LuminanceSource.cpp Example File

 // -*- mode:c++; tab-width:2; indent-tabs-mode:nil; c-basic-offset:2 -*-
 /*
  *  LuminanceSource.cpp
  *  zxing
  *
  *  Copyright 2008 ZXing authors All rights reserved.
  *
  * 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 <sstream>
 #include <zxing/LuminanceSource.h>
 #include <zxing/InvertedLuminanceSource.h>
 #include <zxing/common/IllegalArgumentException.h>

 using zxing::Ref;
 using zxing::LuminanceSource;

 LuminanceSource::LuminanceSource(int width_, int height_) :width(width_), height(height_) {}

 LuminanceSource::~LuminanceSource() {}

 bool LuminanceSource::isCropSupported() const {
   return false;
 }

 Ref<LuminanceSource> LuminanceSource::crop(int, int, int, int) const {
   throw IllegalArgumentException("This luminance source does not support cropping.");
 }

 bool LuminanceSource::isRotateSupported() const {
   return false;
 }

 Ref<LuminanceSource> LuminanceSource::rotateCounterClockwise() const {
     throw IllegalArgumentException("This luminance source does not support rotation.");
 }

 Ref<zxing::LuminanceSource> LuminanceSource::rotateCounterClockwise45() const
 {
     throw IllegalArgumentException("This luminance source does not support rotation 45.");
 }

 LuminanceSource::operator std::string() const {
   ArrayRef<byte> row;
   std::ostringstream oss;
   for (int y = 0; y < getHeight(); y++) {
     row = getRow(y, row);
     for (int x = 0; x < getWidth(); x++) {
       int luminance = row[x] & 0xFF;
       char c;
       if (luminance < 0x40) {
         c = '#';
       } else if (luminance < 0x80) {
         c = '+';
       } else if (luminance < 0xC0) {
         c = '.';
       } else {
         c = ' ';
       }
       oss << c;
     }
     oss << '\n';
   }
   return oss.str();
 }

 Ref<LuminanceSource> LuminanceSource::invert() const {

   // N.B.: this only works because we use counted objects with the
   // count in the object. This is _not_ how things like shared_ptr
   // work. They do not allow you to make a smart pointer from a native
   // pointer more than once. If we ever switch to (something like)
   // shared_ptr's, the luminace source is going to have keep a weak
   // pointer to itself from which it can create a strong pointer as
   // needed. And, FWIW, that has nasty semantics in the face of
   // exceptions during construction.

   return Ref<LuminanceSource>
       (new InvertedLuminanceSource(Ref<LuminanceSource>(const_cast<LuminanceSource*>(this))));
 }