http://sfgui.sfml-dev.de/forum/topic127-random-button-image.html

SFGUITest.cpp

#define SFML_STATIC
#include <SFML/Graphics.hpp>
#define SFGUI_STATIC
#include <SFGUI/SFGUI.hpp>

const int SCREEN_WIDTH = 800;
const int SCREEN_HEIGHT = 600;

class ButtonExample {
public:
	// Our button click handler.
	void OnButtonClick();

	void Run();


	//
	//My Stuff (1/4)
	//


	//Function called when toolboxTileSelectButton is clicked
	void tileSelectButtonClicked();

	//Function called when the tile type buttons are clicked
	void tileTypeClicked();

	//Boolean to indicate if the selection window is open or not
	bool toolboxTileSelectWindowIsShown;

	//Tile Select Window
	sfg::Window::Ptr toolboxTileSelectWindow;

	//
	//End of my stuff (1/4)
	//

private:
	// Create an SFGUI. This is required before doing anything with SFGUI.
	sfg::SFGUI m_sfgui;

	// Create the label pointer here to reach it from OnButtonClick().
	sfg::Label::Ptr m_label;


	//
	//My stuff (2/4)
	//


	//Button to open the selection window
	sfg::Button::Ptr toolboxTileSelectButton;

	//Box to contain toolboxTileSelectButton
	sfg::Box::Ptr tileSelectBox;

	//Alignment to center tileSelectBox
	sfg::Alignment::Ptr tileSelectAlignment;

	//Tile Select Window Stuff
	sfg::Box::Ptr toolboxTileSelectBox;

	sfg::Box::Ptr toolboxTileSelectScrolledWindowBox;

	sfg::ScrolledWindow::Ptr toolboxTileSelectScrolledWindow;


	//
	//End of my stuff (2/4)
	//
};

void ButtonExample::OnButtonClick() {
	m_label->SetText( "Hello SFGUI, pleased to meet you!" );
}

void ButtonExample::Run() {
	// Create SFML's window.
	sf::RenderWindow render_window( sf::VideoMode( SCREEN_WIDTH, SCREEN_HEIGHT ), "Hello world!" );


	//
	//My stuff (3/4)
	//


	// Create the tile select button
	toolboxTileSelectButton = sfg::Button::Create();
	//Creating an SF image for the button default
	sf::Image toolboxTileSelectButtonImage;
	//Loading the default image for the button
	toolboxTileSelectButtonImage.loadFromFile("default_box.png");
	//Creating a SFG image using the previous SF image
	sfg::Image::Ptr toolboxTileSelectButtonImageSFG = sfg::Image::Create(toolboxTileSelectButtonImage);
	//Setting the image of the button to the created default SFG image
	toolboxTileSelectButton->SetImage(toolboxTileSelectButtonImageSFG);
	//Setting the current tool button's ID to the name of the image
	toolboxTileSelectButton->SetId("default_box.png");
	//Setting the button's on click signal to trigger the tile selection window
	toolboxTileSelectButton->GetSignal( sfg::Widget::OnLeftClick ).Connect( &ButtonExample::tileSelectButtonClicked, this );

	//Creating box and alignment to make button small and centered
	tileSelectBox = sfg::Box::Create( sfg::Box::HORIZONTAL, 5.0f );
	tileSelectBox->Pack( toolboxTileSelectButton, false );
	tileSelectAlignment = sfg::Alignment::Create();
	tileSelectBox->Pack( tileSelectAlignment, true, true );
	tileSelectAlignment->Add( toolboxTileSelectButton );
	tileSelectAlignment->SetScale( sf::Vector2f( .0f, .0f ) );
	tileSelectAlignment->SetAlignment( sf::Vector2f( .5f, .5f ) );

	//Box for inside the scrolled window
	toolboxTileSelectScrolledWindowBox = sfg::Box::Create( sfg::Box::VERTICAL );

	// Create the ScrolledWindow.
	toolboxTileSelectScrolledWindow = sfg::ScrolledWindow::Create();

	// Set the ScrolledWindow to always show the horizontal scrollbar
	// and only show the vertical scrollbar when needed.
	toolboxTileSelectScrolledWindow->SetScrollbarPolicy( sfg::ScrolledWindow::HORIZONTAL_AUTOMATIC | sfg::ScrolledWindow::VERTICAL_AUTOMATIC );

	// Add the ScrolledWindow box to the ScrolledWindow
	// and create a new viewport automatically.
	toolboxTileSelectScrolledWindow->AddWithViewport( toolboxTileSelectScrolledWindowBox );

	//Create a box for Tile Select Window and pack the contents
	toolboxTileSelectBox = sfg::Box::Create( sfg::Box::VERTICAL, 5.0f );
	toolboxTileSelectBox->Pack( toolboxTileSelectScrolledWindow );

