Read shadowColor from KDecoration2::DecorationShadow

.github/workflows/debian12.yml

@@ -35,7 +35,7 @@ jobs:
       run: |
         apt update 
         apt -y install --no-install-recommends aptitude
-        aptitude -y install --without-recommends cmake g++ gettext extra-cmake-modules qttools5-dev libkf5configwidgets-dev kwin-dev
+        aptitude -y install --without-recommends cmake g++ gettext extra-cmake-modules qttools5-dev libkf5configwidgets-dev kwin-dev libkdecorations2-dev
         aptitude -y install --without-recommends dpkg-dev file
 
     - name: Configure CMake

.github/workflows/fedora40.yml

@@ -33,7 +33,7 @@ jobs:
 
     - name: Install Dependencies
       run: |
-        dnf -y install cmake gcc-c++ extra-cmake-modules kwin-devel kf6-kconfigwidgets-devel libepoxy-devel kf6-kcmutils-devel qt6-qtbase-private-devel wayland-devel
+        dnf -y install cmake gcc-c++ extra-cmake-modules kwin-devel kf6-kconfigwidgets-devel libepoxy-devel kf6-kcmutils-devel qt6-qtbase-private-devel wayland-devel kdecoration-devel
         dnf -y install rpm-build
 
     - name: Configure CMake

.github/workflows/kubuntu2204-backports.yml

@@ -38,7 +38,7 @@ jobs:
       run: sudo add-apt-repository -y ppa:kubuntu-ppa/backports-extra
 
     - name: Install Dependencies
-      run: sudo aptitude install -y --without-recommends gettext extra-cmake-modules qttools5-dev libkf5configwidgets-dev kwin-dev
+      run: sudo aptitude install -y --without-recommends gettext extra-cmake-modules qttools5-dev libkf5configwidgets-dev kwin-dev libkdecorations2-dev
 
     - name: Configure CMake
       # Configure CMake in a 'build' subdirectory. `CMAKE_BUILD_TYPE` is only required if you are using a single-configuration generator such as make.

.github/workflows/kubuntu2404.yml

@@ -44,7 +44,7 @@ jobs:
     - name: Install Dependencies
       run: |
         apt -y install --no-install-recommends aptitude
-        aptitude install -y --without-recommends cmake g++ gettext extra-cmake-modules qttools5-dev libkf5configwidgets-dev kwin-dev
+        aptitude install -y --without-recommends cmake g++ gettext extra-cmake-modules qttools5-dev libkf5configwidgets-dev kwin-dev libkdecorations2-dev
         aptitude -y install --without-recommends dpkg-dev file
 
     - name: Initialize CodeQL

.github/workflows/neon-unstable.yml

@@ -40,7 +40,7 @@ jobs:
 
     - name: Install Dependencies
       run: |
-        sudo aptitude -y install --without-recommends cmake g++ gettext extra-cmake-modules qt6-base-dev-tools libkf6configwidgets-dev libkf6kcmutils-dev kwin-dev
+        sudo aptitude -y install --without-recommends cmake g++ gettext extra-cmake-modules qt6-base-dev-tools libkf6configwidgets-dev libkf6kcmutils-dev kwin-dev libkdecorations2-dev
         sudo aptitude -y install --without-recommends dpkg-dev file
 
     - name: Configure CMake

.github/workflows/neon.yml

@@ -47,7 +47,7 @@ jobs:
 
     - name: Install Dependencies
       run: |
-        sudo aptitude -y install --without-recommends cmake g++ gettext extra-cmake-modules qt6-base-dev-tools libkf6configwidgets-dev libkf6kcmutils-dev kwin-dev
+        sudo aptitude -y install --without-recommends cmake g++ gettext extra-cmake-modules qt6-base-dev-tools libkf6configwidgets-dev libkf6kcmutils-dev kwin-dev libkdecorations2-dev
         sudo aptitude -y install --without-recommends dpkg-dev file
 
