dmFXGetDataPtr(3dm)

NAME
     dmFXGetDataPtr, dmFXGetRowLength - return a pointer to the pixels stored
     in a DMfxbuffer


SYNOPSIS
     #include <dmedia/fx_buffer.h>

     void* dmFXGetDataPtr
           ( DMfxbuffer* fxbuffer )

     int dmFXGetRowLength
           ( DMfxbuffer* fxbuffer )


PARAMETERS
     fxbuffer   A buffer that was created with dmFXAllocateImageBuffers.


DESCRIPTION
     These functions are used to access the pixels stored in a DMfxbuffer.
     Before calling them, you must first set up the buffer.  To read pixels
     from the buffer, call dmFXSetupInputImageBufferWithUsage, and specify
     bufInputDirect.  To write pixels into a buffer, call
     dmFXSetupOutputImageBuffer and specify bufOutputDirect.


     After the buffer has been set up for input or output access,
     dmFXGetDataPtr will return a pointer to the first pixel in the buffer,
     the one at the upper-left corner of the image.


     When DMfxbuffers are allocated, they may be bigger than necessary to hold
     the requested images.  dmFXGetRowLength will return the number of pixels
     to skip to get from the beginning of one row to the beginning of the
     next.


     If the buffer has not been set up correctly for direct access,
     dmFXGetDataPtr will return NULL and dmFXGetRowLength will return 0.


     Under normal circumstances, dmFXGetRowLength will return the width of the
     buffer, as requested when it was created.  Applications that use
     DMfxbuffers can count on this.  It can be useful, when debugging plugins,
     to create buffers that have a larger internal width.  If you are using
     the debug version of libfxplugutils, setting the environment variable
     FX_STRANGE_ROWBYTES to YES will cause it to create buffers where the
     width of the storage area is greater than is needed.
SEE ALSO
     dmFXAllocateImageBuffers(3dm), dmFXSetupInputImageBuffer(3dm),
     dmFXSetupOutputImageBuffer(3dm), DMbuffer(4).