	// Create a window and add the box layouter to it. Also set the window's title.
	toolboxTileSelectWindow = sfg::Window::Create();
	toolboxTileSelectWindow->SetStyle(sfg::Window::TITLEBAR | sfg::Window::BACKGROUND );
	toolboxTileSelectWindow->SetTitle( "Tile Selection" );
	toolboxTileSelectWindow->Add( toolboxTileSelectBox );
	toolboxTileSelectWindow->SetRequisition( sf::Vector2f( 150.f, 450.f ) );
	sf::Vector2f toolboxTileSelectWindowCenter(  (SCREEN_WIDTH -  toolboxTileSelectWindow->GetClientRect().width )/2 ,
		(SCREEN_HEIGHT - toolboxTileSelectWindow->GetClientRect().height)/2);
	toolboxTileSelectWindow->SetPosition(toolboxTileSelectWindowCenter);

	//Hide Tile Select Window by default
	toolboxTileSelectWindowIsShown = false;
	toolboxTileSelectWindow->Show(false);

	sfg::Button::Ptr tempMapTileButton = sfg::Button::Create();
	sf::Image tempTileSelectButtonImage; 
	tempTileSelectButtonImage.loadFromFile("empty_box.png");
	sfg::Image::Ptr tempTileSelectButtonImageSFG = sfg::Image::Create(tempTileSelectButtonImage);
	tempMapTileButton->SetImage(tempTileSelectButtonImageSFG);
	tempMapTileButton->SetLabel("empty_box.png");
	tempMapTileButton->SetId("empty_box.png");
	tempMapTileButton->GetSignal( sfg::Widget::OnLeftClick ).Connect( &ButtonExample::tileTypeClicked, this );
	sfg::Box::Ptr tempMapTileButtonBox = sfg::Box::Create( sfg::Box::HORIZONTAL, 5.0f );
	tempMapTileButtonBox->Pack( tempMapTileButton, false, false );
	toolboxTileSelectScrolledWindowBox->Pack( tempMapTileButtonBox );

	tempMapTileButton = sfg::Button::Create();
	tempTileSelectButtonImage;
	tempTileSelectButtonImage.loadFromFile("default_box.png");
	tempTileSelectButtonImageSFG = sfg::Image::Create(tempTileSelectButtonImage);
	tempMapTileButton->SetImage(tempTileSelectButtonImageSFG);
	tempMapTileButton->SetLabel("default_box.png");
	tempMapTileButton->SetId("default_box.png");
	tempMapTileButton->GetSignal( sfg::Widget::OnLeftClick ).Connect( &ButtonExample::tileTypeClicked, this );
	tempMapTileButtonBox = sfg::Box::Create( sfg::Box::HORIZONTAL, 5.0f );
	tempMapTileButtonBox->Pack( tempMapTileButton, false, false );
	toolboxTileSelectScrolledWindowBox->Pack( tempMapTileButtonBox );

	tempMapTileButton = sfg::Button::Create();
	tempTileSelectButtonImage;
	tempTileSelectButtonImage.loadFromFile("dirt_box.png");
	tempTileSelectButtonImageSFG = sfg::Image::Create(tempTileSelectButtonImage);
	tempMapTileButton->SetImage(tempTileSelectButtonImageSFG);
	tempMapTileButton->SetLabel("dirt_box.png");
	tempMapTileButton->SetId("dirt_box.png");
	tempMapTileButton->GetSignal( sfg::Widget::OnLeftClick ).Connect( &ButtonExample::tileTypeClicked, this );
	tempMapTileButtonBox = sfg::Box::Create( sfg::Box::HORIZONTAL, 5.0f );
	tempMapTileButtonBox->Pack( tempMapTileButton, false, false );
	toolboxTileSelectScrolledWindowBox->Pack( tempMapTileButtonBox );

	tempMapTileButton = sfg::Button::Create();
	tempTileSelectButtonImage;
	tempTileSelectButtonImage.loadFromFile("moon_box.png");
	tempTileSelectButtonImageSFG = sfg::Image::Create(tempTileSelectButtonImage);
	tempMapTileButton->SetImage(tempTileSelectButtonImageSFG);
	tempMapTileButton->SetLabel("moon_box.png");
	tempMapTileButton->SetId("moon_box.png");
	tempMapTileButton->GetSignal( sfg::Widget::OnLeftClick ).Connect( &ButtonExample::tileTypeClicked, this );
	tempMapTileButtonBox = sfg::Box::Create( sfg::Box::HORIZONTAL, 5.0f );
	tempMapTileButtonBox->Pack( tempMapTileButton, false, false );
	toolboxTileSelectScrolledWindowBox->Pack( tempMapTileButtonBox );

