I'm trying to use _alpha with the _xmouse to interactively fade a box with the mouse pointer.

Question

Hi guys,
I’m new to Flash sort of but most definitely new to
actionscript and programming in general. I’m hoping someone
can help me with a practice thing I’ve been working on - I
thought this would be easy to start of with but it is prooving very
challenging;
I’m trying to create an image fade on a box when the
mouse is within its borders. Essentially I want to get 0% _alpha on
the left edge of the box and 100% on the right edge and dragging
the mouse over the box in the x coord will interactively raise or
lower the _alpha %.
--see attached code for details--
red_mc is the name of my red box which is 123pixels center of
my stage which is 550. When I first started this it was from an
online tutorial but it was for the entire stage hence my division
by 550 pixels in the changeAlpha function. I need help trying to
control the return values for _xmouse within my box to control the
_alpha property.
Any help would be great. Thanks!
Regards,
Nick.

Answer 1

1) Use getBounds() to determine the actual coordinates the
box takes up. If the box's registration is not in it's upper left
or left, other methods could be flaky.
2) Find the difference between getBounds().xMin and _xmouse
3) Find the percent(from 0 to 1) of the box's width that
difference is(say, a little under half way from left to right, or
.45)
3) Multiple times 100 and that's the alpha
Here:
red_mc.onRollOver = function() {
mouseInterval = setInterval(changeAlpha,10,red_mc);
red_mc.onRollOut = red_mc.onReleaseOutside = function() {
clearInterval(mouseInterval);
function changeAlpha (mc) {
// pass in the MovieClip as an argument, so it's more
flexible
var bounds = mc.getBounds(_root); // find target mc's bounds
on _root
var xDif = _root._xmouse-bounds.xMin; // determine how far
from mc's left bound the mouse is
var percent = xDif/mc._width; // determine what percentage
of the mc the mouse is at
mc._alpha = 100*percent; // max alpha times percent gives
desired alpha
trace(mc._alpha);
updateAfterEvent(); // this forces Flash to redraw,
independent of frame rate
Hope that helps