Is anyone interested in a kwin effect (KDE desktop effect) which compresses everything to 16 bit color? I made one a while ago to prevent dithering on my laptop with 6bpc panel. In case there is any interest I can update it and publish it. Update: Link: https://github.com/PrincessDoreena/kwin-effect-limitcolors

PrincessDoreena Hi, yes I'd like to test it, please upload it, thank you 🙂

I use KDE and would love to try it!

It sounds interesting.. how does it work though? If you're receiving an 8+ bit signal, what do you do from there?

i'm using manjaro with KDE. how to know if i have temporel dithering? i hope that you post some documentation about "compressing colors to 16 bit". i'm interested in the script.

Abeabe karut dzwdev https://github.com/PrincessDoreena/kwin-effect-limitcolors Installation instructions in the README. Try all the format and offset settings.

Sunspark I just discard the last two or three bits.

KDE plugin to prevent dithering

Sunspark

PrincessDoreena Hmm.. I don't know that you need to discard.. if you instead re-map to relative colourmetric, all colours that are within the display's gamut in a 16-bit form would stay as they are untouched, and the ones that are outside of it, using relative you could have them instead snap to the nearest matching in-gamut 16-bit colour.

PrincessDoreena

Sunspark

Wouldn't we need to know the gamut?

dzwdev

PrincessDoreena that what i get:
-B build -S . \

> -DCMAKE_BUILD_TYPE=Release \

> -DCMAKE_INSTALL_PREFIX=/usr

CMake Error: The source directory "/home/pc" does not appear to contain CMakeLists.txt.

Specify --help for usage, or press the help button on the CMake GUI.

cmake --build build --parallel

Error: /home/pc/build is not a directory

PrincessDoreena

dzwdev

Full instructions:

wget https://github.com/PrincessDoreena/kwin-effect-limitcolors/archive/refs/heads/master.zip
unzip master.zip
cd kwin-effect-limitcolors-master
cmake -B build -S . \ -DCMAKE_BUILD_TYPE=Release \ -DCMAKE_INSTALL_PREFIX=/usr cmake --build build --parallel sudo cmake --install build

dzwdev

PrincessDoreena thank you. it is installed now

when i open KwinScripts i don't find the limit color plugin there?

how to know that the script is really installed? and i did not understand how to use that gif to test if dithering is disabled or not?

PrincessDoreena

dzwdev

Workspace Behavior -> Desktop Effects

dzwdev

PrincessDoreena

all the screen dither some times after enabling the plugin

https://ibb.co/VJFVHLp

ryans

dzwdev That's an interesting picture, is it VideoDiff and a capture card?

when i changed from x11 to wayland the problem is not occuring

And you are saying with Wayland + this plugin, dithering goes away, but with X11, the dithering remains? Curious your distro and graphics.

dzwdev

when i changed from x11 to wayland the problem is not occuring

ryans

Thanks @PrincessDoreena for making and open-sourcing this! Does the plugin help your symptoms? Applying these changes at the compositor level is an interesting solution. Does the plugin greatly reduce image quality?

@Sunspark The re-map is another interesting idea. This post from @ravipra appears to do similar.

dzwdev

that is not videodiif. it is just the normal manjaro system.

"you are saying with Wayland + this plugin, dithering goes away, but with X11, the dithering remains?"
with the X11 i get sometimes all the screen dithering like the image i've attached.

this is what i'm using:
Operating System: Manjaro Linux

KDE Plasma Version: 5.27.10

KDE Frameworks Version: 5.113.0

Qt Version: 5.15.11

Kernel Version: 6.6.8-2-MANJARO (64-bit)

Graphics Platform: Wayland

Processors: 4 × Intel® Core™ i5-6300U CPU @ 2.40GHz Memory: 7,6 GiB of RAM

Graphics Processor: Mesa Intel® HD Graphics 520 Manufacturer: Dell Inc.

