[gthumb: 3/5] jxl: add metadata provider

[Paolo Bacchilega <paobac src gnome org>]

commit d2be489f105e9a9766a39a2d7f604e9a54d1dea7
Author: Ian Tester <imroykun gmail com>
Date:   Sun Feb 28 04:13:11 2021 +1100

    jxl: add metadata provider

 .../image_viewer/gth-metadata-provider-image.c     | 41 ++++++++++++++++++++++
 1 file changed, 41 insertions(+)
---
diff --git a/extensions/image_viewer/gth-metadata-provider-image.c 
b/extensions/image_viewer/gth-metadata-provider-image.c
index e0aa644e..eb5d01ef 100644
--- a/extensions/image_viewer/gth-metadata-provider-image.c
+++ b/extensions/image_viewer/gth-metadata-provider-image.c
@@ -30,6 +30,9 @@
 #if HAVE_LIBWEBP
 #include <webp/decode.h>
 #endif /* HAVE_LIBWEBP */
+#if HAVE_LIBJXL
+#include <jxl/decode.h>
+#endif /* HAVE_LIBJXL */
 #include "gth-metadata-provider-image.h"
 
 
@@ -185,6 +188,44 @@ gth_metadata_provider_image_read (GthMetadataProvider *self,
                        }
 #endif /* HAVE_LIBWEBP */
 
+#if HAVE_LIBJXL
+                       else if (size >= 12) {
+                               JxlSignature sig = JxlSignatureCheck(buffer, size);
+                               if (sig > JXL_SIG_INVALID) {
+                                       JxlDecoder *dec = JxlDecoderCreate(NULL);
+                                       if (dec != NULL) {
+                                               if (JxlDecoderSubscribeEvents(dec, JXL_DEC_BASIC_INFO) == 
JXL_DEC_SUCCESS) {
+                                                       if (JxlDecoderSetInput(dec, buffer, size) == 
JXL_DEC_SUCCESS) {
+                                                               JxlDecoderStatus status = 
JXL_DEC_NEED_MORE_INPUT;
+                                                               while (status != JXL_DEC_SUCCESS) {
+                                                                       status = JxlDecoderProcessInput(dec);
+                                                                       if (status == JXL_DEC_ERROR)
+                                                                               break;
+                                                                       if (status == JXL_DEC_NEED_MORE_INPUT)
+                                                                               break;
+                                                                       if (status == JXL_DEC_BASIC_INFO) {
+                                                                               JxlBasicInfo info;
+                                                                               if 
(JxlDecoderGetBasicInfo(dec, &info) == JXL_DEC_SUCCESS) {
+                                                                                       width = info.xsize;
+                                                                                       height = info.ysize;
+                                                                                       if (sig == 
JXL_SIG_CONTAINER)
+                                                                                               description = 
_("JPEG XL container");
+                                                                                       else
+                                                                                               description = 
_("JPEG XL");
+                                                                                       mime_type = 
"image/jxl";
+                                                                                       format_recognized = 
TRUE;
+                                                                               }
+                                                                               break;
+                                                                       }
+                                                               }
+                                                       }
+                                               }
+                                               JxlDecoderDestroy(dec);
+                                       }
+                               }
+                       }
+#endif /* HAVE_LIBJXL */
+
                        else if ((size >= 26)
                                 && (strncmp ((char *) buffer, "gimp xcf ", 9) == 0))
                        {