Set Frame Height by Line Count (InDesign script - Draft)

setFrameHeightsByLineCount.jsx

(function setFrameHeightsByLineCount(  ask,NL,tf,pf,dup,mul,a,t,n,k,L)
//--------------------------------------------------------------------
// Select one or more textframes (or have the insertion pt in a frame),
// then enter the desired line number.
{
   const LN_MIN = 1;
   const LN_MAX = 32;

   const SZOF = +AutoSizingTypeEnum.OFF;
   const FITC = +FitOptions.FRAME_TO_CONTENT;
   // ---
   const CS_IN = +CoordinateSpaces.INNER_COORDINATES;
   const AP_TOP = +AnchorPoint.TOP_CENTER_ANCHOR;
   const RM_MUL = +ResizeMethods.MULTIPLYING_CURRENT_DIMENSIONS_BY;

   const WARN = '\u26A0';
   const __ = $.global.localize;

   a = app.selection||0;
   if( !a ) return;

   // Inner text -> parent frame.
   1==a.length
   && (t=a[0]).hasOwnProperty('horizontalOffset')
   && (a=t.parentTextFrames||[]);

   ask = __("Desired Line Number?\r(%1 to %2)", LN_MIN, LN_MAX);

   for( NL=1/0 ; tf=a.pop() ; )
   {
      if( !(tf||0).isValid ) continue;
      if( tf.constructor.name.slice(-9) != 'TextFrame' ) continue;
      pf = tf.textFramePreferences.properties;
      if( +pf.autoSizingType != SZOF ) continue;
      if( pf.textColumnCount != 1 ) continue;
      
      n = tf.lines.length;
      while( ask )
      {
         NL = prompt(ask, ''+n, "Set Height by Line Count");
         if( null===NL ) return;
         NL = parseInt(NL, 10);

         isFinite(NL) && NL >= LN_MIN && NL <= LN_MAX
         ? ( ask=false )
         : ( -1==ask.indexOf(WARN) && ask=ask.split('\r').join('\r'+WARN+' ') );
      }

      (dup = tf.duplicate()).properties = { ignoreWrap:true };

      // Make sure we have enough 'potential' lines in the story.
      dup.parentStory.texts[0].contents += Array(2+NL).join('\r.')

      for
      (
         mult=1, t=-1, L=dup.lines ;
         t != (n=L.length) && NL != n ;
         dup.resize( CS_IN, AP_TOP, RM_MUL, [1,k=(NL/(t=n))] ),
         mult *= k
      );
      
      dup.remove();
      1 != mult && tf.resize( CS_IN, AP_TOP, RM_MUL, [1,mult] );
   }

})();