+ ldx #0
+ jmp umul16x16r32
+
+; Return the width of the string for the vector font. To save some code, we
+; will add up all the character widths and then multiply by the scale factor.
+; Since the output routine will scale each single character, the result may
+; be slightly different.
+
+@L1: sta Text
+ stx Text+1 ; Save pointer to string
+
+ lda _tgi_vectorfont+1
+ tax
+ ora _tgi_vectorfont
+ beq @L9 ; Return zero if no font
+
+ lda _tgi_vectorfont
+ clc
+ adc #<(TGI_VECTORFONT::WIDTHS - TGI_VF_FIRSTCHAR)
+ sta WTab
+ txa
+ adc #>(TGI_VECTORFONT::WIDTHS - TGI_VF_FIRSTCHAR)
+ sta WTab+1
+
+ ldy #0
+ sty Width
+ sty Width+1 ; Zero the total width
+
+; Sum up the widths of the single characters
+
+@L2: ldy #0
+ lda (Text),y ; Get next char
+ beq @L4 ; Bail out if end of text reached
+ jsr _toascii ; Convert to ascii
+ tay
+ lda (WTab),y ; Get width of this char
+ clc
+ adc Width
+ sta Width
+ bcc @L3
+ inc Width+1
+@L3: inc Text
+ bne @L2
+ inc Text+1
+ bne @L2
+
+; We have the total width now, scale and return it
+
+@L4: lda _tgi_textscalew
+ ldx _tgi_textscalew+1
+ jmp tgi_imulround
+
+; Exit point if no font installed
+
+@L9: rts