with the Dataset Browser full screen - you can perceive that the selected row is painted in two parts - but it is not very noticeable - and only while the selection is the screen (once it hits top or bottom the flicker stops). How many active columns do you have in your application?
We are actively investigating whether we can do anything to improve the painting performance in this case - but can't make any promises at this stage.
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flc.net
Joined: 21 Jun 2005
Posts: 89
Location: Switzerland
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| Posted: Wed Oct 05, 2005 6:57 am Post subject: |
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| Infralution wrote: | ... How many active columns do you have in your application?
We are actively investigating whether we can do anything to improve the painting performance in this case - but can't make any promises at this stage. |
Ok... Thanks. We have 20 Active Columns.
Giuseppe |
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Infralution
Joined: 28 Feb 2005
Posts: 5027
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| Posted: Wed Oct 12, 2005 5:17 am Post subject: |
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We are still investigating this - one thing that does have an effect, if you are running on XP, is to set the extended window style as follows by overriding CreateParams
| Code: | protected override CreateParams CreateParams
{
get
{
const int WS_EX_COMPOSITED = 0x02000000;
CreateParams cp = base.CreateParams;
cp.ExStyle = cp.ExStyle | WS_EX_COMPOSITED;
return cp;
}
} |
This does seem to eliminate the flicker on our test machine - but does slow the drawing a little. Maybe you could try this on your implementation to see if it helps. We don't want to introduce this into our released build until we fully understand the possible implications.
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flc.net
Joined: 21 Jun 2005
Posts: 89
Location: Switzerland
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| Posted: Wed Oct 12, 2005 8:00 am Post subject: |
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Hello
It works fine!
Thanks
Giuseppe |
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flc.net
Joined: 21 Jun 2005
Posts: 89
Location: Switzerland
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| Posted: Wed Oct 12, 2005 8:54 am Post subject: |
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after testing on a big grid, the drawing (scroll/expand) is to slow.
best regards
giuseppe |
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Infralution
Joined: 28 Feb 2005
Posts: 5027
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| Posted: Wed Apr 05, 2006 9:32 am Post subject: |
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You'll be happy to know that this issue has finally been resolved in Version 2.5.0 of Virtual Tree. This version includes a new drawing algorithm that allows all drawing to be done double buffered to the main control surface (thus eliminating flicker between pinned/unpinned columns) without sacrificing the ability to scroll active editor controls beneath the pinned columns.
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