Paint Shop Pro (PSP)
File Format Specification
November, 1998
Paint Shop Pro (PSP) File Format Version 3.0
Paint Shop Pro Application Version 5.0
File Format Documentation Version 3.0
Copyright © 1998 Jasc Software, Inc..
All rights reserved.
By downloading and / or using these Specifications, user certifies that they have read and agreed to the following disclaimers and warranties.
The Paint Shop Pro File Format Specification (the “Specification”) is copyright 1998 by Jasc Software, Inc. Jasc grants you a nonexclusive license to use the Specification for the sole purposes of developing software products(s) incorporating the Specification. You are also granted the right to identify your software product(s) as incorporating the Paint Shop Pro Format (PSP) provided that your software in incorporating the Specification complies with the terms, definitions, constraints and specifications contained in the Specification and subject to the following:
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Table of Contents
Format Overview
4 Common Structures and Definitions
4.1 Parlance
4.2 Type Definitions
4.3 Limiting Field Values
4.4 Block Header
4.5 Color Palette Sub-Block
4.6 Channel Sub-Block and channel compression
5 Paint Shop Pro (PSP) File Format Description
5.1 Constraints
5.1.1 Main Block Ordering
5.1.2 One Paletted Layer
5.2 PSP File Header
5.3 The General Image Attributes Block
5.4 The Extended Data Block
5.5 The Tube Data Block
5.6 The Creator Data Block
5.7 The Thumbnail Block
5.8 The Color Palette Block
5.9 The Layer Bank Block
5.10 The Selection Block
5.11 The Alpha Bank Block
|
Date |
Author |
Description |
|
April 20, 1998 |
JMS |
Initial draft, submitted for review. |
|
April 23, 1998 |
JMS |
Minor changes. |
|
April 29, 1998 |
JMS |
Minor changes (changed Layer flags, Layer transparency flags to Boolean Layer visible flag and Transparency protected flag). |
|
August 7, 1998 |
JMS |
Made additions for storing Picture Tube control information in PSP files. |
|
November 16,1998 |
JCO |
Added additional Copyright information, release notes, disclaimers, comments, and cleaned for public release. |
|
November 23, 1998 |
JMS |
Added restrictions for readers and writers. Changes based on latest review. |
|
November 30, 1998 |
JCO |
Restrictions clarified Requests email address added. |
|
December 1, 1998 |
JMS |
Added descriptions of compression types. Added descriptions of non-color channels. |
The Paint Shop Pro (PSP) file format is an extremely rich graphics file format that is capable of describing a multi-layered image document in minute detail. The format facilitates the retention of a great deal of information, including layer bitmaps, layer masks, layer grouping information, a sample thumbnail, image dimension, image resolution, creator name, copyright owner, image description, masks, selections, alpha channels, etc.
The PSP format supports storing an image document in an uncompressed format or, to reduce the size of the file, in either Run Length Encoding (RLE) or LZ77 compressed format. As each of these is a lossless storage method, the PSP format always maintains the original quality of stored image documents.
Finally, the PSP format supports storing image bitmaps at a variety of bit depths, including 24 bit color (16.7 million colors), 8 bit color (256 color), 8 bit greyscale (256 greys), 4 bit color (16 colors) and 1 bit color (2 colors).
When developing an image document in Paint Shop Pro 5, the full-service graphics editing tool from Jasc Software, Inc, the PSP file format is the format of choice because an image document can be maintained in its entirety (saving image documents to less versatile formats results in loss of some image document data).
NOTICE: This document describes the PSP file format, not necessarily the technology or code required to fully read, interpret, or display all aspects of the data that may be contained within the file.
For more information about Jasc Software, Inc, Paint Shop Pro or the PSP file format, please visit the Jasc Software web site and the Paint Shop Pro newsgroup (both listed below). The latest published version of this document is available at the Jasc Software web site. If you have any questions or comments about this document or about the PSP file format, please send them to the Jasc Software PSP File Format email address, listed below.
The Jasc Software web site:
The Paint Shop Pro newsgroup:
comp.graphics.apps.paint-shop-pro
The Jasc Software PSP File Format email address:
PSPFileFormat@jasc.com
The Paint Shop Pro (PSP) file format is a block-oriented format that consists of a file header with a sequence of up to nine main blocks. The nine main blocks are the General Image Attributes Block, the Extended Data Block (optional), the Creator Data Block (optional), the Thumbnail Block (optional), the Color Palette Block (for paletted images), the Layer Bank Block, the Selection Block (optional) and the Alpha Channel Bank Block (optional). Each of these main blocks contains information about the image document and some of these blocks contain sub-blocks. See subsequent sections of this document for more detailed information about each of these main blocks.
The following table contains a high-level view of the PSP file format that includes only the header and the top-level blocks.
|
File Header |
|
General Image Attributes Block |
|
Extended Data Block (optional) |
|
Tube Data Block (optional) |
|
Creator Data Block (optional) |
|
Thumbnail Block (optional) |
|
Color Palette Block (paletted image documents only) |
|
Layer Bank Block |
|
Selection Block (optional) |
|
Alpha Bank Block (optional) |
Table 1 : PSP Format Overview
Restrictions for PSP format readers:
PSP format readers must be able to read and successfully process the PSP File Header, the General Image Attributes Block, the Color Palette Block (if present) and the Layer Bank Block. PSP readers may ignore all other main blocks.
If a PSP reader encounters any unrecognized block (whether documented or not), the reader must ignore (skip over) that block and continue processing the rest of the file.
Restrictions for PSP format writers (Format Version 3.0):
PSP format writers must write the PSP File Header, the General Image Attributes Block, the Color Palette Block (if appropriate) and the Layers Bank Block exactly as described in this specification. Additionally, PSP format writers may write the other blocks described in this document when necessary.
PSP format writers must not write any blocks that are not documented in this specification, or otherwise stray from this specification. Additional block types or specification changes may only be created by Jasc Software. Requests for additional block types and other file format enhancements can be sent to PSPFileFormat@jasc.com.
Color data of multi-layer image documents must be stored in either 24-bit truecolor format, or in 8-bit greyscale format.
Color data of single-layer image documents can be stored in 1, 4 or 8-bit paletted format, in 24-bit truecolor format, or in 8-bit greyscale format.
PSP format writers must not write an image document with more than 64 layers.
