[Qt-interest] Setting the background color of a tab

[Stefan Löffler]

Hi,

On 2011-08-04 10:23, Jonas Gehring wrote:
> Hi Jake,
>
> Here's a short example for a custom QTabBar implementation. You
> need to subclass QTabWidget in order to use it.
>
> class ColorTabBar : public QTabBar
> {
> public:
> 	ColorTabBar(QWidget *parent = 0) : QTabBar(parent) { }
>
> 	void setTabColor(int index, const QColor &color) {
> 		m_colors[index] = color;
> 	}
>
> protected:
> 	void paintEvent(QPaintEvent *event) {
> 		QStylePainter p(this);
> 		for (int i = 0; i < count(); i++) {
> 			QStyleOptionTabV3 option;
> 			QTabBar::initStyleOption(&option, i);
>
> 			// Apply custom background color
> 			if (m_colors.contains(i)) {
> 				option.palette.setColor(backgroundRole(), m_colors[i]);
> 			}
>
> 			p.drawControl(QStyle::CE_TabBarTab, option);
> 		}
> 	}
>
> private:
> 	QMap<int, QColor> m_colors;
> };
>
> This should illustrate the basic idea. You should take a look at QTabBar's
> implementation for corner case handling, though:
> http://qt.gitorious.org/qt/qt/blobs/4.7/src/gui/widgets/qtabbar.cpp#line1526

Wouldn't it be better to simply override initStyleOption in your
subclass? Something like (not tested)

void initStyleOption(QStyleOptionTab *option, int tabIndex) const
{
	QTabBar::initStyleOption(option, tabIndex);
	if (option && m_colors.contains(i)) {
		option->palette.setColor(backgroundRole(), m_colors[i]);
	}

}

HTH
Stefan