cinder::ChannelT< T >::Iter Class Reference

Convenience class for iterating the pixels of a Channel. More...

#include <Channel.h>

List of all members.

Public Member Functions

 Iter (ChannelT< T > &channelT, const Area &area)
T & v () const
 Returns a reference to the value of the pixel that the Iter currently points to.
T & v (int32_t xOff, int32_t yOff) const
 Returns a reference to the value of the pixel that the Iter currently points to, offset by (xOff, yOff) pixels.
T & vClamped (int32_t xOff, int32_t yOff) const
 Returns a reference to the value of the pixel that the Iter currently points to, offset by (xOff, yOff) pixels. Clamps offset to the bounds of the Iter.
const int32_t x () const
 Returns the x coordinate of the pixel the Iter currently points to.
const int32_t y () const
 Returns the y coordinate of the pixel the Iter currently points to.
Vec2i getPos () const
 Returns the coordinate of the pixel the Iter currently points to.
bool pixel ()
 Increments which pixel of the current row the Iter points to, and returns false when no pixels remain in the current row.
bool line ()
 Increments which row the Iter points to, and returns false when no rows remain in the Channel.
int32_t getWidth ()
 Returns the width of the Area the Iter iterates.
int32_t getHeight ()
 Returns the height of the Area the Iter iterates.

Detailed Description

template<typename T>
class cinder::ChannelT< T >::Iter

Convenience class for iterating the pixels of a Channel.

The Iter class can be used to walk the pixels of a Channel using a nested for-loop, where the outer loop calls line(), and the inner calls pixel().
The code below implements an invert on the Area area of channel:

Channel::Iter iter = channel.getIter( area );
while( iter.line() ) {
    while( iter.pixel() ) {
        iter.v() = 255 - iter.v();
    }
}

In addition to v(), the Iter provides an accessor which accepts an offset in x & y relative to the current location:

inputIter.v(1, 1); // will return the value of the pixel to the lower right of the current pixel
inputIter.v(0, -1); // will return the value of the pixel directly above the current pixel

A final accessor, vClamped() also accepts an x & y relative offset, but will not sample outside of the bounds of the iterator.

inputIter.vClamped(-2,0); // when called on the left edge of a row,
                          // this will simply return the left-most pixel's value
See also:
Images in Cinder

Constructor & Destructor Documentation

template<typename T>
cinder::ChannelT< T >::Iter::Iter ( ChannelT< T > &  channelT,
const Area area 
)

Member Function Documentation

template<typename T>
T& cinder::ChannelT< T >::Iter::v (  ) const

Returns a reference to the value of the pixel that the Iter currently points to.

template<typename T>
T& cinder::ChannelT< T >::Iter::v ( int32_t  xOff,
int32_t  yOff 
) const

Returns a reference to the value of the pixel that the Iter currently points to, offset by (xOff, yOff) pixels.

template<typename T>
T& cinder::ChannelT< T >::Iter::vClamped ( int32_t  xOff,
int32_t  yOff 
) const

Returns a reference to the value of the pixel that the Iter currently points to, offset by (xOff, yOff) pixels. Clamps offset to the bounds of the Iter.

template<typename T>
const int32_t cinder::ChannelT< T >::Iter::x (  ) const

Returns the x coordinate of the pixel the Iter currently points to.

template<typename T>
const int32_t cinder::ChannelT< T >::Iter::y (  ) const

Returns the y coordinate of the pixel the Iter currently points to.

template<typename T>
Vec2i cinder::ChannelT< T >::Iter::getPos (  ) const

Returns the coordinate of the pixel the Iter currently points to.

template<typename T>
bool cinder::ChannelT< T >::Iter::pixel (  )

Increments which pixel of the current row the Iter points to, and returns false when no pixels remain in the current row.

template<typename T>
bool cinder::ChannelT< T >::Iter::line (  )

Increments which row the Iter points to, and returns false when no rows remain in the Channel.

template<typename T>
int32_t cinder::ChannelT< T >::Iter::getWidth (  )

Returns the width of the Area the Iter iterates.

template<typename T>
int32_t cinder::ChannelT< T >::Iter::getHeight (  )

Returns the height of the Area the Iter iterates.


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