Introduce the ColorScope class

it's an import in core, and advertises itself as an "attached property"
with this we can:
say that all its chidren are of a certain context, like "button" or
"complementary"

then anywhere there will be available an attached property, as ColorScope,
so like:

PlasmaCore.ColorScope {
 group: PlasmaCore.Theme.Complementary

 PlasmaComponents.Label {
   text: "foo"
   color: ColorScope.textColor
 }
}

src/declarativeimports/core/CMakeLists.txt

@@ -17,6 +17,7 @@ endif()
 
 set(corebindings_SRCS
     corebindingsplugin.cpp
+    colorscope.cpp
     datamodel.cpp
     datasource.cpp
     #    runnermodel.cpp

src/declarativeimports/core/colorscope.cpp

@@ -0,0 +1,100 @@
+/***************************************************************************
+ *   Copyright 2011 Marco Martin <mart@kde.org>                            *
+ *   Copyright 2011 Artur Duque de Souza <asouza@kde.org>                  *
+ *   Copyright 2013 Sebastian Kügler <sebas@kde.org>                       *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ *   This program is distributed in the hope that it will be useful,       *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU General Public License for more details.                          *
+ *                                                                         *
+ *   You should have received a copy of the GNU General Public License     *
+ *   along with this program; if not, write to the                         *
+ *   Free Software Foundation, Inc.,                                       *
+ *   51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA .        *
+ ***************************************************************************/
+
+#include "colorscope.h"
+
+#include <QQmlContext>
+#include <QQmlEngine>
+
+
+ColorScope *ColorScope::s_colorScope = 0;
+
+
+ColorScope::ColorScope(QQuickItem *parent)
+    : QQuickItem(parent),
+      m_group(Plasma::Theme::NormalColorGroup)
+{
+}
+
+ColorScope::~ColorScope()
+{
+
+}
+
+ColorScope *ColorScope::qmlAttachedProperties(QObject *object)
+{
+    QObject *p = object;
+    while (p) {
+        ColorScope *c = qobject_cast<ColorScope *>(p);
+        if (c) {
+            return c;
+        }
+        //this will be parent() for qobjects, parentItem for QQuickItems
+        QQuickItem *item = qobject_cast<QQuickItem *>(p);
+        if (item) {
+            p = item->parentItem();
+        } else {
+            p = p->parent();
+        }
+    }
+
+    if (!s_colorScope) {
+        s_colorScope = new ColorScope;
+    }
+
+    return s_colorScope;
+}
+
+
+
+void ColorScope::setColorGroup(Plasma::Theme::ColorGroup group)
+{
+    if (m_group == group) {
+        return;
+    }
+
+    m_group = group;
+
+    emit colorGroupChanged();
+    emit colorsChanged();
+}
+
+Plasma::Theme::ColorGroup ColorScope::colorGroup() const
+{
+    return m_group;
+}
+
+QColor ColorScope::textColor() const
+{
+    return m_theme.color(Plasma::Theme::TextColor, m_group);
+}
+
+QColor ColorScope::highlightColor() const
+{
+    return m_theme.color(Plasma::Theme::BackgroundColor, m_group);
+}
+
+QColor ColorScope::backgroundColor() const
+{
+    return m_theme.color(Plasma::Theme::BackgroundColor, m_group);
+}
+
+#include "moc_colorscope.cpp"