This section contains information concerning structures and definitions that are used throughout the remainder of this document. They are presented here to give the user a hint as to what to expect in subsequent sections of the document, and to provide references that can be used in subsequent sections of the document to avoid too much repetition (though repetition is used when it provides needed clarification).
With any documentation, it is important to ensure that the author and the audience have a common parlance. With that in mind, the following glossary describes the usage, throughout this document, of various words that otherwise might be ambiguous.
|
Word |
Definition/Usage |
|
Block |
As described above, the PSP format is a block-oriented format. The term “block” will be used to refer to a part of a PSP file that consists of a Block Header (see section 5.4) and all the data following the header that is associated with the header. Since the Block Header indicates the size of the block, it is quickly apparent how much of the data immediately following the block header is associated with it. |
|
Chunk |
The term chunk will be used to represent an “interesting” piece of data within a PSP file that does not have a block header. Throughout the document, there is a need to refer to a piece of data within a block that is not a sub-block. The term “chunk” is used in these cases. |
|
Main block |
The PSP file format is a hierarchical format, with some blocks that are fully contained within other blocks. A main block is any block in a PSP file that is not contained within another block. The main blocks are illustrated in the table in section 4. |
|
Sub-Block |
A sub-block is a block that is fully contained within another block. |
Table 2: Glossary of Terms
The following table contains definitions for simple data types used throughout this document. The PSP file format is always written in Intel® (or little-endian) byte order.
|
Type |
Description |
|
BYTE |
An 8-bit unsigned integer value. |
|
B_ARRAY |
An array of 8-bit unsigned integer values (i.e., an array of BYTE). The length of the array is either fixed, or can be determined from the discussion. |
|
C_ARRAY |
An array of 8-bit signed integer values (i.e., an array of char). The length of the array is either fixed, or can be determined from the discussion. |
|
double |
A 64-bit floating point value. |
|
DWORD |
A 32-bit unsigned integer value. |
|
long |
A 32-bit signed integer value. |
|
RECT |
An array of 4 longs that describe a rectangle (the first two longs are the x-coordinate and y-coordinate (respectively) of the upper-left corner of the rectangle, the third and fourth longs are the x-coordinate and y-coordinate (respectively) of the lower-right corner of the rectangle. |
|
RGBQUAD |
An array of 4 BYTEs representing a color palette entry, where the first BYTE is the entry’s red component, the second BYTE is the entry’s green component and the third BYTE is the entry’s blue component and the fourth BYTE is always 0 (reserved). |
|
WORD |
A 16-bit unsigned integer value. |
Table 3: Common type definitions
The following enumerations are used throughout the document to limit the allowed values of various fields.
As an example, the Block Identifier field in a Block Header is a DWORD, but, as detailed in the Block Identifier field description, the DWORD must be in the range covered by the enumeration PSPBlockID.
/* Block identifiers.
*/
enum PSPBlockID {
PSP_IMAGE_BLOCK = 0, // General Image Attributes Block (main)
PSP_CREATOR_BLOCK, // Creator Data Block (main)
PSP_COLOR_BLOCK, // Color Palette Block (main and sub)
PSP_LAYER_START_BLOCK, // Layer Bank Block (main)
PSP_LAYER_BLOCK, // Layer Block (sub)
PSP_CHANNEL_BLOCK, // Channel Block (sub)
PSP_SELECTION_BLOCK, // Selection Block (main)
PSP_ALPHA_BANK_BLOCK, // Alpha Bank Block (main)
PSP_ALPHA_CHANNEL_BLOCK,// Alpha Channel Block (sub)
PSP_THUMBNAIL_BLOCK, // Thumbnail Block (main)
PSP_EXTENDED_DATA_BLOCK,// Extended Data Block (main)
PSP_TUBE_BLOCK, // Picture Tube Data Block (main)
};
/* Bitmap type.
*/
enum PSPDIBType {
PSP_DIB_IMAGE = 0, // Layer color bitmap
PSP_DIB_TRANS_MASK, // Layer transparency mask bitmap
PSP_DIB_USER_MASK, // Layer user mask bitmap
PSP_DIB_SELECTION, // Selection mask bitmap
PSP_DIB_ALPHA_MASK, // Alpha channel mask bitmap
PSP_DIB_THUMBNAIL // Thumbnail bitmap
};
/* Channel types.
*/
enum PSPChannelType {
PSP_CHANNEL_COMPOSITE = 0, // Channel of single channel bitmap
PSP_CHANNEL_RED, // Red channel of 24 bit bitmap
PSP_CHANNEL_GREEN, // Green channel of 24 bit bitmap
PSP_CHANNEL_BLUE, // Blue channel of 24 bit bitmap
};
/* Possible metrics used to measure resolution.
*/
enum PSP_METRIC {
PSP_METRIC_UNDEFINED = 0, // Metric unknown
PSP_METRIC_INCH, // Resolution is in inches
PSP_METRIC_CM, // Resolution is in centimeters
};
/* Possible types of compression.
*/
enum PSPCompression {
PSP_COMP_NONE = 0, // No compression
PSP_COMP_RLE, // RLE compression
PSP_COMP_LZ77 // LZ77 compression
};
/* Picture tube placement mode.
*/
enum TubePlacementMode {
tpmRandom, // Place tube images in random intervals
tpmConstant, // Place tube images in constant intervals
};
/* Picture tube selection mode.
*/
enum TubeSelectionMode {
tsmRandom, // Randomly select the next image in
// tube to display
tsmIncremental, // Select each tube image in turn
tsmAngular, // Select image based on cursor direction
tsmPressure, // Select image based on pressure
// (from pressure-sensitive pad)
tsmVelocity, // Select image based on cursor speed
};
/* Extended data field types.
*/
enum PSPExtendedDataID {
PSP_XDATA_TRNS_INDEX = 0, // Transparency index field
};
/* Creator field types.
*/
enum PSPCreatorFieldID {
PSP_CRTR_FLD_TITLE = 0, // Image document title field
PSP_CRTR_FLD_CRT_DATE, // Creation date field
PSP_CRTR_FLD_MOD_DATE, // Modification date field
PSP_CRTR_FLD_ARTIST, // Artist name field
PSP_CRTR_FLD_CPYRGHT, // Copyright holder name field
PSP_CRTR_FLD_DESC, // Image document description field
PSP_CRTR_FLD_APP_ID, // Creating app id field
PSP_CRTR_FLD_APP_VER, // Creating app version field
};
/* Creator application identifiers.
