PCX
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|released=~1984 | |released=~1984 | ||
}} | }} | ||
| − | '''PCX''' was the native image format of a DOS-based program PC Paintbrush from ZSoft Corporation, and was for a time (especially the late 1980s) a very popular image format among users of IBM PC compatibles and the PC/MS-DOS operating system. Much clip art was distributed in this format. However, it was tied closely to platform-specific attributes such as the particular graphic modes available in early PCs, and later lost ground to more platform-independent graphic formats like [[GIF]], [[JPEG]], and [[PNG]]. | + | '''PCX''' was the native image format of a DOS-based program ''PC Paintbrush'' from ZSoft Corporation, and was for a time (especially the late 1980s) a very popular image format among users of IBM PC compatibles and the PC/MS-DOS operating system. Much clip art was distributed in this format. However, it was tied closely to platform-specific attributes such as the particular graphic modes available in early PCs, and later lost ground to more platform-independent graphic formats like [[GIF]], [[JPEG]], and [[PNG]]. |
| − | PC Paintbrush was licensed to Microsoft, and it evolved into the Paint/Paintbrush application included with Windows. The versions for Windows 3.0 through Windows 95 support PCX format. | + | PC Paintbrush was licensed to Microsoft, and it evolved into the Paint/Paintbrush application included with Windows. The versions for Windows 3.0 through Windows 95 support PCX format. There was also a product named ''Microsoft Paintbrush 2.0''. |
== Identifiers == | == Identifiers == | ||
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A PCX file consists of a 128-byte fixed header (48 bytes of which may be used for a palette), followed by the pixel data, followed in some cases by a 769-byte palette segment. | A PCX file consists of a 128-byte fixed header (48 bytes of which may be used for a palette), followed by the pixel data, followed in some cases by a 769-byte palette segment. | ||
| − | A number of different | + | A number of different PCX specifications can be found on the internet, but unfortunately, they tend to be incomplete, and ambiguous about certain details. Part of this may be the fault of the PCX format. PC Paintbrush itself reportedly may interpret the same file differently, depending on the version of the software, and the graphics mode being used. |
The variety of a given PCX file is determined primarily by the combination of the ''bits per pixel per plane'' field at offset 3, and the ''number of planes'' field at offset 65. The following varieties of PCX seem to be common and well-supported: | The variety of a given PCX file is determined primarily by the combination of the ''bits per pixel per plane'' field at offset 3, and the ''number of planes'' field at offset 65. The following varieties of PCX seem to be common and well-supported: | ||
* bits=1, planes=1: Bi-level, always black and white | * bits=1, planes=1: Bi-level, always black and white | ||
| − | * bits=1, planes=4: 16-color, using the palette contained in the header | + | * bits=1, planes=4, version≠3: 16-color, using the palette contained in the header |
* bits=8, planes=1: 256-color, using the palette at the end of the file | * bits=8, planes=1: 256-color, using the palette at the end of the file | ||
* bits=8, planes=3: 24-bit truecolor | * bits=8, planes=3: 24-bit truecolor | ||
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=== Compression === | === Compression === | ||
| − | The PCX specifications require that all PCX image data be compressed with a form of [[run-length encoding]], indicated by the ''encoding'' field having the value 1. However, modern | + | The PCX specifications require that all PCX image data be compressed with a form of [[run-length encoding]], indicated by the ''encoding'' field having the value 1. However, modern graphics software often supports uncompressed PCX, in which the ''encoding'' field is 0. You can use [[ImageMagick]] to create such files, if you explicitly disable compression. |
=== Transparency === | === Transparency === | ||
| − | We haven't located any PCX specification that mentions transparency, yet some modern | + | We haven't located any PCX specification that mentions transparency, yet some modern graphics software supports 32-bit RGBA format (bits=8, planes=4). [[ImageMagick]] will readily create such files. |
The Wikipedia article also suggests a 16-bit RGBA format (bits=4, planes=4). | The Wikipedia article also suggests a 16-bit RGBA format (bits=4, planes=4). | ||
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== Specifications == | == Specifications == | ||
| − | * http://www.fileformat.info/format/pcx/spec/ | + | * [http://www.fileformat.info/format/pcx/spec/a10e75307b3a4cc49c3bbe6db4c41fa2/view.htm ZSoft Technical Reference Manual, Revision 5] |
| + | * [http://www.martinreddy.net/gfx/2d/PCX.txt ZSoft Technical Reference Manual] | ||
| + | ** [http://www.textfiles.com/programming/FORMATS/pcx.txt PCX excerpt from the above document] | ||
| + | * [http://www.textfiles.com/programming/FORMATS/pix_fmt.txt Picture format docs (of a number of formats including PCX)] | ||
