Change alpha relative to mouse position

1

Hi
I’m having trouble to solve this: I have a series of images (all movie clips named m1, m2, etc) within a master mc called main which scrolls with the code I’m pasting below. The images are all at an alpha value of 50 and I want each of them to go up to 100 when the dragger is at approximately the same _y position as the images, that is as you scroll the images change their alpha value relative to the dragger position. I’ve tried adding a condition to the dragger.onPress function related to root.xmouse and root.ymouse (i.e. when the mouse pointer is over the dragger at a certain dragger height) to change the alpha value but does not work. Any ideas? Thanks in advance for any help.

fscommand("allowscale", "false");
bar.useHandCursor = dragger.useHandCursor=false;
space = 20;
friction = 0.9;
speed = 4;
y = dragger._y;
top = main._y;
bottom = main._y+mask_mc._height-main._height-space;
dragger.onPress = function() {
    drag = true;
    this.startDrag(false, this._x, this._parent.y, this._x, this._parent.y+this._parent.bar._height-this._height);
    dragger.scrollEase();
};

dragger.onMouseUp = function() {
    this.stopDrag();
    drag = false;
};
bar.onPress = function() {
    drag = true;
    if (this._parent._ymouse>this._y+this._height-this._parent.dragger._height) {
        this._parent.dragger._y = this._parent._ymouse;
        this._parent.dragger._y = this._y+this._height-this._parent.dragger._height;
    } else {
        this._parent.dragger._y = this._parent._ymouse;
    }
    dragger.scrollEase();
};
bar.onMouseUp = function() {
    drag = false;
};
moveDragger = function (d) {
    if ((dragger._y>=y+bar._height-dragger._height && d == 1) || (dragger._y<=y && d == -1)) {
        clearInterval(myInterval);
    } else {
        dragger._y += d;
        dragger.scrollEase();
        updateAfterEvent();
    }
};
up_btn.onPress = function() {
    myInterval = setInterval(moveDragger, 18, -1);
};
down_btn.onPress = function() {
    myInterval = setInterval(moveDragger, 18, 1);
};
up_btn.onMouseUp = down_btn.onMouseUp=function () {
    clearInterval(myInterval);
};
MovieClip.prototype.scrollEase = function() {
    this.onEnterFrame = function() {
        if (Math.abs(dy) == 0 && drag == false) {
            delete this.onEnterFrame;
        }
        r = (this._y-y)/(bar._height-this._height);
        dy = Math.round((((top-(top-bottom)*r)-main._y)/speed)*friction);
        main._y += dy;
    };
};