Method CalculateRequisition

examples/CustomWidget.cpp:152–167

In order for SFGUI to know how much space your widget takes up and position other widgets accordingly, it calls the CalculateRequisition() method. This method should return the total screen size of the widget.

		// CalculateRequisition() method. This method should return the
		// total screen size of the widget.
		sf::Vector2f CalculateRequisition() override {
			// The size of a widget might depend on the current properties
			const std::string& font_name( sfg::Context::Get().GetEngine().GetProperty<std::string>( "FontName", shared_from_this() ) );
			unsigned int font_size( sfg::Context::Get().GetEngine().GetProperty<unsigned int>( "FontSize", shared_from_this() ) );
			const sf::Font& font( *sfg::Context::Get().GetEngine().GetResourceManager().GetFont( font_name ) );

			// The current engine can also be used to retrieve font metric
			// data size as size or line height.
			auto requisition = sfg::Context::Get().GetEngine().GetTextStringMetrics( m_label, font, font_size );
			requisition.y = sfg::Context::Get().GetEngine().GetFontLineHeight( font, font_size );

			requisition *= 3.f;
			requisition += sf::Vector2f( 20.f, 20.f );

			return requisition;
		}

		// You can override certain methods in order to be informed
		// when certain events happen. This handler handles the state change