| + | * [http://www.shikadi.net/moddingwiki/PCX_Format PCX Format], from the DOS Game Modding Wiki | ||
| + | * [http://www.drdobbs.com/pcx-graphics/184402396 Dr. Dobb's: PCX Graphics] | ||
== Software == | == Software == | ||
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* [http://www.irfanview.com/ IrfanView] | * [http://www.irfanview.com/ IrfanView] | ||
* [[XnView]] | * [[XnView]] | ||
| + | * [https://archive.org/details/ZS_1020 PC Paintbrush] | ||
== Sample files == | == Sample files == | ||
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* http://cd.textfiles.com/clipart1996/ ... | * http://cd.textfiles.com/clipart1996/ ... | ||
| − | == | + | == Links == |
| + | * {{EGFF|pcx|PCX File Format Summary}}, from the [[Encyclopedia of Graphics File Formats]] | ||
* [[Wikipedia:PCX|Wikipedia: PCX]] | * [[Wikipedia:PCX|Wikipedia: PCX]] | ||
* [[Wikipedia:PC Paintbrush|Wikipedia: PC Paintbrush]] | * [[Wikipedia:PC Paintbrush|Wikipedia: PC Paintbrush]] | ||
* [[Wikipedia:Microsoft Paint|Wikipedia: Microsoft Paint]] | * [[Wikipedia:Microsoft Paint|Wikipedia: Microsoft Paint]] | ||
| − | * [http://www. | + | * [http://www.danielsays.com/ss-gallery-dos-pc-paintbrush-310.html PC Paintbrush 3.10], from Daniel's Legacy Computer Collections |
| − | + | * [http://www.danielsays.com/ss-gallery-dos-ms-paintbrush-20.html Microsoft Paintbrush 2.0], from Daniel's Legacy Computer Collections | |
| − | * [http://www. | + | * [http://www.betaarchive.com/forum/viewtopic.php?t=29671 BetaArchive forum post about PC Paintbrush and PCX] |
| − | * [http://www. | + | * [https://archive.org/details/bitsavers_mindsetPCP_4931746 PC Paintbrush manual] |
[[Category:Microsoft]] | [[Category:Microsoft]] | ||
Revision as of 03:17, 23 December 2014
PCX was the native image format of a DOS-based program PC Paintbrush from ZSoft Corporation, and was for a time (especially the late 1980s) a very popular image format among users of IBM PC compatibles and the PC/MS-DOS operating system. Much clip art was distributed in this format. However, it was tied closely to platform-specific attributes such as the particular graphic modes available in early PCs, and later lost ground to more platform-independent graphic formats like GIF, JPEG, and PNG.
PC Paintbrush was licensed to Microsoft, and it evolved into the Paint/Paintbrush application included with Windows. The versions for Windows 3.0 through Windows 95 support PCX format. There was also a product named Microsoft Paintbrush 2.0.
Contents |
Identifiers
Identification
The first byte of a PCX file is 0x0a. The second byte (the version number) is 0, 2, 3, 4, or 5. The third byte (the encoding) is 1 or 0.
Format details
A PCX file consists of a 128-byte fixed header (48 bytes of which may be used for a palette), followed by the pixel data, followed in some cases by a 769-byte palette segment.
A number of different PCX specifications can be found on the internet, but unfortunately, they tend to be incomplete, and ambiguous about certain details. Part of this may be the fault of the PCX format. PC Paintbrush itself reportedly may interpret the same file differently, depending on the version of the software, and the graphics mode being used.
The variety of a given PCX file is determined primarily by the combination of the bits per pixel per plane field at offset 3, and the number of planes field at offset 65. The following varieties of PCX seem to be common and well-supported:
- bits=1, planes=1: Bi-level, always black and white
- bits=1, planes=4, version≠3: 16-color, using the palette contained in the header
- bits=8, planes=1: 256-color, using the palette at the end of the file
- bits=8, planes=3: 24-bit truecolor
Unfortunately, there are many other varieties that are not necessarily so portable.
Compression
The PCX specifications require that all PCX image data be compressed with a form of run-length encoding, indicated by the encoding field having the value 1. However, modern graphics software often supports uncompressed PCX, in which the encoding field is 0. You can use ImageMagick to create such files, if you explicitly disable compression.
Transparency
We haven't located any PCX specification that mentions transparency, yet some modern graphics software supports 32-bit RGBA format (bits=8, planes=4). ImageMagick will readily create such files.
The Wikipedia article also suggests a 16-bit RGBA format (bits=4, planes=4).
See also
- DCX - A multi-image form of PCX
Specifications
- ZSoft Technical Reference Manual, Revision 5
- ZSoft Technical Reference Manual
- Picture format docs (of a number of formats including PCX)
- PCX Format, from the DOS Game Modding Wiki
- Dr. Dobb's: PCX Graphics
Software
- ImageMagick
- Netpbm: ppmtopcx, pcxtoppm
- IrfanView
- XnView
- PC Paintbrush
Sample files
Links
- PCX File Format Summary, from the Encyclopedia of Graphics File Formats
- Wikipedia: PCX
- Wikipedia: PC Paintbrush
- Wikipedia: Microsoft Paint
- PC Paintbrush 3.10, from Daniel's Legacy Computer Collections
- Microsoft Paintbrush 2.0, from Daniel's Legacy Computer Collections
- BetaArchive forum post about PC Paintbrush and PCX
- PC Paintbrush manual
