Scrolling Marquee too slow! 1

[RickBerem]

Hello everyone!

Ok, I made this program that is, mainly, a Clock that displays messages stored in a db. (it can also show a slideshow of images but this part works)

My problem is:
The scrolling speed is slow... The computer that will be used to run this is a 733 with 256mb ram and Windows 2000 and runs nothing else.

I use DrawString and a timer to move the marquee. I invalidate only the part that needs to be updated... But it's still slow. (eats up 98% of the cpu according to taskmanager)

Removing the second timer (updates the time on each second) makes things a little better but still a no go.

I probably am doing something wrong.
Anyone has ideas or pointers for me on that one?

Thanks in advance for your help!


SG

 

[RickBerem]

right, little detail.

it's displayed on a 1680 X 1050 screen
So the Marquee is pretty big.

SG

 

[cjelec]

A bit more info would be helpfull...

You say that you are using timers? What interval are they set to?

Or are you using a loop, this is a common 100% cpu usage problem.

How are you displaying the graphics? With OnPaint? event fired by timer? or in a loop?

 

[RickBerem]

Hey,

Ok info coming up

The timer is set to interval : 1
the graphics are drawn in the Paint event using the Invalidate function of the control I paint on. Fired by the timer.

Hope this clears some fog.

SG

 

[TipGiver]

a timer to move the marquee ??
> Why do you use a timer? By saying 'marquee' I assume that you use vb.net 2005 version. If you set the progressbar to 'marquee' then you set MarqueeAnimationSpeed, and you are OK without a timer.
I don't know if this is your problem, but you must run the progessbar from a different thread. (parallel processing)

It seems that the progressbar does not have some 'spare' time to update its animation. The same happens below.... even if it is a label control.

dim i as integer
for i=0 to 34000
label1.text=i.tostring()
next

The above do not work as it should; the label will show the last value only. To fix it, you normally add a 'Application.Doevents()' in the for/loop. The solution with the progress bar is to start it from a different thread.


Regards.

 

[cjelec]

You may want to slow down the timer and add more jumps in the DrawString location (example bellow),

I use between 70-100 for a frame rate timer in general, and then just work out what is best with the number of frames(jumps) to generate the speed.

...
MyTimer.Interval = 75
...

Dim x as Integer
Dim Jump as Integer = 5 'Pixels per render...

Sub MyTimer_Tick(..., ...)
  If x > 1680 Then
   x = 0
  Else
   x += Jump
  End If
  
  MyFrame.Invalidate() 'you could supply region to speed up more
End Sub

...

I think (by the sounds of it) that you have got the rest of the code alright.

Hope this helps.

 

[RickBerem]

Thanks for the help!

Yes, I ended up doing more pixel per tick to speed it up.

By Marquee I meant the equivalent of the <marquee> tag in HTML. I thought it was the correct name for "scrolling left to right text"

Thanks again for all your inputs.

SG