metadataTree.py

This code demonstrates how to store, modify and parse metadata in ImageViews.

This code demonstrates how to store, modify and parse metadata in ImageViews. An ImageView is created and metadata are stored into it. Then the metadata are modified and parsed.

import iolink
 
 
 
# method to create a metadata tree and assign it to given image
def add_metadata(image: iolink.ImageView):
    # if given image does not have write capability, metadata cannot be added
    if not image.support(iolink.ImageCapability.WRITE):
        raise AttributeError("Image does not have WRITE capability")
 
    # create a metadata tree as following
    # root
    #   |- "name" : "generated image for example"
    #   |- "author" : "Arthur Conley"
    #   |- "creation_date" : "2024-08-23"
    #   |- "parameters"
    #       |- "param1" : 42
    #       |- "param2" : 3.14
    #       |- "param3" : "hello world!"
    #       |- "version" : 1
 
    # Nodes are created one by one
    root = iolink.MetadataNodeFactory.create("root", None)
    nameNode = iolink.MetadataNodeFactory.create("name", iolink.VariantDataValueFactory.create("generated image for example"))
    authorNode = iolink.MetadataNodeFactory.create("author", iolink.VariantDataValueFactory.create("Arthur Conley"))
    createDateNode = iolink.MetadataNodeFactory.create("creation_date", iolink.VariantDataValueFactory.create("2024-08-23"))
 
    root.add_child(nameNode)
    root.add_child(authorNode)
    root.add_child(createDateNode)
 
    # you can also use the helper class to create the tree
    # the helper class is more convenient to create trees with complex hierarchies
    iolink.MetadataNodeHelper.create_path(root, "parameters/param1", iolink.VariantDataValueFactory.create(42))
    iolink.MetadataNodeHelper.create_path(root, "parameters/param2", iolink.VariantDataValueFactory.create(3.14))
    iolink.MetadataNodeHelper.create_path(root, "parameters/param3", iolink.VariantDataValueFactory.create("Hello world!"));
 
    iolink.MetadataNodeHelper.create_path(root, "parameters/version", iolink.VariantDataValueFactory.create(1))
 
    # assign the metadata tree to the image
    image.metadata = root
 
# increment 'version' value in metadata of given image
def increment_version_metadata(image: iolink.ImageView):
    # if given image does not have WRITE capability, metadata cannot be updated
    if not image.support(iolink.ImageCapability.WRITE):
        raise AttributeError("Image does not have WRITE capability")
 
    # the node to be updated cannot be modified directly
    # you need to create a new node with the same name and replace the old one
    root = image.metadata
 
    # retrieve version number
    versionValue = iolink.MetadataNodeHelper.get_node(root, "parameters/version")
 
    # if version node does not exist, raise an error
    if versionValue is None:
        raise AttributeError("version node does not exist")
 
    version = versionValue.value[0]
 
    # clone the tree for modification
    rootCloned = root.clone()
    iolink.MetadataNodeHelper.create_path(rootCloned, "parameters/version", iolink.VariantDataValueFactory.create(version + 1))
 
    # assign the new tree including modification to the image
    image.metadata = rootCloned
 
# recursive method to display metadata tree
def recursive_display_method(root: iolink.MetadataNode, level: int):
    indent = " " * level
    print(indent, root.key, ":", end='')
 
    # if the node has a value, display it
    if root.value is not None:
        print(root.value[0], end='')
    print("")
 
    for child in root:
        recursive_display_method(child, level + 1)
 
# display metadata tree of given image
def display_metadata(image:iolink.ImageView):
    if image.metadata is None:
        print("No metadata to dislay")
        return
 
    root = image.metadata
    print("Metadata tree:")
    recursive_display_method(root, 0)
 
 
# create an image view in CPU memory
image = iolink.ImageViewFactory.allocate((100, 200), iolink.DataTypeId.UINT8)
 
# add metadata to the image
add_metadata(image)
 
# display metadata tree
display_metadata(image)
 
# do some modifications in metadata
increment_version_metadata(image)
 
# display metadata tree after modification
display_metadata(image)
 
print("SUCCESS")