Function: lm_innerpixelsize

CALL:

outbordersize = lm_innerpixelsize(hframe, innerborderpixelsize)

DESCRIPTION:

Change pixelsize property of frame based on size of its content

INPUT:

hframe any 
modelit.layout.Frame
innerpixelsize any 
required pixel size (inner border)

OUTPUT:

outbordersize any 
       computed outer border size

SUMMARRY
   Change pixelsize property of frame so that the size of
   the innerframe matches a given size. This utility is useful if the
   size of what goes into the frame is known and one wants to shrink the
   outer frame so that it exactly fits its contents.

APPROACH: 

     In many cases the desired display size of the content of a frame is
     known. However the user must specify the property "pixelsize" of a
     frame. When the frame is plotted, "pixelsize" will determine the
     outerborder size of the frame. The actual innerborder is plotted
     inside the outerborder with margins "minmarges".    
     To obtain the outher border size based on frame content size one must
     add:
     -1- frame content size
     -2- width of border 
     -3- the width of the border must include the height of the title.