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scroll jitters [message #442163] Sat, 28 August 2004 20:41 Go to next message
Jonathan Edwards is currently offline Jonathan EdwardsFriend
Messages: 27
Registered: July 2009
Junior Member
Canvas.scroll causes a jittery effect on the text in my custom control.
It is particularly noticeable when doing many 1 and 2 pixel shifts due
to dragging the scroll bar. Eclipse itself does not have this behaviour.
What's the secret? TIA, Jonathan. [Eclipse 3.0, Win XP]

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Re: scroll jitters [message #442207 is a reply to message #442163] Sat, 28 August 2004 20:47 Go to previous messageGo to next message
Vic Hanson is currently offline Vic HansonFriend
Messages: 23
Registered: July 2009
Junior Member
Check out
http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.swt.sni ppets/src/org/eclipse/swt/snippets/Snippet48.java?rev=HEAD&a mp;content-type=text/vnd.viewcvs-markup

That may help...

Vic Hanson

Jonathan Edwards wrote:

> Canvas.scroll causes a jittery effect on the text in my custom control.
> It is particularly noticeable when doing many 1 and 2 pixel shifts due
> to dragging the scroll bar. Eclipse itself does not have this behaviour.
> What's the secret? TIA, Jonathan. [Eclipse 3.0, Win XP]

Report message to a moderator

Re: scroll jitters [message #442208 is a reply to message #442207] Sat, 28 August 2004 21:04 Go to previous messageGo to next message
Jonathan Edwards is currently offline Jonathan EdwardsFriend
Messages: 27
Registered: July 2009
Junior Member
Thanks, but I did. I am doing scrolling exactly the same way. I have
verified that the scroll calls are correct, and the repaints are being
properly clipped. The scroll() operation itself is causing the flashing.

Jonathan

Vic Hanson wrote:

> Check out
> http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.swt.sni ppets/src/org/eclipse/swt/snippets/Snippet48.java?rev=HEAD&a mp;content-type=text/vnd.viewcvs-markup

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Re: scroll jitters (Diagnosed) [message #442209 is a reply to message #442163] Sat, 28 August 2004 22:49 Go to previous message
Jonathan Edwards is currently offline Jonathan EdwardsFriend
Messages: 27
Registered: July 2009
Junior Member
The problem is with small files that are only somewhat larger than the
window. Dragging the scrollbar causes very fine-grained (1 or 2 pixel)
scrolls, which results in a jittery effect. Eclipse has the same
behaviour with the same size files.

The solution is some form of quantization of scrolling. Microsoft Word
scrolls by entire lines.

Jonathan

Jonathan Edwards wrote:
> Canvas.scroll causes a jittery effect on the text in my custom control.
> It is particularly noticeable when doing many 1 and 2 pixel shifts due
> to dragging the scroll bar. Eclipse itself does not have this behaviour.
> What's the secret? TIA, Jonathan. [Eclipse 3.0, Win XP]

Report message to a moderator

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