[Gegl-developer] npy saving operation

[Dov Grobgeld <dov grobgeld gmail com>]

I finished a saver operation for floating point npy images. It may e.g. be used to debug floating point operations (e.g. gaussian-blur) with numerical python. The resulting image may be read into numpy as follows:

   import numpy

   img = numpy.load('image.npy')

It may also be viewed in my image viewer giv (though it currently does not support color npy images).

Is it ok to commit it?

Follows the code.

Regards,

Dov

/* This file is an image processing operation for GEGL

 *

 * GEGL is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 3 of the License, or (at your option) any later version.

 *

 * GEGL is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with GEGL; if not, see <http://www.gnu.org/licenses/>.

 *

 * Copyright Dov Grobgeld 2013 <dov.grobgeld (a) gmail.com>

 *

 * This operation saves a buffer in the npy file format. It may be

 * read into python as follows:

 *

 *   import numpy

 *   img = numpy.load('image.npy')

 */

#include "config.h"

#include <glib/gi18n-lib.h>

#ifdef GEGL_CHANT_PROPERTIES

gegl_chant_string  (path, _("File"), "",

                    _("Target path and filename, use '-' for stdout."))

#else

#define GEGL_CHANT_TYPE_SINK

#define GEGL_CHANT_C_FILE       "npy-save.c"

#include "gegl-chant.h"

#include <stdio.h>

static int npywrite(FILE *fp, guchar *data, int width, int height, int num_channels)

{

    char header[100];

    unsigned short header_len;

    // Write header and version number to file

    fwrite("\223NUMPY"

           "\001\000"

           , 1, 8, fp);

    if (num_channels == 3)

      sprintf(header,

              "{'descr': '<f4', 'fortran_order': False, 'shape': (%d, %d, 3), } \n",

              height, width);

    else

      sprintf(header,

              "{'descr': '<f4', 'fortran_order': False, 'shape': (%d, %d), } \n",

              height, width);

    header_len = strlen(header);

    fwrite(&header_len, 2, 1, fp);

    fwrite(header, header_len, 1, fp);

    fwrite(data, width*height*num_channels, sizeof(float), fp);

    

    return 0;

}

static gboolean

process (GeglOperation       *operation,

         GeglBuffer          *input,

         const GeglRectangle *rect,

         gint                 level)

{

  GeglChantO *o = GEGL_CHANT_PROPERTIES (operation);

  FILE     *fp;

  guchar   *data;

  gsize     bpc;

  gsize     numsamples;

  gsize     numchannels;

  gboolean  ret = FALSE;

  const Babl *output_format;

  const Babl *input_format = gegl_buffer_get_format(input); 

  // Get the current format and use it to decide whether to save

  // the output in color or gray level formats.

  bpc = sizeof(gfloat);

  if (babl_format_get_n_components(input_format) >= 3)

    {

      numchannels = 3;

      output_format = babl_format("RGB float");

    }

  else

    {

      numchannels = 1;

      output_format = babl_format ("Y float");

    }

  numsamples = rect->width * rect->height * numchannels;

  data = "" (numsamples * bpc);

  gegl_buffer_get (input, rect, 1.0, output_format, data,

                   GEGL_AUTO_ROWSTRIDE, GEGL_ABYSS_NONE);

  fp = (!strcmp (o->path, "-") ? stdout : fopen(o->path, "wb") );

  npywrite(fp, data, rect->width, rect->height, numchannels);

  g_free (data);

  return ret;

}

static void

gegl_chant_class_init (GeglChantClass *klass)

{

  GeglOperationClass     *operation_class;

  GeglOperationSinkClass *sink_class;

  operation_class = GEGL_OPERATION_CLASS (klass);

  sink_class      = GEGL_OPERATION_SINK_CLASS (klass);

  sink_class->process = process;

  sink_class->needs_full = TRUE;

  gegl_operation_class_set_keys (operation_class,

    "name"        , "gegl:npy-save",

    "categories"  , "output",

    "description" ,

        _("NPY image saver (Numerical python file saver.)"),

        NULL);

  gegl_extension_handler_register_saver (".npy", "gegl:npy-save");

}

#endif