*/
enum PSPCreatorAppID {
PSP_CREATOR_APP_UNKNOWN = 0, // Creator application unknown
PSP_CREATOR_APP_PAINT_SHOP_PRO, // Creator is Paint Shop Pro
};
/* Layer types.
*/
enum PSPLayerType {
PSP_LAYER_NORMAL = 0, // Normal layer
PSP_LAYER_FLOATING_SELECTION, // Floating selection layer
};
/* Truth values.
*/
enum PSP_BOOLEAN {
FALSE = 0,
TRUE,
};
The block structure utilized by the PSP file format is quite simple. Each main block consists of a block header that indicates size and type information for the block, followed by the block data. The content of the block data depends on the block’s type.
Moreover, the block structure used in the PSP format is hierarchical, so a block may consist of one or more sub-blocks. The sub-blocks take the same format as the main blocks (block header + block data).
As illustrated in the following table, the Block Header identifies the block’s type, the length of the first “interesting piece of data” and the total block length.
|
Type |
Length |
Name |
Description |
|
B_ARRAY |
4 bytes |
Header identifier |
Always “7E 42 4B 00” (i.e.,“~BK” followed by a zero byte). |
|
WORD |
2 bytes |
Block identifier |
Identifies the type of the block (one of PSPBlockID). |
|
DWORD |
4 bytes |
Initial data chunk length |
Length of first “interesting piece of data” (this “interesting piece of data” may be the header of a sub-block or simply a data chunk containing relevant information). |
|
DWORD |
4 bytes |
Total block length |
Total length of block (including all sub-blocks), not including the header. Use this length to skip past unknown or unwanted blocks. |
Table 3: Block Header
Color Palette Sub-Blocks are used throughout the PSP file format to store palettes associated with paletted bitmaps. For example, when the image document thumbnail is stored as a paletted bitmap, there is a Color Palette Sub-Block in the Thumbnail Block to store the thumbnail’s palette.
As illustrated in the following table, the Color Palette Sub-Block consists of a Color Palette Block Header, a Color Palette Information Chunk, and a Color Palette Entries Chunk.
Color Palette Block Header:
|
Type |
Length |
Name |
Description |
|
B_ARRAY |
4 bytes |
Header identifier |
Always "7E 42 4B 00" (i.e.,"~BK", followed by a zero byte). |
|
WORD |
2 bytes |
Block identifier |
Always PSP_COLOR_BLOCK. |
|
DWORD |
4 bytes |
Initial data chunk length |
Length of following Color Palette Information Chunk. |
|
DWORD |
4 bytes |
Total block length |
Length of complete Color Palette Sub-Block, including Color Palette Information Chunk and Color Palette Entries Chunk. |
Color Palette Information Chunk:
|
DWORD |
4 bytes |
Palette entry count |
Number of entries in the palette (for the purpose of determining the number of fields in the Color Palette Entries Chunk, let’s call this i). |
Color Palette Entries Chunk
|
RGBQUAD |
4 bytes |
Palette entry 1 |
The 1st palette entry. |
|
… |
… |
… |
… |
|
RGBQUAD |
4 bytes |
Palette entry i |
The ith palette entry |
Table 4: Color Palette Sub-Block
Channel Sub-Blocks are used throughout the PSP file format to store image document channel data. Each color channel is stored separately in the PSP format. For example, when the image document thumbnail is stored as an 24-bit bitmap, there are 3 Channel Sub-Blocks (a red Channel Sub-Block, a green Channel Sub-Block and a blue Channel Sub-Block ) in the Thumbnail Block. However, when the image document thumbnail is stored as a paletted bitmap, there will only be one Channel Sub-Block in the Thumbnail Block (because a paletted bitmap contains only one channel).
As illustrated in the table below, the Channel Sub-Block consists of a Channel Block Header, a Channel Information Chunk and a Channel Content Chunk.
A Word About Compression
All channel data in a PSP file can be stored compressed in the LZ77 format, compressed in the Run Length Encoding (RLE) format, or uncompressed (in a “raw” format). This channel data can include thumbnail color channels, layer color channels, layer transparency mask channels, layer user mask channels, alpha channels or selection channels.
The thumbnail color channels are stored in the compression format indicated in the “Thumbnail compression type” field of the “Thumbnail Attributes Chunk,” as described in section 5.7 of this document. All other channels are stored in the compression format indicated in the “Compression type” field of the “General Image Attributes Chunk,” as described in section 5.3 of this document.
The LZ77 compression scheme used in the PSP file format is the LZ77 variant used in the PNG file format. There are a couple of important distinctions between the way this LZ77 variant is utilized in the PNG file format and the way it is utilized in the PSP file format. First, the PNG file format requires that data be sent through one of several filters before it can be compressed, whereas the PSP file format has no such filter. Second, the PNG file format mandates support for a discontiguous compression stream, whereas the PSP file format allows only a contiguous compression stream.
The Run Length Encoding (RLE) scheme used in the PSP file format is a relatively straightforward RLE variant. RLE is a simple compression method that strives to take advantage of contiguous runs of the same data. In the variant used in the PSP file format, the first byte encountered in the compressed stream is a byte that represents a “run count”. While decompressing, if this run count is greater than 128, then 128 should be subtracted from the “run count.” This calculated run count (run count – 128) indicates the number of times the next byte in the compressed stream should be repeated in the decompressed stream. If the “run count” read from compressed stream is less than 128, then it indicates the number of following bytes (in the compressed stream) that should be copied as-is from the compressed stream to the decompressed stream. The compressed stream is comprised of these RLE “packets,” each containing a “run count” and data associated with that run count.
In all compression methods used in the PSP format, each channel is a single compression stream which, when decompressed, represents bitmap data stored from left to right and from top to bottom. Each scanline in the image data is stored on a 4 byte boundary.
All channels that represent something other than color (including layer transparency mask channels, layer user mask channels, alpha channels and selection channels), when decompressed, are 8-bit greyscale bitmaps.
