Add initial CMake & skeleton to support LibRAW.

This will be used to load CR3.

DefineOptions.cmake

@@ -23,6 +23,7 @@ option(USE_AVIF "Enable AVIF support" ON)
 option(USE_HEIF "Enable HEIF/HEIC support" ON)
 option(USE_XCF "Enable XCF support" ON)
 option(USE_ISOBMFF "Enable ISOBMFF support" ON)
+option(USE_LIBRAW "Enable LibRAW support" ON)
 option(BUILD_CMSTEST "Build a test program to check your system's color management setup" ON)
 option(USE_OPENEXR "Enable OpenEXR support" ON)
 option(BUILD_PRINT "Build the print module" ON)

cmake/modules/Findlibraw.cmake

@@ -0,0 +1,51 @@
+#.rst:
+# Findlibraw
+# -------
+#
+# Try to find libraw on a Unix system.
+#
+# This will define the following variables:
+#
+# ``libraw_FOUND``
+#     True if (the requested version of) libraw is available
+# ``libraw_VERSION``
+#     The version of libraw
+# ``libraw_LIBRARIES``
+#     This should be passed to target_compile_options() if the target is not
+#     used for linking
+# ``libraw_INCLUDE_DIRS``
+#     This should be passed to target_include_directories() if the target is not
+#     used for linking
+# ``libraw_DEFINITIONS``
+#     This should be passed to target_compile_options() if the target is not
+#     used for linking
+
+find_package(PkgConfig)
+pkg_check_modules(PKG_libraw QUIET raw)
+
+set(libraw_VERSION ${PKG_libraw_VERSION})
+set(libraw_DEFINITIONS ${PKG_libraw_CFLAGS_OTHER})
+
+find_path(libraw_INCLUDE_DIR
+    NAMES libraw/libraw.h
+    HINTS ${PKG_libraw_INCLUDE_DIRS}
+)
+
+find_library(libraw_LIBRARY
+    NAMES raw
+    HINTS ${PKG_libraw_LIBRARY_DIRS}
+)
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(libraw
+    FOUND_VAR libraw_FOUND
+    REQUIRED_VARS libraw_LIBRARY
+                  libraw_INCLUDE_DIR
+    VERSION_VAR libraw_VERSION
+)
+
+set(libraw_INCLUDE_DIRS ${libraw_INCLUDE_DIR})
+set(libraw_LIBRARIES ${libraw_LIBRARY})
+
+mark_as_advanced(libraw_INCLUDE_DIR)
+mark_as_advanced(libraw_LIBRARY)

src/CMakeLists.txt

@@ -382,6 +382,16 @@ if(USE_HEIF)
   endif()
 endif()
 
+if (USE_LIBRAW)
+    find_package(libraw 0.20.2)
+    if (libraw_FOUND)
+        list(APPEND LIBS ${libraw_LIBRARY})
+        add_definitions(-DHAVE_LIBRAW=1)
+        list(APPEND SOURCES "common/imageio_libraw.c")
+        set(DT_SUPPORTED_EXTENSIONS ${DT_SUPPORTED_EXTENSIONS} libraw CACHE INTERNAL "")
+    endif()
+endif()
+
 if(USE_LENSFUN)
   find_package(LensFun)
   if(LensFun_FOUND)

src/common/image.h

@@ -155,7 +155,8 @@ typedef enum dt_image_loader_t
   LOADER_AVIF     = 11,
   LOADER_IM       = 12,
   LOADER_HEIF     = 13,
-  LOADER_COUNT    = 14, // keep last
+  LOADER_LIBRAW   = 14,
+  LOADER_COUNT    = 15, // keep last
 } dt_image_loader_t;
 
 static const struct

src/common/imageio.c

@@ -48,6 +48,7 @@
 #ifdef HAVE_LIBHEIF
 #include "common/imageio_heif.h"
 #endif
+#include "common/imageio_libraw.h"
 #include "common/mipmap_cache.h"
 #include "common/styles.h"
 #include "control/conf.h"
@@ -1219,6 +1220,10 @@ dt_imageio_retval_t dt_imageio_open(dt_image_t *img,               // non-const
     ret = dt_imageio_open_rawspeed(img, filename, buf);
   }
 
