Source code

/*
 * JPGFileWriter.h 
 * Copyright (c) 2015 Antillia.com TOSHIYUKI ARAI. ALL RIGHTS RESERVED. 
 */


// 2015/08/22 Update write method to take a vertFlip parameter.
//  void write(int width, int height, int depth, unsigned char* data, int quality, bool vertFlip) 

#pragma once

#include <viz++/JPGFile.h>

namespace VIZ {

class JPGFileWriter :public JPGFile {

private:
  struct jpeg_compress_struct cinfo;
  struct jpeg_error_mgr jerr;

public:
  JPGFileWriter(const char* filename)
  :JPGFile(WRITER, filename)
  {
    memset(&cinfo, 0, sizeof(cinfo));
    memset(&jerr, 0, sizeof(jerr));

    cinfo.err = jpeg_std_error(&jerr);
    jpeg_create_compress(&cinfo);

    FILE* fp = getFP();
    jpeg_stdio_dest(&cinfo, fp);
  }

  ~JPGFileWriter()
  {
    jpeg_finish_compress(&cinfo);
    jpeg_destroy_compress(&cinfo);
    close();
  }

public:
  //quality may take a value between 0 and 100.
  //2015/08/22 Updated
  void write(int width, int height, int depth, int channels, unsigned char* data, int quality, bool vertFlip) 
  {
    if (data == NULL) {
      throw IException("Invalid argument: data is NULL");
    }
    if (width <=0 || height <= 0) {
      throw IException("Invalid argument; widht or height is <=0");
    }
    
    cinfo.image_width  = width;
    cinfo.image_height = height;
    cinfo.input_components = 3;
    cinfo.in_color_space = JCS_RGB;

    jpeg_set_defaults(&cinfo);
    jpeg_set_quality(&cinfo, quality, TRUE);
    jpeg_start_compress(&cinfo, TRUE);
    printf("channels %d\n", channels);
    while (cinfo.next_scanline < cinfo.image_height) {
      JSAMPROW row;
      if (vertFlip) {
        row = (JSAMPROW) &data[(height - cinfo.next_scanline - 1) * channels * width];
      } else {
        row = (JSAMPROW) &data[cinfo.next_scanline * channels * width];
      }
      jpeg_write_scanlines(&cinfo, &row, 1);
    }
  }
};

}