Product Name: Latitude 7480

ryans

dzwdev Interesting, so that is an actual screenshot? With the plugin enabled, you see that white colored "noise"? Temporal dithering would not be visible in a static screenshot

dzwdev

by the way, how to know the supported bit per pixel (bpp) in my laptop monitor from linux? and how to know the model of the monitor from linux?

laptopmedia shows this: https://laptopmedia.com/screen/lg-lgd0557-lp140wf7/ but the is no bpp information?

Sunspark

dzwdev try typing xrandr --prop and xrandr --verbose in the terminal.

smilem

anything like this on windows?

ryans

Thanks @PrincessDoreena. Trying this on Ubuntu 22.04 (installing KDE), and following these instructions, I get some build failures after installing the dependencies.

Any idea how to fix it? Thanks!

$  cmake --build build --parallel
[ 10%] Automatic MOC for target kwin4_effect_limitcolors
[ 10%] Automatic MOC for target KWinEffectsInterface
[ 10%] Built target KWinEffectsInterface_autogen
[ 10%] Built target kwin4_effect_limitcolors_autogen
Consolidate compiler generated dependencies of target kwin4_effect_limitcolors
[ 35%] Built target KWinEffectsInterface
[ 40%] Building CXX object CMakeFiles/kwin4_effect_limitcolors.dir/limitcolors.cpp.o
[ 45%] Automatic MOC for target kwin_limitcolors_config
[ 45%] Built target kwin_limitcolors_config_autogen
Consolidate compiler generated dependencies of target kwin_limitcolors_config
[ 50%] Building CXX object CMakeFiles/kwin_limitcolors_config.dir/kwin_limitcolors_config_autogen/mocs_compilation.cpp.o
[ 55%] Building CXX object CMakeFiles/kwin_limitcolors_config.dir/limitcolors_config.cpp.o
In file included from /home/ryan/kwin-effect-limitcolors-master/build/kwin_limitcolors_config_autogen/EWIEGA46WW/moc_limitcolors_config.cpp:10,
                 from /home/ryan/kwin-effect-limitcolors-master/build/kwin_limitcolors_config_autogen/mocs_compilation.cpp:2:
/home/ryan/kwin-effect-limitcolors-master/build/kwin_limitcolors_config_autogen/EWIEGA46WW/../../../limitcolors_config.h:18:46: error: ‘KPluginMetaData’ does not name a type
   18 |     LimitColorsConfig(QObject *parent, const KPluginMetaData &data, const QVariantList &args);
      |                                              ^~~~~~~~~~~~~~~
In file included from /home/ryan/kwin-effect-limitcolors-master/limitcolors_config.cpp:7:
/home/ryan/kwin-effect-limitcolors-master/limitcolors_config.h:18:46: error: ‘KPluginMetaData’ does not name a type
   18 |     LimitColorsConfig(QObject *parent, const KPluginMetaData &data, const QVariantList &args);
      |                                              ^~~~~~~~~~~~~~~
gmake[2]: *** [CMakeFiles/kwin_limitcolors_config.dir/build.make:89: CMakeFiles/kwin_limitcolors_config.dir/kwin_limitcolors_config_autogen/mocs_compilation.cpp.o] Error 1
gmake[2]: *** Waiting for unfinished jobs....
/home/ryan/kwin-effect-limitcolors-master/limitcolors.cpp: In member function ‘virtual void KWin::LimitColorsEffect::reconfigure(KWin::Effect::ReconfigureFlags)’:
/home/ryan/kwin-effect-limitcolors-master/limitcolors.cpp:49:54: warning: unused parameter ‘flags’ [-Wunused-parameter]
   49 | void LimitColorsEffect::reconfigure(ReconfigureFlags flags) {
