rom/graphics/weightamatch.c

   1 /*
   2     Copyright © 1995-2001, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc:
   6     Lang: english
   7 */
   8 #include "graphics_intern.h"
   9 #include <stdlib.h>
  10
  11 /*****************************************************************************
  12
  13     NAME */
  14 #include <clib/graphics_protos.h>
  15
  16         AROS_LH3(WORD, WeighTAMatch,
  17
  18 /*  SYNOPSIS */
  19         AROS_LHA(struct TextAttr *, reqTextAttr, A0),
  20         AROS_LHA(struct TextAttr *, targetTextAttr, A1),
  21         AROS_LHA(struct TagItem  *, targetTags, A2),
  22
  23 /*  LOCATION */
  24         struct GfxBase *, GfxBase, 134, Graphics)
  25
  26 /*  FUNCTION
  27                 Determines how well two font descriptions match.
  28
  29     INPUTS
  30         reqTextAttr             - the required textattr.
  31         targetTextAttr  - textattr of potential match.
  32         targetTags              - tags for the targetTextAttr.
  33
  34     RESULT
  35         A weight number which measures how well the TextAttrs
  36         match. The weight may vary from 0 (no match) to
  37         MAXFONTMATCHWEIGHT (perfect match).
  38
  39     NOTES
  40
  41     EXAMPLE
  42
  43     BUGS
  44         Does not yet take tags into account.
  45
  46     SEE ALSO
  47
  48     INTERNALS
  49
  50
  51     HISTORY
  52         27-11-96    digulla automatically created from
  53                             graphics_lib.fd and clib/graphics_protos.h
  54
  55 *****************************************************************************/
  56 {
  57     AROS_LIBFUNC_INIT
  58     AROS_LIBBASE_EXT_DECL(struct GfxBase *,GfxBase)
  59
  60     WORD matchweight = MAXFONTMATCHWEIGHT;
  61     WORD sizematch = 0; /* for temporary keeping data */
  62     UWORD sizediff;
  63
  64     /* Compare font flags */
  65
  66     /* No match if req is designed and target not */
  67     if ((reqTextAttr->ta_Flags & FPF_DESIGNED) && ! (targetTextAttr->ta_Flags & (FPF_DESIGNED | FPF_DISKFONT)))
  68         return 0;
  69
  70     /* No match if REVPATH is not the same, ignore other flags */
  71     if ((reqTextAttr->ta_Flags ^ targetTextAttr->ta_Flags) & FPF_REVPATH)
  72         return 0;
  73
  74
  75     /* Compare font style */
  76     if ((reqTextAttr->ta_Style & FSF_UNDERLINED) && !(targetTextAttr->ta_Style & FSF_UNDERLINED))
  77         matchweight &= ~(1<<2);
  78     if (!(reqTextAttr->ta_Style & FSF_UNDERLINED) && (targetTextAttr->ta_Style & FSF_UNDERLINED))
  79         matchweight &= ~(1<<11);
  80
  81     if ((reqTextAttr->ta_Style & FSF_BOLD) && !(targetTextAttr->ta_Style & FSF_BOLD))
  82         matchweight &= ~(1<<3);
  83     if (!(reqTextAttr->ta_Style & FSF_BOLD) && (targetTextAttr->ta_Style & FSF_BOLD))
  84         matchweight &= ~(1<<9);
  85
  86     if ((reqTextAttr->ta_Style & FSF_ITALIC) && !(targetTextAttr->ta_Style & FSF_ITALIC))
  87         matchweight &= ~(1<<4);
  88     if (!(reqTextAttr->ta_Style & FSF_ITALIC) && (targetTextAttr->ta_Style & FSF_ITALIC))
  89         matchweight &= ~(1<<10);
  90
  91     /* Now subtract a value depending on the size difference */
  92
  93     sizediff = abs((WORD)reqTextAttr->ta_YSize - (WORD)targetTextAttr->ta_YSize);
  94
  95     if (sizediff > 511)
  96         return 0;
  97
  98     if (reqTextAttr->ta_YSize < targetTextAttr->ta_YSize)
  99         sizematch = sizediff << 7;
 100     else
 101         sizematch = sizediff << 5;
 102
 103     if (sizematch > matchweight)
 104         matchweight = 0;
 105     else
 106         matchweight -= sizematch;
 107
 108     return matchweight;
 109
 110     AROS_LIBFUNC_EXIT
 111 } /* WeighTAMatch */