Channel Block Header:
|
Type |
Length |
Name |
Description |
|
B_ARRAY |
4 bytes |
Header identifier |
Always “7E 42 4B 00” (i.e.,“~BK”, followed by a zero byte). |
|
WORD |
2 bytes |
Block identifier |
Always PSP_CHANNEL_BLOCK. |
|
DWORD |
4 bytes |
Initial data chunk length |
Length of following Channel Information Chunk. |
|
DWORD |
4 bytes |
Total block length |
Length of complete Color Palette Sub-Block, including Channel Information Chunk and Channel Content Chunk. |
Channel Information Chunk:
|
DWORD |
4 bytes |
Compressed channel length |
Size of the channel in compressed form (for the purpose of determining the length of the last field in this block, let’s call this size j). |
|
DWORD |
4 bytes |
Uncompressed channel length |
Size of the channel in uncompressed form. |
|
WORD |
2 bytes |
Bitmap type |
Type of bitmap for which this channel is intended (one of PSPDIBType). |
|
WORD |
2 bytes |
Channel type |
Type of channel (one of PSPChannelType). |
Channel Content Chunk:
|
B_ARRAY |
j bytes |
Channel content |
Content of channel. This field contains (possibly compressed) data that defines the channel. Other blocks define whether the channel is compressed, and define the size of the bitmap associated with this channel (height and width). |
Table 5: Channel Sub-Block
This section details the PSP file format.
This section describes miscellaneous constraints that writers of the PSP file format must follow.
With regard to the order of the nine main blocks, there are two hard and fast rules. First, the General Image Attributes block must come immediately after the File Header. Second, the Thumbnail Block, if present, must come before the Layer Bank Block.
The order of other blocks is not mandated. However, the order in which the main blocks are illustrated in Table 1 of section 4:Format Overview is the preferred order. This order allows programs to quickly obtain information about an image document (information such as bit depth, compression type, resolution, etc) without having to read layer information (such as color bitmap and mask data).
The color bitmaps of images contained in multi-layered image documents must be either 24-bit bitmaps or 8-bit greyscale bitmaps. Color bitmaps of images contained in single-layered image documents can be 1-bit, 4-bit, 8-bit color, 8-bit greyscale or 24-bit bitmaps.
Every PSP file begins with the following header, which should be used for initial validation. Any file that does not begin with this header should be considered an invalid PSP file.
As illustrated in the following table, the PSP file header consists of the PSP file signature, followed by a version number.
|
Type |
Length |
Name |
Description |
|
B_ARRAY |
32 bytes |
PSP file signature |
Always “50 61 69 6E 74 20 53 68 6F 70 20 50 72 6F 20 49 6D 61 67 65 20 46 69 6C 65 0A 1A 00 00 00 00” (i.e., the string “Paint Shop Pro Image File\n\x1a”, padded with zeroes to 32 bytes). |
|
DWORD |
2 bytes |
PSP file major version number |
Currently always 3. |
|
DWORD |
2 bytes |
PSP file minor version |
Currently always 0. |
Table 6: PSP File Header
The General Image Attributes Block, a required block that contains various information about the stored image document, immediately follows the PSP file header. Much of this information is needed to read other parts of the file (for example, the compression type is required to decode any channel blocks (with the exception of the Thumbnail Block channel(s)) and the layer count is required to know how many layers need to be read from the Layers Block).
As illustrated in the following table, the General Image Attributes Block consists of the General Image Attributes Header and the General Image Attributes Chunk.
General Image Attributes Header:
|
Type |
Length |
Name |
Description |
|
B_ARRAY |
4 bytes |
Header identifier |
Always “7E 42 4B 00” (i.e.,“~BK”, followed by a zero byte). |
|
WORD |
2 bytes |
Block identifier |
Always PSP_IMAGE_BLOCK. |
|
DWORD |
4 bytes |
Initial data chunk length |
Length of following General Image Attributes Chunk. |
|
DWORD |
4 bytes |
Total block length |
Length of complete General Image Attributes Block (which includes only the following General Image Attributes Chunk). |
General Image Attributes Chunk:
|
long |
4 bytes |
Image width |
Width of the image. |
|
long |
4 bytes |
Image height |
Height of the image. |
|
double |
8 bytes |
Resolution value |
Number of pixels per metric. |
|
BYTE |
1 byte |
Resolution metric |
Metric used for resolution (one of PSP_METRIC). |
|
WORD |
2 bytes |
Compression type |
Type of compression used to compress all image document channels, except those in the image thumbnail, which has its own compression type field (one of PSPCompression). |
|
WORD |
2 bytes |
Bit depth |
The bit depth of the color bitmap in each Layer of the image document (must be 1, 4, 8 or 24). |
|
WORD |
2 byte |
Plane count |
Number of planes in each layer of the image document (this value must be 1). |
|
DWORD |
4 bytes |
Color count |
Number of colors in each layer of the image document (2Bit depth). |
|
BYTE |
1 byte |
Greyscale flag |
Indicates whether the color bitmap in each layer of image document is a greyscale (0 = not greyscale, 1 = greyscale). |
|
DWORD |
4 byte |
Total image size |
Sum of the sizes of all layer color bitmaps. |
|
long |
4 bytes |
Active layer |
Identifies the layer that was active when the image document was saved. |
|
WORD |
2 bytes |
Layer count |
Number of layers in the document. |
Table 7: General Image Attributes Block
The Extended Data Block is an optional block that contains miscellaneous information about the image document. This information is organized in the PSP field format, which consists of a series of keyword-value pairs.
Using keyword-value pairs in the Extended Data Block facilitates the storage of new, currently undefined, image document attributes. Applications can quickly be modified to make use of the new keywords, while old applications that do not know about the new keywords will simply ignore them (therefore, unknown keywords encountered in the Extended Data Block should be ignored). If the extended data block is present, it must contain at least one extended data field.
As illustrated in the following table, the Extended Data Block consists of a block header, followed by one or more Extended Data Fields (each Extended Data Field consists of a keyword chunk and a value chunk).
