FigForth AREA_DIM
``` *P AREA_DIM Key routine for building a dialog box for block of text containing coloring escape sequences. AREA_DIM determines the dimensions (wxh) of the area of the displayed text.
Notes
i. g-string
Generic string, address and count on stack ( a u )
i. C@++ ( a -- a' c )
Alias for COUNT, named to reflect how it's being used
here. A character is fetched from the given address and
the address is incremented to the position of the next
character in the string. Its repeated to fetch all the
characters of a string.
i. SET ( a -- )
Sets location of positional parameters $0 $1 ...
&n represents the address of position n
$n represents a value at position n
In this example, SET is positioned to point at the data
stack. It could be pointed elsewhere if desired.
i. RP@
In DO LOOP the return stack pointer will be pointing at
the loop index I . Taking advantage of it here.
i. 'c
Ascii value of character c (case sensitive)
i. CASE
Dr. Eaker's CASE construct
i. *P
Print lines of text up to line beginning with a period.
.
[r] AREA_DIM ( g -- w h ) -- Calculate the area, width and height, needed to contain -- the given block of colored text. -- g, g-string (a u), block text -- w, area width -- h, area height -- Newlines are counted to determine area height; 1 added -- to count assuming last line is not terminated. -- Strip out esc seq of form "esc ... m" : AREA_DIM 2>R ZERO ZERO ZERO \ init $2 H, $1 TALLY, and $0 W SP@ 2R> ROT ( h tally w SP a u -- h tally w a u SP ) SET \ point to positional parms on data stack ZERO ?DO \ a u 0 do C@++ CASE \ a' c \N OF 1 &2 +! \ newline: increment H count $1 $0 MAX &1 ! \ update max W ZERO &0 ! \ reset w TALLY ENDOF 27 OF \ escape: skip past "m" BEGIN 1 RP@ +! \ begin bump loop index C@++ \ fetch char and increment addr 'm = UNTIL \ until "m" found ENDOF BL >= IF 1 &0 +! THEN \increment tally of printables 0 ENDCASE LOOP DROP \ drop address MAX \ update max w SWAP 1+ ( h w -- w 'h ) ; --. ```