      |                                     ~~~~~~~~~~~~~~~~~^~~~~
/home/ryan/kwin-effect-limitcolors-master/limitcolors.cpp: In member function ‘bool KWin::LimitColorsEffect::loadData()’:
/home/ryan/kwin-effect-limitcolors-master/limitcolors.cpp:110:111: error: no match for ‘operator=’ (operand types are ‘std::unique_ptr<KWin::GLShader>’ and ‘KWin::GLShader*’)
  110 |     m_shader = ShaderManager::instance()->generateCustomShader(ShaderTrait::MapTexture, vertSource, fragSource);
      |                                                                                                               ^
In file included from /usr/include/c++/11/memory:76,
                 from /usr/include/x86_64-linux-gnu/qt5/QtCore/qsharedpointer_impl.h:71,
                 from /usr/include/x86_64-linux-gnu/qt5/QtCore/qsharedpointer.h:48,
                 from /usr/include/x86_64-linux-gnu/qt5/QtGui/qpixmap.h:48,
                 from /usr/include/x86_64-linux-gnu/qt5/QtGui/qicon.h:46,
                 from /usr/include/x86_64-linux-gnu/qt5/QtGui/QIcon:1,
                 from /usr/include/kwineffects.h:21,
                 from /home/ryan/kwin-effect-limitcolors-master/limitcolors.h:9,
                 from /home/ryan/kwin-effect-limitcolors-master/limitcolors.cpp:7:
/usr/include/c++/11/bits/unique_ptr.h:386:9: note: candidate: ‘template<class _Up, class _Ep> typename std::enable_if<std::__and_<std::__and_<std::is_convertible<typename std::unique_ptr<_Up, _Ep>::pointer, typename std::__uniq_ptr_impl<_Tp, _Dp>::pointer>, std::__not_<std::is_array<_Up> > >, std::is_assignable<_T2&, _U2&&> >::value, std::unique_ptr<_Tp, _Dp>&>::type std::unique_ptr<_Tp, _Dp>::operator=(std::unique_ptr<_Up, _Ep>&&) [with _Up = _Up; _Ep = _Ep; _Tp = KWin::GLShader; _Dp = std::default_delete<KWin::GLShader>]’
  386 |         operator=(unique_ptr<_Up, _Ep>&& __u) noexcept
      |         ^~~~~~~~
/usr/include/c++/11/bits/unique_ptr.h:386:9: note:   template argument deduction/substitution failed:
/home/ryan/kwin-effect-limitcolors-master/limitcolors.cpp:110:111: note:   mismatched types ‘std::unique_ptr<_Tp, _Dp>’ and ‘KWin::GLShader*’
  110 |     m_shader = ShaderManager::instance()->generateCustomShader(ShaderTrait::MapTexture, vertSource, fragSource);
      |                                                                                                               ^
In file included from /usr/include/c++/11/memory:76,
                 from /usr/include/x86_64-linux-gnu/qt5/QtCore/qsharedpointer_impl.h:71,
                 from /usr/include/x86_64-linux-gnu/qt5/QtCore/qsharedpointer.h:48,
                 from /usr/include/x86_64-linux-gnu/qt5/QtGui/qpixmap.h:48,
                 from /usr/include/x86_64-linux-gnu/qt5/QtGui/qicon.h:46,
                 from /usr/include/x86_64-linux-gnu/qt5/QtGui/QIcon:1,
                 from /usr/include/kwineffects.h:21,
                 from /home/ryan/kwin-effect-limitcolors-master/limitcolors.h:9,
                 from /home/ryan/kwin-effect-limitcolors-master/limitcolors.cpp:7:
/usr/include/c++/11/bits/unique_ptr.h:371:19: note: candidate: ‘std::unique_ptr<_Tp, _Dp>& std::unique_ptr<_Tp, _Dp>::operator=(std::unique_ptr<_Tp, _Dp>&&) [with _Tp = KWin::GLShader; _Dp = std::default_delete<KWin::GLShader>]’
