Lottie is a popular format for rendering vector-based animations.

RmlUi comes integrated with the Lottie plugin for drawing Lottie animations. The plugin uses the rlottie library to render the animations.

When RmlUi is built with the Lottie plugin, the <lottie> element is available as a normal RML tag.

<lottie>

The <lottie> element is used to include animations in the document.

Attributes

src = uri (CT)

The source location of the JSON-file describing the Lottie animation.

Building with the Lottie plugin

The Lottie plugin is integrated and built with the Core RmlUi library once it is enabled. Then, the plugin is automatically loaded during the call to Rml::Initialise().

First, we demonstrate how to download and build the required rlottie dependency. Open up a terminal and navigate to RmlUi/Dependecies. Then execute the following commands.

git clone --branch v0.2 https://github.com/Samsung/rlottie.git
cd rlottie
mkdir build
cd build
cmake -DBUILD_SHARED_LIBS=OFF ..
cmake --build . --target rlottie --config Debug
cmake --build . --target rlottie --config Release

You may want to adjust the CMake arguments to your preferences.

Then, during CMake configuration of RmlUi, set the option ENABLE_LOTTIE_PLUGIN=ON. This will ensure that the Lottie plugin is integrated and built together with RmlCore. For example, in the RmlUi/Build directory execute the following:

cmake -DBUILD_SHARED_LIBS=OFF -DENABLE_LOTTIE_PLUGIN=ON -DBUILD_SAMPLES=ON ..

This should automatically locate the rlottie library. You can now build and run the included lottie sample as you would any other sample to try out the plugin.

Including the Lottie plugin

To include the Lottie plugin in your own project, make sure you build RmlUi with the CMake option ENABLE_LOTTIE_PLUGIN enabled as described above, and integrate RmlUi into your project as normal. In addition, you will need to link with the rlottie library.

The plugin is then automatically loaded during the call to Rml::Initialise(). If everything has worked out properly, the log will output a short message about the Lottie plugin being initialised. The <lottie> element should then be available for displaying animations.