android: jpeg: exif: Add functions for setting various values

Add functions for setting the following EXIF fields:

- GPSDatestamp
- GPSTimestamp
- GPSLocation
  - GPSLatitudeRef
  - GPSLatitude
  - GPSLongitudeRef
  - GPSLongitude
  - GPSAltitudeRef
  - GPSAltitude
- GPSProcessingMethod
- FocalLength
- ExposureTime
- FNumber
- ISO
- Flash
- WhiteBalance
- SubsecTime
- SubsecTimeOriginal
- SubsecTimeDigitized

These are in preparation for fixing the following CTS tests:

- android.hardware.camera2.cts.StillCaptureTest#testFocalLengths
- android.hardware.camera2.cts.StillCaptureTest#testJpegExif

Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>

3 files changed, 210 insertions, 16 deletions

diff --git a/src/android/jpeg/exif.cpp b/src/android/jpeg/exif.cpp
index 204a237a..fdd46070 100644
--- a/src/android/jpeg/exif.cpp
+++ b/src/android/jpeg/exif.cpp
@@ -7,7 +7,11 @@
 
 #include "exif.h"
 
+#include <cmath>
+#include <iomanip>
 #include <map>
+#include <sstream>
+#include <tuple>
 #include <uchar.h>
 
 #include "libcamera/internal/log.h"
@@ -151,6 +155,16 @@ ExifEntry *Exif::createEntry(ExifIfd ifd, ExifTag tag, ExifFormat format,
 	return entry;
 }
 
+void Exif::setByte(ExifIfd ifd, ExifTag tag, uint8_t item)
+{
+	ExifEntry *entry = createEntry(ifd, tag, EXIF_FORMAT_BYTE, 1, 1);
+	if (!entry)
+		return;
+
+	entry->data[0] = item;
+	exif_entry_unref(entry);
+}
+
 void Exif::setShort(ExifIfd ifd, ExifTag tag, uint16_t item)
 {
 	ExifEntry *entry = createEntry(ifd, tag);
@@ -267,7 +281,7 @@ void Exif::setSize(const Size &size)
 	setLong(EXIF_IFD_EXIF, EXIF_TAG_PIXEL_X_DIMENSION, size.width);
 }
 
-void Exif::setTimestamp(time_t timestamp)
+void Exif::setTimestamp(time_t timestamp, std::chrono::milliseconds msec)
 {
 	struct tm tm;
 	localtime_r(&timestamp, &tm);
@@ -282,19 +296,126 @@ void Exif::setTimestamp(time_t timestamp)
 
