README.md

"gui" sample introduction

This sample demonstrates that a graphic user interface application in WebAssembly programming with WAMR graphic library(WGL) which is part of WAMR app-framework.

Compared with the littlevgl sample, WGL compiles LittlevGL source code into the WAMR runtime and defines a set of wrapper API's for exporting to Webassembly application.

Below picture shows the WASM application is running on an STM board with an LCD touch panel.

When users click the blue button, the WASM application increases the counter, and the latest counter value is displayed on the top banner of the touch panel. The number on top will plus one each second, and the number on the bottom will plus one when clicked.

Test on Linux

Install required SDK and libraries

• 32 bit SDL(simple directmedia layer) (Note: only necessary when WAMR_BUILD_TARGET is set to X86_32 when building WAMR runtime) Use apt-get: sudo apt-get install libsdl2-dev:i386 Or download source from www.libsdl.org:

./configure C_FLAGS=-m32 CXX_FLAGS=-m32 LD_FLAGS=-m32
make
sudo make install

• 64 bit SDL(simple directmedia layer) (Note: only necessary when WAMR_BUILD_TARGET is set to X86_64 when building WAMR runtime) Use apt-get: sudo apt-get install libsdl2-dev Or download source from www.libsdl.org:

./configure
make
sudo make install

Build and Run

• Build
  ./build.sh
  All binaries are in "out", which contains "host_tool", "lvgl_native_ui_app", "ui_app.wasm", "ui_app_lvgl_compatible.wasm" and "wasm_runtime_wgl".

• Run native Linux application
  ./lvgl_native_ui_app
  

• Run WASM VM Linux applicaton & install WASM APP
  First start wasm_runtime_wgl in server mode.
  ./wasm_runtime_wgl -s
  Then install wasm APP use host tool.
  ./host_tool -i ui_app -f ui_app.wasm
./host_tool -i ui_app -f ui_app_lvgl_compatible.wasm
  

Test on Zephyr

We can use a STM32 NUCLEO_F767ZI board with ILI9341 display and XPT2046 touch screen to run the test. Then use host_tool to remotely install wasm app into STM32.

• Build WASM VM into Zephyr system
  a. clone zephyr source code
  Refer to Zephyr getting started.
  https://docs.zephyrproject.org/latest/getting_started/index.html
  west init zephyrproject
cd zephyrproject
west update
  b. copy samples
  cd zephyr/samples/
cp -a <wamr_root>samples/gui/wasm-runtime-wgl wasm-runtime-wgl
cd wasm-runtime-wgl/zephyr_build
  c. create a link to wamr root dir
  ln -s <wamr_root> wamr
  d. build source code
  mkdir build && cd build
source ../../../../zephyr-env.sh
cmake -GNinja -DBOARD=nucleo_f746zg ..
ninja flash
  

• Hardware Connections

+-------------------+-+------------------+
|NUCLEO-F767ZI       | ILI9341  Display  |
+-------------------+-+------------------+
| CN7.10             |         CLK       |
+-------------------+-+------------------+
| CN7.12             |         MISO      |
+-------------------+-+------------------+
| CN7.14             |         MOSI      |
+-------------------+-+------------------+
| CN11.1             | CS1 for ILI9341   |
+-------------------+-+------------------+
| CN11.2             |         D/C       |
+-------------------+-+------------------+
| CN11.3             |         RESET     |
+-------------------+-+------------------+
| CN9.25             |    PEN interrupt  |
+-------------------+-+------------------+
| CN9.27             |  CS2 for XPT2046  |
+-------------------+-+------------------+
| CN10.14            |    PC UART RX     |
+-------------------+-+------------------+
| CN11.16            |    PC UART RX     |
+-------------------+-+------------------+

• Install WASM application to Zephyr using host_tool
  First, connect PC and STM32 with UART. Then install to use host_tool.
  ./host_tool -D /dev/ttyUSBXXX -i ui_app -f ui_app.wasm

• Install AOT version WASM application wamrc --target=thumbv7 --target-abi=eabi --cpu=cortex-m7 -o ui_app.aot ui_app.wasm ./host_tool -D /dev/ttyUSBXXX -i ui_app -f ui_app.aot