	//
	//End of my stuff (3/4)
	//


	// Create the label.
	m_label = sfg::Label::Create( "Hello world!" );

	// Create a simple button and connect the click signal.
	sfg::Button::Ptr button( sfg::Button::Create( "Greet SFGUI!" ) );
	button->GetSignal( sfg::Widget::OnLeftClick ).Connect( &ButtonExample::OnButtonClick, this );

	// Create a vertical box layouter with 5 pixels spacing and add the label
	// and button to it.
	sfg::Box::Ptr box( sfg::Box::Create( sfg::Box::VERTICAL, 5.0f ) );
	box->Pack( m_label );
	box->Pack( button, false );
	box->Pack( tileSelectBox, false );

	// Create a window and add the box layouter to it. Also set the window's title.
	sfg::Window::Ptr window( sfg::Window::Create() );
	window->SetTitle( "Hello world!" );
	window->Add( box );

	// Create a desktop and add the window to it.
	sfg::Desktop desktop;
	desktop.Add( window );
	desktop.Add( toolboxTileSelectWindow );

	// We're not using SFML to render anything in this program, so reset OpenGL
	// states. Otherwise we wouldn't see anything.
	render_window.resetGLStates();

	// Main loop!
	sf::Event event;
	sf::Clock clock;

	while( render_window.isOpen() ) {
		// Event processing.
		while( render_window.pollEvent( event ) ) {
			desktop.HandleEvent( event );

			// If window is about to be closed, leave program.
			if( event.type == sf::Event::Closed ) {
				render_window.close();
			}
		}

		// Update SFGUI with elapsed seconds since last call.
		desktop.Update( clock.restart().asSeconds() );

		// Rendering.
		render_window.clear();
		m_sfgui.Display( render_window );
		render_window.display();
	}
}

int main() {
	ButtonExample example;
	example.Run();

	return 0;
}


//
//My stuff (4/4)
//


void ButtonExample::tileSelectButtonClicked() {
	if (toolboxTileSelectWindowIsShown){
		toolboxTileSelectWindow->Show(false);
		toolboxTileSelectWindowIsShown = false;
	}
	else{
		toolboxTileSelectWindow->Refresh();
		toolboxTileSelectWindow->Show(true);
		toolboxTileSelectWindowIsShown = true;
	}
}

void ButtonExample::tileTypeClicked(){
	//Getting which button was clicked
	sfg::Widget::Ptr buttonClicked ( sfg::Context::Get().GetActiveWidget() );
	//Creating a new SF image for the current tool button
	//sf::Image toolboxTileSelectButtonImage;
	//Loading the SF image from a file based on which button was clicked
	//toolboxTileSelectButtonImage.loadFromFile(buttonClicked->GetId());
	//std::cout << "Loading \"" << buttonClicked->GetId() << "\"\n";
	//Creating a new SFG image for the current tool button
	//sfg::Image::Ptr toolboxTileSelectButtonImageSFG = sfg::Image::Create(toolboxTileSelectButtonImage);
	//Setting the current tool button's image to the new SFG image
	//toolboxTileSelectButton->SetImage(toolboxTileSelectButtonImageSFG);    
    
    
    
    // buttonClicked is now sfg::Widget pointer, so we need to cast it to sfg::Button pointer first
    sfg::Button::PtrConst buttonPtr = sfg::DynamicPointerCast<sfg::Button>(buttonClicked);
    
    // We can use buttonPtr now to get the Button's sfg::Image
    sfg::Image::PtrConst buttonImage = buttonPtr->GetImage();
    
    // sfg::Image uses sf::Image as a source, so we need to get the sf::Image
    // which contains our tile picture.
    sf::Image picture = buttonImage->GetImage();
    
    // And we can set the sf::Image we got as a new source in Button's sfg::Image.
    toolboxTileSelectButton->GetImage()->SetImage( picture );
    
    /*
    // Or shorter (but still readable) code:
    sf::Image image = sfg::DynamicPointerCast<const sfg::Button>(buttonClicked)->GetImage()->GetImage();
	toolboxTileSelectButton->GetImage()->SetImage( image );
    */
    
	//
	//Resetting the state due to a weird image placement glitch
	//
	
	// Use this to "fix" the glitch instead of setting state.
	toolboxTileSelectButton->Invalidate();


	//toolboxTileSelectButton->SetState(sfg::Widget::INSENSITIVE);
	//toolboxTileSelectButton->SetState(sfg::Widget::NORMAL);

	//
	//Comment out the above to see the aforementioned glitch
	//


	//Hide the tile selection window and set relevant booleans to false
	toolboxTileSelectWindow->Show(false);
	toolboxTileSelectWindowIsShown = false;
}

//
//End of my stuff (4/4)
//