Refresh pieces bar colors once color scheme is changed

PR #21183.
Closes #21155.

src/gui/properties/piecesbar.h

@@ -1,5 +1,6 @@
 /*
  * Bittorrent Client using Qt and libtorrent.
+ * Copyright (C) 2024  Vladimir Golovnev <glassez@yandex.ru>
  * Copyright (C) 2016  Eugene Shalygin
  * Copyright (C) 2006  Christophe Dumez
  *
@@ -54,17 +55,15 @@ public:
 
     virtual void clear();
 
-    // QObject interface
-    bool event(QEvent *e) override;
-
 protected:
-    // QWidget interface
+    bool event(QEvent *e) override;
     void enterEvent(QEnterEvent *e) override;
     void leaveEvent(QEvent *e) override;
     void mouseMoveEvent(QMouseEvent *e) override;
-
     void paintEvent(QPaintEvent *e) override;
-    void requestImageUpdate();
+
+    virtual void updateColors();
+    void redraw();
 
     QColor backgroundColor() const;
     QColor borderColor() const;
@@ -82,11 +81,9 @@ private:
     void highlightFile(int imagePos);
 
     virtual QString simpleToolTipText() const = 0;
+    virtual QImage renderImage() = 0;
 
-    // draw new image to replace the actual image
-    // returns true if image was successfully updated
-    virtual bool updateImage(QImage &image) = 0;
-    void updatePieceColors();
+    void updateColorsImpl();
 
     const BitTorrent::Torrent *m_torrent = nullptr;
     QImage m_image;