rasterfile(4)rasterfile(4)NAMErasterfile - Sun's file format for raster images
SYNOPSIS
#include <rasterfile.h>
DESCRIPTION
A rasterfile is composed of three parts: first, a header containing 8
integers; second, a (possibly empty) set of colormap values; and third,
the pixel image, stored a line at a time, in increasing y order. The
image is layed out in the file as in a memory pixrect. Each line of
the image is rounded up to the nearest 16 bits.
The header is defined by the following structure:
struct rasterfile {
int ras_magic;
int ras_width;
int ras_height;
int ras_depth;
int ras_length;
int ras_type;
int ras_maptype;
int ras_maplength;
};
The ras_magic field always contains the following constant:
#define RAS_MAGIC 0x59a66a95
The ras_width, ras_height, and ras_depth fields contain the image's
width and height in pixels, and its depth in bits per pixel, respec‐
tively. The depth is either 1 or 8, corresponding to standard frame
buffer depths. The ras_length field contains the length in bytes of
the image data. For an unencoded image, this number is computable from
the ras_width, ras_height, and ras_depth fields, but for an encoded
image it must be explicitly stored in order to be available without
decoding the image itself. Note: the length of the header and of the
(possibly empty) colormap values are not included in the value of the
ras_length field; it is only the image data length. For historical
reasons, files of type RT_OLD will usually have a 0 in the ras_length
field, and software expecting to encounter such files should be pre‐
pared to compute the actual image data length if needed. The ras_map‐
type and ras_maplength fields contain the type and length in bytes of
the colormap values, respectively. If ras_maptype is not RMT_NONE and
the ras_maplength is not 0, then the colormap values are the
ras_maplength bytes immediately after the header. These values are
either uninterpreted bytes (usually with the ras_maptype set to
RMT_RAW) or the equal length red, green and blue vectors, in that order
(when the ras_maptype is RMT_EQUAL_RGB). In the latter case, the
ras_maplength must be three times the size in bytes of any one of the
vectors.
29 March 1994 rasterfile(4)
