Merge "ExifInterface: Add support for preview images" (385821b0) · Commits · e / os / android_frameworks_base

media/java/android/media/ExifInterface.java

+33 −3

Original line number	Diff line number	Diff line
		@@ -365,6 +365,7 @@ public class ExifInterface {
		private static final String TAG_THUMBNAIL_OFFSET = "ThumbnailOffset";
		private static final String TAG_THUMBNAIL_LENGTH = "ThumbnailLength";
		private static final String TAG_THUMBNAIL_DATA = "ThumbnailData";
		private static final int MAX_THUMBNAIL_SIZE = 512;

		// Constants used for the Orientation Exif tag.
		public static final int ORIENTATION_UNDEFINED = 0;
		@@ -1043,10 +1044,11 @@ public class ExifInterface {
		private static final int IFD_GPS_HINT = 2;
		private static final int IFD_INTEROPERABILITY_HINT = 3;
		private static final int IFD_THUMBNAIL_HINT = 4;
		private static final int IFD_PREVIEW_HINT = 5;
		// List of Exif tag groups
		private static final ExifTag[][] EXIF_TAGS = new ExifTag[][] {
		IFD_TIFF_TAGS, IFD_EXIF_TAGS, IFD_GPS_TAGS, IFD_INTEROPERABILITY_TAGS,
		IFD_THUMBNAIL_TAGS
		IFD_THUMBNAIL_TAGS, IFD_TIFF_TAGS
		};
		// List of tags for pointing to the other image file directory offset.
		private static final ExifTag[] IFD_POINTER_TAGS = new ExifTag[] {
		@@ -2038,7 +2040,19 @@ public class ExifInterface {
		parseTiffHeaders(dataInputStream, exifBytes.length);

		// Read TIFF image file directories. See JEITA CP-3451C Section 4.5.2. Figure 6.
		readImageFileDirectory(dataInputStream, IFD_THUMBNAIL_HINT);
		readImageFileDirectory(dataInputStream, IFD_PREVIEW_HINT);

		// Check if the preview image data should be a thumbnail image data.
		// In a RAW file, there may be a Preview image, which is smaller than a Primary image but
		// larger than a Thumbnail image. Normally, the Preview image can be considered a thumbnail
		// image if its size meets the requirements. Therefore, when a Thumbnail image has not yet
		// been found, we should check if the Preview image can be one.
		if (!mAttributes[IFD_PREVIEW_HINT].isEmpty() && mAttributes[IFD_THUMBNAIL_HINT].isEmpty()) {
		if (isThumbnail(mAttributes[IFD_PREVIEW_HINT])) {
		mAttributes[IFD_THUMBNAIL_HINT] = mAttributes[IFD_PREVIEW_HINT];
		mAttributes[IFD_PREVIEW_HINT] = new HashMap();
		}
		}

		// Process thumbnail.
		processThumbnail(dataInputStream, bytesRead, exifBytes.length);
		@@ -2452,6 +2466,22 @@ public class ExifInterface {
		}
		}

		// Returns true if the image length and width values are <= 512.
		// See Section 4.8 of http://standardsproposals.bsigroup.com/Home/getPDF/567
		private boolean isThumbnail(HashMap map) throws IOException {
		ExifAttribute imageLengthAttribute = (ExifAttribute) map.get(TAG_IMAGE_LENGTH);
		ExifAttribute imageWidthAttribute = (ExifAttribute) map.get(TAG_IMAGE_WIDTH);

		if (imageLengthAttribute != null && imageWidthAttribute != null) {
		int imageLengthValue = imageLengthAttribute.getIntValue(mExifByteOrder);
		int imageWidthValue = imageWidthAttribute.getIntValue(mExifByteOrder);
		if (imageLengthValue <= MAX_THUMBNAIL_SIZE && imageWidthValue <= MAX_THUMBNAIL_SIZE) {
		return true;
		}
		}
		return false;
		}

		/**
		* Raw images often store extra pixels around the edges of the final image, which results in
		* larger values for TAG_IMAGE_WIDTH and TAG_IMAGE_LENGTH tags.