| Re: oplot in Object Graphics [message #36935 is a reply to message #36930] |
Fri, 14 November 2003 07:42   |
Karl Schultz
Messages: 341
Registered: October 1999
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Senior Member |
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"Miguel Angel Cordoba" <cordoba@grahi.upc.es> wrote in message
news:3FB4CAA2.6030608@grahi.upc.es...
> Hello Rick,
> Yes, I'm capturing the mouse movement with the MOTION_EVENTS
> keyword. The user moves the mouse over one image. This image is a part
> off a volume o 17 images. Then when the user moves the mouse over the
> image I plot the vertical profile off the point where is the mouse and the
> vertical profile off the 8 neighbours. The vertical profile is the
polyline
> with the 17 points, one per image.
> Then in the for statment I modify the DATA property off the 9 plot
Objects.
This part shouldn't be that slow. There are only 17 vertices in each of the
9 objects.
For example, if you fire up the iImage tool that is part of iTools and
create a line profile, the line profile plot updates pretty quickly, even if
there are many more points than 17.
I guess I would try turning stuff off until the performance returns to
isolate the slow component.
What happens if you turn off the vertical profile plots? Is it still slow?
Are you drawing an image with an IDLgrImage object? If you are causing an
IDLgrImage to redraw in response to every motion event, then that could
contribute. There are a couple of ways to avoid drawing the image. Maybe
you simply don't need to redraw it in response to every motion event. You
can also try using instancing if you are drawing some sort of graphic on top
of the image.
What graphics hardware do you have? We had a few machines arrive here at
RSI with $29 graphics cards and of course we were not thrilled over the
object graphics performance.
Karl
>
> Any ideas?
>
>
> Rick Towler wrote:
>
>> "Miguel Angel Cordoba" wrote ...
>>
>>
>>
>>> In my program the for statement only does 9 plots and before this,
>>> I create the Window, the View, the model and a ObjArr of IDLgrPlot.
>>> Then when the user moves the mouse in the for statement I only
>>> change the data property of the IDLgrPlot.
>>>
>>>
>>>
>>
>> How are you capturing the mouse movement? If you set the MOTION_EVENTS
>> keyword to WIDGET_DRAW you'll be generating a *lot* of events and if
inside
>> your event handler you have a FOR loop which updates the DATA property of
>> multiple (in your case 9) IDLgrGraphic objects you will be forcing IDL to
do
>> a lot of work.
>>
>> IDLgrGraphic objects cache internal properties so that they can be
redrawn
>> quickly. When you change certain external properties (such as the DATA
>> property) the object marks the cache as dirty and recalculates these
>> internal properties upon the next call to IDLgrGraphic::Draw. As the
number
>> of data points increase, so does the time it takes to update the internal
>> properties of the object.
>>
>> So your program has a number of possible problems. Do you have to change
>> the DATA property? For all of the objects every event? Can you minimize
>> the size of DATA? Can you minimize the number of events by acquiring
mouse
>> input in a differnt way? Why are you changing the DATA property?
>>
>> I would suspect that the problem can be solved by taking a look at a
pared
>> down version of your code or at least a description of your event loop.
>>
>> -Rick
>>
>>
>>
>>> Karl Schultz wrote:
>>>
>>>
>>>
>>>> It is hard to tell why it may be slow without seeing the entire
program.
>>>>
>>>> However, I have the sneaking suspicion that you are running all of the
>>>>
>>>>
>> code
>>
>>
>>>> listed below for each time you draw to the screen, as you would have to
>>>>
>>>>
>> do
>>
>>
>>>> in Direct Graphics. In Object Graphics, this is not the case. You
>>>>
>>>>
>> create
>>
>>
>>>> all the objects (view, model, plots) just once and then call only the
>>>> window's draw method when you want to draw.
>>>>
>>>> The overall program logic would look something like this:
>>>>
>>>> Create Window
>>>>
>>>> Create View, Model, and Plots (essentially the code quoted below)
>>>>
>>>> Draw the view (e.g., oWindow->Draw, oView)
>>>>
>>>> REPEAT
>>>> user does something.
>>>> modify the data in the plot objects according to what the user did (if
>>>> needed)
>>>> Redraw the view (e.g., oWindow->Draw, oView)
>>>> UNTIL user wants to quit
>>>>
>>>> The important thing is that you want to perform the step of creating
the
>>>> view, model, and plot objects only once. Then everytime you want to
>>>>
>>>>
>> redraw
>>
>>
>>>> the window, you just call Draw.
>>>>
>>>> If you really are doing it in the way I have just described, then
you'll
>>>> have to tell us more about your program. Maybe you can post the entire
>>>> thing if it is not too long. How big is your plot data? How does the
>>>>
>>>>
>> code
>>
>>
>>>> work that triggers the drawing operation, etc..
>>>>
>>>> Karl
>>>>
>>>>
>>>>
>>
>>
>>
>>
>
> --
> ---------------------------------------------------------
> Miguel Angel Cordoba mailto:cordoba@grahi.upc.es
> TEL. 93 4017371
> http://campus.uab.es/~2034008
>
> Grup de Recerca Aplicada en Hidrometeorologia (GRAHi-UPC)
> http://www.grahi.upc.es
> ---------------------------------------------------------
>
>
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