Also Known As: PIX
| Type | Bitmap |
| Colors | Up to 16 |
| Compression | Proprietary, documented |
| Maximum Image Size | 64Kx64K pixels |
| Multiple Images Per File | No |
| Numerical Format | Little-endian |
| Originator | Inset Systems |
| Platform | MS-DOS |
| Supporting Applications | InSet Versions 1 and 2, HiJaak, WordStar, Multimate |
| See Also | None |
Usage
Neutral common format for Inset Systems' products. Also used for graphics storage by the WordStar and Multimate word processors.
Comments
A great little format marred by lack of support for more than 16 colors. It would be a good model for a deep-pixel format, however.
Vendor specifications are available for this format.
Sample images are available for this format.
Inset PIX is an intermediate graphic format created by Inset Systems (now part of Quarterdeck), which sells the InSet and HiJaak applications for use on Intel-based PCs. HiJaak is a widely used and highly regarded screen-capture and graphics file conversion utility. Version 2 of the package supports the graphics, printer, and FAX formats listed below:
| ASCII | Inset IGF |
| AT&T Group 4 | Kofax Group 4 |
| AutoCAD DXF | Lotus Picture |
| CALS raster | Macintosh Paint |
| CGM | Macintosh PICT |
| GIF | MathCAD |
| DataBeam DBX | Microsoft Paint |
| Dr. Halo | Microsoft Windows Bitmap |
| Encapsulated PostScript | Microsoft Windows Metafile |
| FAX formats (various) | PCX |
| GEM raster | Presentation Manager Metafile |
| GEM VDI | Tektronix P10 |
| HPPCL | TGA |
| HPGL | TIFF |
| ILBM | WordPerfect Graphics Metafile |
| Inset PIX |
Contents:
File Organization
File Details
For Further Information
As you might imagine, Inset has a great deal of experience with graphics file formats. The design of PIX reflects this experience, and is a well thought-out and flexible format. If you need to convert a file from an odd format to one on the above list, you might consider converting to PIX as an intermediate step and then using the application to do the rest. (And, no, we don't have any financial or personal interest in Inset Systems or Quarterdeck!)
PIX was designed as an extensible, device-independent format which would allow random access of portions of a compressed image. Although nominally a bitmap format, the file structure supports the future addition of other data types.
Inset documentation describes a PIX file as, "an indexed database of data items." A table of the size and location of data items is included in the beginning of each file. Data items can include information on the following:
This section describes the header, index table, and different types of image data in a PIX file.
PIX files always have a short header:
typedef struct _PIX_HEADER
{
WORD RevisionLevel; /* Currently 3 */
WORD DataItemsInTable; /* Number of data items in the index table */
} PIX_HEADER;
RevisionLevel is the version number for the format; this level is currently 3.
DataItemsInTable is the number of items in the PIX file's index table, described in the next section.
Following the header is an index table containing an array of data item information structures of the following form:
typedef struct DATA_ITEM_INFO
{
WORD DataID; /* Data item ID */
WORD DataLength; /* Length of data item */
LONG DataLocation; /* Location of data item in file */
} DATA_ITEM_INFO;
DataID values may be any of the following:
| 00 | Image information |
| 11 | Printing options |
| 01 | Palette |
| 02 | Tile information |
Empty data items have DataID values of -1.
DataLength is the length of this item in the index table.
DataLocation is the location of the item in the file.
The following information is extracted from the specification document supplied by Inset Systems:
The application ID for the image structure is 0. This data item contains information on the overall image size, type, and origin of the image. The structure (in C) of this data item is:
struct mode_data
{
BYTE hmode;
BYTE htype;
BYTE cfore;
BYTE cback;
BYTE tattr;
BYTE tcpr;
BYTE trows;
BYTE thfnts;
BYTE tlfnts;
BYTE tcpf;
BYTE tfsize[4];
WORD gcols;
WORD grows;
BYTE gfore;
BYTE prepal;
BYTE lodpal;
BYTE lintens;
BYTE lred;
BYTE lgreen;
BYTE lblue;
BYTE pages;
BYTE haspect;
BYTE vaspect;
}
Following is a description of each member of this structure:
Hardware-specific mode. 0 if not specifically related to a particular hardware mode of a board.
