plugins/dialogparent: Disable darkening while picking colors

Integrate with colorpicker effect to disable window darkening while
color picker effect is active. Unfortunately, this solution has couple
of limitations:
- active state of effects is not an observable property, so a new
  property had to be added to the effects singleton;
- consequently, list of active effects is not an observable property, so
  the whole thing could not be implemented in pure QML in the dialog
  parent effects;
- actual isActive() state of the color picker for whatever reason
  required that m_scheduledPosition is not an invalid point,
  effectively making it always inactive except for a brief moment
  between addRepaintFull() call and paintScreen() callback. That check
  had to be removed.
- QColorDialog windows are still modal and darkened by default;
- QColorDialog on X11 does not use portals/KWin, so this trick does not
  apply at all;
- effects->isScreenLocked() which isActive() depends on is not an
  observable property either.

BUG: 172921

src/effect/effecthandler.cpp

@@ -432,6 +432,11 @@ bool EffectsHandler::hasActiveFullScreenEffect() const
     return fullscreen_effect;
 }
 
+bool EffectsHandler::isColorPickerActive() const
+{
+    return isEffectActive(QStringLiteral("colorpicker"));
+}
+
 bool EffectsHandler::grabKeyboard(Effect *effect)
 {
     if (keyboard_grab_effect != nullptr) {

src/effect/effecthandler.h

@@ -146,6 +146,7 @@ class KWIN_EXPORT EffectsHandler : public QObject
     Q_PROPERTY(QSize virtualScreenSize READ virtualScreenSize NOTIFY virtualScreenSizeChanged)
     Q_PROPERTY(QRect virtualScreenGeometry READ virtualScreenGeometry NOTIFY virtualScreenGeometryChanged)
     Q_PROPERTY(bool hasActiveFullScreenEffect READ hasActiveFullScreenEffect NOTIFY hasActiveFullScreenEffectChanged)
+    Q_PROPERTY(bool colorPickerActive READ isColorPickerActive NOTIFY colorPickerActiveChanged)
 
     /**
      * The status of the session i.e if the user is logging out
@@ -699,10 +700,15 @@ public:
     KSharedConfigPtr inputConfig() const;
 
     /**
-     * Returns if activeFullScreenEffect is set
+     * Returns true if activeFullScreenEffect is set
      */
     bool hasActiveFullScreenEffect() const;
 
+    /**
+     * Returns true if color picker effect is currently picking colors.
+     */
+    bool isColorPickerActive() const;
+
     /**
      * Render the supplied OffscreenQuickView onto the scene
      * It can be called at any point during the scene rendering
@@ -1032,6 +1038,8 @@ Q_SIGNALS:
      */
     void hasActiveFullScreenEffectChanged();
 
+    void colorPickerActiveChanged();
+
     /**
      * This signal is emitted when the session state was changed
      * @since 5.18

src/plugins/colorpicker/colorpicker.cpp

@@ -51,7 +51,10 @@ ColorPickerEffect::ColorPickerEffect()
     QDBusConnection::sessionBus().registerObject(QStringLiteral("/ColorPicker"), this, QDBusConnection::ExportScriptableContents);
 }
 
-ColorPickerEffect::~ColorPickerEffect() = default;
+ColorPickerEffect::~ColorPickerEffect()
+{
+    setPicking(false);
+}
 
 void ColorPickerEffect::paintScreen(const RenderTarget &renderTarget, const RenderViewport &viewport, int mask, const QRegion &region, Output *screen)
 {
@@ -67,7 +70,7 @@ void ColorPickerEffect::paintScreen(const RenderTarget &renderTarget, const Rend
         glReadPixels(texturePosition.x(), renderTarget.size().height() - texturePosition.y() - PIXEL_SIZE, PIXEL_SIZE, PIXEL_SIZE, GL_RGBA, GL_FLOAT, data.data());
         QVector3D sRGB = 255 * renderTarget.colorDescription().mapTo(QVector3D(data[0], data[1], data[2]), sRGBencoding);
         QDBusConnection::sessionBus().send(m_replyMessage.createReply(QColor(sRGB.x(), sRGB.y(), sRGB.z())));
-        m_picking = false;
+        setPicking(false);
         m_scheduledPosition = QPoint(-1, -1);
     }
 }
@@ -81,7 +84,7 @@ QColor ColorPickerEffect::pick()
         sendErrorReply(QDBusError::Failed, "Color picking is already in progress");
         return QColor();
     }
-    m_picking = true;
+    setPicking(true);
     m_replyMessage = message();
     setDelayedReply(true);
     showInfoMessage();
@@ -91,7 +94,7 @@ QColor ColorPickerEffect::pick()
             if (p == QPointF(-1, -1)) {
                 // error condition
                 QDBusConnection::sessionBus().send(m_replyMessage.createErrorReply(QStringLiteral("org.kde.kwin.ColorPicker.Error.Cancelled"), "Color picking got cancelled"));
-                m_picking = false;
+                setPicking(false);
             } else {
                 m_scheduledPosition = p;
                 effects->addRepaintFull();
@@ -110,9 +113,17 @@ void ColorPickerEffect::hideInfoMessage()
     effects->hideOnScreenMessage();
 }
 
