src/selectionmode/backgroundcolorhelper.h

   1 /*
   2     This file is part of the KDE project
   3     SPDX-FileCopyrightText: 2022 Felix Ernst <felixernst@zohomail.eu>
   4
   5     SPDX-License-Identifier: LGPL-2.1-only OR LGPL-3.0-only OR LicenseRef-KDE-Accepted-LGPL
   6 */
   7
   8 #ifndef BACKGROUNDCOLORHELPER_H
   9 #define BACKGROUNDCOLORHELPER_H
  10
  11 #include <QColor>
  12 #include <QPointer>
  13
  14 #include <memory>
  15
  16 class QWidget;
  17
  18 namespace SelectionMode
  19 {
  20
  21 /**
  22  * @brief A Singleton class for managing the colors of selection mode widgets.
  23  */
  24 class BackgroundColorHelper
  25 {
  26 public:
  27     static BackgroundColorHelper *instance();
  28
  29     /**
  30      * Changes the background color of @p widget to a distinct color scheme matching color which makes it clear that the widget belongs to the selection mode.
  31      * The background color of @p widget will from now on be updated automatically when the palette of the application changes.
  32      */
  33     void controlBackgroundColor(QWidget *widget);
  34
  35 private:
  36     BackgroundColorHelper();
  37
  38     /**
  39      * Called when the palette of the application changes.
  40      * Triggers updateBackgroundColor() and the updates the background color of m_colorControlledWidgets.
  41      * @see updateBackgroundColor
  42      */
  43     void slotPaletteChanged();
  44
  45     /** Calculates a new m_colorControlledWidgets based on the current colour scheme of the application. */
  46     void updateBackgroundColor();
  47
  48 private:
  49     /// The widgets who have given up control over the background color to BackgroundColorHelper.
  50     std::vector<QPointer<QWidget>> m_colorControlledWidgets;
  51     /// The color to be used for the widgets' backgrounds.
  52     QColor m_backgroundColor;
  53
  54     /// Singleton object
  55     static BackgroundColorHelper *s_instance;
  56 };
  57
  58 }
  59
  60 #endif // BACKGROUNDCOLORHELPER_H