Hardware type. Bit 0 is zero if alphanumeric and 1 if bitmap graphics. Board types are ORed into this byte. Board types include:
| 8 = CGA |
| 16 = Hercules |
| 24 = EGA |
Text foreground color bits (ignore if graphics) 4 for CGA
Text background color bits (ignore if graphics) 3 for CGA
Text characters per row (ignore if graphics)
Text rows (ignore if graphics)
Text hardware fonts (not used)
Text loadable fonts (not used)
Text characters per font (not used)
Font size (not used)
Graphics columns
Graphics rows
Graphics foreground color bits
Number of preset palettes (default to 0)
Number of loadable palettes
Number of palette bits for intensity
Number of palette bits for red
Number of palette bits for green
Number of palette bits for blue
Number of possible pages (not used)
Horizontal component of aspect ratio (number of horizontal pixels to fit in a square)
Vertical component of aspect ratio (number of vertical pixels to fit in a square)
A sample image structure for a 600-row-by-800-column single-bit plane image might be initialized as follows:
struct mode_data
{
BYTE hmode; /* 0 */
BYTE htype; /* 1 */
BYTE cfore; /* 0 */
BYTE cback; /* 0 */
BYTE tattr; /* 0 */
BYTE tcpr; /* 80 */
BYTE trows; /* 25 */
BYTE thfnts; /* 0 */
BYTE tlfnts; /* 0 */
BYTE tcpf; /* 0 */
WORD tfsize[4]; /* 0,0,0,0 */
WORD gcols; /* 800 */
WORD grows; /* 500 */
BYTE gfore; /* 1 */
BYTE prepal; /* 0 */
BYTE lodpal; /* 0 */
BYTE lintens; /* 1 */
BYTE lred; /* 0 */
BYTE lgreen; /* 0 */
BYTE lblue; /* 0 */
BYTE pages; /* 0 */
BYTE haspect; /* 1 */
BYTE vaspect; /* 1 */
}
The application ID for Inset Printing options is 11h. The C structure containing these items follows:
struct prt_options
{
SHORT pitch;
SHORT scol;
SHORT ecol;
SHORT srow;
SHORT erow;
SHORT p_wid;
SHORT siz;
SHORT rotat;
SHORT do_sw;
SHORT res_1;
SHORT res_2;
SHORT pcolor;
SHORT row_dp;
SHORT col_dp;
SHORT flags;
CHAR ink_tab[16];
}
Following is a description of each member of this structure:
Printer Pitch divided by 10 (e.g., 100 = 10 pitch); not required, set to 100
Start column clip boundary
End column clip boundary
Start row clip boundary
End row clip boundary
Printer width (not required, set to 0)
Size (not used, set to 0)
Rotation (0 = horizontal, -1 = left, 1=right)
Option bits ORed. Applicable bits to set include:
| Double Pass | = 2 |
| Letter Quality | = 4 |
| Border On | = 10 (hex) |
Internal use (don't use, set to 0)
Low-order byte indicates whether the image settings are intended for color printer (true = 1, false = 0)
High-order byte indicates which dither pattern type to use (0 = old, 1 = gray, 2 = contrast).