+void ColorPickerEffect::setPicking(bool picking)
+{
+    if (m_picking != picking) {
+        m_picking = picking;
+        Q_EMIT effects->colorPickerActiveChanged();
+    }
+}
+
 bool ColorPickerEffect::isActive() const
 {
-    return m_picking && ((m_scheduledPosition != QPoint(-1, -1))) && !effects->isScreenLocked();
+    return m_picking && !effects->isScreenLocked();
 }
 
 } // namespace

src/plugins/colorpicker/colorpicker.h

@@ -41,6 +41,7 @@ public Q_SLOTS:
 private:
     void showInfoMessage();
     void hideInfoMessage();
+    void setPicking(bool picking);
 
     QDBusMessage m_replyMessage;
     QPointF m_scheduledPosition;

src/plugins/dialogparent/package/contents/code/main.js

@@ -20,7 +20,7 @@ var dialogParentEffect = {
                 dialogParentEffect.restartAnimation(window);
             }
         });
-        window.windowModalityChanged.connect(dialogParentEffect.modalDialogChanged);
+        window.windowModalityChanged.connect(dialogParentEffect.windowModalityChanged);
         window.windowDesktopsChanged.connect(dialogParentEffect.cancelAnimationInstant);
         window.windowDesktopsChanged.connect(dialogParentEffect.restartAnimation);
 
@@ -97,23 +97,19 @@ var dialogParentEffect = {
         // effect has to come after the full screen effect in the effect chain,
         // otherwise this slot will be invoked before the full screen effect can mark
         // itself as a full screen effect.
-        if (effects.hasActiveFullScreenEffect) {
+        if (dialogParentEffect.globallyInhibited()) {
             return;
         }
 
-        var windows = effects.stackingOrder;
-        for (var i = 0; i < windows.length; ++i) {
-            var window = windows[i];
+        const windows = effects.stackingOrder;
+        for (const window of windows) {
             dialogParentEffect.cancelAnimationInstant(window);
             dialogParentEffect.restartAnimation(window);
         }
     },
-    modalDialogChanged: function(dialog) {
+    windowModalityChanged: function (window) {
         "use strict";
-        if (dialog.modal === false)
-            dialogParentEffect.dialogLostModality(dialog);
-        else if (dialog.modal === true)
-            dialogParentEffect.dialogGotModality(dialog);
+        dialogParentEffect.refreshWindowEffect(window);
     },
     restartAnimation: function (window) {
         "use strict";
@@ -125,19 +121,21 @@ var dialogParentEffect = {
             complete(window.dialogParentAnimation);
         }
     },
-    activeFullScreenEffectChanged: function () {
+    activeFullScreenOrColorPickerChanged: function () {
         "use strict";
-        var windows = effects.stackingOrder;
-        for (var i = 0; i < windows.length; ++i) {
-            var dialog = windows[i];
-            if (!dialog.modal) {
-                continue;
-            }
-            if (effects.hasActiveFullScreenEffect) {
-                dialogParentEffect.dialogLostModality(dialog);
-            } else {
-                dialogParentEffect.dialogGotModality(dialog);
-            }
+        const windows = effects.stackingOrder;
+        for (const window of windows) {
+            dialogParentEffect.refreshWindowEffect(window);
+        }
+    },
+    globallyInhibited: function () {
+        return effects.hasActiveFullScreenEffect || effects.colorPickerActive;
+    },
+    refreshWindowEffect: function (window) {
+        if (dialogParentEffect.globallyInhibited() || !window.modal) {
+            dialogParentEffect.dialogLostModality(window);
+        } else {
+            dialogParentEffect.dialogGotModality(window);
         }
     },
     init: function () {
@@ -147,7 +145,9 @@ var dialogParentEffect = {
         effects.windowClosed.connect(dialogParentEffect.windowClosed);
         effects.desktopChanged.connect(dialogParentEffect.desktopChanged);
         effects.activeFullScreenEffectChanged.connect(
-            dialogParentEffect.activeFullScreenEffectChanged);
+            dialogParentEffect.activeFullScreenOrColorPickerChanged);
+        effects.colorPickerActiveChanged.connect(
+            dialogParentEffect.activeFullScreenOrColorPickerChanged);
 
         windows = effects.stackingOrder;
         for (i = 0; i < windows.length; i += 1) {