Add a second frame to the clip and use the following code...
Code for frame 1
// the x-coord is the starting point of the slider knob
x_coord = 650;
// 700 is as far as the
x_limit = 700;
if (mouse_down eq "true") {
play ();
} else {
stop ();
}
Code for frame 2
//get the current x of the knob and compare it to what it was previously to see if we need to update anything
var cur_x = _root.zoom_knob._x;
if (Number(cur_x)<>Number(prev_x)) {
//the x has changed...use this *simple* equation below
// It's based on 50 px movement, 400% zoom & a base mag_factor of 5 (that's where the 6 comes from)
var zoom_perc = 400 - (6*(x_limit - cur_x));
// Figure out the inverse percentage for the magnifying glass
// 20 is the maximum mag_factor (400% with a base mag_factor of 5 and defaulted at 100%)
var mag_perc = (100/zoom_perc)*20;
// Call the scaling function and moving function
_root.scale_mag(zoom_perc,mag_perc);
_root.move_panel();
}
// Set the current x as previous and do it again...as long as the knob is moving
prev_x = cur_x;
gotoAndPlay (1);
This code works like the panning routine in the 'mag' MC. Like that one you could also put frame 2's code in the MC using OnClipEvent(EnterFrame).
Note: You could do a vertical zoom (track _y instead of _x).