Generation of not found fonts with Metafont

If the previewer cannot find a font needed for displaying, and the environment variable ``CALLMF'' is set, the contents of this variable is used as the name of an ARexx script to execute.

This is called for the generation of not found fonts with the three following parameters:

<#270#>-- <#270#> the fontname of the font to be generated, the resolution of the font in DPI (Dots Per Inch -TT) the basic resolution, which is presently set in the previewer.

This means that after

;SPMnbsp;;SPMnbsp;;SPMnbsp;;SPMnbsp;;SPMnbsp;;SPMnbsp;;SPMnbsp;;SPMnbsp;<#271#>setenv CALLMF callmf<#271#>

the previewer would call the script with

;SPMnbsp;;SPMnbsp;;SPMnbsp;;SPMnbsp;;SPMnbsp;;SPMnbsp;;SPMnbsp;;SPMnbsp;<#272#>callmf cmr10 120 100<#272#>

in case the font ``cmr10'' with the resolution ``magstep1'' has not been found and the previewer would presently work with a ground resolution of 100dpi.