rom/graphics/fontextent.c

   1 /*
   2     Copyright © 1995-2007, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Graphics function FontExtent()
   6     Lang: English
   7 */
   8
   9 #include <proto/graphics.h>
  10 #include <graphics/text.h>
  11
  12 #define max(a,b)  (((a) > (b)) ? (a) : (b))
  13 #define min(a,b)  (((a) < (b)) ? (a) : (b))
  14
  15 /*****************************************************************************
  16
  17     NAME */
  18
  19         AROS_LH2(void, FontExtent,
  20
  21 /*  SYNOPSIS */
  22         AROS_LHA(struct TextFont   *, font      , A0),
  23         AROS_LHA(struct TextExtent *, fontExtent, A1),
  24
  25 /*  LOCATION */
  26         struct GfxBase *, GfxBase, 127, Graphics)
  27
  28 /*  FUNCTION
  29
  30     Fill out a text extent structure with the maximum extent of the
  31     characters for the font in question.
  32
  33     INPUTS
  34
  35     font        --  The font the extent of which to calculate.
  36     fontExtent  --  TextExtent structure to hold the values.
  37
  38     RESULT
  39
  40     The extent is stored in 'fontExtent'.
  41
  42     NOTES
  43
  44     Neither effects of algorithmic additions nor rp_TxSpacing is included
  45     when the bounding box and font size are calculated. Note that te_Width
  46     only will be negative when FPF_REVPATH is specified for the font; left
  47     moving characters are ignored considering the font width (right moving
  48     character when FPF_REVPATH is set), but affects the bounding box size.
  49
  50     EXAMPLE
  51
  52     BUGS
  53
  54     SEE ALSO
  55
  56     TextExtent(), <graphics/text.h>
  57
  58     INTERNALS
  59
  60     HISTORY
  61
  62     990617   SDuvan  Implemented
  63
  64 *****************************************************************************/
  65 {
  66     AROS_LIBFUNC_INIT
  67
  68     WORD i;                        /* Loop variable */
  69     WORD maxwidth = -0x7fff;
  70     WORD minwidth =  0x7fff;
  71     WORD width    =  0;
  72
  73     for(i = 0; i <= font->tf_HiChar - font->tf_LoChar; i++)
  74     {
  75         WORD kern;                 /* Kerning value for the character */
  76         WORD wspace;               /* Width of character including CharSpace */
  77
  78         kern = 0;
  79
  80         if(font->tf_CharKern != NULL)
  81             kern = ((WORD *)font->tf_CharKern)[i];
  82
  83         minwidth = min(minwidth, kern);
  84
  85         /* tf_CharLoc[2*i+1] contains the width of the glyph bitmap.
  86            But in AROS tf_CharLoc is being handled like an LONG array,
  87            not a WORD array, so the width is tf_CarLoc[i] & 0xFFFF */
  88         maxwidth = max(maxwidth, kern + ((((LONG *)font->tf_CharLoc)[i]) & 0xFFFF));
  89
  90         if(font->tf_CharSpace != NULL)
  91             wspace = kern + ((WORD *)font->tf_CharSpace)[i];
  92         else
  93             /* Is it possible to have kerning values but no CharSpace? */
  94             wspace = kern + font->tf_XSize;
  95
  96
  97         if(font->tf_Flags & FPF_REVPATH)
  98             width = min(wspace, width);
  99         else
 100             width = max(wspace, width);
 101     }
 102
 103     fontExtent->te_Width       = width;
 104     fontExtent->te_Height      = font->tf_YSize;
 105     fontExtent->te_Extent.MinX = minwidth;
 106     fontExtent->te_Extent.MaxX = maxwidth - 1;
 107     fontExtent->te_Extent.MinY = -font->tf_Baseline;
 108     fontExtent->te_Extent.MaxY = font->tf_YSize - font->tf_Baseline - 1;
 109
 110     AROS_LIBFUNC_EXIT
 111 } /* FontExtent */