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/*=========================================================================
Program: Visualization Toolkit
Module: vtkLabelHierarchy.h
Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
All rights reserved.
See Copyright.txt or http://www.kitware.com/Copyright.htm for details.
This software is distributed WITHOUT ANY WARRANTY; without even
the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the above copyright notice for more information.
=========================================================================*/
/*-------------------------------------------------------------------------
Copyright 2008 Sandia Corporation.
Under the terms of Contract DE-AC04-94AL85000 with Sandia Corporation,
the U.S. Government retains certain rights in this software.
-------------------------------------------------------------------------*/
/**
* @class vtkLabelHierarchy
* @brief contains an octree of labels
*
*
* This class represents labels in a hierarchy used to denote rendering priority.
* A binary tree of labels is maintained that subdivides the bounds of the
* of the label anchors spatially. Which level of the tree a label occupies
* determines its priority; those at higher levels of the tree will be
* more likely to render than those at lower levels of the tree.
*
* Pass vtkLabelHierarchy objects to a vtkLabelPlacementMapper filter for dynamic,
* non-overlapping, per-frame placement of labels.
*
* Note that if we have a d-dimensional binary tree and we want a fixed
* number \f$n\f$ of labels in each node (all nodes, not just leaves),
* we can compute the depth of tree required assuming a uniform distribution
* of points. Given a total of \f$N\f$ points we know that
* \f$\frac{N}{|T|} = n\f$, where \f$|T|\f$ is the cardinality of the tree (i.e.,
* the number of nodes it contains).
* Because we have a uniform distribution, the tree will be uniformly subdivided
* and thus \f$|T| = 1 + 2^d + \left(2^d\right)^2 + \cdots + \left(2^d\right)^k\f$,
* where \f$d\f$ is the dimensionality of the input points (fixed at 3 for now).
* As \f$k\f$ becomes large, \f$|T|\approx 2 \left(2^d\right)^k\f$.
* Using this approximation, we can solve for \f$k\f$:
* \f[ k = \frac{\log{\frac{N}{2n}}}{\log{2^d}} \f]
* Given a set of \f$N\f$ input label anchors, we'll compute \f$k\f$ and then
* bin the anchors into tree nodes at level \f$k\f$ of the tree. After this,
* all the nodes will be in the leaves of the tree and those leaves will be at
* the \f$k\f$-th level; no anchors will be in levels \f$1, 2, \ldots, k-1\f$.
* To fix that, we'll choose to move some anchors upwards.
* The exact number to move upwards depends on \a TargetLabelCount. We'll
* move as many up as required to have \a TargetLabelCount at each node.
*
* You should avoid situations where \a MaximumDepth does not allow for
* \a TargetLabelCount or fewer entries at each node. The \a MaximumDepth
* is a hard limit while \a TargetLabelCount is a suggested optimum. You will
* end up with many more than \a TargetLabelCount entries per node and things
* will be sloooow.
*/
#ifndef vtkLabelHierarchy_h
#define vtkLabelHierarchy_h
#include "vtkPointSet.h"
#include "vtkRenderingLabelModule.h" // For export macro
class vtkAbstractArray;
class vtkCamera;
class vtkCoincidentPoints;
class vtkCoordinate;
class vtkDataArray;
class vtkIntArray;
class vtkLabelHierarchyIterator;
class vtkPoints;
class vtkPolyData;
class vtkRenderer;
class vtkTextProperty;
class VTKRENDERINGLABEL_EXPORT vtkLabelHierarchy : public vtkPointSet
{
public:
static vtkLabelHierarchy* New();
vtkTypeMacro(vtkLabelHierarchy, vtkPointSet);
void PrintSelf(ostream& os, vtkIndent indent) override;
/**
* Override SetPoints so we can reset the hierarchy when the points change.
*/
void SetPoints(vtkPoints*) override;
/**
* Fill the hierarchy with the input labels.
*/
virtual void ComputeHierarchy();
//@{
/**
* The number of labels that is ideally present at any octree node.
* It is best if this is a multiple of \f$2^d\f$.
*/
vtkSetMacro(TargetLabelCount, int);
vtkGetMacro(TargetLabelCount, int);
//@}
//@{
/**
* The maximum depth of the octree.
*/
vtkSetMacro(MaximumDepth, int);
vtkGetMacro(MaximumDepth, int);
//@}
/**
* Enumeration of iterator types.
*/
enum IteratorType
{
FULL_SORT,
QUEUE,
DEPTH_FIRST,
FRUSTUM
};
//@{
/**
* The default text property assigned to labels in this hierarchy.
*/
virtual void SetTextProperty(vtkTextProperty* tprop);
vtkGetObjectMacro(TextProperty, vtkTextProperty);
//@}
//@{
/**
* Set/get the array specifying the importance (priority) of each label.
*/
virtual void SetPriorities(vtkDataArray* arr);
vtkGetObjectMacro(Priorities, vtkDataArray);
//@}
//@{
/**
* Set/get the array specifying the text of each label.
*/
virtual void SetLabels(vtkAbstractArray* arr);
vtkGetObjectMacro(Labels, vtkAbstractArray);
//@}
//@{
/**
* Set/get the array specifying the orientation of each label.