 	/* Query and set timezone information if available. */
 	int r = strftime(str, sizeof(str), "%z", &tm);
-	if (r > 0) {
-		std::string tz(str);
-		tz.insert(3, 1, ':');
-		setString(EXIF_IFD_EXIF,
-			  static_cast<ExifTag>(_ExifTag::OFFSET_TIME),
-			  EXIF_FORMAT_ASCII, tz);
-		setString(EXIF_IFD_EXIF,
-			  static_cast<ExifTag>(_ExifTag::OFFSET_TIME_ORIGINAL),
-			  EXIF_FORMAT_ASCII, tz);
-		setString(EXIF_IFD_EXIF,
-			  static_cast<ExifTag>(_ExifTag::OFFSET_TIME_DIGITIZED),
-			  EXIF_FORMAT_ASCII, tz);
-	}
+	if (r <= 0)
+		return;
+
+	std::string tz(str);
+	tz.insert(3, 1, ':');
+	setString(EXIF_IFD_EXIF,
+		  static_cast<ExifTag>(_ExifTag::OFFSET_TIME),
+		  EXIF_FORMAT_ASCII, tz);
+	setString(EXIF_IFD_EXIF,
+		  static_cast<ExifTag>(_ExifTag::OFFSET_TIME_ORIGINAL),
+		  EXIF_FORMAT_ASCII, tz);
+	setString(EXIF_IFD_EXIF,
+		  static_cast<ExifTag>(_ExifTag::OFFSET_TIME_DIGITIZED),
+		  EXIF_FORMAT_ASCII, tz);
+
+	std::stringstream sstr;
+	sstr << std::setfill('0') << std::setw(3) << msec.count();
+	std::string subsec = sstr.str();
+
+	setString(EXIF_IFD_EXIF, EXIF_TAG_SUB_SEC_TIME,
+		  EXIF_FORMAT_ASCII, subsec);
+	setString(EXIF_IFD_EXIF, EXIF_TAG_SUB_SEC_TIME_ORIGINAL,
+		  EXIF_FORMAT_ASCII, subsec);
+	setString(EXIF_IFD_EXIF, EXIF_TAG_SUB_SEC_TIME_DIGITIZED,
+		  EXIF_FORMAT_ASCII, subsec);
+}
+
+void Exif::setGPSDateTimestamp(time_t timestamp)
+{
+	struct tm tm;
+	gmtime_r(&timestamp, &tm);
+
+	char str[11];
+	strftime(str, sizeof(str), "%Y:%m:%d", &tm);
+	std::string tsStr(str);
+
+	setString(EXIF_IFD_GPS, static_cast<ExifTag>(EXIF_TAG_GPS_DATE_STAMP),
+		  EXIF_FORMAT_ASCII, tsStr);
+
+	/* Set GPS_TIME_STAMP */
+	ExifEntry *entry =
+		createEntry(EXIF_IFD_GPS,
+			    static_cast<ExifTag>(EXIF_TAG_GPS_TIME_STAMP),
+			    EXIF_FORMAT_RATIONAL, 3, 3 * sizeof(ExifRational));
+	if (!entry)
+		return;
+
+	ExifRational ts[] = {
+		{ static_cast<ExifLong>(tm.tm_hour), 1 },
+		{ static_cast<ExifLong>(tm.tm_min),  1 },
+		{ static_cast<ExifLong>(tm.tm_sec),  1 },
+	};
+
+	for (int i = 0; i < 3; i++)
+		exif_set_rational(entry->data + i * sizeof(ExifRational),
+				  order_, ts[i]);
+
+	exif_entry_unref(entry);
+}
+
+std::tuple<int, int, int> Exif::degreesToDMS(double decimalDegrees)
+{
+	int degrees = std::trunc(decimalDegrees);
+	double minutes = std::abs((decimalDegrees - degrees) * 60);
+	double seconds = (minutes - std::trunc(minutes)) * 60;
+
+	return { degrees, std::trunc(minutes), std::round(seconds) };
+}
+
+void Exif::setGPSDMS(ExifIfd ifd, ExifTag tag, int deg, int min, int sec)
+{
+	ExifEntry *entry = createEntry(ifd, tag, EXIF_FORMAT_RATIONAL, 3,
+				       3 * sizeof(ExifRational));
+	if (!entry)
+		return;
+
+	ExifRational coords[] = {
+		{ static_cast<ExifLong>(deg), 1 },
+		{ static_cast<ExifLong>(min), 1 },
+		{ static_cast<ExifLong>(sec), 1 },
+	};
+
+	for (int i = 0; i < 3; i++)
+		exif_set_rational(entry->data + i * sizeof(ExifRational),
+				  order_, coords[i]);
+
+	exif_entry_unref(entry);
+}
+
+/*
+ * \brief Set GPS location (lat, long, alt)
+ * \param[in] coords Pointer to coordinates latitude, longitude, and altitude,
+ * first two in degrees, the third in meters
+ */
+void Exif::setGPSLocation(const double *coords)
+{
+	int deg, min, sec;
+
+	std::tie<int, int, int>(deg, min, sec) = degreesToDMS(coords[0]);
+	setString(EXIF_IFD_GPS, static_cast<ExifTag>(EXIF_TAG_GPS_LATITUDE_REF),
+		  EXIF_FORMAT_ASCII, deg >= 0 ? "N" : "S");
+	setGPSDMS(EXIF_IFD_GPS, static_cast<ExifTag>(EXIF_TAG_GPS_LATITUDE),
+		  std::abs(deg), min, sec);
+
+	std::tie<int, int, int>(deg, min, sec) = degreesToDMS(coords[1]);
+	setString(EXIF_IFD_GPS, static_cast<ExifTag>(EXIF_TAG_GPS_LONGITUDE_REF),
+		  EXIF_FORMAT_ASCII, deg >= 0 ? "E" : "W");
+	setGPSDMS(EXIF_IFD_GPS, static_cast<ExifTag>(EXIF_TAG_GPS_LATITUDE),
+		  std::abs(deg), min, sec);
+
+	setByte(EXIF_IFD_GPS, static_cast<ExifTag>(EXIF_TAG_GPS_ALTITUDE_REF),
+		coords[2] >= 0 ? 0 : 1);
+	setRational(EXIF_IFD_GPS, static_cast<ExifTag>(EXIF_TAG_GPS_ALTITUDE),
+		    ExifRational{ static_cast<ExifLong>(std::abs(coords[2])), 1 });
+}
+
+void Exif::setGPSMethod(const std::string &method)
+{
+	setString(EXIF_IFD_GPS, static_cast<ExifTag>(EXIF_TAG_GPS_PROCESSING_METHOD),
+		  EXIF_FORMAT_UNDEFINED, method, Unicode);
 }
 