src/declarativeimports/core/colorscope.h

@@ -0,0 +1,66 @@
+/***************************************************************************
+ *   Copyright 2014 Marco Martin <mart@kde.org>                            *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ *   This program is distributed in the hope that it will be useful,       *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU General Public License for more details.                          *
+ *                                                                         *
+ *   You should have received a copy of the GNU General Public License     *
+ *   along with this program; if not, write to the                         *
+ *   Free Software Foundation, Inc.,                                       *
+ *   51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA .        *
+ ***************************************************************************/
+
+#ifndef COLORSCOPE_H
+#define COLORSCOPE_H
+
+#include <QQuickItem>
+#include <QWeakPointer>
+#include <QtCore/QVariant>
+#include <Plasma/Plasma>
+#include <Plasma/Theme>
+
+class QQuickItem;
+
+
+class ColorScope : public QQuickItem
+{
+    Q_OBJECT
+    Q_PROPERTY(Plasma::Theme::ColorGroup colorGroup READ colorGroup WRITE setColorGroup)
+    Q_PROPERTY(QColor textColor READ textColor NOTIFY colorsChanged)
+    Q_PROPERTY(QColor highlightColor READ highlightColor NOTIFY colorsChanged)
+    Q_PROPERTY(QColor backgroundColor READ backgroundColor NOTIFY colorsChanged)
+
+public:
+    ColorScope(QQuickItem *parent = 0);
+    ~ColorScope();
+
+    void setColorGroup(Plasma::Theme::ColorGroup group);
+    Plasma::Theme::ColorGroup colorGroup() const;
+
+    QColor textColor() const;
+    QColor highlightColor() const;
+    QColor backgroundColor() const;
+    
+    ////NEEDED BY QML TO CREATE ATTACHED PROPERTIES
+    static ColorScope *qmlAttachedProperties(QObject *object);
+
+Q_SIGNALS:
+    void colorGroupChanged();
+    void colorsChanged();
+
+private:
+    Plasma::Theme m_theme;
+    Plasma::Theme::ColorGroup m_group;
+    static ColorScope *s_colorScope;
+};
+
+QML_DECLARE_TYPEINFO(ColorScope, QML_HAS_ATTACHED_PROPERTIES)
+
+#endif

src/declarativeimports/core/corebindingsplugin.cpp

@@ -38,6 +38,7 @@
 #include "dialog.h"
 #include "iconitem.h"
 #include "serviceoperationstatus.h"
+#include "colorscope.h"
 
 #include "tooltip.h"
 #include "units.h"
@@ -81,6 +82,7 @@ void CoreBindingsPlugin::registerTypes(const char *uri)
 
     //qmlRegisterType<ThemeProxy>(uri, 2, 0, "Theme");
     qmlRegisterUncreatableType<Plasma::Theme>(uri, 2, 0, "Theme", "It is not possible to instantiate Theme directly.");
+    qmlRegisterType<ColorScope>(uri, 2, 0, "ColorScope");
 
     qmlRegisterType<Plasma::DataSource>(uri, 2, 0, "DataSource");
     qmlRegisterType<Plasma::DataModel>(uri, 2, 0, "DataModel");

src/plasma/private/theme_p.cpp

@@ -526,17 +526,47 @@ void ThemePrivate::saveSvgElementsCache()
     }
 }
 
-QColor ThemePrivate::color(Theme::ColorRole role) const
+QColor ThemePrivate::color(Theme::ColorRole role, Theme::ColorGroup group) const
 {
     switch (role) {
-    case Theme::TextColor:
+    case Theme::TextColor: {
-        return colorScheme.foreground(KColorScheme::NormalText).color();
+        switch (group) {
+        case Theme::ButtonColorGroup:
+            return buttonColorScheme.foreground(KColorScheme::NormalText).color();
+        case Theme::ViewColorGroup:
+            return viewColorScheme.foreground(KColorScheme::NormalText).color();
+        case Theme::ComplementaryColorGroup:
+            return color(Theme::ComplementaryTextColor, group);
+        default:
+            return colorScheme.foreground(KColorScheme::NormalText).color();
+        }
+    }
 
-    case Theme::HighlightColor:
+    case Theme::HighlightColor: {
-        return colorScheme.decoration(KColorScheme::HoverColor).color();
+        switch (group) {
+        case Theme::ButtonColorGroup:
+            return buttonColorScheme.decoration(KColorScheme::HoverColor).color();
+        case Theme::ViewColorGroup:
+            return viewColorScheme.decoration(KColorScheme::HoverColor).color();
+        case Theme::ComplementaryColorGroup:
+            return color(Theme::ComplementaryHoverColor, group);
+        default:
+            return colorScheme.decoration(KColorScheme::HoverColor).color();
+        }
+    }
 
