mod128.cpp

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/**********************************************************************
 * File:        mod128.cpp  (Formerly dir128.c)
 * Description: Code to convert a DIR128 to an ICOORD.
 * Author:      Ray Smith
 *
 * (C) Copyright 1991, Hewlett-Packard Ltd.
 ** Licensed under the Apache License, Version 2.0 (the "License");
 ** you may not use this file except in compliance with the License.
 ** You may obtain a copy of the License at
 ** http://www.apache.org/licenses/LICENSE-2.0
 ** Unless required by applicable law or agreed to in writing, software
 ** distributed under the License is distributed on an "AS IS" BASIS,
 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 ** See the License for the specific language governing permissions and
 ** limitations under the License.
 *
 **********************************************************************/
 
#include "mod128.h"
 
namespace tesseract {
 
static const TDimension idirtab[] = {
    1000, 0,    998,  49,   995,  98,   989,  146,  980,   195,  970,  242,  956,  290,   941,
    336,  923,  382,  903,  427,  881,  471,  857,  514,   831,  555,  803,  595,  773,   634,
    740,  671,  707,  707,  671,  740,  634,  773,  595,   803,  555,  831,  514,  857,   471,
    881,  427,  903,  382,  923,  336,  941,  290,  956,   242,  970,  195,  980,  146,   989,
    98,   995,  49,   998,  0,    1000, -49,  998,  -98,   995,  -146, 989,  -195, 980,   -242,
    970,  -290, 956,  -336, 941,  -382, 923,  -427, 903,   -471, 881,  -514, 857,  -555,  831,
    -595, 803,  -634, 773,  -671, 740,  -707, 707,  -740,  671,  -773, 634,  -803, 595,   -831,
    555,  -857, 514,  -881, 471,  -903, 427,  -923, 382,   -941, 336,  -956, 290,  -970,  242,
    -980, 195,  -989, 146,  -995, 98,   -998, 49,   -1000, 0,    -998, -49,  -995, -98,   -989,
    -146, -980, -195, -970, -242, -956, -290, -941, -336,  -923, -382, -903, -427, -881,  -471,
    -857, -514, -831, -555, -803, -595, -773, -634, -740,  -671, -707, -707, -671, -740,  -634,
    -773, -595, -803, -555, -831, -514, -857, -471, -881,  -427, -903, -382, -923, -336,  -941,
    -290, -956, -242, -970, -195, -980, -146, -989, -98,   -995, -49,  -998, 0,    -1000, 49,
    -998, 98,   -995, 146,  -989, 195,  -980, 242,  -970,  290,  -956, 336,  -941, 382,   -923,
    427,  -903, 471,  -881, 514,  -857, 555,  -831, 595,   -803, 634,  -773, 671,  -740,  707,
    -707, 740,  -671, 773,  -634, 803,  -595, 831,  -555,  857,  -514, 881,  -471, 903,   -427,
    923,  -382, 941,  -336, 956,  -290, 970,  -242, 980,   -195, 989,  -146, 995,  -98,   998,
    -49};
 
static const ICOORD *dirtab = reinterpret_cast<const ICOORD *>(idirtab);
 
/**********************************************************************
 * DIR128::DIR128
 *
 * Quantize the direction of an FCOORD to make a DIR128.
 **********************************************************************/
 
DIR128::DIR128(     // from fcoord
    const FCOORD fc // vector to quantize
) {
  int high, low, current; // binary search
 
  low = 0;
  if (fc.y() == 0) {
    if (fc.x() >= 0) {
      dir = 0;
    } else {
      dir = MODULUS / 2;
    }
    return;
  }
  high = MODULUS;
  do {
    current = (high + low) / 2;
    if (dirtab[current] * fc >= 0) {
      low = current;
    } else {
      high = current;
    }
  } while (high - low > 1);
  dir = low;
}
 
} // namespace tesseract