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6.3 The 8-Bit Raster Image Interface

The HDF library contains routines for reading and writing 8-bit raster image sets. The functions DFR8addimage, DFR8putimage and DFR8getimage are sufficient for most reading and writing operations.

6.3.1 8-Bit Raster Image Library Routines

The names of all C functions in the 8-bit raster image interface are prefaced by "DFR8" and the names of the equivalent Fortran-77 functions are prefaced by "d8". These routines are divided into the following categories:

The DFR8 function calls are further defined in Table 6B and in the HDF Reference Guide.

TABLE 6B DFR8 Library Routines
Category

Routine Name

Description

C

Fortran-77

Write

DFR8writeref

d8wref

Stores the raster image using the specified reference number.

DFR8setpalette

d8spal

Sets palette for multiple 8-bit raster images.

DFR8addimage

d8aimg

Appends an 8-bit raster image to a file.

DFR8putimage

d8pimg

Writes an 8-bit raster image to an existing file or creates the file.

DFR8setcompress

d8setcomp

Sets the compression type.

None

d8sjpeg

Passes the quality and compatibility factors needed for the JPEG compression algorithm.

Read

DFR8getdims

d8gdims

Retrieves dimensions for an 8-bit raster image.

DFR8getimage

d8gimg

Retrieves an 8-bit raster image and its palette.

DFR8readref

d8rref

Gets the next raster image with the specified reference number.

DFR8restart

d8first

Ignores information about last file accessed and restarts from beginning.

DFR8nimages

d8nims

Returns number of raster images in a file.

DFR8lastref

d8lref

Returns reference number of the last element accessed.

DFR8getpalref

None

Returns the reference number of the palette associated with the last image accessed.



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HDF User's Guide - 06/04/97, NCSA HDF Development Group.