libjava/classpath/gnu/java/awt/font/autofit/Utils.java

   1 /* Utils.java -- A collection of utility functions for the autofitter
   2    Copyright (C) 2006 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19 02110-1301 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38
  39 package gnu.java.awt.font.autofit;
  40
  41 import gnu.java.awt.font.opentype.truetype.Fixed;
  42
  43 /**
  44  * A collection of utility methods used all around the auto fitter.
  45  */
  46 class Utils
  47   implements Constants
  48 {
  49
  50   private static final int ATAN_BITS = 8;
  51   private static final byte[] ATAN = new byte[]
  52   {
  53      0,  0,  1,  1,  1,  2,  2,  2,
  54      3,  3,  3,  3,  4,  4,  4,  5,
  55      5,  5,  6,  6,  6,  7,  7,  7,
  56      8,  8,  8,  9,  9,  9, 10, 10,
  57     10, 10, 11, 11, 11, 12, 12, 12,
  58     13, 13, 13, 14, 14, 14, 14, 15,
  59     15, 15, 16, 16, 16, 17, 17, 17,
  60     18, 18, 18, 18, 19, 19, 19, 20,
  61     20, 20, 21, 21, 21, 21, 22, 22,
  62     22, 23, 23, 23, 24, 24, 24, 24,
  63     25, 25, 25, 26, 26, 26, 26, 27,
  64     27, 27, 28, 28, 28, 28, 29, 29,
  65     29, 30, 30, 30, 30, 31, 31, 31,
  66     31, 32, 32, 32, 33, 33, 33, 33,
  67     34, 34, 34, 34, 35, 35, 35, 35,
  68     36, 36, 36, 36, 37, 37, 37, 38,
  69     38, 38, 38, 39, 39, 39, 39, 40,
  70     40, 40, 40, 41, 41, 41, 41, 42,
  71     42, 42, 42, 42, 43, 43, 43, 43,
  72     44, 44, 44, 44, 45, 45, 45, 45,
  73     46, 46, 46, 46, 46, 47, 47, 47,
  74     47, 48, 48, 48, 48, 48, 49, 49,
  75     49, 49, 50, 50, 50, 50, 50, 51,
  76     51, 51, 51, 51, 52, 52, 52, 52,
  77     52, 53, 53, 53, 53, 53, 54, 54,
  78     54, 54, 54, 55, 55, 55, 55, 55,
  79     56, 56, 56, 56, 56, 57, 57, 57,
  80     57, 57, 57, 58, 58, 58, 58, 58,
  81     59, 59, 59, 59, 59, 59, 60, 60,
  82     60, 60, 60, 61, 61, 61, 61, 61,
  83     61, 62, 62, 62, 62, 62, 62, 63,
  84     63, 63, 63, 63, 63, 64, 64, 64
  85   };
  86
  87   private static final int ANGLE_PI = 256;
  88   private static final int ANGLE_PI2 = ANGLE_PI / 2;
  89   private static final int ANGLE_PI4 = ANGLE_PI / 4;
  90   private static final int ANGLE_2PI = ANGLE_PI * 2;
  91
  92   /**
  93    * Computes the direction constant for the specified vector. The vector is
  94    * given as differential value already.
  95    *
  96    * @param dx the x vector
  97    * @param dy the y vector
  98    *
  99    * @return the direction of that vector, or DIR_NONE, if that vector is not
 100    *         approximating against one of the major axises
 101    */
 102   static int computeDirection(int dx, int dy)
 103   {
 104     int dir = DIR_NONE;
 105     if (dx < 0)
 106       {
 107         if (dy < 0)
 108           {
 109             if (-dx * 12 < -dy)
 110               dir = DIR_UP;
 111             else if (-dy * 12 < -dx)
 112               dir = DIR_LEFT;
 113           }
 114         else // dy >= 0 .
 115           {
 116             if (-dx * 12 < dy)
 117               dir = DIR_DOWN;
 118             else if (dy * 12 < -dx)
 119               dir = DIR_LEFT;
 120           }
 121       }
 122     else // dx >= 0 .
 123       {
 124         if (dy < 0)
 125           {
 126             if (dx * 12 < -dy)
 127               dir = DIR_UP;
 128             else if (-dy * 12 < dx)
 129               dir = DIR_RIGHT;
 130           }
 131         else // dy >= 0 .
 132           {
 133             if (dx * 12 < dy)
 134               dir = DIR_DOWN;
 135             else if (dy * 12 < dx)
 136               dir = DIR_RIGHT;
 137           }
 138       }
 139     return dir;
 140   }
 141
 142   public static int atan(int dx, int dy)
 143   {
 144     int angle;
 145     // Trivial cases.
 146     if (dy == 0)
 147       {
 148         angle = 0;
 149         if (dx < 0)
 150           angle = ANGLE_PI;
 151         return angle;
 152       }
 153     else if (dx == 0)
 154       {
 155         angle = ANGLE_PI2;
 156         if (dy < 0)
 157           angle = - ANGLE_PI2;
 158         return angle;
 159       }
 160
 161
 162     angle = 0;
 163     if (dx < 0)
 164       {
 165         dx = -dx;
 166         dy = -dy;
 167         angle = ANGLE_PI;
 168       }
 169     if (dy < 0)
 170       {
 171         int tmp = dx;
 172         dx = -dy;
 173         dy = tmp;
 174         angle -= ANGLE_PI2;
 175       }
 176     if (dx == 0 && dy == 0)
 177       return 0;
 178
 179     if (dx == dy)
 180       angle += ANGLE_PI4;
 181     else if (dx > dy)
 182       {
 183         angle += ATAN[Fixed.div(dy, dx) << (ATAN_BITS - 6)];
 184       }
 185     else
 186       {
 187         angle += ANGLE_PI2 - ATAN[Fixed.div(dx, dy) << (ATAN_BITS - 6)];
 188       }
 189
 190     if (angle > ANGLE_PI)
 191       angle -= ANGLE_2PI;
 192     return angle;
 193   }
 194
 195   public static int angleDiff(int ang1, int ang2)
 196   {
 197     int delta = ang2 - ang1;
 198     delta %= ANGLE_2PI;
 199     if (delta < 0)
 200       delta += ANGLE_2PI;
 201     if (delta > ANGLE_PI)
 202       delta -= ANGLE_2PI;
 203     return delta;
 204   }
 205
 206   static void sort(int num, int[] array)
 207   {
 208     int swap;
 209     for (int i = 1; i < num; i++)
 210       {
 211         for (int j = i; j > 0; j--)
 212           {
 213             if (array[j] > array[j - 1])
 214               break;
 215             swap = array[j];
 216             array[j] = array[j - 1];
 217             array[j - 1] = swap;
 218           }
 219       }
 220   }
 221
 222   static void sort(int num, Width[] array)
 223   {
 224     Width swap;
 225     for (int i = 1; i < num; i++)
 226       {
 227         for (int j = 1; j > 0; j--)
 228           {
 229             if (array[j].org > array[j - 1].org)
 230               break;
 231             swap = array[j];
 232             array[j] = array[j - 1];
 233             array[j - 1] = swap;
 234           }
 235       }
 236   }
 237
 238   static int pixRound(int val)
 239   {
 240     return pixFloor(val + 32);
 241   }
 242
 243   static int pixFloor(int val)
 244   {
 245     return val & ~63;
 246   }
 247
 248   public static int mulDiv(int a, int b, int c)
 249   {
 250     long prod = a * b;
 251     long div = (prod / c);
 252     return (int) div;
 253   }
 254
 255 }