rom/graphics/textfit.c

   1 /*
   2     Copyright © 1995-2012, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Tell how many characters will fit into a box.
   6     Lang: english
   7 */
   8 #include "graphics_intern.h"
   9
  10 /*****************************************************************************
  11
  12     NAME */
  13 #include <graphics/rastport.h>
  14 #include <graphics/text.h>
  15 #include <proto/graphics.h>
  16
  17         AROS_LH8(ULONG, TextFit,
  18
  19 /*  SYNOPSIS */
  20         AROS_LHA(struct RastPort   *, rp, A1),
  21         AROS_LHA(CONST_STRPTR       , string, A0),
  22         AROS_LHA(ULONG              , strLen, D0),
  23         AROS_LHA(struct TextExtent *, textExtent, A2),
  24         AROS_LHA(struct TextExtent *, constrainingExtent, A3),
  25         AROS_LHA(LONG               , strDirection, D1),
  26         AROS_LHA(ULONG              , constrainingBitWidth, D2),
  27         AROS_LHA(ULONG              , constrainingBitHeight, D3),
  28
  29 /*  LOCATION */
  30         struct GfxBase *, GfxBase, 116, Graphics)
  31
  32 /*  FUNCTION
  33         Tries to fill the given space with as many characters of the
  34         font in rp as possible and returns that number.
  35
  36     INPUTS
  37         rp - Use the settings in this RastPort (e.g. Font)
  38         string - Use this string
  39         strLen - The length of the string
  40         textExtent - The size actually occupied will be returned here
  41         constrainingExtent - If non-NULL, the routine will use the
  42                 dimensions of the box described here
  43         strDirection - In which is the next character. Must be either 1
  44                 or -1. If it is -1, then string must point to the end (the
  45                 first character to check) of the text to fit (this is for
  46                 checking text which runs from right to left).
  47         constrainingBitWidth - If constrainingExtent is NULL, then this
  48                 is the width of the bounding box.
  49         constrainingBitHeight - If constrainingExtent is NULL, then this
  50                 is the height of the bounding box.
  51
  52     RESULT
  53         The number of characters which fit in the bounding box.
  54         If any characters fit in the bounding box, then textExtent will
  55         tell how large the minimal bounding box for the string is.
  56
  57     NOTES
  58
  59     EXAMPLE
  60
  61     BUGS
  62
  63     SEE ALSO
  64         TextLength()
  65
  66     INTERNALS
  67
  68 *****************************************************************************/
  69 {
  70     AROS_LIBFUNC_INIT
  71
  72     struct TextFont *tf = rp->Font;
  73     ULONG retval = 0;
  74
  75     if (strLen && (constrainingBitHeight >= tf->tf_YSize))
  76     {
  77         BOOL ok = TRUE;
  78
  79         textExtent->te_Extent.MinX = 0;
  80         textExtent->te_Extent.MinY = -tf->tf_Baseline;
  81         textExtent->te_Extent.MaxX = 0;
  82         textExtent->te_Extent.MaxY = tf->tf_YSize - tf->tf_Baseline - 1;
  83         textExtent->te_Width       = 0;
  84         textExtent->te_Height      = tf->tf_YSize;
  85
  86         if (constrainingExtent)
  87         {
  88             if (constrainingExtent->te_Extent.MinY > textExtent->te_Extent.MinY
  89                 ||
  90                 constrainingExtent->te_Extent.MaxY < textExtent->te_Extent.MaxY
  91                 ||
  92                 constrainingExtent->te_Height < textExtent->te_Height)
  93             {
  94                 ok = FALSE;
  95             }
  96         }
  97
  98         if (ok)
  99         {
 100             while (strLen--)
 101             {
 102                 struct TextExtent char_extent;
 103                 WORD newwidth, newminx, newmaxx, minx, maxx;
 104
 105                 TextExtent(rp, string, 1, &char_extent);
 106                 string += strDirection;
 107
 108                 newwidth = textExtent->te_Width + char_extent.te_Width;
 109                 minx = textExtent->te_Width + char_extent.te_Extent.MinX;
 110                 maxx = textExtent->te_Width + char_extent.te_Extent.MaxX;
 111
 112                 newminx = (minx < textExtent->te_Extent.MinX) ?
 113                     minx : textExtent->te_Extent.MinX;
 114                 newmaxx = (maxx > textExtent->te_Extent.MaxX) ?
 115                     maxx : textExtent->te_Extent.MaxX;
 116
 117                 if ((ULONG)(newmaxx - newminx + 1) > constrainingBitWidth)
 118                     break;
 119
 120                 if (constrainingExtent)
 121                 {
 122                     if (constrainingExtent->te_Extent.MinX > newminx) break;
 123                     if (constrainingExtent->te_Extent.MaxX < newmaxx) break;
 124                     if (constrainingExtent->te_Width < newwidth) break;
 125                 }
 126
 127                 textExtent->te_Width = newwidth;
 128                 textExtent->te_Extent.MinX = newminx;
 129                 textExtent->te_Extent.MaxX = newmaxx;
 130
 131                 retval++;
 132
 133             } /* while(strLen--) */
 134
 135         } /* if (ok) */
 136
 137     } /* if (strLen && (constrainingBitHeight >= tf->tf_YSize)) */
 138
 139     if (retval == 0)
 140     {
 141         textExtent->te_Width = 0;
 142         textExtent->te_Height = 0;
 143         textExtent->te_Extent.MinX = 0;
 144         textExtent->te_Extent.MinY = 0;
 145         textExtent->te_Extent.MaxX = 0;
 146         textExtent->te_Extent.MaxY = 0;
 147     }
 148
 149     return retval;
 150
 151     AROS_LIBFUNC_EXIT
 152
 153 } /* TextFit */