*/
virtual void SetOrientations(vtkDataArray* arr);
vtkGetObjectMacro(Orientations, vtkDataArray);
//@}
//@{
/**
* Set/get the array specifying the icon index of each label.
*/
virtual void SetIconIndices(vtkIntArray* arr);
vtkGetObjectMacro(IconIndices, vtkIntArray);
//@}
//@{
/**
* Set/get the array specifying the size of each label.
*/
virtual void SetSizes(vtkDataArray* arr);
vtkGetObjectMacro(Sizes, vtkDataArray);
//@}
//@{
/**
* Set/get the array specifying the maximum width and height in world coordinates of each label.
*/
virtual void SetBoundedSizes(vtkDataArray* arr);
vtkGetObjectMacro(BoundedSizes, vtkDataArray);
//@}
/**
* Returns an iterator for this data object.
* positionsAsNormals should only be true when labels are on a sphere centered at the origin
* (3D world).
* @param type - the type should be one of FULL_SORT, QUEUE, DEPTH_FIRST, or FRUSTUM.
* @param ren - the current renderer (used for viewport information)
* @param cam - the current camera.
* @param frustumPlanes - should be the output of the camera's frustum planes.
* @param positionsAsNormals - throws out octree nodes on the opposite side of the origin.
* @param bucketSize - an array of 2 integers describing the width and height of label placer
* buckets.
*/
VTK_NEWINSTANCE vtkLabelHierarchyIterator* NewIterator(int type, vtkRenderer* ren, vtkCamera* cam,
double frustumPlanes[24], bool positionsAsNormals, float bucketSize[2]);
/**
* Given a depth in the hierarchy (\a level) and a point \a pt in world space, compute \a ijk.
* This is used to find other octree nodes at the same \a level that are within the search radius
* for candidate labels to be placed. It is called with \a pt set to the camera eye point and
* pythagorean quadruples increasingly distant from the origin are added to \a ijk to identify
* octree nodes whose labels should be placed.
* @param[out] ijk - discrete coordinates of the octree node at \a level containing \a pt.
* @param[in] pt - input world point coordinates
* @param[in] level - input octree level to be considered
*/
void GetDiscreteNodeCoordinatesFromWorldPoint(int ijk[3], double pt[3], int level);
/**
* Given a \a level of the tree and \a ijk coordinates in a lattice,
* compute a \a path down the tree to reach the corresponding lattice node.
* If the lattice coordinates are outside the tree, this returns
* false. Otherwise it returns true. This does <b>not</b> guarantee that
* the path exists in the hierarchy.
* @param[out] path - a vector of \a level integers specifying which child to descend at each
* level to reach \a ijk
* @param[in] ijk - discrete coordinates of the octree node at \a level
* @param[in] level - input octree level to be considered
*/
static bool GetPathForNodalCoordinates(int* path, int ijk[3], int level);
//@{
/**
* Inherited members (from vtkDataSet)
*/
vtkIdType GetNumberOfCells() override;
using vtkDataSet::GetCell;
vtkCell* GetCell(vtkIdType) override;
void GetCell(vtkIdType, vtkGenericCell*) override;
int GetCellType(vtkIdType) override;
void GetCellPoints(vtkIdType, vtkIdList*) override;
void GetPointCells(vtkIdType, vtkIdList*) override;
vtkIdType FindCell(double*, vtkCell*, vtkIdType, double, int&, double*, double*) override;
vtkIdType FindCell(
double*, vtkCell*, vtkGenericCell*, vtkIdType, double, int&, double*, double*) override;
int GetMaxCellSize() override;
//@}
class Implementation;
Implementation* GetImplementation() { return this->Impl; }
//@{
/**
* Provide access to original coordinates of sets of coincident points
*/
vtkGetObjectMacro(CenterPts, vtkPoints);
//@}
//@{
/**
* Provide access to the set of coincident points that have been
* perturbed by the hierarchy in order to render labels for each
* without overlap.
*/
vtkGetObjectMacro(CoincidentPoints, vtkCoincidentPoints);
//@}
//@{
/**
* Compute frustum for quickly excluding labels from rendering
* that are outside the visible region.
* This is a shared utility function.
*/
static void GetAnchorFrustumPlanes(
double frustumPlanes[24], vtkRenderer* ren, vtkCoordinate* anchorTransform);
//@}
protected:
vtkLabelHierarchy();
~vtkLabelHierarchy() override;
int TargetLabelCount;
int MaximumDepth;
vtkDataArray* Priorities;
vtkAbstractArray* Labels;
vtkDataArray* Orientations;
vtkIntArray* IconIndices;
vtkDataArray* Sizes;
vtkDataArray* BoundedSizes;
vtkCoincidentPoints* CoincidentPoints;
vtkPoints* CenterPts;
vtkTextProperty* TextProperty;
Implementation* Impl;
friend class vtkLabelHierarchyFrustumIterator;
friend class vtkLabelHierarchyFullSortIterator;
friend class implementation;
private:
vtkLabelHierarchy(const vtkLabelHierarchy&) = delete;
void operator=(const vtkLabelHierarchy&) = delete;
};
#endif // vtkLabelHierarchy_h