Shared resources

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Current version: 0.1. See Revisions History below for list of changes between versions.

Warning: This specification is a work in progress. It's not recommended to follow it in its current state.

Contents

Abstract

Today opensource graphics applications seem to like to work out uniform solutions. Krita uses GIMP's brushes, Inkscape uses GIMP's color swatches files. Still missing are ways to share resources like brushes, so that users wouldn't need to install all of these resources separately for each and every application that can read such data.

The intention of this specification is to work out uniform rules for storing possibly shared data, which would let

  • developers benefit from no efforts duplication;
  • packagers benefit from no efforts duplication;
  • users benefit from using one root directory for all art supplies and one art supplies registry for all applications.

Applications

Following applications (in strict alphabetical order) are taken into consideration while writing this specification (as of current version):

Types of resources and directories at present time

Brushes

Bitmap brushes

A brush file is usually a container format that can store different types of raster graphics (e.g. PNG).

Table 1. Bitmap brushes
CinePaint Uses GIMP's .gbr and .gih brushes, but with higher color resolution ~/.cinepaint/brushes and $INSTALL_PATH/share/cinepaint/$VERSION/brushes
Inkscape Doesn't use bitmap brushes
Karbon14 Doesn't use bitmap brushes
Krita Uses GIMP's .gbr and .gih brushes $INSTALL_PATH/share/apps/krita/brushes/
mtPaint Doesn't use bitmap brushes
Scribus Doesn't use bitmap brushes and doesn't need them
sK1 Doesn't use bitmap brushes
Skencil Doesn't use bitmap brushes
GIMP Supported file formats are: .gbr (GIMP Brush 8bit grayscale or 24bit RGB, also CinePaint's 16bit .gbr), .abr (Photoshop Brush, 8bit grayscale), .gih (GIMP image hose, a format for animated brushes; PSP image tubes can be loaded using the PSP import plug-in, saving them again as .gih makes them available to GIMP), .vbr (GIMP parametric brush, a simple format for vector brushes). ~/.gimp-$VERSION/brushes and $INSTALL_PATH/share/gimp/$VERSION/brushes

Vector brushes

Vector brushes are different from bitmap/raster brushes being freely scalable up and down without losing much quality. So far they are not implemented in any of opensource software, but should be kept in mind in the long run.

XML brushes

XML brushes describe types of behaviour, like paint deposition, fringe spatter and so on.

Gradients

Gradient files store description of gradients

Table 2. Gradients
CinePaint Uses GIMP's .ggr gradients of higher than originally color resolution ~/.cinepaint/gradients and $INSTALL_PATH/share/cinepaint/$VERSION/gradients
Inkscape Stores gradients in documents
Karbon14 Uses its own .kgr files, openclipart svg gradient files (.svg), GIMP's .gpl files $INSTALL_PATH/share/apps/karbon/gradients/ and ~/.kde/share/apps/karbon/gradients
Krita Uses GIMP's .ggr gradients $INSTALL_PATH/share/apps/krita/gradients/
mtPaint Doesn't use gradients
Scribus Gradients come from vector code
sK1 Stores gradients in documents, uses *.skg CMYK gradients files ~/.sK1/gradients $sK1_HOME/RESOURCES/gradients
Skencil Stores gradients in documents
GIMP Uses GIMP's .ggr files (GIMP Gradient, RGB colors stored as floats) and .svg files (as defined in the SVG spec) ~/.gimp-$VERSION/gradients and $INSTALL_PATH/share/gimp/$VERSION/gradients
OpenOffice.org Draw Uses Star Office Gradients (.sog) which is written using draw XML (swatches, and hatches (patterns) are also specified)
OpenOffice.org Impress Uses Star Office Gradients (.sog) which is written using draw XML (swatches, and hatches (patterns) are also specified)

Color swatches

There is some confusion in terms. Color swatches are same as palettes and color sets: these are files that store a set of predefined colors. Currently, apart from Scribus, all of the opensource applications support RGB based color swatches files only.

Table 3. Color swatches
CinePaint Uses GIMP's .gpl palette files of higher than originally color resolution ~/.cinepaint/palettes and $INSTALL_PATH/share/cinepaint/$VERSION/palettes
Inkscape Uses GIMP's .gpl palette files ~/.inkscape/palettes and $INSTALL_PATH/share/inkscape/palettes
Karbon14 Doesn't support palette files yet.
Krita Uses GIMP's .gpl palette files $INSTALL_PATH/share/apps/krita/palettes/
mtPaint Uses GIMP's .gpl palette files n/a
Scribus Currently the same as X11/gimp ones, they are loaded from the installed files into the documents
sK1 4-bytes CMYK palettes (.skp) ~/.sK1/palettes, $sK1_HOME/RESOURCES/palettes
Skencil RGB palettes with three floats (0.0 -- 1.0) and an optional name per color (.spl). Can read gimp palette files as well. $skencil_HOME/Resources/Misc
GIMP Uses GIMP's .gpl palette files (8bit RGB), RIFF palette files (8bit RGB), Photoshop's .act binary color palettes (8bit RGB), JASC's Paint Shop Pro .psp color palettes (8bit RGB) ~/.gimp-$VERSION/palettes and $INSTALL_PATH/share/gimp/$VERSION/palettes

Patterns

Bitmap patterns

Bitmap patterns are same as textures - files with an image inside (a container format as well) to fill a selected area multiply times creating a pattern.