 void Exif::setOrientation(int orientation)
@@ -333,6 +454,39 @@ void Exif::setThumbnail(Span<const unsigned char> thumbnail,
 	setShort(EXIF_IFD_0, EXIF_TAG_COMPRESSION, compression);
 }
 
+void Exif::setFocalLength(float length)
+{
+	ExifRational rational = { static_cast<ExifLong>(length * 1000), 1000 };
+	setRational(EXIF_IFD_EXIF, EXIF_TAG_FOCAL_LENGTH, rational);
+}
+
+void Exif::setExposureTime(uint64_t nsec)
+{
+	ExifRational rational = { static_cast<ExifLong>(nsec), 1000000000 };
+	setRational(EXIF_IFD_EXIF, EXIF_TAG_EXPOSURE_TIME, rational);
+}
+
+void Exif::setAperture(float size)
+{
+	ExifRational rational = { static_cast<ExifLong>(size * 10000), 10000 };
+	setRational(EXIF_IFD_EXIF, EXIF_TAG_FNUMBER, rational);
+}
+
+void Exif::setISO(uint16_t iso)
+{
+	setShort(EXIF_IFD_EXIF, EXIF_TAG_ISO_SPEED_RATINGS, iso);
+}
+
+void Exif::setFlash(Flash flash)
+{
+	setShort(EXIF_IFD_EXIF, EXIF_TAG_FLASH, static_cast<ExifShort>(flash));
+}
+
+void Exif::setWhiteBalance(WhiteBalance wb)
+{
+	setShort(EXIF_IFD_EXIF, EXIF_TAG_WHITE_BALANCE, static_cast<ExifShort>(wb));
+}
+
 /**
  * \brief Convert UTF-8 string to UTF-16 string
  * \param[in] str String to convert
diff --git a/src/android/jpeg/exif.h b/src/android/jpeg/exif.h
index 8b84165b..b0d61402 100644
--- a/src/android/jpeg/exif.h
+++ b/src/android/jpeg/exif.h
@@ -7,6 +7,7 @@
 #ifndef __ANDROID_JPEG_EXIF_H__
 #define __ANDROID_JPEG_EXIF_H__
 
+#include <chrono>
 #include <string>
 #include <time.h>
 
@@ -26,6 +27,27 @@ public:
 		JPEG = 6,
 	};
 
