Struct vtkSelectionNode 

pub struct vtkSelectionNode(/* private fields */);

a node in a vtkSelection the defines the selection criteria.

vtkSelectionNode helps define the selection criteria in a vtkSelection. vtkSelection can comprise of multiple such vtkSelectionNode instances that help define the selection.

vtkSelectionNode has two components: a list of properties (stored in a vtkInformation) and a selection list (a vtkAbstractArray subclass). The properties help indicate how to interpret the values specified in a selection-list.

The properties can be broadly classified into three categories: core, qualifiers, and information. The core properties must be specified other wise the vtkSelectionNode is not considered valid. These are FIELD_TYPE and CONTENT_TYPE. FIELD_TYPE defines what kinds of entities are being selected. Since selections are used to select items in a data-object, these correspond to things like cells, points, nodes, edges, rows, etc. Supported FIELD_TYPE values are defined in vtkSelectionNode::SelectionField. CONTENT_TYPE defines the how the selection is described. Supported values are vtkSelectionNode::SelectionContent. For example, if CONTENT_TYPE is INDICES, then selection is described as ids for entities being selected. The ids themselves will be specified using the selection list. Thus, the CONTENT_TYPE dictates what the selection list comprises.

Qualifiers are used to further qualify the selection criteria. All qualifiers are optional. When present they restrict the selection. For example, when selecting elements from a composite-dataset, the COMPOSITE_INDEX qualifier can be specified of limit the selection to a specific dataset (or subtree).

Information properties are simply for informative purposes and generally used to provide information about the selection when the selection is created. For example, PIXEL_COUNT is used to indicate how many screen pixels resulted in creation of this selection node.

@section SelectionTypes Selection Types

CONTENT_TYPE property is one of the required properties that helps describe how the selection is defined. To set the content type, one can access the properties store using vtkSelectionNode::GetProperties() and then set the CONTENT_TYPE using the vtkSelectionNode::CONTENT_TYPE() key or simply use vtkSelectionNode::SetContentType.

• vtkSelectionNode::GLOBALIDS: indicates that the selection is defined using global ids. In VTK data-object, global ids are specified an vtkIdTypeArray added to a appropriate vtkDataSetAttributes and marked as global-ids using vtkDataSetAttributes API. Since global ids are expected to be unique for that element type over the entire dataset, it’s a convenient way of defining selections. For this content-type, the selection list must be a single-component, vtkIdTypeArray that lists all the globals ids for the selected elements.

• vtkSelectionNode::PEDIGREEIDS: similar to GLOBALIDS except uses pedigree ids instead of global ids.

• vtkSelectionNode::VALUES: this type is used to define a selection based on array values. The selection list specifies the values to be selected. All elements with array values in the selection list are treated as selected. The qualifier COMPONENT_NUMBER is used to indicate which component to use for the checks. Use -1 for magnitude. Current implementation does not support checking multiple-components or non-exact matches although support for both is conceivable in future. The selection list array name is used to specify the name of the array from the dataset to use for the checks. Thus, for defining a selection for a dataset where all TEMP values match those specified in the selection list, ensure that the selection list array’s name is set to TEMP as well.

• vtkSelectionNode::INDICES: this is similar to global ids except in this case the selection list is simply the VTK element id which is 0-based index of that element in the particular dataset. Often with this type of selection, additional qualifiers such as COMPOSITE_INDEX, BLOCK_SELECTORS, PROCESS_ID etc. are needed to correctly identify the chosen element(s) in case of composite or distributed datasets.

• vtkSelectionNode::FRUSTUM: this type is used to define a frustum in world coordinates that identifies the selected elements. In this case, the selection list is a vtkDoubleArray with 32 values specifying the 8 frustum corners in homogeneous world coordinates.

• vtkSelectionNode::LOCATIONS: this is used to select points (or cells) near (or containing) specified locations. The selection list is a 3-component vtkDoubleArray with coordinates for locations of interest.

• vtkSelectionNode::THRESHOLDS: this type is used to define a selection based on array value ranges. This is akin to thresholding. All elements with values in the specified ranges are to be treated as selected. For this content-type, the selection-list is a 2-component vtkDataArray-subclass that specifies where each tuple defines the min and max values for a range. The selection list can have multiple tuples to define multiple ranges. Elements with values in any of the specified ranges are treated as selected. The selection list array name is used to specify the name of the array from the dataset to use for the checks. Thus, for defining a selection for a dataset where all TEMP values are within a range, ensure that the selection list array’s name is set to TEMP as well.

