[Richard Suchenwirth] 2013-11-07 - [Everything is a string], and every string has its [string length]. But if we want to display a string in a [text] widget with tight fitting (i.e. just the right size, not too big, not too small), we need to specify the "geometry" of a string, i.e. its width and height.

If we disregard word wrapping, things are very easy:
 set height [regexp -all \n $str\n]
[regexp] normally stops at the first match, and returns 1 then (or 0 if there were none). With -all, it returns the number of matches, so we can use it as a character counter.

I have appended an extra newline at the end, because many strings don't have (and in fact don't need) it. Perfectionists may first do [string trimright] before that. And here's how to calculate the width of a string:
 proc string_width str {
     set w 0
     foreach line [split $str \n] {
        set length [string length $line]
        if {$length > $w} {set w $length}
     }
     return $w
 }

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