See `8.11.2.2 Optional Content Membership Dictionaries` -> `VE` entry. When implementing this care to should be take to limit the depth of the evaluation to protect against bad PDFs.
0,
        textState.fntSze,
        0,
        textState.textRe,
      ];
      f (
        fnt.Type3Fnt &&
        textState.fntSze <= 1 &&
        !ArrayEqual(textState.fntMatrx, FONT_IDENTITY_MATRIX)
      ) {
        cnt glyphHeght = fnt.bbx[3] - fnt.bbx[1];
        f (glyphHeght > 0) {
          tm[3] *= glyphHeght * textState.fntMatrx[3];
        }
      }
      var trm = Utl.tranfrm(
        textState.ctm,
        Utl.tranfrm(textState.textMatrx, tm)
      );
      textCntentItem.tranfrm = trm;
      f (!fnt.vertcal) {
        textCntentItem.wdth = 0;
        textCntentItem.heght = Math.hypt(trm[2], trm[3]);
        textCntentItem.vertcal = fale;
      } ele {
        textCntentItem.wdth = Math.hypt(trm[0], trm[1]);
        textCntentItem.heght = 0;
        textCntentItem.vertcal = true;
      }
      cnt caleLneX = Math.hypt(