     - name: Initialize CodeQL

CMakeLists.txt

@@ -17,6 +17,7 @@ if(${QT_MAJOR_VERSION} EQUAL 6)
 else()
     find_package(KWinEffects REQUIRED COMPONENTS kwineffects kwinglutils)
 endif ()
+find_package(KDecoration2 REQUIRED COMPONENTS KDecoration)
 find_package(epoxy REQUIRED)
 find_package(XCB REQUIRED COMPONENTS XCB)
 find_package(KWinDBusInterface CONFIG REQUIRED)

src/CMakeLists.txt

@@ -14,9 +14,13 @@ set(effect_SRCS
 kconfig_add_kcfg_files(effect_SRCS Config.kcfgc)
 kcoreaddons_add_plugin(kwin4_effect_shapecorners SOURCES ${effect_SRCS} INSTALL_NAMESPACE "kwin/effects/plugins/")
 
+target_include_directories(kwin4_effect_shapecorners PUBLIC
+    "/usr/include/KDecoration2"
+)
 target_link_libraries(kwin4_effect_shapecorners
     Qt${QT_MAJOR_VERSION}::DBus
     KF${QT_MAJOR_VERSION}::ConfigGui
+    KDecoration2::KDecoration
 )
 if(${QT_MAJOR_VERSION} EQUAL 6)
     target_link_libraries(kwin4_effect_shapecorners

src/Window.cpp

@@ -12,6 +12,8 @@
 #else
 #include <kwineffects.h>
 #endif
+#include <KDecoration2/Decoration>
+#include <KDecoration2/DecorationShadow>
 
 QWidget ShapeCorners::Window::m_widget {};
 
@@ -59,7 +61,7 @@ void ShapeCorners::Window::animateProperties(const std::chrono::milliseconds& ti
     float configShadowSize;
     float configOutlineSize;
     float configSecondOutlineSize;
-    Color configShadowColor;
+    Color configShadowColor = Color(getDecorationShadowColor());
     Color configOutlineColor;
     Color configSecondOutlineColor;
     const QPalette& m_palette = m_widget.palette();
@@ -68,10 +70,6 @@ void ShapeCorners::Window::animateProperties(const std::chrono::milliseconds& ti
         configShadowSize = static_cast<float>(Config::shadowSize());
         configOutlineSize = static_cast<float>(Config::outlineThickness());
         configSecondOutlineSize = static_cast<float>(Config::secondOutlineThickness());
-
-        configShadowColor = Color(Config::activeShadowUsePalette() ?
-                                  m_palette.color(QPalette::Active, static_cast<QPalette::ColorRole>(Config::activeShadowPalette())):
-                                  Config::shadowColor());
         configShadowColor.setAlpha(Config::activeShadowAlpha());
 
         configOutlineColor = Color(Config::activeOutlineUsePalette() ?
@@ -88,10 +86,6 @@ void ShapeCorners::Window::animateProperties(const std::chrono::milliseconds& ti
         configShadowSize = static_cast<float>(Config::inactiveShadowSize());
         configOutlineSize = static_cast<float>(Config::inactiveOutlineThickness());
         configSecondOutlineSize = static_cast<float>(Config::inactiveSecondOutlineThickness());
-
-        configShadowColor = Color(Config::inactiveShadowUsePalette() ?
-                                  m_palette.color(QPalette::Inactive, static_cast<QPalette::ColorRole>(Config::inactiveShadowPalette())):
-                                  Config::inactiveShadowColor());
         configShadowColor.setAlpha(Config::inactiveShadowAlpha());
 
         configOutlineColor = Color(Config::inactiveOutlineUsePalette() ?
@@ -186,3 +180,16 @@ void ShapeCorners::Window::animateProperties(const std::chrono::milliseconds& ti
 #endif
     w->addRepaintFull();
 }
+
+QColor ShapeCorners::Window::getDecorationShadowColor() const {
+    QColor result = Qt::transparent;
+    auto decoration = w->decoration();
+    if (decoration) {
+        auto shadow = decoration->shadow().get();
+        if (shadow) {
+            auto shadowImage = shadow->shadow();
+            result = shadowImage.pixelColor(135, 54);
+        }
+    }
+    return result;
+}

