vtkImageBlend Class Reference

#include <vtkImageBlend.h>

Inheritance diagram for vtkImageBlend:

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Collaboration diagram for vtkImageBlend:

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List of all members.


Detailed Description

blend images together using alpha or opacity

vtkImageBlend takes L, LA, RGB, or RGBA images as input and blends them according to the alpha values and/or the opacity setting for each input.

The spacing, origin, extent, and number of components of the output are the same as those for the first input. If the input has an alpha component, then this component is copied unchanged into the output. In addition, if the first input has either one component or two components i.e. if it is either L (greyscale) or LA (greyscale + alpha) then all other inputs must also be L or LA.

Different blending modes are available:

Normal (default) : This is the standard blending mode used by OpenGL and other graphics packages. The output always has the same number of components and the same extent as the first input. The alpha value of the first input is not used in the blending computation, instead it is copied directly to the output.

 output <- input[0]
 foreach input i {
   foreach pixel px {
     r <- input[i](px)(alpha) * opacity[i]
     f <- (255 - r)
     output(px) <- output(px) * f + input(px) * r
   }
 }

Compound : Images are compounded together and each component is scaled by the sum of the alpha/opacity values. Use the CompoundThreshold method to set specify a threshold in compound mode. Pixels with opacity*alpha less or equal than this threshold are ignored. The alpha value of the first input, if present, is NOT copied to the alpha value of the output. The output always has the same number of components and the same extent as the first input.

 output <- 0
 foreach pixel px {
   sum <- 0
   foreach input i {
     r <- input[i](px)(alpha) * opacity(i)
     sum <- sum + r
     if r > threshold {
       output(px) <- output(px) + input(px) * r
     }
   }
   output(px) <- output(px) / sum
 }

Tests:
vtkImageBlend (Tests)

Definition at line 87 of file vtkImageBlend.h.


Public Types

typedef vtkThreadedImageAlgorithm Superclass

Public Member Functions

virtual const char * GetClassName ()
virtual int IsA (const char *type)
void PrintSelf (ostream &os, vtkIndent indent)
virtual void ReplaceNthInputConnection (int idx, vtkAlgorithmOutput *input)
int GetNumberOfInputs ()
void SetInput (int num, vtkDataObject *input)
void SetInput (vtkDataObject *input)
vtkDataObjectGetInput (int num)
vtkDataObjectGetInput ()
void SetOpacity (int idx, double opacity)
double GetOpacity (int idx)
void SetStencil (vtkImageStencilData *stencil)
vtkImageStencilDataGetStencil ()
virtual void SetBlendMode (int)
virtual int GetBlendMode ()
void SetBlendModeToNormal ()
void SetBlendModeToCompound ()
const char * GetBlendModeAsString (void)
virtual void SetCompoundThreshold (double)
virtual double GetCompoundThreshold ()

Static Public Member Functions

static vtkImageBlendNew ()
static int IsTypeOf (const char *type)
static vtkImageBlendSafeDownCast (vtkObject *o)

Protected Member Functions

 vtkImageBlend ()
 ~vtkImageBlend ()
virtual int RequestUpdateExtent (vtkInformation *, vtkInformationVector **, vtkInformationVector *)
void InternalComputeInputUpdateExtent (int inExt[6], int outExt[6], int inWExtent[6])
void ThreadedRequestData (vtkInformation *request, vtkInformationVector **inputVector, vtkInformationVector *outputVector, vtkImageData ***inData, vtkImageData **outData, int ext[6], int id)
virtual int FillInputPortInformation (int, vtkInformation *)
virtual int RequestData (vtkInformation *request, vtkInformationVector **inputVector, vtkInformationVector *outputVector)

Protected Attributes

double * Opacity
int OpacityArrayLength
int BlendMode
double CompoundThreshold
int DataWasPassed

Member Typedef Documentation

Reimplemented from vtkThreadedImageAlgorithm.

Definition at line 91 of file vtkImageBlend.h.


Constructor & Destructor Documentation

vtkImageBlend::vtkImageBlend (  )  [protected]

vtkImageBlend::~vtkImageBlend (  )  [protected]


Member Function Documentation

static vtkImageBlend* vtkImageBlend::New (  )  [static]

Create an object with Debug turned off, modified time initialized to zero, and reference counting on.

Reimplemented from vtkAlgorithm.

virtual const char* vtkImageBlend::GetClassName (  )  [virtual]

Reimplemented from vtkThreadedImageAlgorithm.

static int vtkImageBlend::IsTypeOf ( const char *  name  )  [static]

Return 1 if this class type is the same type of (or a subclass of) the named class. Returns 0 otherwise. This method works in combination with vtkTypeMacro found in vtkSetGet.h.

Reimplemented from vtkThreadedImageAlgorithm.

virtual int vtkImageBlend::IsA ( const char *  name  )  [virtual]

Return 1 if this class is the same type of (or a subclass of) the named class. Returns 0 otherwise. This method works in combination with vtkTypeMacro found in vtkSetGet.h.

Reimplemented from vtkThreadedImageAlgorithm.

static vtkImageBlend* vtkImageBlend::SafeDownCast ( vtkObject o  )  [static]

Reimplemented from vtkThreadedImageAlgorithm.

void vtkImageBlend::PrintSelf ( ostream &  os,
vtkIndent  indent 
) [virtual]

Methods invoked by print to print information about the object including superclasses. Typically not called by the user (use Print() instead) but used in the hierarchical print process to combine the output of several classes.

