Data-Loading Functions(IM:Q)

Chapter 3 - Image Compression Manager / Image Compression Manager Reference

Data-Loading Functions
Compressors use the data-loading and data-unloading functions when working with images that do not fit into memory. The data-loading function supplies compressed data during a decompression operation.
The DataProcPtr data type defines a pointer to a data-loading function. You assign a data-loading function to an image or a sequence by passing a pointer to a structure that identifies the function to the appropriate decompress function.
/* data-loading function structure */
typedef struct DataProcRecord DataProcRecord;
typedef DataProcRecord *DataProcRecordPtr;
The data-loading function structure contains the following fields:
struct DataProcRecord 
{
   DataProcPtr dataProc;   /* pointer to data-loading function */
   long        dataRefCon; /* reference constant */
};
Field Description

dataProc
Contains a pointer to your data-loading function.
dataRefCon
Contains a reference constant for use by your data-loading function.

DESCRIPTION
If your data-loading function returns a nonzero result code, the Image Compression Manager terminates the current operation.

Subtopics
DESCRIPTION

MyDataLoadingProc