Instruction manual

0 and specify the X/Y dimension of each image buffer allocated by the user.

Then el_NewMemBuffer does not allocate image memory it uses the supplied image buffers. The size of

the current acquisition window is adapted to the supplied SizeX/SizeY values to make the image data fit

into the supplied memory buffers.

FrameCount specifies the number of buffers in a sequence. If FrameCount is 0/1 only a single buffer is

used for image acquisition.

Pitch specifies the offset between the start locations of two following lines in an image. Pitch must supply

the value (horizontal X dimension) used to allocate the image memory buffer. With user defined image

buffers the Pitch is fixed to the specified value, e.g. a call to el_SetAcqWindow will not change the Pitch.

The image buffer pointers supplied with MemStart are returned by el_InitHW for compatibility reasons.

Identification of Image Memory Buffers:

If new memory buffers should be created by el_NewMemBuffer or if new user defined memory buffers are

passed to el_NewMemBuffer the pointer used as parameter 'BuffNo' has to point to a long value initialised

with 0. Then a new buffer or sequence is added and the identifier of the new buffer is placed in *BuffNo. If

the pointer used for'BuffNo" points not to a 0 value the value is interpreted as a buffer handle and the

function tries to switch to the specified buffer sequence. In this case no new buffer sequence is created.

For a discussion of sequences used as swing buffers see Sequences

CAVEATS: When the function is called a new buffer or sequence is created depending on the parameters

of the function. Single buffers and sequences can be freed by the function el_FreeMemBuffer .

User defined image memory

To use user defined image memory together with el_NewMemBuffer() some conditions have to

mentioned:

If image memory is allocated with malloc() or with user specific allocation routines (on HiPerCam1

0x20000) the start address of each image buffer passed to el_NewMemBuffer must be page aligned

otherwise el_NewMemBuffer will return with error.

Windows only:

To request page aligned memory, please use one of the following methods:

The function VirtualAlloc() reserves or commits a region of memory in the virtual address space of your

application. Memory allocated with VirtualAlloc() can not be exported to other applications.

To use memory mapped files as shared memory for multiple applications use the functions

CreateFileMapping() and MapViewOfFiles(). For detailed information please refer to the function

description within the Windows SDK. Allocating Image Memory