Init create_thumbnail_from_iiif.

iiif_prezi3/helpers/add_thumbnail.py

@@ -1,7 +1,7 @@
 from ..loader import monkeypatch_schema
 from ..skeleton import (AccompanyingCanvas, Annotation, AnnotationCollection,
                         AnnotationPage, Canvas, Collection, Manifest,
-                        PlaceholderCanvas, Range, Reference, ResourceItem)
+                        PlaceholderCanvas, Range, Reference, ResourceItem, ServiceItem, ServiceItem1)
 
 
 class AddThumbnail:
@@ -20,6 +20,80 @@ def add_thumbnail(self, image_url, **kwargs):
             self.thumbnail = list()
         self.thumbnail.append(new_thumbnail)
         return new_thumbnail
+
+    def create_thumbnail_from_iiif(self, url, preferred_width=500, **kwargs):
+        """Adds an image thumbnail to a manifest or canvas based on a IIIF service.
+
+        Args:
+            url (str): An HTTP URL which points at a IIIF Image response.
+            preferred_width (int, optional): the preferred width of the thumbnail.
+            **kwargs (): see ResourceItem.
+
+        Returns:
+            list[ResourceItem]: The updated list of thumbnails, including the newly-created one.
+        """
+        image_response = ResourceItem(id=url, type='Image')
+        image_info = image_response.set_hwd_from_iiif(url)
+        context = image_info.get('@context', '')
+        if context == "http://iiif.io/api/image/2/context.json":
+            if 'sizes' not in image_info:
+                thumbnail_id = f"{url}/full/full/0/default.jpg"
+            else:
+                best_fit_size = min(
+                    image_info.get('sizes'), key=lambda d: abs(d["width"] - preferred_width)
+                )
+                thumbnail_id = f"{url}/full/{best_fit_size['width']},{best_fit_size['height']}/0/default.jpg"
+            profile = next(
+                (item for item in image_info.get('profile', []) if isinstance(item, str)),
+                ''
+            )
+            service = ServiceItem1(
+                id=image_info['@id'],
+                profile=profile,
+                type="ImageService2",
+                format="image/jpeg"
+            )
+        else:
+            if 'sizes' not in image_info:
+                thumbnail_id = f"{url}/full/max/0/default.jpg"
+            service = ServiceItem(
+                id=image_info['id'],
+                profile=image_info.get('profile', ''),
+                type=image_info.get('type', 'ImageService'),
+                format="image/jpeg"
+            )
+        new_thumbnail = ResourceItem(
+            id=thumbnail_id,
+            type='Image',
+            # height=best_fit_size['height'],
+            # width=best_fit_size['width'],
+            format="image/jpeg",
+            **kwargs
+        )
+        if not hasattr(self, 'thumbnail') or self.thumbnail is None:
+            self.thumbnail = []
+        context = image_info.get('@context', '')
+        if context == "http://iiif.io/api/image/2/context.json":
+            profile = next(
+                (item for item in image_info.get('profile', []) if isinstance(item, str)),
+                ''
+            )
+            service = ServiceItem1(
+                id=image_info['@id'],
+                profile=profile,
+                type="ImageService2",
+                format="image/jpeg"
+            )
+        else:
+            service = ServiceItem(
+                id=image_info['id'],
+                profile=image_info.get('profile', ''),
+                type=image_info.get('type', 'ImageService'),
+                format="image/jpeg"
+            )
+        new_thumbnail.add_service(service)
+        self.thumbnail.append(new_thumbnail)
+        return self.thumbnail
 
 
 monkeypatch_schema([Canvas, PlaceholderCanvas, AccompanyingCanvas, AnnotationPage, Collection, Manifest, Annotation, Range, ResourceItem, AnnotationCollection, Reference], AddThumbnail)