  371 |       unique_ptr& operator=(unique_ptr&&) = default;
      |                   ^~~~~~~~
/usr/include/c++/11/bits/unique_ptr.h:371:29: note:   no known conversion for argument 1 from ‘KWin::GLShader*’ to ‘std::unique_ptr<KWin::GLShader>&&’
  371 |       unique_ptr& operator=(unique_ptr&&) = default;
      |                             ^~~~~~~~~~~~
/usr/include/c++/11/bits/unique_ptr.h:395:7: note: candidate: ‘std::unique_ptr<_Tp, _Dp>& std::unique_ptr<_Tp, _Dp>::operator=(std::nullptr_t) [with _Tp = KWin::GLShader; _Dp = std::default_delete<KWin::GLShader>; std::nullptr_t = std::nullptr_t]’
  395 |       operator=(nullptr_t) noexcept
      |       ^~~~~~~~
/usr/include/c++/11/bits/unique_ptr.h:395:17: note:   no known conversion for argument 1 from ‘KWin::GLShader*’ to ‘std::nullptr_t’
  395 |       operator=(nullptr_t) noexcept
      |                 ^~~~~~~~~
/home/ryan/kwin-effect-limitcolors-master/limitcolors.cpp: In member function ‘virtual void KWin::LimitColorsEffect::paintScreen(int, const QRegion&, KWin::ScreenPaintData&)’:
/home/ryan/kwin-effect-limitcolors-master/limitcolors.cpp:135:58: error: invalid use of incomplete type ‘class KWin::GLFramebuffer’
  135 |     m_frameBuffer.reset(new GLFramebuffer(m_texture.get()));
      |                                                          ^
In file included from /home/ryan/kwin-effect-limitcolors-master/limitcolors.cpp:7:
/home/ryan/kwin-effect-limitcolors-master/limitcolors.h:16:7: note: forward declaration of ‘class KWin::GLFramebuffer’
   16 | class GLFramebuffer;
      |       ^~~~~~~~~~~~~
/home/ryan/kwin-effect-limitcolors-master/limitcolors.cpp:137:20: error: incomplete type ‘KWin::GLFramebuffer’ used in nested name specifier
  137 |     GLFramebuffer::pushFramebuffer(m_frameBuffer.get());
      |                    ^~~~~~~~~~~~~~~
/home/ryan/kwin-effect-limitcolors-master/limitcolors.cpp:139:20: error: incomplete type ‘KWin::GLFramebuffer’ used in nested name specifier
  139 |     GLFramebuffer::popFramebuffer();
      |                    ^~~~~~~~~~~~~~
/home/ryan/kwin-effect-limitcolors-master/limitcolors.cpp:154:43: error: cannot convert ‘int’ to ‘const QRect&’
  154 |     m_texture->render(screen->geometry(), 1);
      |                                           ^
      |                                           |
      |                                           int
In file included from /usr/include/kwinglutils.h:17,
                 from /home/ryan/kwin-effect-limitcolors-master/limitcolors.cpp:15:
/usr/include/kwingltexture.h:106:53: note:   initializing argument 2 of ‘void KWin::GLTexture::render(const QRegion&, const QRect&, bool)’
  106 |     void render(const QRegion &region, const QRect& rect, bool hardwareClipping = false);
      |                                        ~~~~~~~~~~~~~^~~~
gmake[2]: *** [CMakeFiles/kwin4_effect_limitcolors.dir/build.make:99: CMakeFiles/kwin4_effect_limitcolors.dir/limitcolors.cpp.o] Error 1
gmake[1]: *** [CMakeFiles/Makefile2:414: CMakeFiles/kwin4_effect_limitcolors.dir/all] Error 2
gmake[1]: *** Waiting for unfinished jobs....
In file included from /usr/include/KF5/KCoreAddons/KPluginFactory:1,
