distance2point: Distance to Point
In eyetracking: Eyetracking Helper Functions

Description Usage Arguments Value Author(s) Examples

Takes an x and y screen coordinate and returns the physical distance (in centimeters) from the observer to that point on the screen.

1	distance2point(x, y, viewerDistance, viewerHeight, resolutionX, resolutionY, screenWidth, screenHeight)

`x`	The x coordinate of a point on a screen
`y`	The y coordinate of point on a screen
`viewerDistance`	Perpendicular distance from the viewer to the screen (cm)
`viewerHeight`	Vertical height of the viewer above screen center (cm)
`resolutionX`	The x resolution of the monitor (pixels)
`resolutionY`	The y resolution of the monitor (pixels)
`screenWidth`	The physical screen width (cm)
`screenHeight`	The physical screen height (cm)

A distance in centimeters

Ryan M. Hope

function( x, y, viewerDistance, viewerHeight, resolutionX, resolutionY, screenWidth, screenHeight ) {
    
    centerX <- screenWidth / 2
    centerY <- screenHeight / 2 - viewerHeight
    
    targetX <- x / resolutionX * screenWidth
    targetY <- y / resolutionY * screenHeight
    
    dX <- targetX - centerX
    dY <- targetY - centerY
    
    screenDistance <- sqrt( dX^2 + dY^2 )
    
    sqrt( ( viewerDistance^2 + screenDistance^2) )
    
  }