+  /* fallback that tries to open file via LibRAW to support Canon CR3 */
+  if(ret != DT_IMAGEIO_OK && ret != DT_IMAGEIO_CACHE_FULL)
+    ret = dt_imageio_open_libraw(img, filename, buf);
+
   /* fallback that tries to open file via GraphicsMagick */
   if(ret != DT_IMAGEIO_OK && ret != DT_IMAGEIO_CACHE_FULL)
     ret = dt_imageio_open_exotic(img, filename, buf);

src/common/imageio_libraw.c

@@ -0,0 +1,87 @@
+/*
+    This file is part of darktable,
+    Copyright (C) 2021 darktable developers.
+
+    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/>.
+*/
+
+#ifdef HAVE_LIBRAW
+#include "common/darktable.h"
+#include "imageio.h"
+#include "imageio_gm.h"
+#include "develop/develop.h"
+#include "common/exif.h"
+#include "common/colorspaces.h"
+#include "control/conf.h"
+
+#include <memory.h>
+#include <stdio.h>
+#include <inttypes.h>
+#include <strings.h>
+#include <assert.h>
+
+#include <libraw/libraw.h>
+
+
+/* LibRAW is expected to read only new canon CR3 files */
+
+static gboolean _supported_image(const gchar *filename)
+{
+  const char *extensions_whitelist[] = { "cr3", NULL };
+  gboolean supported = FALSE;
+  char *ext = g_strrstr(filename, ".");
+  if(!ext) return FALSE;
+  ext++;
+  for(const char **i = extensions_whitelist; *i != NULL; i++)
+    if(!g_ascii_strncasecmp(ext, *i, strlen(*i)))
+    {
+      supported = TRUE;
+      break;
+    }
+  return supported;
+}
+
+
+dt_imageio_retval_t dt_imageio_open_libraw(dt_image_t *img, const char *filename, dt_mipmap_buffer_t *mbuf)
+{
+  int err = DT_IMAGEIO_FILE_CORRUPTED;
+
+  if(!_supported_image(filename)) return DT_IMAGEIO_FILE_CORRUPTED;
+
+  if(!img->exif_inited) (void)dt_exif_read(img, filename);
+
+  libraw_data_t *raw_data = libraw_init(0);
+
+  if(!libraw_open_file(raw_data, filename))
+    goto error;
+
+  img->buf_dsc.cst = iop_cs_RAW;
+  img->flags |= DT_IMAGE_4BAYER;
+  img->flags &= ~DT_IMAGE_LDR;
+  img->flags |= DT_IMAGE_RAW;
+  img->loader = LOADER_LIBRAW;
+
+  libraw_close(raw_data);
+
+  return DT_IMAGEIO_OK;
+
+error:
+  libraw_close(raw_data);
+  return err;
+}
+#endif
+
+// modelines: These editor modelines have been set for all relevant files by tools/update_modelines.sh
+// vim: shiftwidth=2 expandtab tabstop=2 cindent
+// kate: tab-indents: off; indent-width 2; replace-tabs on; indent-mode cstyle; remove-trailing-spaces modified;

src/common/imageio_libraw.h

@@ -0,0 +1,38 @@
+/*
+    This file is part of darktable,
+    Copyright (C) 2021 darktable developers.
+
+    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/>.
+*/
+
+#ifndef DT_IMAGEIO_LIBRAW_H
+#define DT_IMAGEIO_LIBRAW_H
+
+#include "common/image.h"
+#include "common/mipmap_cache.h"
+
+#ifdef HAVE_LIBRAW
+dt_imageio_retval_t dt_imageio_open_libraw(dt_image_t *img, const char *filename, dt_mipmap_buffer_t *buf);
+#else
+inline dt_imageio_retval_t dt_imageio_open_libraw(dt_image_t *img, const char *filename,
+                                                  dt_mipmap_buffer_t *buf)
+{
+  return DT_IMAGEIO_FILE_NOT_FOUND;
+}
+#endif
+
+#endif
+// modelines: These editor modelines have been set for all relevant files by tools/update_modelines.sh
+// vim: shiftwidth=2 expandtab tabstop=2 cindent
+// kate: tab-indents: off; indent-width 2; replace-tabs on; indent-mode cstyle; remove-trailing-spaces modified;