Hi all,
Don, after some months, I came back to the project and implemented the ideas
you suggested me. To improve the performance I'm only generating and drawing
the objects which pixels position have changed, instead of checking lat/lon
position. I've also coded a new BufferedRenderTrace class where I'm only
generating and writing the new points as soon as they are received while I
draw a buffer with the old points. This let me to draw a huge amount of
points with no performance rendering in a non-movement map way. Now, the
problem appears when a zoom or pan is done, where points must be generated
and rendered. This causes latences and delays problems, increasing the cpu
usage (specially java process).
I was trying to use ListResetPCPolicy since I thought the list would be
reset and it would take automatically the points that I can see on the map.
However it does not work because points are not appeared on the screen (even
with no "projection changed" event)....and i don't know how do it. Is there
any way to catch the points from a OMGraphicList that are showed in a
specific moment in the map? thus I'd only generate and render those points
instead all of them. I know the points must be always on the OMGraphicList,
but I only want to generate and render those points that appears in the
screen of the map when I zoom or pan it..
Thanks in advance!
2011/6/6 Don Dietrick <dfdietrick_at_gmail.com>
> Hi Ruben,
>
> On Mon, Jun 6, 2011 at 12:39 PM, Ruben DF <rdocasalf_at_gmail.com> wrote:
> > Hi Don,
> >
> > 2011/5/23 Don Dietrick <dfdietrick_at_gmail.com>
>
> >> You might want to check to see if the map
> >> location of your objects have changed before deciding to repaint,
> >> instead of checking whether the objects have moved geospatially.
> >
> > I'm afraid I don't understand this...what is the difference between
> checking
> > whether the objets have moved geospatially or checking whether have
> changed
> > their map location??
>
> Map pixels cover a certain amount of area, so lat/lons that are
> projected onto the map may be resolved to the same pixel. It's
> possible, depending on the map scale, where objects are moving (their
> lat/lons change) but their pixel position on the map doesn't change.
> If that's the case, you don't have to redraw the map.
>
>
> >> If
> >> you are changing how things look (vibrating map objects to highlight
> >> them, changing their color, etc), I can understand why you would want
> >> the update rate to be something higher. In that case, you might want
> >> to buffer several maps together with different rendering parameters,
> >> and then loop that set.
> >
> > I think the problem is on a layer which contains the trace of the plains,
> > i.e, contains a set of OMPoints which is growing each second (36 points
> are
> > created per second, so after 10 minutes, there are more than 20000 points
> > and cpu is collapsed). I generate only the 36 new points which are
> created
> > per second, but I have a problem on the render method, since I need to
> > render all of them if I want to see them on the map...is it possible to
> make
> > a layer and set Background as true and only render the last point? If
> > backgroud is true there are no movement (only when zoom or pan since
> > projectionchanged() is called) and right now I must render all the points
> to
> > see them on the map...
>
> I don't think I'd mess with the Background setting of the layer, since
> that drops the layer below any other layer not marked as a background
> layer. You could do something similar - by writing a new RenderPolicy
> similar to the BufferedImageRenderPolicy, or by managing a
> BufferedImage in your layer and drawing old points into that, and then
> just draw that image.
>
> You don't have to generate older points/OMGraphics if the map doesn't
> change and their position doesn't change. If the zoom level, window
> size or position of the map changes, you'll have to generate all the
> points and you'll lose any image buffering savings for one render
> cycle. But if you are watching a non-moving map, drawing the latest
> points into an image buffer and simply rendering that buffer should
> work well.
>
> - Don
>
> >
> >>
> >> - Don
> >>
> >> On Mon, May 23, 2011 at 7:25 AM, Jesper Berglund
> >> <jesper.berglund_at_pertexo.se> wrote:
> >> > Has the map changed during the 40ms, like panning or zooming?
> >> > Is there objects on the map which has changed?
> >> >
> >> > Don't repaint all layers, only those who might have changed.
> >> >
> >> > Repaint only on changes of data.
> >> >
> >> > If there is a burst of events, coalesce during a timeperiod and then
> >> > repaint
> >> > using javax.swing.Timer .
> >> >
> >> > These are the measures that I have made in my Openmap app.
> >> >
> >> > HTH
> >> >
> >> > /Jesper
> >> >
> >> > Ruben DF skrev 2011-05-23 11:30:
> >> >>
> >> >> Hi,
> >> >>
> >> >> I'm afraid I cannot repaint each 500 ms or longer...it's a customer's
> >> >> requirement... :(
> >> >>
> >> >> Thanks anyway!
> >> >
> >> > --
> >> > [To unsubscribe to this list send an email to "majdart_at_bbn.com"
> >> > with the following text in the BODY of the message "unsubscribe
> >> > openmap-users"]
> >> >
> >
> >
>
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Received on Wed Sep 21 2011 - 08:15:39 EDT