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) 2009-2011 Cyril Hrubis <metan@ucw.cz>                       *
  23  *                                                                           *
  24  *****************************************************************************/
  25
  26 #include "core/GP_Common.h"
  27 #include "GP_TextMetric.h"
  28
  29 extern GP_TextStyle GP_DefaultStyle;
  30
  31 /*
  32  * Returns glyph width from the basepoint to the end of the glyph bitmap.
  33  */
  34 static unsigned int glyph_width(const GP_TextStyle *style, char ch)
  35 {
  36         unsigned int pixel_multiplier = style->pixel_xmul + style->pixel_xspace;
  37         const GP_GlyphBitmap *glyph = GP_GetGlyphBitmap(style->font, ch);
  38
  39         if (glyph == NULL)
  40                 glyph = GP_GetGlyphBitmap(style->font, ' ');
  41
  42         return (glyph->width + glyph->bearing_x) * pixel_multiplier;
  43 }
  44
  45 /*
  46  * Returns space that is added after the glyph.
  47  *
  48  * Eg. the advance minus glyph width.
  49  *
  50  * TODO: kerning
  51  */
  52 static unsigned int glyph_space(const GP_TextStyle *style, char ch)
  53 {
  54         unsigned int pixel_multiplier = style->pixel_xmul + style->pixel_xspace;
  55         const GP_GlyphBitmap *glyph = GP_GetGlyphBitmap(style->font, ch);
  56
  57         if (glyph == NULL)
  58                 glyph = GP_GetGlyphBitmap(style->font, ' ');
  59
  60         return (glyph->advance_x - glyph->width - glyph->bearing_x)
  61                * pixel_multiplier + style->char_xspace;
  62 }
  63
  64 /*
  65  * Returns maximal character width for a given string.
  66  */
  67 static unsigned int max_glyph_width(const GP_TextStyle *style, const char *str)
  68 {
  69         unsigned int max = 0, i;
  70
  71         for (i = 0; str[i] != '\0'; i++)
  72                 max = GP_MAX(max, glyph_width(style, str[i]));
  73
  74         return max;
  75 }
  76
  77 /*
  78  * Return maximal character space after an glyph.
  79  */
  80 static unsigned int max_glyph_space(const GP_TextStyle *style, const char *str)
  81 {
  82         unsigned int max = 0, i;
  83
  84         for (i = 0; str[i] != '\0'; i++)
  85                 max = GP_MAX(max, glyph_space(style, str[i]));
  86
  87         return max;
  88 }
  89
  90 unsigned int GP_TextWidth(const GP_TextStyle *style, const char *str)
  91 {
  92         unsigned int i, len = 0;
  93
  94         if (style == NULL)
  95                 style = &GP_DefaultStyle;
  96
  97         if (str == NULL || str[0] == '\0')
  98                 return 0;
  99
 100         for (i = 0; str[i] != '\0'; i++) {
 101                 len += glyph_width(style, str[i]);
 102
 103                 if (str[i+1] != '\0')
 104                         len += glyph_space(style, str[i]);
 105         }
 106
 107         return len;
 108 }
 109
 110 GP_Size GP_TextMaxWidth(const GP_TextStyle *style, unsigned int len)
 111 {
 112         unsigned int glyph_width;
 113         //TODO: !
 114         unsigned int space_width = style->char_xspace;
 115
 116         if (style == NULL)
 117                 style = &GP_DefaultStyle;
 118
 119         glyph_width = style->font->max_glyph_width
 120                       * (style->pixel_xmul + style->pixel_xspace);
 121
 122         if (len == 0)
 123                 return 0;
 124
 125         return len * glyph_width + (len - 1) * space_width;
 126 }
 127
 128 GP_Size GP_TextMaxStrWidth(const GP_TextStyle *style, const char *str,
 129                            unsigned int len)
 130 {
 131         unsigned int space_width;
 132         unsigned int glyph_width;
 133
 134         if (style == NULL)
 135                 style = &GP_DefaultStyle;
 136
 137         space_width = max_glyph_space(style, str);
 138
 139         if (len == 0 || str == NULL)
 140                 return 0;
 141
 142         glyph_width = max_glyph_width(style, str);
 143
 144         return len * glyph_width + (len - 1) * space_width;
 145 }
 146
 147 GP_Size GP_TextHeight(const GP_TextStyle *style)
 148 {
 149         unsigned int h;
 150
 151         if (style == NULL)
 152                 style = &GP_DefaultStyle;
 153
 154         h = style->font->ascend + style->font->descend;
 155
 156         return h * style->pixel_ymul +
 157                (h - 1) * style->pixel_yspace;
 158 }
 159
 160 GP_Size GP_TextAscent(const GP_TextStyle *style)
 161 {
 162         unsigned int h;
 163
 164         if (style == NULL)
 165                 style = &GP_DefaultStyle;
 166
 167         h = style->font->ascend;
 168
 169         return h * style->pixel_ymul + (h - 1) * style->pixel_yspace;
 170 }
 171
 172 GP_Size GP_TextDescent(const GP_TextStyle *style)
 173 {
 174         unsigned int h;
 175
 176         if (style == NULL)
 177                 style = &GP_DefaultStyle;
 178
 179         h = style->font->descend;
 180
 181         return h * style->pixel_ymul + (h - 1) * style->pixel_yspace;
 182 }