CustomProcess

CustomProcess_GetRow Function

Applies To: Implementing a custom process

Processes and returns one row of pixels.

This function takes in a row index and requests an input row using the callback function getRowfn and returns an output buffer containing a row of processed pixels. The size of the output row has to match the information communicated by the rasterInfo object provided in CustomProcess_Initialize and the parameters provided in CustomProcess_SetWindow.

[C++]

CustomProcess_API const unsigned char* __stdcall CustomProcess_GetRow(

void* clientHandle, unsigned long rowIndex);

Arguments

[in] clientHandle

Unique ID used to identify the caller.

[in] rowIndex

Index of the row being requested. (Usually in the range [startRow, endRow))

Return Value

A row of processed pixels as an array of unsigned characters.

Reporting errors and warnings: Any errors can be obtained by calling the GetLastError function which will give out the error message for the last error in the SLL.

Example

The following example represents a partial C++ implementation of this function:

[C++]

CustomProcess_API const unsigned char* __stdcall CustomProcess_GetRow(void* clientHandle,

unsigned long rowIndex)

{

ClientHandle* myClientHandle = (ClientHandle*)clientHandle;

unsigned char* myInputBuffer = (unsigned char*)myClientHandle->myGetRowfn(

myClientHandle->myCallbackObject, rowIndex);

unsigned long i = 0;

for (;i < myClientHandle->bufferSize; ++i)

{

value = myInputBuffer[i] + 10;

forceBounds(0, value, 255);

myClientHandle->myOutputBuffer[i] = (unsigned char)value;

}

return myClientHandle->myOutputBuffer;

}

For a detailed example on how to implement this function, see Sample custom process.