107 lines
3.6 KiB
Markdown
107 lines
3.6 KiB
Markdown
|
|
|
|
# Lottie player
|
|
Allows to use Lottie animations in LVGL. Taken from this [base repository](https://github.com/ValentiWorkLearning/lv_rlottie)
|
|
|
|
LVGL provides the interface to [Samsung/rlottie](https://github.com/Samsung/rlottie) library's C API. That is the actual Lottie player is not part of LVGL, it needs to be built separately.
|
|
|
|
## Build Rlottie
|
|
To build Samsung's Rlottie C++14-compatible compiler and optionally CMake 3.14 or higher is required.
|
|
|
|
To build on desktop you can follow the instructions from Rlottie's [README](https://github.com/Samsung/rlottie/blob/master/README.md). In the most basic case it looks like this:
|
|
```
|
|
mkdir rlottie_workdir
|
|
cd rlottie_workdir
|
|
git clone https://github.com/Samsung/rlottie.git
|
|
mkdir build
|
|
cd build
|
|
cmake ../rlottie
|
|
make -j
|
|
sudo make install
|
|
```
|
|
|
|
And finally add the `-lrlottie` flag to your linker.
|
|
|
|
On embedded systems you need to take care of integrating Rlottie to the given build system.
|
|
|
|
|
|
## Usage
|
|
|
|
You can use animation from files or raw data (text). In either case first you need to enable `LV_USE_RLOTTIE` in `lv_conf.h`.
|
|
|
|
|
|
The `width` and `height` of the object be set in the *create* function and the animation will be scaled accordingly.
|
|
|
|
### Use Rlottie from file
|
|
|
|
To create a Lottie animation from file use:
|
|
```c
|
|
lv_obj_t * lottie = lv_rlottie_create_from_file(parent, width, height, "path/to/lottie.json");
|
|
```
|
|
|
|
Note that, Rlottie uses the standard STDIO C file API, so you can use the path "normally" and no LVGL specific driver letter is required.
|
|
|
|
|
|
### Use Rlottie from raw string data
|
|
|
|
`lv_example_rlottie_approve.c` contains an example animation in raw format. Instead storing the JSON string a hex array is stored for the following reasons:
|
|
- avoid escaping `"` in the JSON file
|
|
- some compilers don't support very long strings
|
|
|
|
`lvgl/scripts/filetohex.py` can be used to convert a Lottie file a hex array. E.g.:
|
|
```
|
|
./filetohex.py path/to/lottie.json > out.txt
|
|
```
|
|
|
|
To create an animation from raw data:
|
|
|
|
```c
|
|
extern const uint8_t lottie_data[];
|
|
lv_obj_t* lottie = lv_rlottie_create_from_raw(parent, width, height, (const char *)lottie_data);
|
|
```
|
|
|
|
## Getting animations
|
|
|
|
Lottie is standard and popular format so you can find many animation files on the web.
|
|
For example: https://lottiefiles.com/
|
|
|
|
You can also create your own animations with Adobe After Effects or similar software.
|
|
|
|
## Controlling animations
|
|
|
|
LVGL provides two functions to control the animation mode: `lv_rlottie_set_play_mode` and `lv_rlottie_set_current_frame`.
|
|
You'll combine your intentions when calling the first method, like in these examples:
|
|
```c
|
|
lv_obj_t * lottie = lv_rlottie_create_from_file(scr, 128, 128, "test.json");
|
|
lv_obj_center(lottie);
|
|
// Pause to a specific frame
|
|
lv_rlottie_set_current_frame(lottie, 50);
|
|
lv_rlottie_set_play_mode(lottie, LV_RLOTTIE_CTRL_PAUSE); // The specified frame will be displayed and then the animation will pause
|
|
|
|
// Play backward and loop
|
|
lv_rlottie_set_play_mode(lottie, LV_RLOTTIE_CTRL_PLAY | LV_RLOTTIE_CTRL_BACKWARD | LV_RLOTTIE_CTRL_LOOP);
|
|
|
|
// Play forward once (no looping)
|
|
lv_rlottie_set_play_mode(lottie, LV_RLOTTIE_CTRL_PLAY | LV_RLOTTIE_CTRL_FORWARD);
|
|
```
|
|
|
|
The default animation mode is **play forward with loop**.
|
|
|
|
If you don't enable looping, a `LV_EVENT_READY` is sent when the animation can not make more progress without looping.
|
|
|
|
To get the number of frames in an animation or the current frame index, you can cast the `lv_obj_t` instance to a `lv_rlottie_t` instance and inspect the `current_frame` and `total_frames` members.
|
|
|
|
## Example
|
|
```eval_rst
|
|
|
|
.. include:: ../../examples/libs/rlottie/index.rst
|
|
|
|
```
|
|
|
|
## API
|
|
|
|
```eval_rst
|
|
|
|
.. doxygenfile:: lv_rlottie.h
|
|
:project: lvgl
|