Extended Data Block Header:
|
Type |
Length |
Name |
Description |
|
B_ARRAY |
4 bytes |
Header identifier |
Always “7E 42 4B 00” (i.e.,“~BK”, followed by a zero byte). |
|
WORD |
2 bytes |
Block identifier |
Always PSP_EXTENDED_DATA_BLOCK. |
|
DWORD |
4 bytes |
Initial data chunk length |
Undefined. |
|
DWORD |
4 bytes |
Total block length |
Length of following Extended Data Block (includes all following extended data fields – each of which consists of an Extended Data Keyword Chunk and an Extended Data Value Chunk). |
Extended Data Keyword Chunk (first extended data field):
|
B_ARRAY |
4 bytes |
Field signature |
Always “7E 46 4C 00” (i.e.,“~FL”, followed by a zero byte). |
|
WORD |
2 bytes |
Field keyword |
Keyword identifying type of extended data that is contained in the Extended Data Value Chunk (must be one of PSPExtendedDataID). |
|
DWORD |
4 bytes |
Extended Data Value Chunk length |
Length of following Extended Data Value Chunk (lets call this k). |
Extended Data Value Chunk (first extended data field):
|
B_ARRAY |
k bytes |
Field value |
The contents of the Extended Data Value Chunk are dependent upon the keyword extracted from the Extended Data Keyword Chunk (currently there is only one defined keyword). Unknown keywords should be ignored: |
|
|
|
|
|
Field keyword: |
Field value description: |
|
PSP_XDATA_TRNS_INDEX |
A WORD that identifies the palette index of the transparent color (this field is not valid for image documents whose color bitmaps are non-paletted, and should be ignored in this case). |
|||
…
Extended Data Keyword Chunk (last extended data field):
|
B_ARRAY |
4 bytes |
Field identifier |
Always “7E 46 4C 00” (i.e.,“~FL”, followed by a zero byte). |
|
WORD |
2 bytes |
Field keyword |
Keyword identifying type of extended data that is contained in the Extended Data Value Chunk (must be one of PSPExtendedDataID). |
|
DWORD |
4 bytes |
Data length |
Length of following Extended Data Value Chunk (lets call this k). |
Extended Data Value Chunk (last extended data field):
|
B_ARRAY |
k bytes |
Field value |
The contents of the Extended Data Value Chunk are dependent upon the keyword extracted from the previous Extended Data Keyword Chunk (currently there is only one defined keyword): |
|
|
|
Field keyword: |
Field value description: |
||
|
PSP_XDATA_TRNS_INDEX |
A 2 byte WORD that identifies the palette index of the transparent color (this field is not valid for image documents whose color bitmaps are non-paletted, and should be ignored in this case). |
|||
Table 4: Extended Data Block
The Tube Data Block is an optional block that contains Paint Shop Pro Picture Tube control data. This block controls how Picture Tube files (which are PSP files) act.
Tube Data Block Header:
|
Type |
Length |
Name |
Description |
|
B_ARRAY |
4 bytes |
Header identifier |
Always “7E 42 4B 00” (i.e.,“~BK”, followed by a zero byte). |
|
WORD |
2 bytes |
Block identifier |
Always PSP_TUBE_BLOCK. |
|
DWORD |
4 bytes |
Initial data chunk length |
Length of following Tube Data chunk. |
|
DWORD |
4 bytes |
Total block length |
Length of following Tube Data chunk. |
Tube Data Chunk:
|
WORD |
2 bytes |
Block version |
Version of following Tube Data Block. |
|
C_ARRAY |
513 bytes |
Tube name |
User friendly name of the tube. |
|
long |
4 bytes |
Tube step size |
Tube step size. |
|
long |
4 byte |
Tube column count |
Number of columns in tube file. |
|
long |
4 bytes |
Tube row count |
Number of rows in tub. |
|
long |
4 bytes |
Tube cell count |
Number of cells in tube. |
|
long |
4 bytes |
Tube placement mode |
Controls tube placement mode (one of TubePlacementMode). |
|
long |
4 bytes |
Tube selection mode |
Controls tube selection mode (one of TubeSelectionMode). |
The Creator Data Block is an optional block that contains miscellaneous information about the creator of the image document. This information is organized in the PSP field format, which consists of a series of keyword-value pairs.
Using keyword-value pairs in the Creator Data Block facilitates the storage of new, currently undefined, creator attributes. Applications can quickly be modified to make use of the new keywords, while old applications that do not know about the new keywords will simply ignore them (therefore, unknown keywords encountered in the Creator Data Block should be ignored). If the Creator Data Block is present, it must contain at least one creator field.
As illustrated in the following table, the Creator Data Block consists of a block header, followed by one or more Creator Data Fields (each Creator Data Field consists of a keyword chunk and a value chunk).
Creator Block Header:
|
Type |
Length |
Name |
Description |
|
B_ARRAY |
4 bytes |
Header identifier |
Always “7E 42 4B 00” (i.e.,“~BK”, followed by a zero byte). |
|
WORD |
2 bytes |
Block identifier |
Always PSP_CREATOR_BLOCK. |
|
DWORD |
4 bytes |
Initial data chunk length |
Undefined. |
|
DWORD |
4 bytes |
Total block length |
Length of following Creator Block (includes all following creator data fields, each of which consists of a Creator Keyword Chunk and a Creator Value Chunk). |
Creator Keyword Chunk (first creator field):
|
B_ARRAY |
4 bytes |
Field identifier |
Always “7E 46 4C 00” (i.e.,“~FL”, followed by a zero byte). |
|
WORD |
2 bytes |
Field keyword |
Keyword identifying the type of data that is contained in the Creator Value Chunk (must be one of PSPCreatorFieldID). |
|
DWORD |
4 bytes |
Data length |
Length of the Creator Value Chunk (lets call this n). |
Creator Value Chunk (first creator field):
|
B_ARRAY |
n bytes |
Field value |
The contents of the field value are dependent upon the field keyword extracted from the previous Creator Keyword Chunk: |
|
|
|
Field keyword: |
Field value description |
||
|
PSP_CRTR_FLD_TITLE |
Title of image document (in ASCII format). |
|||
|
PSP_CRTR_FLD_CRT_DATE |
DWORD indicating date of image document creation (in MSVC time_t format). |
|||
|
PSP_CRTR_FLD_MOD_DATE |
DWORD indicating date of last image document modification (in MSVC time_t format). |
|||
|
PSP_CRTR_FLD_ARTIST |
Name of artist (in ASCII text). |
|||
|
PSP_CRTR_FLD_CPYRGHT |
Name of copyright holder (in ASCII text). |
|||
|
PSP_CRTR_FLD_DESC |
Description of image document (in ASCII text). |
|||
|
PSP_CRTR_FLD_APP_ID |
DWORD identifying application that created image document (one of PSPCreatorAppID). |
|||
|
PSP_CRTR_FLD_APP_VER |
DWORD identifying version of application that created image document. |
|||
…
Creator Keyword Chunk (last creator field):
|
B_ARRAY |
4 bytes |
Field identifier |
Always “7E 46 4C 00” (i.e.,“~FL”, followed by a zero byte). |
|
WORD |
2 bytes |
Field keyword |
Keyword identifying the type of data that is contained Creator Value Chunk (must be one of PSPCreatorFieldID). |
|
DWORD |
4 bytes |
Data length |
Length of the Creator Value Chunk (lets call this p). |
Creator Value Chunk (last creator field):
|
B_ARRAY |
p bytes |
Field value |
The contents of the field value are dependent upon the field keyword extracted from the previous Creator Keyword Chunk: |
|
|
|
Field keyword: |
Field value description: |
||
|
PSP_CRTR_FLD_TITLE |
Title of text (in ASCII format). |
|||
|
PSP_CRTR_FLD_CRT_DATE |
DWORD indicating date of image document creation (in MSVC time_t format). |
|||
|
PSP_CRTR_FLD_MOD_DATE |
DWORD indicating date of last image document modification (in MSVC time_t format). |
|||
|
PSP_CRTR_FLD_ARTIST |
Name of artist (in ASCII text). |
|||
|
PSP_CRTR_FLD_CPYRGHT |
Name of copyright holder (in ASCII text). |
|||
|
PSP_CRTR_FLD_DESC |
Description of image document (in ASCII text). |
|||
|
PSP_CRTR_FLD_APP_ID |
DWORD identifying application that created image document (one of PSPCreatorAppID). |
|||
|
PSP_CRTR_FLD_APP_VER |
DWORD identifying version of application that created image document. |
|||
Table 5: Creator Data Block
The thumbnail block is an optional block that contains a miniature bitmap of the merged document.
