/* 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 <https://www.gnu.org/licenses/>.
 *
 * Copyright 2006 Øyvind Kolås <pippin@gimp.org>
 */


#include "config.h"
#include <glib/gi18n-lib.h>

#define EPSILON 1e-6

#ifdef GEGL_PROPERTIES

property_double (in_low, _("Low input"), 0.0)
    description ( _("Input luminance level to become lowest output"))
    ui_range    (0.0, 1.0)

property_double (in_high, _("High input"), 1.0)
    description (_("Input luminance level to become white"))
    ui_range    (0.0, 1.0)

property_double (out_low, _("Low output"), 0.0)
    description (_("Lowest luminance level in output"))
    ui_range    (0.0, 1.0)

property_double (out_high, _("High output"), 1.0)
    description (_("Highest luminance level in output"))
    ui_range    (0.0, 1.0)

#else

#define GEGL_OP_POINT_FILTER
#define GEGL_OP_NAME     levels
#define GEGL_OP_C_SOURCE levels.c

#include "gegl-op.h"

/* GeglOperationPointFilter gives us a linear buffer to operate on
 * in our requested pixel format
 */
static gboolean
process (GeglOperation       *op,
         void                *in_buf,
         void                *out_buf,
         glong                n_pixels,
         const GeglRectangle *roi,
         gint                 level)
{
  GeglProperties *o = GEGL_PROPERTIES (op);
  gfloat     *in_pixel;
  gfloat     *out_pixel;
  gfloat      in_range;
  gfloat      out_range;
  gfloat      in_offset;
  gfloat      out_offset;
  gfloat      scale;
  glong       i;

  in_pixel = in_buf;
  out_pixel = out_buf;

  in_offset = o->in_low * 1.0;
  out_offset = o->out_low * 1.0;
  in_range = o->in_high-o->in_low;
  out_range = o->out_high-o->out_low;

  if (fabsf (in_range) <= EPSILON)
    in_range = copysignf (EPSILON, in_range);

  scale = out_range/in_range;

  for (i=0; i<n_pixels; i++)
    {
      int c;
      for (c=0;c<3;c++)
        out_pixel[c] = (in_pixel[c]- in_offset) * scale + out_offset;
      out_pixel[3] = in_pixel[3];
      out_pixel += 4;
      in_pixel += 4;
    }
  return TRUE;
}

#include "opencl/gegl-cl.h"

#include "opencl/levels.cl.h"

static GeglClRunData *cl_data = NULL;

/* OpenCL processing function */
static gboolean
cl_process (GeglOperation       *op,
            cl_mem               in_tex,
            cl_mem               out_tex,
            size_t               global_worksize,
            const GeglRectangle *roi,
            gint                 level)
{
  /* Retrieve a pointer to GeglProperties structure which contains all the
   * chanted properties
   */

  GeglProperties *o = GEGL_PROPERTIES (op);

  gfloat      in_range;
  gfloat      out_range;
  gfloat      in_offset;
  gfloat      out_offset;
  gfloat      scale;

  cl_int cl_err = 0;

  in_offset = o->in_low * 1.0;
  out_offset = o->out_low * 1.0;
  in_range = o->in_high-o->in_low;
  out_range = o->out_high-o->out_low;

  if (in_range == 0.0)
    in_range = 0.00000001;

  scale = out_range/in_range;

  if (!cl_data)
    {
      const char *kernel_name[] = {"kernel_levels", NULL};
      cl_data = gegl_cl_compile_and_build (levels_cl_source, kernel_name);
    }
  if (!cl_data) return TRUE;

  cl_err = gegl_clSetKernelArg(cl_data->kernel[0], 0, sizeof(cl_mem),   (void*)&in_tex);
  CL_CHECK;
  cl_err = gegl_clSetKernelArg(cl_data->kernel[0], 1, sizeof(cl_mem),   (void*)&out_tex);
  CL_CHECK;
  cl_err = gegl_clSetKernelArg(cl_data->kernel[0], 2, sizeof(cl_float), (void*)&in_offset);
  CL_CHECK;
  cl_err = gegl_clSetKernelArg(cl_data->kernel[0], 3, sizeof(cl_float), (void*)&out_offset);
  CL_CHECK;
  cl_err = gegl_clSetKernelArg(cl_data->kernel[0], 4, sizeof(cl_float), (void*)&scale);
  CL_CHECK;

  cl_err = gegl_clEnqueueNDRangeKernel(gegl_cl_get_command_queue (),
                                        cl_data->kernel[0], 1,
                                        NULL, &global_worksize, NULL,
                                        0, NULL, NULL);
  CL_CHECK;

  return FALSE;

error:
  return TRUE;
}



static void
gegl_op_class_init (GeglOpClass *klass)
{
  GeglOperationClass            *operation_class;
  GeglOperationPointFilterClass *point_filter_class;
  gchar                         *composition =
    "<?xml version='1.0' encoding='UTF-8'?>"
    "<gegl>"
    "  <node operation='gegl:crop' width='200' height='200'/>"
    "  <node operation='gegl:over'>"
    "    <node operation='gegl:levels'>"
    "      <params>"
    "        <param name='in-low'>0.54</param>"
    "        <param name='in-high'>0.60</param>"
    "        <param name='out-low'>0.57</param>"
    "        <param name='out-high'>0.68</param>"
    "      </params>"
    "    </node>"
    "    <node operation='gegl:load' path='standard-input.png'/>"
    "  </node>"
    "  <node operation='gegl:checkerboard'>"
    "    <params>"
    "      <param name='color1'>rgb(0.25,0.25,0.25)</param>"
    "      <param name='color2'>rgb(0.75,0.75,0.75)</param>"
    "    </params>"
    "  </node>"    
    "</gegl>";

  operation_class    = GEGL_OPERATION_CLASS (klass);
  point_filter_class = GEGL_OPERATION_POINT_FILTER_CLASS (klass);

  point_filter_class->process = process;
  point_filter_class->cl_process = cl_process;

  operation_class->opencl_support = TRUE;

  gegl_operation_class_set_keys (operation_class,
    "name",        "gegl:levels",
    "title",       _("Levels"),
    "categories" , "color",
    "description", _("Remaps the intensity range of the image"),
    "reference-hash", "b26ace9ce32e98b8ffa2a57f10a42e0d",
    "reference-composition", composition,
    NULL);
}

#endif
