Alternatives for Tailoring QTabBar's Look and Feel in Qt

• Custom Styles
  

  • If you're using a custom style for your QTabBar, you might need to handle the drawing of the base yourself in the style's paint event. In this case, you can check the value of drawBase and implement the desired visual style for the base area.

• Style Interaction
  

  • The drawBase property acts as a hint for the current style to customize the drawing of the base area. Different styles might render the base differently based on this property.
• • When set to true (default), the QTabBar draws a base area behind the tabs. This base provides a visual background for the tabs and helps separate them from the surrounding content.
  • Setting it to false hides the base, leaving only the individual tabs visible.

Important points to remember

• You cannot directly access or modify the drawing implementation of drawBase.
• drawBase doesn't directly control the drawing itself. It provides a hint for the style to handle the base appearance.

Resources

• While the source code for QTabBar::drawBase isn't publicly exposed, you can explore the general implementation of QTabBar for a better understanding: Qt source code for QTabBar is not publicly available, but you can explore related classes [invalid URL removed] (This link might not be directly accessible due to security restrictions, but it refers to the Qt source code browser).

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Setting drawBase to true (default)

#include <QApplication>
#include <QMainWindow>
#include <QTabBar>

int main(int argc, char *argv[])
{
  QApplication app(argc, argv);

  QMainWindow window;
  QTabBar* tabBar = new QTabBar();

  // Add some tabs
  tabBar->addTab("Tab 1");
  tabBar->addTab("Tab 2");

  // Set the tab bar as the central widget (shows base by default)
  window.setCentralWidget(tabBar);

  window.show();

  return app.exec();
}

This code creates a simple QMainWindow with a QTabBar as its central widget. Since drawBase is the default true, the base area will be drawn behind the tabs.

Disabling drawBase for a custom look

#include <QApplication>
#include <QMainWindow>
#include <QTabBar>
#include <QPainter>

class CustomTabBar : public QTabBar
{
  Q_OBJECT

public:
  void paintEvent(QPaintEvent* event) override
  {
    // Don't call the base class paintEvent (avoids default drawing)
    // Implement your custom drawing logic here

    // Example: Draw a simple background rectangle
    QPainter painter(this);
    painter.fillRect(rect(), Qt::lightGray);

    // Draw your custom tab visuals...

  }
};

int main(int argc, char *argv[])
{
  QApplication app(argc, argv);

  QMainWindow window;
  CustomTabBar* tabBar = new CustomTabBar();

  // Disable drawBase for custom painting
  tabBar->setDrawBase(false);

  // Add some tabs
  tabBar->addTab("Tab 1");
  tabBar->addTab("Tab 2");

  window.setCentralWidget(tabBar);

  window.show();

  return app.exec();
}

This example creates a custom CustomTabBar class that inherits from QTabBar. It overrides the paintEvent to handle the drawing itself. Here, drawBase is set to false to prevent the default base drawing. The paintEvent then implements a simple background fill with light gray, but you can replace this with your desired custom visuals for the tab bar.

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1. Sub-classing and Custom Painting
   

   As shown in the previous example, you can create a custom tab bar class that inherits from QTabBar and override the paintEvent. This gives you complete control over the drawing of the entire tab bar area, including the background and the tabs themselves. You can implement the desired visual style for the base area within the paintEvent.

2. Using Stylesheets
   

   Qt provides stylesheets as a way to customize the look and feel of widgets without subclassing. While stylesheets cannot directly target drawBase, you can use them to modify the styling of the tab bar itself. This might influence the visual appearance of the base area indirectly.

   For example, you could set a custom background color or image for the QTabBar using a stylesheet, which would effectively cover the default base drawing.

3. Creating a Custom Widget
   

   If you need more flexibility than QTabBar offers, you can create a custom widget from scratch. This widget can handle all the drawing and behavior related to your tab bar design. This approach requires more development effort but provides maximum control over the look and feel.

• If the built-in QTabBar functionality doesn't meet your needs at all, creating a custom widget from scratch offers the most flexibility.
• For more complex customizations or custom functionality, subclassing QTabBar and custom painting is the way to go.
• If you only need to modify the background appearance of the base area, using stylesheets might be sufficient.