1  /*
       2   * fontconfig/src/fcweight.c
       3   *
       4   * Permission to use, copy, modify, distribute, and sell this software and its
       5   * documentation for any purpose is hereby granted without fee, provided that
       6   * the above copyright notice appear in all copies and that both that
       7   * copyright notice and this permission notice appear in supporting
       8   * documentation, and that the name of the author(s) not be used in
       9   * advertising or publicity pertaining to distribution of the software without
      10   * specific, written prior permission.  The authors make no
      11   * representations about the suitability of this software for any purpose.  It
      12   * is provided "as is" without express or implied warranty.
      13   *
      14   * THE AUTHOR(S) DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
      15   * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
      16   * EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY SPECIAL, INDIRECT OR
      17   * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
      18   * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
      19   * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
      20   * PERFORMANCE OF THIS SOFTWARE.
      21   */
      22  
      23  #include "fcint.h"
      24  
      25  static const struct {
      26    int ot;
      27    int fc;
      28  } map[] = {
      29      {   0, FC_WEIGHT_THIN },
      30      { 100, FC_WEIGHT_THIN },
      31      { 200, FC_WEIGHT_EXTRALIGHT },
      32      { 300, FC_WEIGHT_LIGHT },
      33      { 350, FC_WEIGHT_DEMILIGHT },
      34      { 380, FC_WEIGHT_BOOK },
      35      { 400, FC_WEIGHT_REGULAR },
      36      { 500, FC_WEIGHT_MEDIUM },
      37      { 600, FC_WEIGHT_DEMIBOLD },
      38      { 700, FC_WEIGHT_BOLD },
      39      { 800, FC_WEIGHT_EXTRABOLD },
      40      { 900, FC_WEIGHT_BLACK },
      41      {1000, FC_WEIGHT_EXTRABLACK },
      42  };
      43  
      44  static double lerp(double x, int x1, int x2, int y1, int y2)
      45  {
      46    int dx = x2 - x1;
      47    int dy = y2 - y1;
      48    assert (dx > 0 && dy >= 0 && x1 <= x && x <= x2);
      49    return y1 + (x-x1) * dy / dx;
      50  }
      51  
      52  double
      53  FcWeightFromOpenTypeDouble (double ot_weight)
      54  {
      55  	int i;
      56  
      57  	if (ot_weight < 0)
      58  	    return -1;
      59  
      60  	ot_weight = FC_MIN (ot_weight, map[(sizeof (map) / sizeof (map[0])) - 1].ot);
      61  
      62  	for (i = 1; ot_weight > map[i].ot; i++)
      63  	  ;
      64  
      65  	if (ot_weight == map[i].ot)
      66  	  return map[i].fc;
      67  
      68  	/* Interpolate between two items. */
      69  	return lerp (ot_weight, map[i-1].ot, map[i].ot, map[i-1].fc, map[i].fc);
      70  }
      71  
      72  double
      73  FcWeightToOpenTypeDouble (double fc_weight)
      74  {
      75  	int i;
      76  	if (fc_weight < 0 || fc_weight > FC_WEIGHT_EXTRABLACK)
      77  	    return -1;
      78  
      79  	for (i = 1; fc_weight > map[i].fc; i++)
      80  	  ;
      81  
      82  	if (fc_weight == map[i].fc)
      83  	  return map[i].ot;
      84  
      85  	/* Interpolate between two items. */
      86  	return lerp (fc_weight, map[i-1].fc, map[i].fc, map[i-1].ot, map[i].ot);
      87  }
      88  
      89  int
      90  FcWeightFromOpenType (int ot_weight)
      91  {
      92  	return FcWeightFromOpenTypeDouble (ot_weight) + .5;
      93  }
      94  
      95  int
      96  FcWeightToOpenType (int fc_weight)
      97  {
      98  	return FcWeightToOpenTypeDouble (fc_weight) + .5;
      99  }
     100  
     101  #define __fcweight__
     102  #include "fcaliastail.h"
     103  #undef __fcweight__