WFavicon

A WFavicon is an object that represents a favicon that can be set for the application. Changing the favicon can be used to notify the user that something happened on the application, even when the user is looking at another tab. This is less intrusive than a WNotification, and does not require permission from the user.

Changing Favicon

You can change the favicon to any image that a browser accepts as a favicon (e.g. PNG, JPEG, ICO). This will only modify the favicon for the application, so it will only affect the user. You can go back to the default favicon of the application by setting the favicon of the application to nullptr.

Tips: You can set the default favicon for an application when adding the entry point for the application, or you can configure the default favicon in thewt_config.xml, by setting the property named favicon.

Example
source 
#include <Wt/WApplication.h>
#include <Wt/WContainerWidget.h>
#include <Wt/WDocRootDataInfo.h>
#include <Wt/WPushButton.h>
#include <Wt/WResourceFavicon.h>


auto container = std::make_unique<Wt::WContainerWidget>();
auto sunFaviconButton = container->addWidget(std::make_unique<Wt::WPushButton>("Change the favicon to a sun"));
auto cloudFaviconButton = container->addWidget(std::make_unique<Wt::WPushButton>("Change the favicon to a cloud"));
auto snowFaviconButton = container->addWidget(std::make_unique<Wt::WPushButton>("Change the favicon to a snowflake"));
auto defaultFaviconButton = container->addWidget(std::make_unique<Wt::WPushButton>("Go back to the default favicon"));

sunFaviconButton->clicked().connect([=]() {
  auto favicon = std::make_unique<Wt::WResourceFavicon>(Wt::WDocRootDataInfo("icons/sun01.png").filePath());
  Wt::WApplication::instance()->setFavicon(std::move(favicon));
});

cloudFaviconButton->clicked().connect([=]() {
  auto favicon = std::make_unique<Wt::WResourceFavicon>(Wt::WDocRootDataInfo("icons/w_cloud.png").filePath());
  Wt::WApplication::instance()->setFavicon(std::move(favicon));
});

snowFaviconButton->clicked().connect([=]() {
  auto favicon = std::make_unique<Wt::WResourceFavicon>(Wt::WDocRootDataInfo("icons/snow.png").filePath());
  Wt::WApplication::instance()->setFavicon(std::move(favicon));
});

defaultFaviconButton->clicked().connect([=]() {
  Wt::WApplication::instance()->setFavicon(nullptr);
});

Favicon Pair

A WFavicon has 2 states: the default state and the updated state. This state can be changed using the update() and reset() methods. Basic WFavicon are the same image in both states, but a WFaviconPair is a favicon that shows a different WFavicon in each state.

Example
source 
#include <Wt/WApplication.h>
#include <Wt/WContainerWidget.h>
#include <Wt/WDocRootDataInfo.h>
#include <Wt/WFaviconPair.h>
#include <Wt/WPushButton.h>
#include <Wt/WResourceFavicon.h>


auto container = std::make_unique<Wt::WContainerWidget>();
auto setCustomFaviconButton = container->addWidget(std::make_unique<Wt::WPushButton>("Set custom favicon"));
auto updateFaviconButton = container->addWidget(std::make_unique<Wt::WPushButton>("Update favicon"));
auto resetFaviconButton = container->addWidget(std::make_unique<Wt::WPushButton>("Reset favicon"));

setCustomFaviconButton->clicked().connect([=](){
  auto defaultFavicon = std::make_unique<Wt::WResourceFavicon>(Wt::WDocRootDataInfo("icons/wt.png").filePath());
  auto updatedFavicon = std::make_unique<Wt::WResourceFavicon>(Wt::WDocRootDataInfo("icons/wt-update.png").filePath());
  auto faviconPair = std::make_unique<Wt::WFaviconPair>(std::move(defaultFavicon), std::move(updatedFavicon));
  Wt::WApplication::instance()->setFavicon(std::move(faviconPair));
});

updateFaviconButton->clicked().connect([=](){
  Wt::WApplication::instance()->favicon()->update();
});

resetFaviconButton->clicked().connect([=](){
  Wt::WApplication::instance()->favicon()->reset();
});