| In our news
ticker tool, text links are scrolled from the bottom
to the top (and loop around after reaching to the top).
The idea behind is very simple; just keep moving the
movie clip (that holds the text links) up and up...
We used the following actionscripts to achieve the scrolling
effect.
var g_interval = 300;
var g_step = 1;
var g_iid = -1;
var m; // this is the movie clip we created to
hold the text links
function start_scroll()
{
if(g_iid != -1)
clearInterval(g_iid);
g_iid = setInterval(scrolling, g_interval);
}
function scrolling()
{
var y = m._y;
y -= g_step;
if(y + m._height < 0) {
m._y = Stage.height;
} else {
m._y = y;
}
}
function stop_scroll()
{
clearInterval(g_iid);
}
start_scroll();
|
In the example, we created a movie clip "m"
to hold the text links (the corresponding code/steps
were omitted here). The movie clip is initially placed
below the bottom of the stage area.
There are a couple of functions that we've defined:
start_scroll: we used the "setInterval" api
to set the time interval to re-position the movie clip
m. In this case, for every 300 ms (the value of g_interval),
the "scrolling" function will be called.
scrolling: this function will move the movie clip m
up by 1 pixel (the value of g_step) until it reach the
top of the stage. Then it will re-position the clip
to the bottom of the stage.
stop_scroll: this function use "clearInterval"
to stop the scrolling. In the above code, we haven't
make any call to "stop_scroll", but in case
you need to start/stop scrolling (as in our news ticker
tool), you will find this function useful.
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