Table 4. Bitmap brushes
CinePaint Uses GIMP's pattern files (.pat) of higher than originally color resolution ~/.cinepaint/patterns and $INSTALL_PATH/share/cinepaint/$VERSION/patterns
Inkscape Doesn't use bitmap patterns
Karbon14 Doesn't use bitmap patterns
Krita Uses GIMP's pattern files (.pat)
mtPaint Doesn't use bitmap patterns
Scribus Doesn't use bitmap patterns
sK1 CMYK bitmap patterns (.tiff, .jpg) ~/.sK1/patterns , $sK1_HOME/RESOURCES/patterns
Skencil Any raster image the Python Imaging Library can read $skencil_HOME/Resources/Misc
GIMP Uses GIMP's .pat files (GIMP pattern, RGB or RGBA, 8bit per channel) and all image formats supported by gdk-pixbuf, most importantly PNG, JPEG and SVG (rendered at librsvg's default resolution) ~/.gimp-$VERSION/patterns and $INSTALL_PATH/share/gimp/$VERSION/patterns

Vector patterns

Vector patterns are same as bitmap ones being just vector based and thus scalable up/down without losing much quality. So far they are not implemented in any of opensource software, but should be kept in mind in the long run.

Clipart

Under clipart we understand files that are all-sufficient and can be reused as part of some other artwork. It can be either bitmap or vector graphics.

Table 5. Clipart
CinePaint Not implemented
Inkscape There is a separately shipped clip art navigator (currently v0.4)
Karbon14 There is an initial implementation of a clipart browser
Krita Not implemented
mtPaint Not implemented
Scribus Clipart browser is at design stage
sK1 B&W .sk1 clipart $sK1_HOME/RESOURCES/symbols and user defined symbols in ~/.sK1/symbols
Skencil Not implemented
GIMP Not implemented

Proposed changes

Make all of the above applications use one root directory for all art supplies:

On UNIX (GNU/Linux, FreeBSD etc.) systems:

/usr/share/create/ and ~/.create/ (for local use)

On Windows systems:

%COMMONAPPDATA%\create and %APPDATA%\create (for local use)

Note that while %APPDATA% is actually available as an environment variable (at least on Windows XP), %COMMONAPPDATA% is not, it is meant to be the Application Data directory for the "All Users" profile. A good way to retrieve the above directories is by using the SHGetFolderPath function (be sure to link against shfolder.lib and package shfolder.dll with your application if you want it to work on older versions of Windows, like Windows 95, a redistributable is available from Microsoft), this should work on pretty much all versions of Windows (verified on a clean Windows 95, as well as Windows 2000 and XP). PathAppend can be used to append the "create" part. Instead of SHGetFolderPath it is also possible to get the paths from the registry, at (HKLM|HKCU)\Software\Microsoft\Windows\Current Version\Explorer\Shell Folders (also verified for Windows 95, 2000 and XP).

On Mac OS X systems:

/Library/Application\ Support/create and ~/Library/Application\ Support/create (for local use)

The outline for subdirectories would look the following way then: 

/usr/share/create/
			brushes
				gimp
				photoshop
				pipe
				vector
				xml 
			clipart
			gradients
				gimp
				karbon14
				svg
			patterns
				bitmap
				vector 
			swatches

Needs further investigation

  • directories of all of the above and below mentioned applications in Mac OS X;
  • more information about Karbon14;
  • information about Abiword (clipart);
  • possibility of application icons reuse.
  • usage of the XDG Base Directory Specification at Freedesktop.org. On Unix that would mean storing local files in $XDG_DATA_HOME/create rather than $HOME/.create

References

  1. A bug report covering paths to search for ICC by Scribus.
  2. A letter from Alan Horkan to gimp-developer@ list, which initiated an offlist discussion among GIMP, Krita, Inkscape and Scribus developers.
  3. An initial request by Alexandre Prokoudine for a new project covering shared graphics applications resources at Freedesktop.org.
  4. A blog entry by Jon Philips', where in comments it was decided to merge efforts with CREATE project at Freedesktop.org
  5. OpenIcc — a project with two main goals: 1) to work out a common set of settings for color savvy applications to share ICC/ICM profiles and settings; 2) to bring together those developers in areas like printing, display and desktop applications to work together to make color management end to end work for open source applications. OpenIcc and ICC in common aren't covered by 'Shared resources' spec beginning from v0.0.4.
  6. OpenDocument specification

Contributors

Tim Beaulen

Craig Bradney

Alan Horkan

Sven Neumann

Igor Novikov

Alexandre Prokoudine

Boudewijn Rempt

Robin Rowe

Mark Tyler

License

License applied to this specification is Creative Commons No Derivative Works

Revisions History

  • Revision 0.1 (5 December 2005). Added more info about Karbon14, Krita. Added mtPaint and its author, Mark Tyler. Added Sven's elaboration on file formats supported by GIMP. Changed "Authors" to "Contributors". Integrated suggestion of anonymous user about locale sensitive path variable on Windows. Added suggestion for OS X folders. Added link to OpenDocument spec. Added XDG Base Directory Specification to the list "Needs further investigation".
  • Revision 0.0.5 (9 September 2005). Added sK1 to the list of considered applications. Added information about Sketch and sK1. Cleaned up "Needs further investigation" section. Added Robin Rowe to the list of contributors and moved to alphabetical order instead of order of appearance.
  • Revision 0.0.4 (4 September 2005). Switched to DocBook/XML. ICC is moved away from the spec, because OpenIcc spec should be informative enough. Lots of typos are fixed. Changed structure of the document and added section "XML brushes". Added mentioning openclipart gradients to Karbon14 (Section "Gradients"). Reorganised subdirectories definition and changed it to an outline. Added info about Cinepaint. Changed mentioned version of Clipart browser which was written for Google's Summer Of Code contest.
  • Revision 0.0.3 (16 August 2005). Added a References section and several references.
  • Revision 0.0.2 (16 August 2005). Fixed description for Scribus in color swatches and ICC aspect.
  • Revision 0.0.1 (16 August 2005). Initial version
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