+	enum Flash {
+		/* bit 0 */
+		Fired = 0x01,
+		/* bits 1 and 2 */
+		StrobeDetected = 0x04,
+		StrobeNotDetected = 0x06,
+		/* bits 3 and 4 */
+		ModeCompulsoryFiring = 0x08,
+		ModeCompulsorySuppression = 0x10,
+		ModeAuto = 0x18,
+		/* bit 5 */
+		FlashNotPresent = 0x20,
+		/* bit 6 */
+		RedEye = 0x40,
+	};
+
+	enum WhiteBalance {
+		Auto = 0,
+		Manual = 1,
+	};
+
 	enum StringEncoding {
 		NoEncoding = 0,
 		ASCII = 1,
@@ -39,7 +61,18 @@ public:
 	void setSize(const libcamera::Size &size);
 	void setThumbnail(libcamera::Span<const unsigned char> thumbnail,
 			  Compression compression);
-	void setTimestamp(time_t timestamp);
+	void setTimestamp(time_t timestamp, std::chrono::milliseconds msec);
+
+	void setGPSDateTimestamp(time_t timestamp);
+	void setGPSLocation(const double *coords);
+	void setGPSMethod(const std::string &method);
+
+	void setFocalLength(float length);
+	void setExposureTime(uint64_t nsec);
+	void setAperture(float size);
+	void setISO(uint16_t iso);
+	void setFlash(Flash flash);
+	void setWhiteBalance(WhiteBalance wb);
 
 	libcamera::Span<const uint8_t> data() const { return { exifData_, size_ }; }
 	[[nodiscard]] int generate();
@@ -49,6 +82,7 @@ private:
 	ExifEntry *createEntry(ExifIfd ifd, ExifTag tag, ExifFormat format,
 			       unsigned long components, unsigned int size);
 
+	void setByte(ExifIfd ifd, ExifTag tag, uint8_t item);
 	void setShort(ExifIfd ifd, ExifTag tag, uint16_t item);
 	void setLong(ExifIfd ifd, ExifTag tag, uint32_t item);
 	void setString(ExifIfd ifd, ExifTag tag, ExifFormat format,
@@ -56,6 +90,9 @@ private:
 		       StringEncoding encoding = NoEncoding);
 	void setRational(ExifIfd ifd, ExifTag tag, ExifRational item);
 
+	std::tuple<int, int, int> degreesToDMS(double decimalDegrees);
+	void setGPSDMS(ExifIfd ifd, ExifTag tag, int deg, int min, int sec);
+
 	std::u16string utf8ToUtf16(const std::string &str);
 
 	bool valid_;
diff --git a/src/android/jpeg/post_processor_jpeg.cpp b/src/android/jpeg/post_processor_jpeg.cpp
index 436a50f8..aa0f783d 100644
--- a/src/android/jpeg/post_processor_jpeg.cpp
+++ b/src/android/jpeg/post_processor_jpeg.cpp
@@ -7,6 +7,8 @@
 
 #include "post_processor_jpeg.h"
 
+#include <chrono>
+
 #include "../camera_device.h"
 #include "../camera_metadata.h"
 #include "encoder_libjpeg.h"
@@ -17,6 +19,7 @@
 #include "libcamera/internal/log.h"
 
 using namespace libcamera;
+using namespace std::chrono_literals;
 
 LOG_DEFINE_CATEGORY(JPEG)
 
@@ -97,7 +100,7 @@ int PostProcessorJpeg::process(const FrameBuffer &source,
 	 * Since the precision we need for EXIF timestamp is only one
 	 * second, it is good enough.
 	 */
-	exif.setTimestamp(std::time(nullptr));
+	exif.setTimestamp(std::time(nullptr), 0ms);
 
 	std::vector<unsigned char> thumbnail;
 	generateThumbnail(source, &thumbnail);