                 from /home/ryan/kwin-effect-limitcolors-master/limitcolors_config.cpp:15:
/home/ryan/kwin-effect-limitcolors-master/limitcolors_config.cpp: In constructor ‘kwin_limitcolors_config_factory::kwin_limitcolors_config_factory()’:
/home/ryan/kwin-effect-limitcolors-master/limitcolors_config.cpp:19:1: error: no matching function for call to ‘kwin_limitcolors_config_factory::registerPlugin<LimitColorsConfig>()’
   19 | K_PLUGIN_CLASS(LimitColorsConfig)
      | ^~~~~~~~~~~~~~
In file included from /usr/include/KF5/KCoreAddons/KPluginFactory:1,
                 from /home/ryan/kwin-effect-limitcolors-master/limitcolors_config.cpp:15:
/usr/include/KF5/KCoreAddons/kpluginfactory.h:719:10: note: candidate: ‘void KPluginFactory::registerPlugin(const QString&, KPluginFactory::CreateInstanceFunction) [with T = LimitColorsConfig; KPluginFactory::CreateInstanceFunction = QObject* (*)(QWidget*, QObject*, const QList<QVariant>&)]’
  719 |     void registerPlugin(const QString &keyword, CreateInstanceFunction instanceFunction)
      |          ^~~~~~~~~~~~~~
/usr/include/KF5/KCoreAddons/kpluginfactory.h:719:10: note:   candidate expects 2 arguments, 0 provided
/usr/include/KF5/KCoreAddons/kpluginfactory.h:746:10: note: candidate: ‘template<class T, typename std::enable_if<KPluginFactory::InheritanceChecker<impl>::enabled, int>::type <anonymous> > void KPluginFactory::registerPlugin()’
  746 |     void registerPlugin()
      |          ^~~~~~~~~~~~~~
/usr/include/KF5/KCoreAddons/kpluginfactory.h:746:10: note:   template argument deduction/substitution failed:
/usr/include/KF5/KCoreAddons/kpluginfactory.h:745:74: error: no type named ‘type’ in ‘struct std::enable_if<false, int>’
  745 |     template<class T, enable_if_t<InheritanceChecker<T>::enabled, int> = 0>
      |                                                                          ^
/usr/include/KF5/KCoreAddons/kpluginfactory.h:759:10: note: candidate: ‘template<class T, typename std::enable_if<KPluginFactory::InheritanceChecker<impl>::enabled, int>::type <anonymous> > void KPluginFactory::registerPlugin(const QString&)’
  759 |     void registerPlugin(const QString &keyword)
      |          ^~~~~~~~~~~~~~
/usr/include/KF5/KCoreAddons/kpluginfactory.h:759:10: note:   template argument deduction/substitution failed:
In file included from /usr/include/KF5/KCoreAddons/KPluginFactory:1,
                 from /home/ryan/kwin-effect-limitcolors-master/limitcolors_config.cpp:15:
/home/ryan/kwin-effect-limitcolors-master/limitcolors_config.cpp:19:1: note:   candidate expects 1 argument, 0 provided
   19 | K_PLUGIN_CLASS(LimitColorsConfig)
      | ^~~~~~~~~~~~~~
In file included from /usr/include/KF5/KCoreAddons/KPluginFactory:1,
                 from /home/ryan/kwin-effect-limitcolors-master/limitcolors_config.cpp:15:
/usr/include/KF5/KCoreAddons/kpluginfactory.h:788:10: note: candidate: ‘void KPluginFactory::registerPlugin(const QString&, KPluginFactory::CreateInstanceWithMetaDataFunction) [with T = LimitColorsConfig; KPluginFactory::CreateInstanceWithMetaDataFunction = QObject* (*)(QWidget*, QObject*, const KPluginMetaData&, const QList<QVariant>&)]’
  788 |     void registerPlugin(const QString &keyword, CreateInstanceWithMetaDataFunction instanceFunction)
