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authorJörg Frings-Fürst <debian@jff-webhosting.net>2014-07-23 09:06:59 +0200
committerJörg Frings-Fürst <debian@jff-webhosting.net>2014-07-23 09:06:59 +0200
commit4ea2cc3bd4a7d9b1c54a9d33e6a1cf82e7c8c21d (patch)
treed2e54377d14d604356c86862a326f64ae64dadd6 /src/photos/PngSupport.vala
Imported Upstream version 0.18.1upstream/0.18.1
Diffstat (limited to 'src/photos/PngSupport.vala')
-rw-r--r--src/photos/PngSupport.vala181
1 files changed, 181 insertions, 0 deletions
diff --git a/src/photos/PngSupport.vala b/src/photos/PngSupport.vala
new file mode 100644
index 0000000..ffc7faa
--- /dev/null
+++ b/src/photos/PngSupport.vala
@@ -0,0 +1,181 @@
+/* Copyright 2010-2014 Yorba Foundation
+ *
+ * This software is licensed under the GNU LGPL (version 2.1 or later).
+ * See the COPYING file in this distribution.
+ */
+
+class PngFileFormatProperties : PhotoFileFormatProperties {
+ private static string[] KNOWN_EXTENSIONS = { "png" };
+ private static string[] KNOWN_MIME_TYPES = { "image/png" };
+
+ private static PngFileFormatProperties instance = null;
+
+ public static void init() {
+ instance = new PngFileFormatProperties();
+ }
+
+ public static PngFileFormatProperties 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 _("PNG");
+ }
+
+ 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 PngSniffer : GdkSniffer {
+ private const uint8[] MAGIC_SEQUENCE = { 137, 80, 78, 71, 13, 10, 26, 10 };
+
+ public PngSniffer(File file, PhotoFileSniffer.Options options) {
+ base (file, options);
+ }
+
+ private static bool is_png_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);
+
+ for (int i = 0; i < MAGIC_SEQUENCE.length; i++) {
+ if (file_lead_sequence[i] != MAGIC_SEQUENCE[i])
+ return false;
+ }
+
+ return true;
+ }
+
+ public override DetectedPhotoInformation? sniff() throws Error {
+ if (!is_png_file(file))
+ return null;
+
+ DetectedPhotoInformation? detected = base.sniff();
+ if (detected == null)
+ return null;
+
+ return (detected.file_format == PhotoFileFormat.PNG) ? detected : null;
+ }
+}
+
+public class PngReader : GdkReader {
+ public PngReader(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 PngWriter : PhotoFileWriter {
+ public PngWriter(string filepath) {
+ base (filepath, PhotoFileFormat.PNG);
+ }
+
+ public override void write(Gdk.Pixbuf pixbuf, Jpeg.Quality quality) throws Error {
+ pixbuf.save(get_filepath(), "png", "compression", "9", null);
+ }
+}
+
+public class PngMetadataWriter : PhotoFileMetadataWriter {
+ public PngMetadataWriter(string filepath) {
+ base (filepath, PhotoFileFormat.PNG);
+ }
+
+ public override void write_metadata(PhotoMetadata metadata) throws Error {
+ metadata.write_to_file(get_file());
+ }
+}
+
+public class PngFileFormatDriver : PhotoFileFormatDriver {
+ private static PngFileFormatDriver instance = null;
+
+ public static void init() {
+ instance = new PngFileFormatDriver();
+ PngFileFormatProperties.init();
+ }
+
+ public static PngFileFormatDriver get_instance() {
+ return instance;
+ }
+
+ public override PhotoFileFormatProperties get_properties() {
+ return PngFileFormatProperties.get_instance();
+ }
+
+ public override PhotoFileReader create_reader(string filepath) {
+ return new PngReader(filepath);
+ }
+
+ public override bool can_write_image() {
+ return true;
+ }
+
+ public override bool can_write_metadata() {
+ return true;
+ }
+
+ public override PhotoFileWriter? create_writer(string filepath) {
+ return new PngWriter(filepath);
+ }
+
+ public override PhotoFileMetadataWriter? create_metadata_writer(string filepath) {
+ return new PngMetadataWriter(filepath);
+ }
+
+ public override PhotoFileSniffer create_sniffer(File file, PhotoFileSniffer.Options options) {
+ return new PngSniffer(file, options);
+ }
+
+ public override PhotoMetadata create_metadata() {
+ return new PhotoMetadata();
+ }
+}
+