imageio.h

/* LIBRARY:   ImageIO Library v0.13
*
* FILE:      imageio.hpp
*
* COPYRIGHT: Copyright (c) 2003-2004 Adrien Treuille
*
* AUTHORS:   Adrien Treuille (treuille [AT] cs [DOT] washington [DOT] edu)
*            Kristin Siu
*
* LICENSE:   The ImageIO Library is supplied "AS IS".  The Authors
*            disclaim all warranties, expressed or implied,
*            including, without limitation, the warranties of
*            merchantability and of fitness for any purpose.
*            The Authors assume no liability for direct, indirect,
*            incidental, special, exemplary, or consequential
*            damages, which may result from the use of the ImageIO
*            Library, even if advised of the possibility of such
*            damage.
*
*            Permission is hereby granted to use, copy, modify,
*            and distribute this source code, or portions hereof,
*            for any purpose, without fee, for non-commercial
*            purposes. All rights reserved for commercial uses of
*            this source code.
*/

#ifndef IMAGEIO_HPP_
#define IMAGEIO_HPP_

#include <cstdlib>
#include <string.h>

namespace Lumiverse {

  // Sets tbe width and height to the appropriate values and mallocs
  // a char *buffer loading up the values in row-major, RGBA format.
  // The memory associated with the buffer can be deallocated with free().
  // If there was an error reading file, then 0 is returned, and
  // width = height are set to -1.
  unsigned char* imageio_load_image(const char* filename, int *width, int *height);

  // Saves image given by buffer with specicified width and height
  // to the given file name, returns true on success, false otherwise.
  // The image format is RGBA.
  bool imageio_save_image(const char* filename, unsigned char* buffer, int width, int height);

  // puts a default filename in name, up to len characters
  void imageio_gen_name(char* filename, size_t len);

  // Converts from float image to byte image.
  inline void floats_to_bytes(unsigned char *arr, float *rgba, int width, int height)
  {
    for (int j = 0; j < height; j++) {
      for (int i = 0; i < width; i++) {
        int offset = (j * width + i) * 4;
        int inv_offset = ((height - 1 - j) * width + i) * 4;
        
        // convert to bytes
        arr[offset] = static_cast<unsigned char>(rgba[inv_offset] * 0xff);
        arr[offset + 1] = static_cast<unsigned char>(rgba[inv_offset + 1] * 0xff);
        arr[offset + 2] = static_cast<unsigned char>(rgba[inv_offset + 2] * 0xff);
        arr[offset + 3] = static_cast<unsigned char>(rgba[inv_offset + 3] * 0xff);
      }
    }
  }

  // Converts from byte image to float image.
  inline void bytes_to_floats(float *rgba, unsigned char *arr, int width, int height)
  {
    for (int j = 0; j < height; j++) {
      for (int i = 0; i < width; i++) {
        int offset = (j * width + i) * 4;
        int inv_offset = ((height - 1 - j) * width + i) * 4;

        // convert to float
        rgba[offset] = static_cast<float>(arr[inv_offset]) / 0xff;
        rgba[offset + 1] = static_cast<float>(arr[inv_offset + 1]) / 0xff;
        rgba[offset + 2] = static_cast<float>(arr[inv_offset + 2]) / 0xff;
        rgba[offset + 3] = static_cast<float>(arr[inv_offset + 3]) / 0xff;
      }
    }
  }
} 

#endif /* IMAGEIO_HPP_ */