NAME

libfdpicio− fast disk picture encoding library

DESCRIPTION

libfdpicio is a library of C-callable functions for loading and unloading Fast-Disk picture files.  The following documentation exists for the picture encoding library routines:

FdPicCreat(3H) discusses the routines FdPicCreat, FdPicOpen, and FdPicFind for creating and opening Fast-Disk picture files. 

FdPicRead(3H) documents the FdPicReadBuffer and FdPicWriteBuffer routines for communications between Fast-Disk picture tiles on disk and RGBA arrays in a program. 

FdPicClose(3H) documents the FdPicClose routine. 

Note the parallelism between the above routines and the creat, open, read, write, and close routines for normal files. 

FdPicDecode(3H) discusses the routines picPreDecodeScanline, picDecodeScanline, and picPostDecodeScanline, used for decoding individual scanlines of picture tiles on disk. These routines are provided as a more convenient alternative to the FdPicRead function. 

FdPicEncode(3H) discusses the routines picPreEncodeScanline, picEncodeScanline, and picPostEncodeScanline used for encoding individual scanlines of picture tiles on disk.  These routines are provided as a more convenient alternative to the FdPicWrite function. 

FdPicLabel(3H) discusses the routines FdPicLseekLabel, FdPicReadLabel, and FdPicWriteLabel, used for general reading and writing of arbitrary text information in the picture file.

The header file fdpicio.h includes all the picture file definitions needed for programs using fdpicio routines.  The file header addresses, specifying the position of the label, picture descriptor, and tile map, for example, are listed in this file.  User access to header information should be done through library routines; the addresses are convenient for visual decoding of an octal dump. 

The major structure upon which pictures are based is the PFILE picture descriptor, defined in picio.h.  Each picture file on disk contains a picture descriptor in its header; each picture file referred to in a program is accessed via a pointer to a PFILE held in memory.  User access to this structure is normally handled via library routines; occasional reading of individual fields is best handled directly. 

The currently stored fields of a PFILE are the height and width of the picture, the height and width of the tiles, the picture’s format, storage, blocksize, and matting indicator, and the x-y offsets of the picture.  PFILEs for open picture files include an open file number. 

The picture height (Pheight) and width (Pwidth) are the height and width of the picture in pixels.  The tile height (Theight) and width (Twidth) are the height and width of the tiles in pixels.

Fast-Disk pictures have the following dimensional restrictions: 1) the pictures’ width, height, tile width and tile height must all be multiples of 32 pixels, 2) any picture offset must also be a multiple of 32 pixels, 3) no encoding is performed so pictures must be in “dump” mode, and 4) only four-channel pictures are supported (i.e., PF_RGBA). 

The picture format (Pformat) is a short that contains PF_RGBA as defined in picio.h.  The picture storage (Pstorage) indicates whether the stored file is 8 or 12 bits, encoded or dumped.  Appropriate macros (PF_8BIT, etc.) are included.  Pictures are blocked to speed their recovery; the blocksize (Pblocksize) is tuned to the machine upon which the picture file was created (1024 on a VAX). 

The x-y offsets (Xoffset, Yoffset) indicate how many pixels to translate the upper left corner of the picture from the standard upper left corner origin of the frame buffer.

Further macros listed in picio.h aid in computing the number of tiles (PM_NTILES(pdptr)) and number of components (PM_NOFC(pdptr)) of a picture. 

LIBRARY

/usr/pixar/hsi/host/lib/libfdpicio.a

SEE ALSO

intro(1)− list of shell-callable Pixar programs
intro(3C)− list of libraries of device-resident routines
intro(3H)− list of libraries of host-resident routines

FdPicClose(3H), FdPicCreat(3H), FdPicLabel(3H), FdPicRead(3H), PicDecode(3H), PicEncode(3H). 

LIST OF FUNCTIONS

NameAppears on PageDescription
FdPicCloseFdPicClose(3H)− close a picture file
FdPicCreatFdPicCreat(3H)− create/open a picture file
FdPicFindFdPicCreat(3H)− open a picture file, searching for it using PIXPATH
FdPicGetFrameFdPicFrame(3H)− get pictures from frame buffer to picture file
FdPicLseekLabelFdPicLabel(3H)− determine the length of a picture label
FdPicOpenFdPicCreat(3H)− open a picture file
FdPicPutFrame FdPicFrame(3H)− put pictures from picture file into frame buffer
FdPicReadBufferFdPicRead(3H)− read a picture tile
FdPicReadLabelFdPicLabel(3H)− read a picture label
FdPicSetForceFdPicCreat(3H)− force a picture-file overwrite
FdPicSetLabelFdPicCreat(3H)− label a picture
FdPicSetOffsetFdPicCreat(3H)− set a picture’s offset
FdPicSetPformatFdPicCreat(3H)− set format of a picture
FdPicSetPmattingFdPicCreat(3H)− set a picture matting indicator
FdPicSetPsizeFdPicCreat(3H)− set size of a picture
FdPicSetPstorageFdPicCreat(3H)− set a picture storage flag
FdPicSetTsizeFdPicCreat(3H)− set tile size of a picture
FdPicWriteBufferFdPicRead(3H)− write a picture tile
FdPicWriteLabelFdPicLabel(3H)− write a picture label
picDecodeScanlineFdPicDecode(3H)− decode a picture scan line
picEncodeScanlineFdPicEncode(3H)− encode a picture scan line
picPostDecodeScanlineFdPicDecode(3H)− finish decoding a picture tile
picPostEncodeScanlineFdPicEncode(3C)− finish encoding a picture tile
picPreDecodeScanlineFdPicDecode(3C)− start decoding a picture tile
picPreEncodeScanlineFdPicEncode(3C)− start encoding a picture tile

Release β  —  Last change: 3/30/89