Height of image in decipoints (1/720 inches)
Width of image in decipoints (1/720 inches)
Modify flags
Size option bits:
| #define INDATA_USE_COL 0x1 |
| #define INDATA_USE_INCH 0x2 |
| #define INDATA_USE_DP 0x3 |
Modify ink selection:
| #define INDATA_INK_INV 0x8 |
| #define INDATA_INK_BW 0x10 |
| #define INDATA_INK_TAB 0x18 |
| #define INDATA_VDISK 0x20 |
| #define INDATA_VSIZE 0x40 |
| #define INDATA_DYNAMIC 0x80 |
Sixteen-byte table mapping screen colors to printer colors/gray patterns (see the MODIFY/INKS section of the Inset manual for more information on ink tables). If you want to select your own Ink table mapping, the flags variable must have a 0x18 OR'ed in. Preset Inset Ink tables are set as follows:
Color Number 0 1 2 3 4 5 6 7 8 9 A B C D E F Standard F 1 2 3 4 5 6 7 8 9 A B C D E 0 Invert 0 1 2 3 4 5 6 7 8 9 A B C D E F B&W F 0 0 0 0 0 0 0 F 0 0 0 0 0 0 0
Application ID = 1 contains display palette information. Palette information is stored in an array of palette structures of the following form:
struct pallette
{
CHAR intens, red, green, blue;
}
The number of significant palette items in the array is determined by the number of available colors (the "gfore" member in the image data structure) in the image. The significant bits are determined by the lintens lred, lgreen, and lblue items in the mode_data structure.
Application ID = 2 contains information as to how the image is broken down into tiles. The Tile_Data structure follows:
struct Tile_Data
{
WORD page_rows;
WORD page_cols;
WORD stp_rows;
WORD stp_cols;
}
Following is a description of each member of this structure:
| page_rows | Number of rows within each tile |
| page_cols | Number of columns in each tile (must be divisible by 8) |
| stp_rows | Number of horizontal tile strips within the image |
| stp_cols | Number of vertical tile strips |
Each tile is limited to a maximum of 4096 bytes of uncompressed data. The actual tiles are numbered starting with the upper left row as tile 0 and incremented from left to right as illustrated below.
0 |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
A |
B |
The ID of a tile is the tile number ORed with a 8000h. For example, the lower-right tile can be found by finding the record with ID=800Bh.
Images may be broken down into checkerboard sections or horizontal strips. However, if an image is broken into horizontal strips for processing, the image as rotated by Inset will be slowed.
Each individual pixel tile ID is determined by ORing in 8000h with the tile number, as described in the preceding section on tile information.
The image is organized into bit planes with eight pixels per byte; the most significant bit contains the leftmost pixel. For multiple-bit plane images, all scan lines for a plane are written out before the scan lines in the next plane.
If the actual column boundary of the tile exceeds the column boundary of the image, the image is padded with blank bytes to fill out the tile. If the actual row boundary of the tile exceeds that of the image, the extra rows are not present.
When the tile is stored on disk, it is in a vertically compressed format. The first scan line of each tile is written out with no modification. Then, before the following scan lines, there are compression bytes that indicate which bytes in the scan line are different from the preceding line. Each bit in the compression byte indicates whether a particular byte in that scan has changed (1 if changed, 0 if not). Then, following the compression bytes, only the modified scan bytes are written to the file.
For example, suppose we have a tile that is eight columns wide, the first scan line is all blank, and there is a dot at the beginning and end of the second scan line. This tile would be written to disk as follows:
00 00 00 00 00 00 00 00 <- First scan line 81 80 01 <- changed bytes ^ Compression Byte
In multiple-bit plane images, the first scan is uncompressed, and the following lines are compressed in the same manner as described above.
Alphanumeric images can be generally described as two-plane images with the first plane containing the alphanumeric character data and the second containing the attribute information. Alphanumeric characters are presumed to correspond to the IBM extended ASCII character set, with attribute information corresponding to the IBM CGA standard.
The character and text planes are compressed in the same manner as image bit planes with one caveat. The text scan-line length is twice what it should be (i.e., 160 bytes go out uncompressed for an 80-column screen).
For further information about Inset PIX, see the specification included on the CD-ROM. You can also contact:
Inset Systems
Developer Relations
71 Commerce Drive
Brookfield, CT 06804
Voice: 203-740-2400
Also see the Quarterdeck homepage:
http://www.insetusa.com/
Copyright © 1996, 1994 O'Reilly & Associates, Inc. All Rights Reserved.
