hmtx.lisp

   1 ;;; Copyright (c) 2006 Zachary Beane, All Rights Reserved
   2 ;;;
   3 ;;; Redistribution and use in source and binary forms, with or without
   4 ;;; modification, are permitted provided that the following conditions
   5 ;;; are met:
   6 ;;;
   7 ;;;   * Redistributions of source code must retain the above copyright
   8 ;;;     notice, this list of conditions and the following disclaimer.
   9 ;;;
  10 ;;;   * Redistributions in binary form must reproduce the above
  11 ;;;     copyright notice, this list of conditions and the following
  12 ;;;     disclaimer in the documentation and/or other materials
  13 ;;;     provided with the distribution.
  14 ;;;
  15 ;;; THIS SOFTWARE IS PROVIDED BY THE AUTHOR 'AS IS' AND ANY EXPRESSED
  16 ;;; OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  17 ;;; WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  18 ;;; ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
  19 ;;; DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  20 ;;; DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
  21 ;;; GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  22 ;;; INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  23 ;;; WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  24 ;;; NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  25 ;;; SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26 ;;;
  27 ;;; Loading data from the "hmtx" table.
  28 ;;;
  29 ;;;  https://learn.microsoft.com/en-us/typography/opentype/spec/hmtx
  30 ;;;  https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6hmtx.html
  31 ;;;
  32 ;;; $Id: hmtx.lisp,v 1.3 2006/02/18 23:13:43 xach Exp $
  33
  34 (in-package #:zpb-ttf)
  35
  36 (defmethod load-hmtx-info ((font-loader font-loader))
  37   (let* ((horizontal-metrics-count (horizontal-metrics-count font-loader))
  38          (advance-widths (make-array horizontal-metrics-count))
  39          (left-side-bearings (make-array horizontal-metrics-count)))
  40     (seek-to-table "hmtx" font-loader)
  41     (with-slots (input-stream) font-loader
  42       (dotimes (i horizontal-metrics-count)
  43         (setf (svref advance-widths i) (read-uint16 input-stream))
  44         (setf (svref left-side-bearings i) (read-int16 input-stream))))
  45     (setf (advance-widths font-loader) advance-widths
  46           (left-side-bearings font-loader) left-side-bearings)))