As illustrated in the following table, the Thumbnail Block consists of a Block Header, a Thumbnail Attributes Chunk, a Thumbnail Color Palette Sub-Block (containing the thumbnail’s color palette, if any) and the Thumbnail Channel Sub-Blocks.
Thumbnail Block Header:
|
Type |
Length |
Name |
Description |
|
B_ARRAY |
4 bytes |
Header identifier |
Always “7E 42 4B 00” (i.e.,“~BK”, followed by a zero byte). |
|
WORD |
2 bytes |
Block identifier |
Always PSP_THUMBNAIL_BLOCK. |
|
DWORD |
4 bytes |
Initial data chunk length |
Length of following Thumbnail Attributes chunk. |
|
DWORD |
4 bytes |
Total block length |
Length of complete Thumbnail Block, including Thumbnail Attributes Chunk, Thumbnail Color Palette Sub-Block (if any) and all Thumbnail Channel Sub-Blocks. |
Thumbnail Attributes Chunk:
|
long |
4 bytes |
Thumbnail width |
Width of the thumbnail. |
|
long |
4 bytes |
Thumbnail height |
Height of the thumbnail. |
|
WORD |
2 bytes |
Thumbnail bit depth |
Number of bits used to represent each color pixel of the thumbnail (must be 1, 4, 8 or 24). |
|
WORD |
2 bytes |
Thumbnail compression type |
Type of compression used to compress thumbnail channels (one of PSPCompression). |
|
WORD |
2 byte |
Thumbnail plane count |
Number of planes in thumbnail (this value must be 1). |
|
DWORD |
4 bytes |
Thumbnail color count |
Number of colors in the image (2Bit depth). |
|
DWORD |
4 bytes |
Thumbnail palette entry count |
Number of entries in following color palette (0 for 24 bit bitmaps). |
|
WORD |
2 bytes |
Thumbnail channel count |
Number of channels following (1 for paletted bitmaps, 3 for 24-bit bitmaps). |
Thumbnail Color Palette Sub-Block:
|
Color Palette Sub-Block containing the thumbnail’s color palette (this Sub-Block is not present in 24-bit thumbnails). See section 5.5. |
Thumbnail Channel Sub-Blocks:
|
One or Three Channel Sub-Blocks defining the thumbnail bitmap. If the thumbnail is a paletted bitmap, there is one channel, if the thumbnail is a 24-bit bitmap, there are three channels. See section 5.6. |
Table 6: Thumbnail Block
The Color Palette Block contains a global color palette to be used with the color bitmaps in all layers of the document. This block is required for image documents that contain paletted bitmaps, and should not be written for image documents that contain 24-bit bitmaps (the block can be ignored in the latter case).
As illustrated in the following table, the Color Palette Block consists of a Color Palette Sub-Block.
|
A Color Palette Block containing the color palette for color bitmaps in all of the image document’s layers. This block should not be present in image documents whose color bitmaps are 24-bit bitmaps, and can be ignored in this case. See section 5.5. |
Table 7: Color Palette Block
The Layer Bank Block is a required block that contains data describing all the layers in the image document.
As illustrated in the following table, the Layer Bank Block consists of a Block Header, and a separate Layer Sub-Block for each layer in the image document (the number of layers in the document is indicated in the General Image Attributes Block). Each Layer Sub-Block consists of a Layer Sub-Block Header, a Layer Information Sub-Block and one or more Channel Sub-Blocks.
