imageio_exr.cc

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/*
    This file is part of darktable,
    Copyright (C) 2010, 2014 Henrik Andersson.
    Copyright (C) 2010-2012, 2014 johannes hanika.
    Copyright (C) 2012 Richard Wonka.
    Copyright (C) 2012-2016 Tobias Ellinghaus.
    Copyright (C) 2014, 2016 Roman Lebedev.
    Copyright (C) 2019 Claude Heiland-Allen.
    Copyright (C) 2020, 2025 Aurélien PIERRE.
    Copyright (C) 2020 Hubert Kowalski.
    Copyright (C) 2020-2021 Pascal Obry.
    Copyright (C) 2020 Philippe Weyland.
    Copyright (C) 2022 Martin Bařinka.
    Copyright (C) 2022 Miloš Komarčević.
    Copyright (C) 2023, 2025 Alynx Zhou.
    
    darktable is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
    
    darktable 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 General Public License for more details.
    
    You should have received a copy of the GNU General Public License
    along with darktable.  If not, see <http://www.gnu.org/licenses/>.
*/
 
#define __STDC_FORMAT_MACROS
 
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
 
#include <assert.h>
#include <inttypes.h>
#include <memory>
#include <stdio.h>
#include <string.h>
 
#include <OpenEXR/ImfChannelList.h>
#include <OpenEXR/ImfFrameBuffer.h>
#include <OpenEXR/ImfInputFile.h>
#include <OpenEXR/ImfStandardAttributes.h>
#include <OpenEXR/ImfTestFile.h>
#include <OpenEXR/ImfThreading.h>
#include <OpenEXR/ImfTiledInputFile.h>
 
#include "glib.h"
 
#include "system/macros.h"
#include "system/openmp.h"
#include "metadata/exif.h"
#include "imageio/imageio_exr.h"
#include "develop/develop.h"
 
#include "imageio/imageio_exr.hh"
 
dt_imageio_retval_t dt_imageio_open_exr(dt_image_t *img, const char *filename, dt_mipmap_buffer_t *mbuf)
{
  bool isTiled = false;
 
  Imf::setGlobalThreadCount(dt_get_num_openmp_threads());
 
  std::unique_ptr<Imf::TiledInputFile> fileTiled;
  std::unique_ptr<Imf::InputFile> file;
 
  Imath::Box2i dw;
  Imf::FrameBuffer frameBuffer;
  uint32_t xstride, ystride;
 
 
  /* verify openexr image */
  if(!Imf::isOpenExrFile((const char *)filename, isTiled)) return DT_IMAGEIO_FILE_CORRUPTED;
 
  /* open exr file */
  try
  {
    if(isTiled)
    {
      std::unique_ptr<Imf::TiledInputFile> temp(new Imf::TiledInputFile(filename));
      fileTiled = std::move(temp);
    }
    else
    {
      std::unique_ptr<Imf::InputFile> temp(new Imf::InputFile(filename));
      file = std::move(temp);
    }
  }
  catch(const std::exception &e)
  {
    return DT_IMAGEIO_FILE_CORRUPTED;
  }
 
  const Imf::Header &header = isTiled ? fileTiled->header() : file->header();
 
  /* check that channels available is any of supported RGB(a) */
  bool hasR = false, hasG = false, hasB = false;
  for(Imf::ChannelList::ConstIterator i = header.channels().begin(); i != header.channels().end(); ++i)
  {
    std::string name(i.name());
    if(name == "R") hasR = true;
    if(name == "G") hasG = true;
    if(name == "B") hasB = true;
  }
  if(!(hasR && hasG && hasB))
  {
    fprintf(stderr, "[exr_read] Warning, only files with RGB(A) channels are supported.\n");
    return DT_IMAGEIO_FILE_CORRUPTED;
  }
 
  if(!img->exif_inited)
  {
    // read back exif data
    // if another software is able to update these exif data, the former test
    // should be removed to take the potential changes in account (not done
    // by normal import image flow)
    const Imf::BlobAttribute *exif = header.findTypedAttribute<Imf::BlobAttribute>("exif");
    // we append a jpg-compatible exif00 string, so get rid of that again:
    if(exif && exif->value().size > 6)
      dt_exif_read_from_blob(img, ((uint8_t *)(exif->value().data.get())) + 6, exif->value().size - 6);
  }
 
  /* Get image width and height from displayWindow */
  dw = header.displayWindow();
  img->width = dw.max.x - dw.min.x + 1;
  img->height = dw.max.y - dw.min.y + 1;
 
  // Try to allocate image data
  img->dsc.channels = 4;
  img->dsc.datatype = TYPE_FLOAT;
  img->dsc.bpp = 4 * sizeof(float);
  img->dsc.cst = IOP_CS_RGB;
  img->dsc.filters = 0u;
  img->flags &= ~DT_IMAGE_RAW;
  img->flags &= ~DT_IMAGE_S_RAW;
  img->flags &= ~DT_IMAGE_LDR;
  img->flags |= DT_IMAGE_HDR;
  img->loader = LOADER_EXR;
 
  if(IS_NULL_PTR(mbuf)) return DT_IMAGEIO_OK;
 
  float *buf = (float *)dt_mipmap_cache_alloc(mbuf, img);
  if(!buf)
  {
    fprintf(stderr, "[exr_read] could not alloc full buffer for image `%s'\n", img->filename);
    return DT_IMAGEIO_CACHE_FULL;
  }
 