      |          ^~~~~~~~~~~~~~
/usr/include/KF5/KCoreAddons/kpluginfactory.h:788:10: note:   candidate expects 2 arguments, 0 provided
/usr/include/KF5/KCoreAddons/kpluginfactory.h:813:10: note: candidate: ‘template<class T, typename std::enable_if<KPluginFactory::InheritanceWithMetaDataChecker<impl>::enabled, int>::type <anonymous> > void KPluginFactory::registerPlugin()’
  813 |     void registerPlugin()
      |          ^~~~~~~~~~~~~~
/usr/include/KF5/KCoreAddons/kpluginfactory.h:813:10: note:   template argument deduction/substitution failed:
/usr/include/KF5/KCoreAddons/kpluginfactory.h:812:86: error: no type named ‘type’ in ‘struct std::enable_if<false, int>’
  812 |     template<class T, enable_if_t<InheritanceWithMetaDataChecker<T>::enabled, int> = 0>
      |                                                                                      ^
/usr/include/KF5/KCoreAddons/kpluginfactory.h:826:10: note: candidate: ‘template<class T, typename std::enable_if<KPluginFactory::InheritanceWithMetaDataChecker<impl>::enabled, int>::type <anonymous> > void KPluginFactory::registerPlugin(const QString&)’
  826 |     void registerPlugin(const QString &keyword)
      |          ^~~~~~~~~~~~~~
/usr/include/KF5/KCoreAddons/kpluginfactory.h:826:10: note:   template argument deduction/substitution failed:
In file included from /usr/include/KF5/KCoreAddons/KPluginFactory:1,
                 from /home/ryan/kwin-effect-limitcolors-master/limitcolors_config.cpp:15:
/home/ryan/kwin-effect-limitcolors-master/limitcolors_config.cpp:19:1: note:   candidate expects 1 argument, 0 provided
   19 | K_PLUGIN_CLASS(LimitColorsConfig)
      | ^~~~~~~~~~~~~~
/home/ryan/kwin-effect-limitcolors-master/limitcolors_config.cpp: At global scope:
/home/ryan/kwin-effect-limitcolors-master/limitcolors_config.cpp:21:1: error: no declaration matches ‘LimitColorsConfig::LimitColorsConfig(QObject*, const KPluginMetaData&, const QVariantList&)’
   21 | LimitColorsConfig::LimitColorsConfig(QObject *parent, const KPluginMetaData &data, const QVariantList &args)
      | ^~~~~~~~~~~~~~~~~
In file included from /home/ryan/kwin-effect-limitcolors-master/limitcolors_config.cpp:7:
/home/ryan/kwin-effect-limitcolors-master/limitcolors_config.h:13:7: note: candidates are: ‘LimitColorsConfig::LimitColorsConfig(const LimitColorsConfig&)’
   13 | class LimitColorsConfig : public KCModule
      |       ^~~~~~~~~~~~~~~~~
/home/ryan/kwin-effect-limitcolors-master/limitcolors_config.h:18:5: note:                 ‘LimitColorsConfig::LimitColorsConfig(QObject*, const int&, const QVariantList&)’
   18 |     LimitColorsConfig(QObject *parent, const KPluginMetaData &data, const QVariantList &args);
      |     ^~~~~~~~~~~~~~~~~
/home/ryan/kwin-effect-limitcolors-master/limitcolors_config.h:13:7: note: ‘class LimitColorsConfig’ defined here
   13 | class LimitColorsConfig : public KCModule
      |       ^~~~~~~~~~~~~~~~~
gmake[2]: *** [CMakeFiles/kwin_limitcolors_config.dir/build.make:103: CMakeFiles/kwin_limitcolors_config.dir/limitcolors_config.cpp.o] Error 1
gmake[1]: *** [CMakeFiles/Makefile2:467: CMakeFiles/kwin_limitcolors_config.dir/all] Error 2
gmake: *** [Makefile:146: all] Error 2

dzwdev

not working on plasma6