libexif experiment

CMakeMod/FindExif.cmake

@@ -0,0 +1,28 @@
+# - Try to find LibExif
+# Once done this will define
+#  Exif_FOUND - System has LibExif
+#  Exif_INCLUDE_DIRS - The LibExif include directories
+#  Exif_LIBRARIES - The libraries needed to use LibExif
+#  Exif_DEFINITIONS - Compiler switches required for using LibExif
+
+find_package(PkgConfig)
+pkg_check_modules(PC_Exif QUIET libExif)
+set(Exif_DEFINITIONS ${PC_Exif_CFLAGS_OTHER})
+
+find_path(Exif_INCLUDE_DIR exif-utils.h
+    HINTS ${PC_Exif_INCLUDEDIR} ${PC_Exif_INCLUDE_DIRS}
+    PATH_SUFFIXES libexif )
+
+find_library(Exif_LIBRARY NAMES exif
+    HINTS ${PC_Exif_LIBDIR} ${PC_Exif_LIBRARY_DIRS} )
+
+set(Exif_LIBRARIES ${Exif_LIBRARY} )
+set(Exif_INCLUDE_DIRS ${Exif_INCLUDE_DIR} )
+
+include(FindPackageHandleStandardArgs)
+# handle the QUIETLY and REQUIRED arguments and set Exif_FOUND to TRUE
+# if all listed variables are TRUE
+find_package_handle_standard_args(Exif  DEFAULT_MSG
+    Exif_LIBRARY Exif_INCLUDE_DIR)
+
+mark_as_advanced(Exif_INCLUDE_DIR Exif_LIBRARY )

README.md

@@ -34,7 +34,7 @@ All captured with Nikon D5100, raw processed by Rawtherapee, then assembled by T
 ## Build
 
 This project is written in C++ with usage of QT framework and some other libraries 
-(ImageMagic, VidStab, V4L, GPHOTO2). 
+(ImageMagic, VidStab, V4L, GPHOTO2, exif). 
 I invest effort to create tools multiplatform, but I tested it on Ubuntu Linux only. 
 Moreover, V4L is Linux-only api.
 It uses avconv or ffmpeg to build final videos.

src/CMakeLists.txt

@@ -9,7 +9,8 @@ FIND_PACKAGE(Qt5 REQUIRED COMPONENTS Core Multimedia)
 FIND_PACKAGE(ImageMagick REQUIRED COMPONENTS Magick++ MagickCore)
 FIND_PACKAGE(VidStab REQUIRED) 
 FIND_PACKAGE(V4L REQUIRED) 
-FIND_PACKAGE(GPHOTO2 REQUIRED) 
+FIND_PACKAGE(GPHOTO2 REQUIRED)
+FIND_PACKAGE(Exif REQUIRED)
 
 set(DESCRIBE_CMD "git describe --tags --dirty=+dirty --match 'v[0-9]*' | sed -E 's/^v//' ")
 execute_process(
@@ -33,7 +34,8 @@ include_directories(
   ${VIDSTAB_INCLUDE_DIRS}
   ${CMAKE_CURRENT_BINARY_DIR} # timelapse_version.h
   ${V4L_INCLUDE_DIRS}
-  ${GPHOTO2_INCLUDE_DIR})
+  ${GPHOTO2_INCLUDE_DIR}
+  ${Exif_INCLUDE_DIRS})
 
 # enable warnings
 ADD_DEFINITIONS( -Wall -Wextra -pedantic -fPIC)
@@ -74,6 +76,9 @@ message(STATUS "V4L_FOUND:                ${V4L_FOUND}")
 message(STATUS "GPHOTO2_FOUND:            ${GPHOTO2_FOUND}")
 message(STATUS "GPHOTO2_INCLUDE_DIR:      ${GPHOTO2_INCLUDE_DIR}")
 message(STATUS "GPHOTO2_LIBRARIES:        ${GPHOTO2_LIBRARIES}")
+message(STATUS "Exif_FOUND:               ${Exif_FOUND}")
+message(STATUS "Exif_INCLUDE_DIR:         ${Exif_INCLUDE_DIR}")
+message(STATUS "Exif_LIBRARIES:           ${Exif_LIBRARIES}")
 
 set(CMAKE_AUTOMOC ON)
 set(CMAKE_AUTORCC ON)
@@ -164,7 +169,8 @@ target_link_libraries(timelapse
 	${ImageMagick_LIBRARIES} # Magick++-6.Q16
 	${VIDSTAB_LIBRARIES}
 	${V4L_LIBRARIES}
-	${GPHOTO2_LIBRARIES})
+	${GPHOTO2_LIBRARIES}
+	${Exif_LIBRARIES})
 
 target_link_libraries(timelapse_assembly
 	timelapse

src/capture.cpp

@@ -26,6 +26,8 @@
 #include <vector>
 #include <utility>
 
+#include <exif-data.h>
+
 namespace timelapse {
 
 AdaptiveShutterSpeedAlg::AdaptiveShutterSpeedAlg(
@@ -374,13 +376,41 @@ void TimeLapseCapture::onImageCaptured(QString format, Magick::Blob blob, Magick
         shutterSpdAlg->update(capturedImage);
       }
 
-      QDateTime now = QDateTime::currentDateTime();
-      QString exifDateTime = now.toString("yyyy:MM:dd HH:mm:ss");\
+      if (capturedImage.attribute("EXIF:DateTime").length() == 0) {
+        QDateTime now = QDateTime::currentDateTime();
+        QString exifDateTime = now.toString("yyyy:MM:dd HH:mm:ss");
+
+        Magick::Blob profile = capturedImage.exifProfile();
+        ExifData *data = exif_data_new();
+
+        exif_data_set_option(data, EXIF_DATA_OPTION_FOLLOW_SPECIFICATION);
+        exif_data_set_data_type(data, EXIF_DATA_TYPE_COMPRESSED);
+        exif_data_set_byte_order(data, EXIF_BYTE_ORDER_INTEL);
+
+        exif_data_load_data(data, static_cast<const unsigned char *>(profile.data()), profile.length());
 
-      // ImageMagick don't support writing of exif data
-      // TODO: setup exif timestamp correctly
-      capturedImage.attribute("EXIF:DateTime", exifDateTime.toStdString());
-      //capturedImage.defineValue("EXIF", "DateTime", exifDateTime.toStdString());
+        ExifMem *exifMem = exif_mem_new_default();
+        ExifEntry *pE = exif_entry_new();
+        exif_content_add_entry(data->ifd[EXIF_IFD_0], pE);
+        exif_entry_initialize(pE, EXIF_TAG_DATE_TIME);
+        std::string dateStr = exifDateTime.toStdString();
+        pE->data = static_cast<unsigned char *>(exif_mem_alloc(exifMem, dateStr.length() +1 +8));
+        memcpy(pE->data, dateStr.c_str(), dateStr.length() +1);
+        //memcpy(pE->data, "ASCII\0\0\0", 8);
+        //memcpy(pE->data+8, dateStr.c_str(), dateStr.length() +1);
+
+        unsigned char *d;
+        unsigned int ds;
+
+        exif_data_dump(data);
+        exif_data_save_data(data, &d, &ds);
+        profile = Magick::Blob(d, ds);
+        capturedImage.exifProfile(profile);
+
+        exif_entry_unref(pE);
+        exif_mem_free(exifMem, d);
+        exif_data_free(data);
+      }
 
       capturedImage.compressType(Magick::JPEGCompression);
       capturedImage.magick("JPEG");