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