This file lists TODO items for the compositing code.
See file COMPOSITE_HOWTO for setting up kwin_composite.
See file HACKING for details on developing KWin, including building
the kwin_composite branch.
See effects/howto.* for a HOWTO on writting effects.
See documentation in source (mainly in scene.cpp) for description
of the design of the compositing framework.
TODO
=================================
* = not done, will be either done by me, or should be at least discussed first with me
+ = not done, I don't plan on doing it that soon
- in other words, these should be the best ones for you if you want to help
! = like +, but they should be relatively simple
- in other words, these should be the best if you want to get started with the code
/ = work in progress
? = should it be done?
% = should be probably done later, during cleanups and preparations for being stable
KDE 4.0 TODO
=================================
- effects (to do)
- add generic support to use effect only for certain window types [Seli]
- window-specific rules need to apply to unmanaged windows as well (where applicable)
- some window-specific rules also related to compositing
- opacity
/ handling of window pixmaps for unmapped windows [Seli]
- config option?
- shm mode needs support for more data formats than GL_BGRA
- check what works with XRender
- documentation
- disable application effects when kwin can provide them, e.g. shadow/transparency
General TODO
=================================
+ suspend repaints if not visible or dpms is active
- there is already 'overlay_visible', but it still polls the mouse in such case
- it should turn off the timer
? wait for decoration repaints
- it is sometimes visible that the window contents are painted first and the decoration
only afterwards with a small delay
? - this has been already greatly improved by r632378, so it's maybe not worth it anymore
- maybe posted paint events need to be processed immediatelly, or maybe the compositing
code should not update the window until the decoration is finished painting
% paint throttling
- there's 5ms grace period per repaint to avoid overloading the system with just compositing
and not letting the system do anything else - check and evaluate
* handle properly stacking order of deleted windows for showing in effects
* handle properly deleted windows that reappear (windowReadded() function?)
% during screensaving, do no let non-screensaver windows show above screensaver
- kdesktop_lock watches for such things and raises again, but there's a small gap
% nvidia drivers by default use fake refresh rates as a workaround for some X limitations
- see the DynamicTwinView section in nvidia README
- this makes KWin repaint at a different rate than it should
/ handling of window pixmap for unmapped windows
- currently it's kept around after a window is unmapped
* - but it's still discarded on e.g. resize - how to solve this?
* - windows could be unmapped but quickly mapped back when a live thumbnail is needed
* window grouping is not implemented for unmanaged windows (used e.g. by DimInactive)
% clean up and sort out shortcuts so that they don't conflict and make sense
? hidden previews currently needs input shape extension, otherwise the window can possibly interfere
- not very likely though, so is this worth bothering at all?
OpenGL TODO
=================================
/ Check/make it work with other gfx cards
% Xgl support
- should work
- in SceneGL::Texture::findTarget() there is a hack that makes KWin work with XGL
without requiring KWin to be built against the libGL version that Compiz is
built against
% - that may not be necessary somewhen later
- interesting observation: normally run glxgears performs somewhat poorly compared
to normal nvidia mode, changing glxgears to be override-redirect (i.e. no reparenting)
however makes glxgears to be even faster than without any compositing at all,
in this case however kwin's redrawing speed drops somewhat
% AIGLX support
- should work
/ GL_ARB_texture_rectangle vs GL_ARB_texture_non_power_of_two
% - works; bugs in tfp_mode with power_of_two textures
- ati (others?): power_of_two windows are drawn white unless non-tfp_mode
is forced in findTextureTarget()
% bindTexture() optimize copied areas
- right now bindTexture() updates every damaged area and resets the window damage
- it might make things faster to update only areas that need to be repainted
and keep the rest damaged until needed
% clipping optimization
- like XRender code has paintTransformedScreen(), avoid painting parts that are
obscured (makes a difference with many windows open)
- http://lists.kde.org/?l=kwin&m=116585618111882&w=2
! shm mode needs support for more data formats than GL_BGRA
- http://www.xfree86.org/current/glTexImage2D.3.html
- this now works for 16bpp, but maybe not 15bpp or less
- endian issues?
+ support for __GL_YIELD=NOTHING and LIBGL_ALWAYS_INDIRECT should be possibly less hacky
- or at least not hardcoded (although, does that matter?)
- (http://lists.kde.org/?l=kwin&m=116439615124838&w=2)
- (http://lists.freedesktop.org/archives/xorg/2006-December/020323.html)
XRender TODO
==============================
+ SceneXrender::paintTransformedScreen() doesn't handle properly extending of painted area
in window's pre-paint - see the transformedShape() comment
- and currently seems to be generally broken
Effects framework TODO
==============================
* more notification functions for effects are needed
- currently there are only very few notification functions (windowAdded, windowActivated,...)
! - window state changes
? more
/ support for grabbing input
- during some more complicated effects, input (at least mouse) should be disabled,
because currently there is no way to do input redirection
+ EffectWindow should be completely opaque when kept as the only API for effects
- no inlines, etc.
+ EffectsHandler should not have virtuals but should instead use an internal object
for communication with KWin core, so that adding new functions doesn't break BC all the time
+ API for tabbox for effects should be cleaned up
* check Scene::updateTimeDiff() - should the time be 0 or 1?
% post calls are probably not necessary by now (http://lists.kde.org/?t=117770818100003&r=1&w=2)
% consider using http://lists.kde.org/?l=kwin&m=118094888517415&w=2 for notification functions
% API cleanups and making sure it will stay backwards compatible
Effects TODO
===============================
! add reloadConfig() to effects
- currently changing the global animation speed in the kcm does not change effect
+ minimize/shade effects
- to replace the ones from KWin core
/ - minimizing
- check support for it and the avoid_animation flag
+ - shading
- shading will probably need special support
/ zoom effect
- enlarge a portion of the screen
- Should it react to meta+wheel?
+ logout effect
* - should be triggered by ksmserver somehow
+ effects to replace widget effects (the ones in the Effects tab in "kcmshell style")
/ showfps effect
- should also detect kwin being idle - it probably should detect in pre-paint that the only
damage is its own area and avoid damaging for the next round in post-paint
/ scalein
+ - should scale in from e.g. 80%, not 0%, to just "pop up"
+ effect for drawing attention to windows demanding attention
- Rays? Ripples?
* DimInactive flickers when switching between windows (temporarily no window becomes active)
- focus effect (windows waves a little when it gets focus)
+ shadow
+ - follow the shape of the window (currently is disabled completely using the hasOwnShadow() hack)
+ window thumbnails directly in panel
- i.e. the panel (taskbar?) could show window previews directly, without tooltips
Performance
==================
+ various caching - there are many things that usually don't change and could gain few fps (is it worth it?)
- Workspace::performCompositing()
- WindowQuadList could perhaps cache quads split by contents/decoration (for select())
+ avoiding X roundtrips each compositing pass
- right now it at least always polls the mouse position and the current stacking order
) is private.
