Smooth Move - NOT

I have an array of Rectangles (tbl) and I need to be able to drag them around smoothly
This code (Swift) however, is jerky, and sometimes undoes what it just did :frowning:

Functionaly this should be nearly identical syntax to Xojo (kinda)

	public func tbl_mouseDown (_ index:Int,_ x:Int,_ y:Int,_ rightButton:Bool=false) -> Bool {
		if rightButton == false {
                       // remember the coor of where the mouse was clicked 
			last_x = CGFloat(x)
			last_y = CGFloat(y)
			return true
		} else {
			return false // not dealing with righbutton yet
		}
	}

	public func tbl_mouseDrag (_ index:Int,_ x:Int,_ y:Int,_ rightButton:Bool=false) {
		let fX     = CGFloat(x) // Swift is strict types, so convert to float
		let fY     = CGFloat(y)
		let deltaX = last_x-fX // calc the delta between last mouse position and current
		let deltaY = last_y-fY
		if (deltaX != 0) || (deltaY != 0) {
			last_x = fX // remember new position
			last_y = fY
			tbl[index].frame.origin.x -= deltaX // move rectangle by delta
			tbl[index].frame.origin.y -= deltaY
			print("VERIFY : tbl_mouseDrag \(tbl[index].frame) : \(deltaX),\(deltaY)")
		}
	}

example : note how the delta keeps flipping :frowning:

VERIFY : tbl_mouseDrag (7.0, 5.0, 315.0, 195.0) : -5.0,-5.0
VERIFY : tbl_mouseDrag (2.0, 0.0, 315.0, 195.0) : 5.0,5.0
VERIFY : tbl_mouseDrag (7.0, 5.0, 315.0, 195.0) : -5.0,-5.0
VERIFY : tbl_mouseDrag (3.0, 0.0, 315.0, 195.0) : 4.0,5.0
VERIFY : tbl_mouseDrag (7.0, 5.0, 315.0, 195.0) : -4.0,-5.0
VERIFY : tbl_mouseDrag (3.0, 0.0, 315.0, 195.0) : 4.0,5.0
VERIFY : tbl_mouseDrag (7.0, 5.0, 315.0, 195.0) : -4.0,-5.0

any idea what Iā€™m doing wrong?

turns out there was a bug in the code the got the X,Y values to start with, so I need to fix that.

Thanks

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