Reimplemented from vtkThreadedImageAlgorithm.

virtual void vtkImageBlend::ReplaceNthInputConnection ( int  idx,
vtkAlgorithmOutput input 
) [virtual]

Replace one of the input connections with a new input. You can only replace input connections that you previously created with AddInputConnection() or, in the case of the first input, with SetInputConnection().

void vtkImageBlend::SetInput ( int  num,
vtkDataObject input 
)

Set an Input of this filter. This method is only for support of old-style pipeline connections. When writing new code you should use SetInputConnection(), AddInputConnection(), and ReplaceNthInputConnection() instead.

Reimplemented from vtkImageAlgorithm.

void vtkImageBlend::SetInput ( vtkDataObject input  )  [inline]

Set an Input of this filter. This method is only for support of old-style pipeline connections. When writing new code you should use SetInputConnection(), AddInputConnection(), and ReplaceNthInputConnection() instead.

Reimplemented from vtkImageAlgorithm.

Definition at line 106 of file vtkImageBlend.h.

vtkDataObject* vtkImageBlend::GetInput ( int  num  ) 

Get one input to this filter. This method is only for support of old-style pipeline connections. When writing new code you should use vtkAlgorithm::GetInputConnection(0, num).

Reimplemented from vtkImageAlgorithm.

vtkDataObject* vtkImageBlend::GetInput (  )  [inline]

Get one input to this filter. This method is only for support of old-style pipeline connections. When writing new code you should use vtkAlgorithm::GetInputConnection(0, num).

Reimplemented from vtkImageAlgorithm.

Definition at line 114 of file vtkImageBlend.h.

int vtkImageBlend::GetNumberOfInputs (  )  [inline]

Get the number of inputs to this filter. This method is only for support of old-style pipeline connections. When writing new code you should use vtkAlgorithm::GetNumberOfInputConnections(0).

Definition at line 120 of file vtkImageBlend.h.

void vtkImageBlend::SetOpacity ( int  idx,
double  opacity 
)

Set the opacity of an input image: the alpha values of the image are multiplied by the opacity. The opacity of image idx=0 is ignored.

double vtkImageBlend::GetOpacity ( int  idx  ) 

Set the opacity of an input image: the alpha values of the image are multiplied by the opacity. The opacity of image idx=0 is ignored.

void vtkImageBlend::SetStencil ( vtkImageStencilData stencil  ) 

Set a stencil to apply when blending the data.

vtkImageStencilData* vtkImageBlend::GetStencil (  ) 

Set a stencil to apply when blending the data.

virtual void vtkImageBlend::SetBlendMode ( int   )  [virtual]

Set the blend mode

virtual int vtkImageBlend::GetBlendMode (  )  [virtual]

Set the blend mode

void vtkImageBlend::SetBlendModeToNormal (  )  [inline]

Set the blend mode

Definition at line 141 of file vtkImageBlend.h.

void vtkImageBlend::SetBlendModeToCompound (  )  [inline]

Set the blend mode

Definition at line 143 of file vtkImageBlend.h.

const char * vtkImageBlend::GetBlendModeAsString ( void   )  [inline]

Get the blending mode as a descriptive string

Definition at line 193 of file vtkImageBlend.h.

virtual void vtkImageBlend::SetCompoundThreshold ( double   )  [virtual]

Specify a threshold in compound mode. Pixels with opacity*alpha less or equal the threshold are ignored.

virtual double vtkImageBlend::GetCompoundThreshold (  )  [virtual]

Specify a threshold in compound mode. Pixels with opacity*alpha less or equal the threshold are ignored.

virtual int vtkImageBlend::RequestUpdateExtent ( vtkInformation ,
vtkInformationVector **  ,
vtkInformationVector  
) [protected, virtual]

Reimplemented from vtkImageAlgorithm.

void vtkImageBlend::InternalComputeInputUpdateExtent ( int  inExt[6],
int  outExt[6],
int  inWExtent[6] 
) [protected]

void vtkImageBlend::ThreadedRequestData ( vtkInformation request,
vtkInformationVector **  inputVector,
vtkInformationVector outputVector,
vtkImageData ***  inData,
vtkImageData **  outData,
int  extent[6],
int  threadId 
) [protected, virtual]

If the subclass does not define an Execute method, then the task will be broken up, multiple threads will be spawned, and each thread will call this method. It is public so that the thread functions can call this method.

Reimplemented from vtkThreadedImageAlgorithm.

virtual int vtkImageBlend::FillInputPortInformation ( int  port,
vtkInformation info 
) [protected, virtual]

Fill the input port information objects for this algorithm. This is invoked by the first call to GetInputPortInformation for each port so subclasses can specify what they can handle.

Reimplemented from vtkImageAlgorithm.

virtual int vtkImageBlend::RequestData ( vtkInformation request,
vtkInformationVector **  inputVector,
vtkInformationVector outputVector 
) [protected, virtual]

This is called by the superclass. This is the method you should override.

Reimplemented from vtkThreadedImageAlgorithm.


Member Data Documentation

double* vtkImageBlend::Opacity [protected]

Definition at line 180 of file vtkImageBlend.h.

Definition at line 181 of file vtkImageBlend.h.

int vtkImageBlend::BlendMode [protected]

Definition at line 182 of file vtkImageBlend.h.

Definition at line 183 of file vtkImageBlend.h.

Definition at line 184 of file vtkImageBlend.h.


The documentation for this class was generated from the following file:

Generated on Wed Aug 24 11:40:19 2011 for VTK by  doxygen 1.5.6