ScreenTransform horizontal

hi every one

im trying to move a screen image inside the ScreenTransform horizontal 

but when the move start its just moving every where in the screen (up down right lift) 

i want the move online inside the ScreenTransform horizontal (right and lift only )

i tried :

// @input Component.ScreenTransform screenTransform
// @input Component.ScreenTransform screenTransform2

// Check if a touch starts inside the ScreenTransform
script.createEvent("TouchStartEvent").bind(function(eventData) {
    var touchPos = eventData.getTouchPosition();
    if (script.screenTransform.containsScreenPoint(touchPos)) {
       
// Move the ScreenTransform to match the position of touch events
function onTouch(eventData) {
    var touchPos = eventData.getTouchPosition();
    var parentPos = script.screenTransform2.screenPointToParentPoint(touchPos);
    script.screenTransform2.anchors.setCenter(parentPos);
}


script.createEvent("TouchMoveEvent").bind(onTouch);
} });

i just dont know how to make the move only inside the first screenTransform
horizontal 


thank you