Our custom plugin is now finished. Because we added a custom Build command to automatically deploy the filter-widget library, it should be visible in Qt Designer. The deploy path we specified is inside the Qt Creator directory. Qt Creator integrates Qt Designer via a plugin that displays the UI inside Qt Creator.

When Qt Creator starts, it will try to load every library available in its specific paths. This means that you have to restart Qt Creator each time you modify the plugin (if you want to see the result of your modifications in the designer).

To see the plugin in action, we now have to create the application project of the chapter. Create a Qt Widgets Application sub-project in the ch07-image-filter project named image-filter. In the wizard, let it generate the form, MainWindow.ui.

To properly use the plugin, just link the filter-plugin-designer library in image-filter.pro like so:

QT       += core gui 
 
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets 
...