Layer Bank Block Header:
|
Type |
Length |
Name |
Description |
|
B_ARRAY |
4 bytes |
Header identifier |
Always “7E 42 4B 00” (i.e.,“~BK”, followed by a zero byte). |
|
WORD |
2 bytes |
Block identifier |
Always PSP_LAYER_START_BLOCK. |
|
DWORD |
4 bytes |
Initial data chunk length |
Always 0. |
|
DWORD |
4 bytes |
Total block length |
Length of complete Layers Block, including all Layer Sub-Blocks. |
Layer Sub-Block Header (first layer):
|
Type |
Length |
Name |
Description |
|
B_ARRAY |
4 bytes |
Header identifier |
Always “7E 42 4B 00” (i.e.,“~BK”, followed by a zero byte). |
|
WORD |
2 bytes |
Block identifier |
Always PSP_LAYER_BLOCK. |
|
DWORD |
4 bytes |
Initial data chunk length |
Size of following Layer Information Chunk. |
|
DWORD |
4 bytes |
Total block length |
Length of complete Layer Block, including Layer Information Chunk and all Channel Sub-Blocks. |
Layer Information Chunk (first layer):
|
C_ARRAY |
256 bytes |
Layer name |
Name of layer (in ASCII text). |
|
BYTE |
1 byte |
Layer type |
Type of layer (must be one of PSPLayerType). |
|
RECT |
16 bytes |
Image rectangle |
Rectangle defining image border. |
|
RECT |
16 bytes |
Saved image rectangle |
Rectangle within image rectangle that contains “significant” data (only the contents of this rectangle are saved to the file). |
|
BYTE |
1 byte |
Layer opacity |
Overall layer opacity. |
|
BYTE |
1 byte |
Blending mode |
Mode to use when blending layer. |
|
BYTE |
1 byte |
Layer visibility flag |
TRUE if layer was visible at time of save, FALSE otherwise. |
|
BYTE |
1 byte |
Transparency protected flag |
TRUE if transparency is protected. |
|
BYTE |
1 byte |
Link group identifier |
Identifies group to which this layer belongs. |
|
RECT |
16 bytes |
Mask rectangle |
Rectangle defining user mask border. |
|
RECT |
16 bytes |
Saved mask rectangle |
Rectangle within mask rectangle that contains “significant” data (only the contents of this rectangle are saved to the file). |
|
BYTE |
1 byte |
Mask linked |
TRUE if mask linked to layer (i.e., mask moves relative to layer), FALSE otherwise. |
|
BYTE |
1 byte |
Mask disabled |
TRUE if mask is disabled, false otherwise. |
|
BYTE |
1 byte |
Invert mask on blend |
TRUE if mask should be inverted when the layer is merged, FALSE otherwise. |
|
WORD |
2 bytes |
Blend range count |
Number of valid source-destination field pairs to follow (note, there are currently always 5 such pairs, but they are not necessarily all valid). |
|
B_ARRAY |
4 bytes |
Source blend range #1 |
First source blend range value. |
|
B_ARRAY |
4 bytes |
Destination blend range #1 |
First destination blend range value. |
|
B_ARRAY |
4 bytes |
Source blend range #2 |
Second source blend range value. |
|
B_ARRAY |
4 bytes |
Destination blend range #2 |
Second destination blend range value. |
|
B_ARRAY |
4 bytes |
Source blend range #3 |
Third source blend range value. |
|
B_ARRAY |
4 bytes |
Destination blend range #3 |
Third destination blend range value. |
|
B_ARRAY |
4 bytes |
Source blend range #4 |
Fourth source blend range value. |
|
B_ARRAY |
4 bytes |
Destination blend range #4 |
Fourth destination blend range value. |
|
B_ARRAY |
4 bytes |
Source blend range #5 |
Fifth source blend range value. |
|
B_ARRAY |
4 bytes |
Destination blend range #5 |
Fifth destination blend range value. |
|
WORD |
2 bytes |
Count of bitmaps |
Number of bitmaps to follow. |
|
WORD |
2 bytes |
Channel count |
Number of channels to follow. |
Layer Channel Sub-Blocks (first layer):
|
All the Layer’s channels. Possible channels include 1) one or three Channel Sub-Blocks defining the layer’s color bitmap, 2) one channel defining the Layer’s transparency mask and 3) one channel defining the Layer’s user mask. Note that the type of each channel can be obtained from the Channel Sub-Block (see section 5.6) and the number of channels is specified in the previous Layer Information Chunk. Note also that the Layer’s transparency mask and the Layer’s user mask are stored as 8-bit greyscale bitmaps. |
…
Layer Sub-Block Header (last layer):
|
Type |
Length |
Name |
Description |
|
B_ARRAY |
4 bytes |
Header identifier |
Always “7E 42 4B 00” (i.e.,“~BK”, followed by a zero byte). |
|
WORD |
2 bytes |
Block identifier |
Always PSP_LAYER_BLOCK. |
|
DWORD |
4 bytes |
Initial data chunk length |
Always 0. |
|
DWORD |
4 bytes |
Total block length |
Length of complete Layers Block, including all Layer Sub-Blocks. |
Layer Information Chunk (last layer):
|
C_ARRAY |
256 bytes |
Layer name |
Name of layer (in ASCII text). |
|
BYTE |
1 byte |
Layer type |
Type of layer (must be one of PSPLayerType). |
|
RECT |
16 bytes |
Image rectangle |
Rectangle defining image border. |
|
RECT |
16 bytes |
Saved image rectangle |
Rectangle within image rectangle that contains “significant” data (only the contents of this rectangle are saved to the file). |
|
BYTE |
1 byte |
Layer opacity |
Overall layer opacity. |
|
BYTE |
1 byte |
Blending mode |
Mode to use when blending layer. |
|
BYTE |
1 byte |
Layer flags |
PSPLayerFlags values, bitwise-ored together. |
|
BYTE |
1 byte |
Layer transparency flag |
PSPLayerTransparencyFlags values, bitwise-ored together. |
|
BYTE |
1 byte |
Link group identifier |
Identifies group to which this layer belongs. |
|
RECT |
16 bytes |
Mask rectangle |
Rectangle defining user mask border. |
|
RECT |
16 bytes |
Saved mask rectangle |
Rectangle within mask rectangle that contains “significant” data (only the contents of this rectangle are saved to the file). |
|
BYTE |
1 byte |
Mask linked |
TRUE if mask linked to layer (i.e., mask moves relative to layer), FALSE otherwise. |
|
BYTE |
1 byte |
Mask disabled |
TRUE if mask is disabled, false otherwise. |
|
BYTE |
1 byte |
Invert mask on blend |
TRUE if mask should be inverted when the layer is merged. |
|
WORD |
2 bytes |
Blend range count |
Number of valid source-destination field pairs to follow (note, there are currently always 5 such pairs, but they are not necessarily all valid). |
|
B_ARRAY |
4 bytes |
Source blend range #1 |
First source blend range value. |
|
B_ARRAY |
4 bytes |
Destination blend range #1 |
First destination blend range value. |
|
B_ARRAY |
4 bytes |
Source blend range #2 |
Second source blend range value. |
|
B_ARRAY |
4 bytes |
Destination blend range #2 |
Second destination blend range value. |
|
B_ARRAY |
4 bytes |
Source blend range #3 |
Third source blend range value. |
|
B_ARRAY |
4 bytes |
Destination blend range #3 |
Third destination blend range value. |
|
B_ARRAY |
4 bytes |
Source blend range #4 |
Fourth source blend range value. |
|
B_ARRAY |
4 bytes |
Destination blend range #4 |
Fourth destination blend range value. |
|
B_ARRAY |
4 bytes |
Source blend range #5 |
Fifth source blend range value. |
|
B_ARRAY |
4 bytes |
Destination blend range #5 |
Fifth destination blend range value. |
|
WORD |
2 bytes |
Count of bitmaps |
Number of bitmaps to follow. |
|
WORD |
2 bytes |
Channel count |
Number of channels to follow. |
Layer Channel Sub-Blocks (last layer):
|
All the Layer’s channels. Possible channels include 1) one or three Channel Sub-Blocks defining the layer’s color bitmap, 2) one channel defining the Layer’s transparency mask and 3) one channel defining the Layer’s user mask. Note that the type of each channel can be obtained from the Channel Sub-Block (see section 5.6) and the number of channels is specified in the previous Layer Information Chunk. Note also that the Layer’s transparency mask and the Layer’s user mask are stored as 8-bit greyscale bitmaps. |
Table 8: Layer Bank Block
The Selection Block is an optional block that defines the area that was selected when the image document was saved.
