1. flicker problem
I gotta question.
How do you get rid of flicker on list boxes when they are changing
several times per second?
This, run several times per second, causes flicker:
[example 1]
eraseItems(lstCity)
<begin loop>
addItem(lstCity,data)
<end loop>
What I would like to do is something like:
[example 2]
eraseItems_without_redrawing(lstCity)
<begin loop>
addItem_without_redrawing(lstCity,data)
<end loop>
redraw(lstCity)
This would produce no flicker except the items that are changed, if any.
Is there any way in win32lib.ew to do this, or to fake it?
Jerry Story
2. Re: flicker problem
- Posted by francis at gmx.co.uk
Jun 30, 2001
I cannot replicate the problem on my computer, but from memory try this:
Use this function to turn redrawing off before adding bulk items:
SendMessage(hwndList,WM_SETREDRAW,False,0)
Then call this function to turn it on again after all additions are made.
SendMessage(hwndList,WM_SETREDRAW,True,0)
You might have to redraw the window too, I haven't tried it
----- Original Message -----
From: <jstory at freenet.edmonton.ab.ca>
To: "EUforum" <EUforum at topica.com>
Sent: Saturday, June 30, 2001 4:49 PM
Subject: flicker problem
>
>
> I gotta question.
> How do you get rid of flicker on list boxes when they are changing
> several times per second?
>
> This, run several times per second, causes flicker:
>
> [example 1]
>
> eraseItems(lstCity)
> <begin loop>
> addItem(lstCity,data)
> <end loop>
>
> What I would like to do is something like:
>
> [example 2]
>
> eraseItems_without_redrawing(lstCity)
> <begin loop>
> addItem_without_redrawing(lstCity,data)
> <end loop>
> redraw(lstCity)
>
> This would produce no flicker except the items that are changed, if any.
>
> Is there any way in win32lib.ew to do this, or to fake it?
>
>
> Jerry Story
>
>
>
>
>
3. Re: flicker problem
Hi Jerry,
Faking it:
Set the listview so it is not visible whilst loading and when finished make
it visible again.
setVisible(1stCity, False)
eraseItems(lstCity)
<begin loop>
addItem(lstCity,data)
<end loop>
setVisible(1stCity, True)
Regards
Tony Steward
Come Visit Me At www.locksdownunder.com
----- Original Message -----
From: <jstory at freenet.edmonton.ab.ca>
To: "EUforum" <EUforum at topica.com>
Sent: Saturday, June 30, 2001 2:49 PM
Subject: flicker problem
>
>
> I gotta question.
> How do you get rid of flicker on list boxes when they are changing
> several times per second?
>
> This, run several times per second, causes flicker:
>
> [example 1]
>
> eraseItems(lstCity)
> <begin loop>
> addItem(lstCity,data)
> <end loop>
>
> What I would like to do is something like:
>
> [example 2]
>
> eraseItems_without_redrawing(lstCity)
> <begin loop>
> addItem_without_redrawing(lstCity,data)
> <end loop>
> redraw(lstCity)
>
> This would produce no flicker except the items that are changed, if any.
>
> Is there any way in win32lib.ew to do this, or to fake it?
>
>
> Jerry Story
>
>
>
>
>
>
4. Re: flicker problem
On 2001 xxx -1, Tony Steward wrote:
> Hi Jerry,
> Faking it:
> Set the listview so it is not visible whilst loading and when finished make
> it visible again.
> setVisible(1stCity, False)
> eraseItems(lstCity)
> <begin loop>
> addItem(lstCity,data)
> <end loop>
> setVisible(1stCity, True)
>
Tried that. Doesn't work. Still flickers.
Jerry Story
5. Re: flicker problem
Jerry,
I tried the "fix" of using WM_SETREDRAW to enclose the loading of the list
box and only got a single flicker, no matter how many items I loaded in. Is
this what you get? Is that a problem? Can you send me a small example of the
effect you have got?
------
Derek Parnell
Melbourne, Australia
"To finish a job quickly, go slower."
----- Original Message -----
From: <jstory at freenet.edmonton.ab.ca>
To: "EUforum" <EUforum at topica.com>
Sent: Saturday, June 30, 2001 2:49 PM
Subject: flicker problem
>
>
> I gotta question.
> How do you get rid of flicker on list boxes when they are changing
> several times per second?
>
> This, run several times per second, causes flicker:
>
> [example 1]
>
> eraseItems(lstCity)
> <begin loop>
> addItem(lstCity,data)
> <end loop>
>
> What I would like to do is something like:
>
> [example 2]
>
> eraseItems_without_redrawing(lstCity)
> <begin loop>
> addItem_without_redrawing(lstCity,data)
> <end loop>
> redraw(lstCity)
>
> This would produce no flicker except the items that are changed, if any.
>
> Is there any way in win32lib.ew to do this, or to fake it?
>
>
> Jerry Story
>
>
>
>
>
6. Re: flicker problem
On Mon, 2 Jul 2001, Derek Parnell wrote:
> Jerry,
> I tried the "fix" of using WM_SETREDRAW to enclose the loading of the list
> box and only got a single flicker, no matter how many items I loaded in. Is
> this what you get? Is that a problem? Can you send me a small example of the
> effect you have got?
I tried it. It greatly reduced the flicker, down to where it is
probably acceptable. I have a bunch of list boxes, and I applied
WM_SETREDRAW to all of them. Sometimes one of them flickers.
The list boxes are controlled by a timer. When the timer ticks, all the
list boxes get fresh data.
The program is developed to where it would no longer be a "small
sample", but maybe I'll make a small sample.
Jerry Story
7. Re: flicker problem
On Mon, 2 Jul 2001, Derek Parnell wrote:
> Jerry,
> I tried the "fix" of using WM_SETREDRAW to enclose the loading of the list
> box and only got a single flicker, no matter how many items I loaded in. Is
> this what you get? Is that a problem? Can you send me a small example of the
> effect you have got?
http://www.edmc.net/~jstory/BLINKING.ZIP
It's not bad, but you can check it out anyway.
Jerry Story
