wp_read_image_metadata

Source code

function wp_read_image_metadata( $file ) {

	if ( ! file_exists( $file ) )

		return false;



	list( , , $sourceImageType ) = getimagesize( $file );



	// exif contains a bunch of data we'll probably never need formatted in ways

	// that are difficult to use. We'll normalize it and just extract the fields

	// that are likely to be useful.  Fractions and numbers are converted to

	// floats, dates to unix timestamps, and everything else to strings.

	$meta = array(

		'aperture' => 0,

		'credit' => '',

		'camera' => '',

		'caption' => '',

		'created_timestamp' => 0,

		'copyright' => '',

		'focal_length' => 0,

		'iso' => 0,

		'shutter_speed' => 0,

		'title' => '',

	);



	// read iptc first, since it might contain data not available in exif such

	// as caption, description etc

	if ( is_callable( 'iptcparse' ) ) {

		getimagesize( $file, $info );



		if ( ! empty( $info['APP13'] ) ) {

			$iptc = iptcparse( $info['APP13'] );



			// headline, "A brief synopsis of the caption."

			if ( ! empty( $iptc['2#105'][0] ) )

				$meta['title'] = utf8_encode( trim( $iptc['2#105'][0] ) );

			// title, "Many use the Title field to store the filename of the image, though the field may be used in many ways."

			elseif ( ! empty( $iptc['2#005'][0] ) )

				$meta['title'] = utf8_encode( trim( $iptc['2#005'][0] ) );



			if ( ! empty( $iptc['2#120'][0] ) ) { // description / legacy caption

				$caption = utf8_encode( trim( $iptc['2#120'][0] ) );

				if ( empty( $meta['title'] ) ) {

					// Assume the title is stored in 2:120 if it's short.

					if ( strlen( $caption ) < 80 )

						$meta['title'] = $caption;

					else

						$meta['caption'] = $caption;

				} elseif ( $caption != $meta['title'] ) {

					$meta['caption'] = $caption;

				}

			}



			if ( ! empty( $iptc['2#110'][0] ) ) // credit

				$meta['credit'] = utf8_encode(trim($iptc['2#110'][0]));

			elseif ( ! empty( $iptc['2#080'][0] ) ) // creator / legacy byline

				$meta['credit'] = utf8_encode(trim($iptc['2#080'][0]));



			if ( ! empty( $iptc['2#055'][0] ) and ! empty( $iptc['2#060'][0] ) ) // created date and time

				$meta['created_timestamp'] = strtotime( $iptc['2#055'][0] . ' ' . $iptc['2#060'][0] );



			if ( ! empty( $iptc['2#116'][0] ) ) // copyright

				$meta['copyright'] = utf8_encode( trim( $iptc['2#116'][0] ) );

		 }

	}



	// fetch additional info from exif if available

	if ( is_callable( 'exif_read_data' ) && in_array( $sourceImageType, apply_filters( 'wp_read_image_metadata_types', array( IMAGETYPE_JPEG, IMAGETYPE_TIFF_II, IMAGETYPE_TIFF_MM ) ) ) ) {

		$exif = @exif_read_data( $file );



		if ( !empty( $exif['Title'] ) )

			$meta['title'] = utf8_encode( trim( $exif['Title'] ) );



		if ( ! empty( $exif['ImageDescription'] ) ) {

			if ( empty( $meta['title'] ) && strlen( $exif['ImageDescription'] ) < 80 ) {

				// Assume the title is stored in ImageDescription

				$meta['title'] = utf8_encode( trim( $exif['ImageDescription'] ) );

				if ( ! empty( $exif['COMPUTED']['UserComment'] ) && trim( $exif['COMPUTED']['UserComment'] ) != $meta['title'] )

					$meta['caption'] = utf8_encode( trim( $exif['COMPUTED']['UserComment'] ) );

			} elseif ( trim( $exif['ImageDescription'] ) != $meta['title'] ) {

				$meta['caption'] = utf8_encode( trim( $exif['ImageDescription'] ) );

			}

		} elseif ( ! empty( $exif['Comments'] ) && trim( $exif['Comments'] ) != $meta['title'] ) {

			$meta['caption'] = utf8_encode( trim( $exif['Comments'] ) );

		}



		if ( ! empty( $exif['Artist'] ) )

			$meta['credit'] = utf8_encode( trim( $exif['Artist'] ) );

		elseif ( ! empty($exif['Author'] ) )

			$meta['credit'] = utf8_encode( trim( $exif['Author'] ) );



		if ( ! empty( $exif['Copyright'] ) )

			$meta['copyright'] = utf8_encode( trim( $exif['Copyright'] ) );

		if ( ! empty($exif['FNumber'] ) )

			$meta['aperture'] = round( wp_exif_frac2dec( $exif['FNumber'] ), 2 );

		if ( ! empty($exif['Model'] ) )

			$meta['camera'] = utf8_encode( trim( $exif['Model'] ) );

		if ( ! empty($exif['DateTimeDigitized'] ) )

			$meta['created_timestamp'] = wp_exif_date2ts($exif['DateTimeDigitized'] );

		if ( ! empty($exif['FocalLength'] ) )

			$meta['focal_length'] = wp_exif_frac2dec( $exif['FocalLength'] );

		if ( ! empty($exif['ISOSpeedRatings'] ) )

			$meta['iso'] = utf8_encode( trim( $exif['ISOSpeedRatings'] ) );

		if ( ! empty($exif['ExposureTime'] ) )

			$meta['shutter_speed'] = wp_exif_frac2dec( $exif['ExposureTime'] );

	}



	return apply_filters( 'wp_read_image_metadata', $meta, $file, $sourceImageType );



}