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authorJörg Frings-Fürst <debian@jff.email>2018-09-30 14:11:00 +0200
committerJörg Frings-Fürst <debian@jff.email>2018-09-30 14:11:00 +0200
commit0ac947a9070322180e94d1b71e30836cce4d74bc (patch)
tree4a6f3923c250377536a5004ed203768111a1d27f /src/photos/GifSupport.vala
parenteca5837e235a356c8db9416bbbc13577db3e6f76 (diff)
parent01b2b5ec9177046f64c6d0a6e73a6ac8a42089a1 (diff)
Merge branch 'feature/upstream' into develop
Diffstat (limited to 'src/photos/GifSupport.vala')
-rw-r--r--src/photos/GifSupport.vala173
1 files changed, 173 insertions, 0 deletions
diff --git a/src/photos/GifSupport.vala b/src/photos/GifSupport.vala
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+++ b/src/photos/GifSupport.vala
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+/* Copyright 2016 Software Freedom Conservancy Inc.
+ *
+ * This software is licensed under the GNU LGPL (version 2.1 or later).
+ * See the COPYING file in this distribution.
+ */
+
+namespace Photos {
+
+class GifFileFormatProperties : PhotoFileFormatProperties {
+ private static string[] KNOWN_EXTENSIONS = { "gif" };
+ private static string[] KNOWN_MIME_TYPES = { "image/gif" };
+
+ private static GifFileFormatProperties instance = null;
+
+ public static void init() {
+ instance = new GifFileFormatProperties();
+ }
+
+ public static GifFileFormatProperties get_instance() {
+ return instance;
+ }
+
+ public override PhotoFileFormat get_file_format() {
+ return PhotoFileFormat.PNG;
+ }
+
+ public override PhotoFileFormatFlags get_flags() {
+ return PhotoFileFormatFlags.NONE;
+ }
+
+ public override string get_user_visible_name() {
+ return _("GIF");
+ }
+
+ public override string get_default_extension() {
+ return KNOWN_EXTENSIONS[0];
+ }
+
+ public override string[] get_known_extensions() {
+ return KNOWN_EXTENSIONS;
+ }
+
+ public override string get_default_mime_type() {
+ return KNOWN_MIME_TYPES[0];
+ }
+
+ public override string[] get_mime_types() {
+ return KNOWN_MIME_TYPES;
+ }
+}
+
+public class GifSniffer : GdkSniffer {
+ private const uint8[] MAGIC_SEQUENCE = { (uint8)'G', (uint8)'I', (uint8)'F', (uint8)'8' };
+
+ public GifSniffer(File file, PhotoFileSniffer.Options options) {
+ base (file, options);
+ }
+
+ private static bool is_gif_file(File file) throws Error {
+ FileInputStream instream = file.read(null);
+
+ uint8[] file_lead_sequence = new uint8[MAGIC_SEQUENCE.length];
+
+ instream.read(file_lead_sequence, null);
+
+ return Posix.memcmp (file_lead_sequence, MAGIC_SEQUENCE, MAGIC_SEQUENCE.length) == 0;
+ }
+
+ public override DetectedPhotoInformation? sniff(out bool is_corrupted) throws Error {
+ // Rely on GdkSniffer to detect corruption
+ is_corrupted = false;
+
+ if (!is_gif_file(file))
+ return null;
+
+ DetectedPhotoInformation? detected = base.sniff(out is_corrupted);
+
+ if (detected == null)
+ return null;
+
+ return (detected.file_format == PhotoFileFormat.GIF) ? detected : null;
+ }
+}
+
+public class GifReader : GdkReader {
+ public GifReader(string filepath) {
+ base (filepath, PhotoFileFormat.PNG);
+ }
+
+ public override Gdk.Pixbuf scaled_read(Dimensions full, Dimensions scaled) throws Error {
+ Gdk.Pixbuf result = null;
+ /* if we encounter a situation where there are two orders of magnitude or more of
+ difference between the full image size and the scaled size, and if the full image
+ size has five or more decimal digits of precision, Gdk.Pixbuf.from_file_at_scale( ) can
+ fail due to what appear to be floating-point round-off issues. This isn't surprising,
+ since 32-bit floats only have 6-7 decimal digits of precision in their mantissa. In
+ this case, we prefetch the image at a larger scale and then downsample it to the
+ desired scale as a post-process step. This short-circuits Gdk.Pixbuf's buggy
+ scaling code. */
+ if (((full.width > 9999) || (full.height > 9999)) && ((scaled.width < 100) ||
+ (scaled.height < 100))) {
+ Dimensions prefetch_dimensions = full.get_scaled_by_constraint(1000,
+ ScaleConstraint.DIMENSIONS);
+
+ result = new Gdk.Pixbuf.from_file_at_scale(get_filepath(), prefetch_dimensions.width,
+ prefetch_dimensions.height, false);
+
+ result = result.scale_simple(scaled.width, scaled.height, Gdk.InterpType.HYPER);
+ } else {
+ result = new Gdk.Pixbuf.from_file_at_scale(get_filepath(), scaled.width,
+ scaled.height, false);
+ }
+
+ return result;
+ }
+}
+
+public class GifMetadataWriter : PhotoFileMetadataWriter {
+ public GifMetadataWriter(string filepath) {
+ base (filepath, PhotoFileFormat.GIF);
+ }
+
+ public override void write_metadata(PhotoMetadata metadata) throws Error {
+ metadata.write_to_file(get_file());
+ }
+}
+
+public class GifFileFormatDriver : PhotoFileFormatDriver {
+ private static GifFileFormatDriver instance = null;
+
+ public static void init() {
+ instance = new GifFileFormatDriver();
+ GifFileFormatProperties.init();
+ }
+
+ public static GifFileFormatDriver get_instance() {
+ return instance;
+ }
+
+ public override PhotoFileFormatProperties get_properties() {
+ return GifFileFormatProperties.get_instance();
+ }
+
+ public override PhotoFileReader create_reader(string filepath) {
+ return new GifReader(filepath);
+ }
+
+ public override bool can_write_image() {
+ return false;
+ }
+
+ public override bool can_write_metadata() {
+ return true;
+ }
+
+ public override PhotoFileWriter? create_writer(string filepath) {
+ return null;
+ }
+
+ public override PhotoFileMetadataWriter? create_metadata_writer(string filepath) {
+ return new GifMetadataWriter(filepath);
+ }
+
+ public override PhotoFileSniffer create_sniffer(File file, PhotoFileSniffer.Options options) {
+ return new GifSniffer(file, options);
+ }
+
+ public override PhotoMetadata create_metadata() {
+ return new PhotoMetadata();
+ }
+}
+
+}