As illustrated in the following table, the Selection Block consists of a block header, a Selection Information Chunk and a Selection Channel Sub-Block.
Selection Header:
|
Type |
Length |
Name |
Description |
|
B_ARRAY |
4 bytes |
Header identifier |
Always “7E 42 4B 00” (i.e.,“~BK”, followed by a zero byte). |
|
WORD |
2 bytes |
Block identifier |
Always PSP_SELECTION_BLOCK. |
|
DWORD |
4 bytes |
Initial data chunk length |
Length of following Selection Information Chunk. |
|
DWORD |
4 bytes |
Total block length |
Length of complete Selection Block, including Selection Information Chunk and Selection Channel Sub-Block. |
Selection Information Chunk:
|
RECT |
16 bytes |
Selection rectangle |
Rectangle containing selected data. |
|
RECT |
16 bytes |
Saved selection rectangle |
Rectangle within selection rectangle that contains “significant” data (only the contents of this rectangle are saved to the file). |
|
WORD |
2 bytes |
Selection bitmap count |
Count of following selection bitmaps. Currently always 1. |
|
WORD |
2 bytes |
Channel count |
Count of following channels. Currently always 1. |
Selection Channel Sub-Block:
|
Selection Channel Sub-Block. See section 5.6. Note that selections are stored as 8-bit greyscale bitmaps. |
Table 9: Selection Block
The Alpha Bank Block is an optional block that defines alpha channels associated with the image document.
As is illustrated in the following table, the Alpha Bank Block consists of a block header, an Alpha Channel Information Chunk, and an Alpha Channel Sub-Block for each alpha channel in the image document (each Alpha Channel Sub-Block consists of a block header and a Channel Sub-Block).
Alpha Channel Bank Header:
|
Type |
Length |
Name |
Description |
|
B_ARRAY |
4 bytes |
Header identifier |
Always “7E 42 4B 00” (i.e.,“~BK”, followed by a zero byte). |
|
WORD |
2 bytes |
Block identifier |
Always PSP_ALPHA_BANK_BLOCK. |
|
DWORD |
4 bytes |
Initial data chunk length |
Length of following Alpha Bank Information Chunk. |
|
DWORD |
4 bytes |
Total block length |
Length of complete Alpha Bank Block, including Alpha Bank Information Chunk, and Alpha Channel Headers and Alpha Channel Information Chunks and Alpha Channel Sub-Blocks for all alpha channels. |
Alpha Bank Information Chunk:
|
WORD |
2 bytes |
Alpha channel count |
Number of Alpha channels. |
Alpha Channel Header (first alpha channel):
|
Type |
Length |
Name |
Description |
|
B_ARRAY |
4 bytes |
Header identifier |
Always “7E 42 4B 00” (i.e.,“~BK”, followed by a zero byte). |
|
WORD |
2 bytes |
Block identifier |
Always PSP_ALPHA_CHANNEL_BLOCK. |
|
DWORD |
4 bytes |
Initial data chunk length |
Length of following Alpha Channel Information Chunk. |
|
DWORD |
4 bytes |
Total block length |
Length of complete Alpha Channel Block, including following Alpha Channel Information Chunk and Alpha Channel Sub-Block. |
Alpha Channel Information Chunk (last alpha channel):
|
C_ARRAY |
256 bytes |
Alpha channel name |
Name of alpha channel. |
|
RECT |
16 bytes |
Alpha channel rectangle |
Rectangle containing alpha channel. |
|
RECT |
16 bytes |
Saved alpha channel rectangle |
Rectangle within alpha channel rectangle that contains “significant” data (only the contents of this rectangle are saved to the file). |
|
WORD |
2 bytes |
Alpha channel bitmap count |
Number of following alpha channel bitmaps (currently always 1). |
|
WORD |
2 bytes |
Channel count |
Number of following channels (currently always 1). |
Alpha Channel Sub-Block (first alpha channel):
|
Channel Sub-Block defining the alpha channel. See section 5.6. Note that alpha channels are stored as 8-bit greyscale bitmaps. |
…
Alpha Channel Header (last alpha channel):
|
Type |
Length |
Name |
Description |
|
B_ARRAY |
4 bytes |
Header identifier |
Always “7E 42 4B 00” (i.e.,“~BK”, followed by a zero byte). |
|
WORD |
2 bytes |
Block identifier |
Always PSP_ALPHA_CHANNEL_BLOCK. |
|
DWORD |
4 bytes |
Initial data chunk length |
Length of following Alpha Channel Information Chunk. |
|
DWORD |
4 bytes |
Total block length |
Length of complete Alpha Channel Block, including Alpha Channel Information Chunk and Alpha Channel Sub-Block. |
Alpha Channel Information Chunk (last alpha channel):
|
C_ARRAY |
256 bytes |
Alpha channel name |
Name of alpha channel. |
|
RECT |
16 bytes |
Alpha channel rectangle |
Rectangle containing alpha channel. |
|
RECT |
16 bytes |
Saved alpha channel rectangle |
Rectangle within alpha channel rectangle that contains “significant” data (only the contents of this rectangle are saved to the file). |
|
WORD |
2 bytes |
Alpha channel bitmap count |
Number of following alpha channel bitmaps (currently always 1). |
|
WORD |
2 bytes |
Channel count |
Number following channels (currently always 1). |
Alpha Channel Sub-Block (last alpha channel):
|
Channel Sub-Block defining the alpha channel. See section 5.6. Note that alpha channels are stored as 8-bit greyscale bitmaps. |
Table 10: Alpha Bank Block