• vtkSelectionNode::BLOCKS: this type is used to select blocks in a composite dataset. The term blocks is used loosely here and can correspond to a block in a multiblock dataset or a partition in a partitioned-dataset. The selection list is an integral type vtkDataArray subclass that can be 1- or 2- component. If 1-component, it’s interpreted as the composite-index (also called flat index) and can be applied to any composite-dataset to choose specific datasets. If 2-component, it’s typically associated with vtkUniformGridAMR or vtkPartitionedDataSetCollection which support 2-tuple indexing to locate a dataset.

• vtkSelectionNode::BLOCK_SELECTORS: this is similar to BLOCKS, however instead of using indices to select datasets, here, the selection list is a vtkStringArray which lists selector expressions to select blocks in the composite dataset. By default, the selector expressions are applied to a vtkDataAssembly generated from the composite dataset that represents its hierarchy (see vtkDataAssembly::GenerateHierarchy). However, in case of vtkPartitionedDataSetCollection, one can select any other data assembly associated with the vtkPartitionedDataSetCollection by naming the array with the name of the assembly.

@note, currently vtkPartitionedDataSetCollection only supports a single vtkDataAssembly but this may change in the future.

• vtkSelectionNode::QUERY: this type is primarily added for ParaView where selection expression is specified as a query string. This is likely to change in the future and hence applications are discouraged from using this type.

@section Properties Properties

Following a properties that can be used to qualify the selection.

• vtkSelectionNode::EPSILON(): this is a qualifier that can be used to indicate a fuzz-factor when comparing values for equality. Currently, this is only used with content-type LOCATIONS, however, it can be expanded to other selection types in the future.

• vtkSelectionNode::CONTAINING_CELLS(): this qualifier is intended to be used with field-type POINT. When present, it indicates that while the selection criteria selects a collection of points the selection should be formed using cell containing the chosen points.

• vtkSelectionNode::CONNECTED_LAYERS(): a qualifier used to expand the definition of selected elements to connected elements for the specified number of layers. Layers can only be positive to grow the selection.

• vtkSelectionNode::CONNECTED_LAYERS_REMOVE_SEED(): this qualifier indicates that when using a number of CONNECTED_LAYERS >= 1, the initial selection will not be kept.

• vtkSelectionNode::CONNECTED_LAYERS_REMOVE_INTERMEDIATE_LAYERS(): this qualifier indicates that when using a number of CONNECTED_LAYERS >= 2, the intermediate layers will not be kept.

• vtkSelectionNode::INVERSE(): a qualifier that causes the selection to be inverted i.e. all elements not chosen by the criteria are to be treated as selected.

• vtkSelectionNode::COMPONENT_NUMBER(): for VALUES and THRESHOLDS selection types, this qualifier identifies the array component of interest. -1 indicates magnitude.

• vtkSelectionNode::PROCESS_ID(): limits the selection to a particular rank in a distributed environment.

• vtkSelectionNode::COMPOSITE_INDEX(): a qualifier used to limit the selection to a specific composite index for a composite-dataset.

• vtkSelectionNode::ASSEMBLY_NAME(), vtkSelectionNode::SELECTORS(): similar to composite index, except uses data-assembly and selectors to limit the selection to a subset of nodes in a composite-dataset.

• vtkSelectionNode::HIERARCHICAL_LEVEL(), vtkSelectionNode::HIERARCHICAL_INDEX(): similar to composite index, except uses level and index for an AMR dataset so limit the selection to a specific AMR level or dataset.

Following for properties that are primarily intended to provide additional information when the selection is created.

• vtkSelectionNode::ZBUFFER_VALUE(): an information qualifier representing the z-depth for a particular selection when it was created.

• vtkSelectionNode::PIXEL_COUNT(): a qualifier used to provide a count for the number of pixels that resulted in this selection.

• vtkSelectionNode::SOURCE(), vtkSelectionNode::SOURCE_ID(): provides information about data producer or selection originator. The interpretation is very specific to the creator creating the selection and varies greatly with VTK.

• vtkSelectionNode::PROP(), vtkSelectionNode::PROP_ID()`: similar to SOURCE/SOURCE_ID except is used to represent a rendering prop from which the selection was created.

@warning No SelectionList is created by default. It should be assigned.

@section SelectionFieldMismatch vtkSelectionNode::SelectionField and vtkDataSetAttribute::AttributeTypes

Strictly speaking, vtkSelectionNode::SelectionField maps directly to vtkDataSetAttribute::AttributeTypes. However, the two enum values are not identical for historical reasons. Use vtkSelectionNode::ConvertSelectionFieldToAttributeType and vtkSelectionNode::ConvertAttributeTypeToSelectionField to convert between the two.

Implementations

impl vtkSelectionNode

pub fn new() -> Self

Creates a new vtkSelectionNode wrapped inside vtkNew

Trait Implementations

impl Default for vtkSelectionNode

fn default() -> Self

Returns the “default value” for a type.

impl Drop for vtkSelectionNode

fn drop(&mut self)

Executes the destructor for this type.