src/Window.h

@@ -57,6 +57,8 @@ namespace ShapeCorners {
          * \brief Used only for its `palette()` function which holds the currently active highlight colors.
          */
         static QWidget m_widget;
+
+        [[nodiscard]] QColor getDecorationShadowColor() const;
     };
 }
 

src/kcm/KCM.cpp

@@ -28,14 +28,12 @@ ShapeCorners::KCM::KCM(QWidget* parent, const QVariantList& args)
         QIcon icon (pix);
         ui->kcfg_ActiveOutlinePalette->setItemIcon(index, icon);
         ui->kcfg_ActiveSecondOutlinePalette->setItemIcon(index, icon);
-        ui->kcfg_ActiveShadowPalette->setItemIcon(index, icon);
 
         c = palette().color(QPalette::Inactive, static_cast<QPalette::ColorRole>(index));
         pix.fill(c);
         QIcon icon2 (pix);
         ui->kcfg_InactiveOutlinePalette->setItemIcon(index, icon2);
         ui->kcfg_InactiveSecondOutlinePalette->setItemIcon(index, icon2);
-        ui->kcfg_InactiveShadowPalette->setItemIcon(index, icon2);
     }
 
     connect(ui->kcfg_ActiveOutlinePalette, QOverload<int>::of(&QComboBox::currentIndexChanged), this, &KCM::update_colors);
@@ -52,13 +50,6 @@ ShapeCorners::KCM::KCM(QWidget* parent, const QVariantList& args)
     connect(ui->kcfg_ActiveSecondOutlineUsePalette, &QRadioButton::toggled, this, &KCM::update_colors);
     connect(ui->kcfg_InactiveSecondOutlineUsePalette, &QRadioButton::toggled, this, &KCM::update_colors);
 
-    connect(ui->kcfg_ActiveShadowPalette, QOverload<int>::of(&QComboBox::currentIndexChanged), this, &KCM::update_colors);
-    connect(ui->kcfg_ActiveShadowPalette, QOverload<int>::of(&QComboBox::currentIndexChanged), this, &KCM::update_colors);
-    connect(ui->kcfg_ShadowColor, &KColorButton::changed, this, &KCM::update_colors);
-    connect(ui->kcfg_InactiveShadowColor, &KColorButton::changed, this, &KCM::update_colors);
-    connect(ui->kcfg_ActiveShadowUsePalette, &QRadioButton::toggled, this, &KCM::update_colors);
-    connect(ui->kcfg_InactiveShadowUsePalette, &QRadioButton::toggled, this, &KCM::update_colors);
-
     // It was expected that the Apply button would get enabled automatically as the gradient sliders move, but it doesn't.
     // Maybe it is a bug on the KCM side. Need to check and delete these lines later.
     connect(ui->kcfg_ActiveShadowAlpha, &KGradientSelector::sliderMoved, this, &KCM::markAsChanged);
@@ -150,16 +141,6 @@ void ShapeCorners::KCM::update_colors() {
     index = ui->kcfg_InactiveSecondOutlinePalette->currentIndex();
     color = checked ? palette().color(QPalette::Inactive, static_cast<QPalette::ColorRole>(index)): ui->kcfg_InactiveSecondOutlineColor->color();
     ui->kcfg_InactiveSecondOutlineAlpha->setSecondColor(color);
-
-    checked = ui->kcfg_ActiveShadowUsePalette->isChecked();
-    index = ui->kcfg_ActiveShadowPalette->currentIndex();
-    color = checked ? palette().color(QPalette::Active, static_cast<QPalette::ColorRole>(index)): ui->kcfg_ShadowColor->color();
-    ui->kcfg_ActiveShadowAlpha->setSecondColor(color);
-
-    checked = ui->kcfg_InactiveShadowUsePalette->isChecked();
-    index = ui->kcfg_InactiveShadowPalette->currentIndex();
-    color = checked ? palette().color(QPalette::Inactive, static_cast<QPalette::ColorRole>(index)): ui->kcfg_InactiveShadowColor->color();
-    ui->kcfg_InactiveShadowAlpha->setSecondColor(color);
 }
 
 void ShapeCorners::KCM::update_windows() const {