rom/graphics/textlength.c

   1 /*
   2     Copyright © 1995-2012, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Graphics function TextLength()
   6     Lang: english
   7 */
   8 #include "graphics_intern.h"
   9
  10 #undef NUMCHARS
  11 #define NUMCHARS(tf) ((tf->tf_HiChar - tf->tf_LoChar) + 2)
  12
  13 /*****************************************************************************
  14
  15     NAME */
  16 #include <graphics/rastport.h>
  17 #include <proto/graphics.h>
  18
  19         AROS_LH3(WORD, TextLength,
  20
  21 /*  SYNOPSIS */
  22         AROS_LHA(struct RastPort *, rp, A1),
  23         AROS_LHA(CONST_STRPTR     , string, A0),
  24         AROS_LHA(ULONG            , count, D0),
  25
  26 /*  LOCATION */
  27         struct GfxBase *, GfxBase, 9, Graphics)
  28
  29 /*  FUNCTION
  30         Determines the length of a string in pixels.
  31
  32     INPUTS
  33         rp     - RastPort
  34         string - address of string
  35         count  - number of characters of string
  36
  37     RESULT
  38         Length of string in pixels.
  39
  40     NOTES
  41         Use the newer TextExtent() to get more information.
  42
  43     EXAMPLE
  44
  45     BUGS
  46
  47     SEE ALSO
  48         Text(), TextExtent()
  49
  50     INTERNALS
  51
  52 *****************************************************************************/
  53 {
  54     AROS_LIBFUNC_INIT
  55
  56     struct TextFont *tf = rp->Font;
  57     WORD strlen;
  58
  59     if ((tf->tf_Flags & FPF_PROPORTIONAL) || tf->tf_CharKern
  60         || tf->tf_CharSpace)
  61     {
  62         WORD  idx;
  63         WORD  defaultidx = NUMCHARS(tf) - 1; /* Last glyph is default glyph */
  64         UBYTE c;
  65
  66         for(strlen = 0; count; count--)
  67         {
  68             c = *string++;
  69
  70             if ( c < tf->tf_LoChar || c > tf->tf_HiChar)
  71             {
  72                 idx = defaultidx;
  73             }
  74             else
  75             {
  76                 idx = c - tf->tf_LoChar;
  77             }
  78
  79             strlen += ((WORD *)tf->tf_CharKern)[idx];
  80             strlen += ((WORD *)tf->tf_CharSpace)[idx];
  81             strlen += rp->TxSpacing;
  82         }
  83     }
  84     else
  85     {
  86         strlen = count * (tf->tf_XSize + rp->TxSpacing);
  87     }
  88
  89     return strlen;
  90
  91     AROS_LIBFUNC_EXIT
  92
  93 } /* TextLength */