pynetdicom.pdu_items.PresentationContextItemRQ¶
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class
pynetdicom.pdu_items.
PresentationContextItemRQ
¶ A Presentation Context (RQ) Item.
Presentation Contexts (RQ) Items are used by the association requestor to propose Abstract Syntaxes (specifications of data elements with associated semantics) and Transfer Syntaxes (sets of encoding rules) [1].
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abstract_syntax
¶ The Presentation Context Item’s Abstract Syntax (if available).
Type: pydicom.uid.UID or None.
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abstract_transfer_syntax_sub_items
¶ The Abstract/Transfer Syntax Sub-Items field value. The order of the items is not guaranteed.
Type: list of AbstractSyntaxSubItem and TransferSyntaxSubItem
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item_length
¶ The number of bytes from the first byte following the Item Length field to the last byte of the Item.
Type: int
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item_type
¶ The Item Type field value (0x20).
Type: int
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presentation_context_id
¶ The Presentation Context ID field value, an odd integer between 1 and 255.
Type: int or None
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transfer_syntax
¶ The Presentation Context Item’s Transfer Syntax(es) (if available).
Type: list of pydicom.uid.UID
Notes
A Presentation Context (RQ) Item requires the following parameters:
- Item type (1, fixed value, 0x20)
- Item length (1)
- Presentation context ID (1)
- Abstract/Transfer Syntax Sub-items (1)
- Abstract Syntax Sub-item (1)
- Item type (1, fixed, 0x30)
- Item length (1)
- Abstract syntax name (1)
- Transfer Syntax Sub-items (1 or more)
- Item type (1, fixed, 0x40)
- Item length (1)
- Transfer syntax name(s) (1 or more)
- Abstract Syntax Sub-item (1)
Encoding
When encoded, a Presentation Context (RQ) Item has the following structure, taken from Table 9-13 [2] (offsets shown with Python indexing). Items are always encoded using Big Endian [3].
Offset Length Description 0 1 Item type 1 1 Reserved 2 2 Item length 4 1 Presentation context ID 5 1 Reserved 6 1 Reserved 7 1 Reserved 8 Variable Abstract/transfer syntax sub-items References
[1] DICOM Standard, Part 8, Annex B [2] DICOM Standard, Part 8, Section 9.3.2.2 [3] DICOM Standard, Part 8, Section 9.3.1 -
__init__
()¶ Initialise a new Presentation Context (RQ) Item.
Methods
__init__
()Initialise a new Presentation Context (RQ) Item. decode
(bytestream)Decode bytestream and use the result to set the field values of the PDU item. encode
()Return the encoded PDU as bytes. from_primitive
(primitive)Set the item’s values using a Presentation Context primitive. to_primitive
()Return a PresentationContext primitive from the current Item. Attributes
abstract_syntax
Return the Abstract Syntax, if available. context_id
Return the item’s Presentation Context ID field value as an int. item_length
Return the item’s Item Length field value as an int. item_type
Return the item’s Item Type field value as an int. transfer_syntax
Return the Transfer Syntax(es). -
abstract_syntax
Return the Abstract Syntax, if available.
Returns: Return type: pydicom.uid.UID or None
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context_id
¶ Return the item’s Presentation Context ID field value as an int.
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decode
(bytestream)¶ Decode bytestream and use the result to set the field values of the PDU item.
Parameters: bytestream (bytes) – The PDU data to be decoded.
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encode
()¶ Return the encoded PDU as bytes.
Returns: The encoded PDU. Return type: bytes
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from_primitive
(primitive)¶ Set the item’s values using a Presentation Context primitive.
Parameters: primitive (presentation.PresentationContext) – The primitive to use to set the Item’s field values.
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item_length
Return the item’s Item Length field value as an int.
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item_type
Return the item’s Item Type field value as an int.
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to_primitive
()¶ Return a PresentationContext primitive from the current Item.
Returns: The primitive representation of the current Item. Return type: presentation.PresentationContext
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transfer_syntax
Return the Transfer Syntax(es).
Returns: Return type: list of pydicom.uid.UID
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