Copia de Screen Coordinates

I would like points that stay put on the screen. Here are some requirements: -stay pinned to screen coordinates -stay in the viewport -they may be freely moved -we may use them as reference points for other objects.
None of the methods in GGB meet these requirements (try it). Why? (Hint: there is no such thing as absolute coordinates). The points U1, V1, W1, Z1, however, do. Procedure:
  1. imgWhite = (blank, 32×32 pixel image). Set ObjectProperties>Position>Corner1 to Corner[1]
  2. crn3 = Corner[imgWhite, 3]
  3. track the ratio Pixels/(GGB Unit): ppu = 32/x(crn3 - Corner[1])
Now we can place points in screen coordiantes: U1'' = (Free Point) U1' = (Free Point) Update Script: SetValue[U1'', (U1' - Corner[4]) ppu] U1 =DynamicCoordinates[U1', x(Corner[4] + U1'' / ppu), y(Corner[4] + U1'' / ppu)] Points V1, Z1, W1 measure from the other three screen corners. Object updates can still cause problems; additional update script is needed to keep points from occasionally jumping about. More later.