-    case Theme::BackgroundColor:
+    case Theme::BackgroundColor: {
-        return colorScheme.background(KColorScheme::NormalBackground).color();
+        switch (group) {
+        case Theme::ButtonColorGroup:
+            return buttonColorScheme.background(KColorScheme::NormalBackground).color();
+        case Theme::ViewColorGroup:
+            return viewColorScheme.background(KColorScheme::NormalBackground).color();
+        case Theme::ComplementaryColorGroup:
+            return color(Theme::ComplementaryBackgroundColor, group);
+        default:
+            return colorScheme.background(KColorScheme::NormalBackground).color();
+        }
+    }
 
     case Theme::ButtonTextColor:
         return buttonColorScheme.foreground(KColorScheme::NormalText).color();

src/plasma/private/theme_p.h

@@ -79,7 +79,7 @@ public:
 
     const QString processStyleSheet(const QString &css);
     const QString svgStyleSheet(Plasma::Theme::ColorGroup group);
-    QColor color(Theme::ColorRole role) const;
+    QColor color(Theme::ColorRole role, Theme::ColorGroup group = Theme::NormalColorGroup) const;
 
 public Q_SLOTS:
     void compositingChanged(bool active);

src/plasma/svg.cpp

@@ -686,7 +686,7 @@ qreal Svg::devicePixelRatio()
     return d->devicePixelRatio;
 }
 
-void Svg::setColorGroup(Theme::ColorGroup group)
+void Svg::setColorGroup(Plasma::Theme::ColorGroup group)
 {
     if (d->colorGroup == group) {
         return;
@@ -695,9 +695,10 @@ void Svg::setColorGroup(Theme::ColorGroup group)
     d->colorGroup = group;
     d->renderer = 0;
     emit colorGroupChanged();
+    emit repaintNeeded();
 }
 
-Theme::ColorGroup Svg::colorGroup() const
+Plasma::Theme::ColorGroup Svg::colorGroup() const
 {
     return d->colorGroup;
 }

src/plasma/svg.h

@@ -61,7 +61,7 @@ class PLASMA_EXPORT Svg : public QObject
     Q_PROPERTY(bool multipleImages READ containsMultipleImages WRITE setContainsMultipleImages)
     Q_PROPERTY(QString imagePath READ imagePath WRITE setImagePath NOTIFY imagePathChanged)
     Q_PROPERTY(bool usingRenderingCache READ isUsingRenderingCache WRITE setUsingRenderingCache)
-    Q_PROPERTY(Theme::ColorGroup colorGroup READ colorGroup WRITE setColorGroup NOTIFY colorGroupChanged);
+    Q_PROPERTY(Plasma::Theme::ColorGroup colorGroup READ colorGroup WRITE setColorGroup NOTIFY colorGroupChanged);
 
 public:
     /**
@@ -101,12 +101,12 @@ public:
      * make them use ButtonTextColor/ButtonBackgroundColor
      * or ViewTextColor/ViewBackgroundColor
      */
-    void setColorGroup(Theme::ColorGroup group);
+    void setColorGroup(Plasma::Theme::ColorGroup group);
 
     /**
      * @return the color group for this Svg
      */
-    Theme::ColorGroup colorGroup() const;
+    Plasma::Theme::ColorGroup colorGroup() const;
 
     /**
      * Returns a pixmap of the SVG represented by this object.

src/plasma/theme.cpp

@@ -272,9 +272,9 @@ KSharedConfigPtr Theme::colorScheme() const
     return d->colors;
 }
 
-QColor Theme::color(ColorRole role) const
+QColor Theme::color(ColorRole role, ColorGroup group) const
 {
-    return d->color(role);
+    return d->color(role, group);
 }
 
 void Theme::setUseGlobalSettings(bool useGlobal)

src/plasma/theme.h

@@ -185,8 +185,9 @@ public:
      * Returns the text color to be used by items resting on the background
      *
      * @param role which role (usage pattern) to get the color for
+     * @param group which group we want a color of
      */
-    QColor color(ColorRole role) const;
+    QColor color(ColorRole role, ColorGroup group = NormalColorGroup) const;
 
     /**
      * Tells the theme whether to follow the global settings or use application