631: Highlights

To assist you in displaying information graphically, Smalltalk offers the Point and Rectangle classes.

If you want to create a point, then instantiate one of the following patterns:

Point x: x coordinate value y: y coordinate value 

x coordinate value @ y coordinate value

If you want to extract information from a point, then send an x or y message to the point.

If you want to create a rectangle, then instantiate one of the following patterns:

Rectangle origin: upper-left point  
          corner: lower-right point 

Rectangle origin: upper-left point  
          extent: point representing width and height 

upper-left point 
  rightBottom: lower-right point

If you want to extract information from a rectangle, then send an origin, corner, extent, height, width, or center message to the rectangle.