  // FIXME: is this really needed?
  memset(buf, 0, sizeof(float) * 4 * img->width * img->height);
 
  /* setup framebuffer */
  xstride = sizeof(float) * 4;
  ystride = sizeof(float) * img->width * 4;
  frameBuffer.insert("R", Imf::Slice(Imf::FLOAT, (char *)(buf + 0), xstride, ystride, 1, 1, 0.0));
  frameBuffer.insert("G", Imf::Slice(Imf::FLOAT, (char *)(buf + 1), xstride, ystride, 1, 1, 0.0));
  frameBuffer.insert("B", Imf::Slice(Imf::FLOAT, (char *)(buf + 2), xstride, ystride, 1, 1, 0.0));
  frameBuffer.insert("A", Imf::Slice(Imf::FLOAT, (char *)(buf + 3), xstride, ystride, 1, 1, 0.0));
 
  try
  {
    if(isTiled)
    {
      fileTiled->setFrameBuffer(frameBuffer);
      fileTiled->readTiles(0, fileTiled->numXTiles() - 1, 0, fileTiled->numYTiles() - 1);
    }
    else
    {
      /* read pixels from dataWindow */
      dw = header.dataWindow();
      file->setFrameBuffer(frameBuffer);
      file->readPixels(dw.min.y, dw.max.y);
    }
  }
  catch(const std::exception &e)
  {
    fprintf(stderr, "[exr_read] error reading pixels from `%s': %s\n", filename, e.what());
    return DT_IMAGEIO_FILE_CORRUPTED;
  }
 
  /* try to get the chromaticities and whitepoint. this will add the default linear rec709 profile when nothing
   * was embedded and look as if it was embedded in colorin. better than defaulting to something wrong there. */
  Imf::Chromaticities chromaticities;
  float whiteLuminance = 1.0;
 
  if(Imf::hasChromaticities(header))
  {
    chromaticities = Imf::chromaticities(header);
 
    /* adapt chromaticities to D65 expected by colorin */
    cmsCIExyY red_xy = { chromaticities.red[0], chromaticities.red[1], 1.0 };
    cmsCIEXYZ srcRed;
    cmsxyY2XYZ(&srcRed, &red_xy);
 
    cmsCIExyY green_xy = { chromaticities.green[0], chromaticities.green[1], 1.0 };
    cmsCIEXYZ srcGreen;
    cmsxyY2XYZ(&srcGreen, &green_xy);
 
    cmsCIExyY blue_xy = { chromaticities.blue[0], chromaticities.blue[1], 1.0 };
    cmsCIEXYZ srcBlue;
    cmsxyY2XYZ(&srcBlue, &blue_xy);
 
    const cmsCIExyY srcWhite_xy = { chromaticities.white[0], chromaticities.white[1], 1.0 };
    cmsCIEXYZ srcWhite;
    cmsxyY2XYZ(&srcWhite, &srcWhite_xy);
 
    /* use Imf::Chromaticities definition */
    const cmsCIExyY d65_xy = {0.3127f, 0.3290f, 1.0};
    cmsCIEXYZ d65;
    cmsxyY2XYZ(&d65, &d65_xy);
 
    cmsCIEXYZ dstRed;
    cmsAdaptToIlluminant(&dstRed, &srcWhite, &d65, &srcRed);
 
    cmsCIEXYZ dstGreen;
    cmsAdaptToIlluminant(&dstGreen, &srcWhite, &d65, &srcGreen);
 
    cmsCIEXYZ dstBlue;
    cmsAdaptToIlluminant(&dstBlue, &srcWhite, &d65, &srcBlue);
 
    cmsXYZ2xyY(&red_xy, &dstRed);
    chromaticities.red[0] = (float)red_xy.x;
    chromaticities.red[1] = (float)red_xy.y;
 
    cmsXYZ2xyY(&green_xy, &dstGreen);
    chromaticities.green[0] = (float)green_xy.x;
    chromaticities.green[1] = (float)green_xy.y;
 
    cmsXYZ2xyY(&blue_xy, &dstBlue);
    chromaticities.blue[0] = (float)blue_xy.x;
    chromaticities.blue[1] = (float)blue_xy.y;
 
    chromaticities.white[0] = 0.3127f;
    chromaticities.white[1] = 0.3290f;
  }
 
  if(Imf::hasWhiteLuminance(header))
    whiteLuminance = Imf::whiteLuminance(header);
 
//   printf("hasChromaticities: %d\n", Imf::hasChromaticities(header));
//   printf("hasWhiteLuminance: %d\n", Imf::hasWhiteLuminance(header));
//   std::cout << chromaticities.red << std::endl;
//   std::cout << chromaticities.green << std::endl;
//   std::cout << chromaticities.blue << std::endl;
//   std::cout << chromaticities.white << std::endl;
 
  Imath::M44f m = Imf::XYZtoRGB(chromaticities, whiteLuminance);
 
  for(int i = 0; i < 3; i++)
    for(int j = 0; j < 3; j++)
    {
      img->d65_color_matrix[3 * i + j] = m[j][i];
    }
 
  return DT_IMAGEIO_OK;
}
 
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