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How to test the proof-of-concept MyPaint+GEGL work.
The status of this work is tracked in
== Prerequsites ==
These are in addition to the normal prerequsites for MyPaint.
1. BABL from git master
2. GEGL from git master
3. GEGL-GTK from git master
All projects must be built with GObject Introspection support.
Pass --enable-introspection to configure to enable.
It is recommended that the projects are installed into
a custom prefix. Pass --prefix $prefix to configure,
and set the following env vars.
export XDG_DATA_DIRS=$prefix/share/:$XDG_DATA_DIRS
export GI_TYPELIB_PATH=$prefix/lib/girepository-1.0
export PKG_CONFIG_PATH=$prefix/lib/pkgconfig
export LD_LIBRARY_PATH=$prefix/lib
After this build MyPaint with the enable_gegl flag
scons enable_gegl=true
== Testing ==
Currently MyPaint + GEGL can run a couple of test, and power
a simple test application.
python tests/
Currently the normal MyPaint application will not work correctly
when built together with GEGL. But for the daring, here is how to try:
== TODO ==
Milestone 1: Use GeglBuffer as surface backend
* Make the performance of GeglBuffer based implementation equal or better. See brushlib/PERFORMANCE for hints
* Remove lib/tiledsurface.hpp, lib/pythontiledsurface.c
+ Benefit: MyPaint can operate on larger-than-ram images
+ Benefit: Remove ~400 sloc
Milestone 2: Use a GEGL graph for compositing of document
* Move brushlib to 32bit floats. To avoid color conversions between other GEGL compositing ops
* Add a GEGL graph to lib.document.Document that is kept in sync with changes
* Use a gegl:layer with appropriate layer modes instead of current tile-based blending modes
* Remove lib/pixops.hpp lib/composite_rgbx.hpp
* Make layer move be done by changing the offset of a gegl:layer instead of lib.tiledsurface.InteractiveMove
\ Depends on: sRGB compositing ops in GEGL
+ Benefit: MyPaint can make use of GEGL operations for post-processing. Filters, color-correction
+ Benefit: Remove ~600 sloc
Milestone 3: Use GeglGtkView for the rendering widget
* Use GeglGtkView in gui.tileddrawwidget.TiledDrawWidget instead of CanvasRenderer
\ Depends on: Rotation support in GeglGtkView
+ Benefit: Overloading of stroke drawing will give incremental user feedback, not freeze UI
+ Benefit: Remove ~300 sloc
Milestone 4: Use PNG import/export support from GEGL
* Make the GEGL PNG load/save performance be as good or better as current
* Make load/save of PNGs in GEGL respect ICC profiles
\ Depends on: ICC-based color conversions in GEGL
* Benefit: Everyone using GEGL will have fast, color-managed PNG export/import
* Benefit: Remove ~400 sloc
Milestone 5: Move OpenRaster support into GEGL
* Implement load/save support of OpenRaster as GEGL operations
* Use these in lib.document.Document, maintaining a mapping between opened GEGL graph and internal document structure
* Remove save_ora / load_ora from lib.document.Document
+ Benefit: OpenRaster implementation can be used by everyone using GEGL
+ Benefit: OpenRaster load-save roundtrips should be able to preserve data MyPaint does not know
+ Benefit: Remove ~150 sloc
Milestone 6: Make paint strokes be GEGL operations
* Create a GEGL operation "mypaint:stroke", making use of MyPaintBrush and MyPaintGeglSurface
the operation has two attributes, the path and the brush(settings)
* Use this in lib.document.Document: every new stroke is a new GeglNode that is inserted in graph
\ Depends on: Additions to GeglPath to store pressure,tilt,time information
+ Benefit: GEGL gets a painting system that applications can share
+ Benefit: Unified way of handling changes to the document, it is all changes in the GEGL graph
Milestone 7: Use GEGL graph journal for undo/redo system
* Change lib.document.Document to make do()/undo() wrap the GEGL graph journal
* Remove lib/
\ Depends on: Journal implementation in GEGL
+ Benefit: Undo/redo history can be shared between applications using GEGL
+ Benefit: User could operate on a document using multiple applications
+ Benefit: Remove ~300 sloc