libs/text/GP_TextMetric.c

   1 /*****************************************************************************
   2  * This file is part of gfxprim library.                                     *
   3  *                                                                           *
   4  * Gfxprim is free software; you can redistribute it and/or                  *
   5  * modify it under the terms of the GNU Lesser General Public                *
   6  * License as published by the Free Software Foundation; either              *
   7  * version 2.1 of the License, or (at your option) any later version.        *
   8  *                                                                           *
   9  * Gfxprim is distributed in the hope that it will be useful,                *
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of            *
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU         *
  12  * Lesser General Public License for more details.                           *
  13  *                                                                           *
  14  * You should have received a copy of the GNU Lesser General Public          *
  15  * License along with gfxprim; if not, write to the Free Software            *
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor,                        *
  17  * Boston, MA  02110-1301  USA                                               *
  18  *                                                                           *
  19  * Copyright (C) 2009-2010 Jiri "BlueBear" Dluhos                            *
  20  *                         <jiri.bluebear.dluhos@gmail.com>                  *
  21  *                                                                           *
  22  * Copyright (C) 2009-2010 Cyril Hrubis <metan@ucw.cz>                       *
  23  *                                                                           *
  24  *****************************************************************************/
  25
  26 #include "core/GP_Common.h"
  27 #include "GP_TextMetric.h"
  28
  29 static unsigned int SpaceWidth(const GP_TextStyle *style)
  30 {
  31         //TODO: Does space change with pixel_yspace?
  32         return style->char_xspace * style->pixel_xmul;
  33 }
  34
  35 // FIXME: This is not quite right - due to offsets, characters
  36 // can exceed their bounding box and then the reported width will be
  37 // shorter than expected.
  38 static unsigned int CharWidth(const GP_TextStyle *style, char ch)
  39 {
  40         unsigned int pixel_multiplier = style->pixel_xmul + style->pixel_xspace;
  41         const GP_CharData *data = GP_GetCharData(style->font, ch);
  42
  43         if (data == NULL)
  44                 data = GP_GetCharData(style->font, ' ');
  45
  46         return data->pre_offset * pixel_multiplier
  47                + data->post_offset * pixel_multiplier;
  48 }
  49
  50 static unsigned int MaxCharsWidth(const GP_TextStyle *style, const char *str)
  51 {
  52         unsigned int max = 0, i;
  53
  54         for (i = 0; str[i] != '\0'; i++)
  55                 max = GP_MAX(max, CharWidth(style, str[i]));
  56
  57         return max;
  58 }
  59
  60 unsigned int GP_TextWidth(const GP_TextStyle *style, const char *str)
  61 {
  62         GP_CHECK_TEXT_STYLE(style);
  63         GP_CHECK(str, "NULL string specified");
  64
  65         unsigned int i, len = 0;
  66         unsigned int space = SpaceWidth(style);
  67
  68         if (str[0] == '\0')
  69                 return 0;
  70
  71         for (i = 0; str[i] != '\0'; i++)
  72                 len += CharWidth(style, str[i]);
  73
  74         return len + (i - 1) * space;
  75 }
  76
  77 unsigned int GP_TextMaxWidth(const GP_TextStyle *style, unsigned int len)
  78 {
  79         GP_CHECK_TEXT_STYLE(style);
  80
  81         unsigned int space_width = SpaceWidth(style);
  82         unsigned int char_width  = style->font->max_bounding_width
  83                                    * (style->pixel_xmul + style->pixel_xspace);
  84
  85         if (len == 0)
  86                 return 0;
  87
  88         return len * char_width + (len - 1) * space_width;
  89 }
  90
  91 unsigned int GP_TextMaxStrWidth(const GP_TextStyle *style, const char *str,
  92                                 unsigned int len)
  93 {
  94         GP_CHECK_TEXT_STYLE(style);
  95         GP_CHECK(str, "NULL string specified");
  96
  97         unsigned int space_width = SpaceWidth(style);
  98         unsigned int char_width;
  99
 100         if (len == 0)
 101                 return 0;
 102
 103         char_width = MaxCharsWidth(style, str);
 104
 105         return len * char_width + (len - 1) * space_width;
 106 }
 107
 108 unsigned int GP_TextHeight(const GP_TextStyle *style)
 109 {
 110         GP_CHECK_TEXT_STYLE(style);
 111
 112         return style->font->height * style->pixel_ymul +
 113                (style->font->height - 1) * style->pixel_yspace;
 114 }
 115
 116 unsigned int GP_TextAscent(const GP_TextStyle *style)
 117 {
 118         GP_CHECK_TEXT_STYLE(style);
 119
 120         unsigned int h = style->font->height - style->font->baseline;
 121         return h * style->pixel_ymul + (h - 1) * style->pixel_yspace;
 122 }
 123
 124 unsigned int GP_TextDescent(const GP_TextStyle *style)
 125 {
 126         GP_CHECK_TEXT_STYLE(style);
 127
 128         unsigned int h = style->font->baseline;
 129         return h * style->pixel_ymul + (h - 1) * style->pixel_yspace;
 130 }
 131