The related code/working directory of this example resides in directory {WAMR_DIR}/samples/gui

"gui" sample introduction

Note: The sample has been migrated to bytecodealliance/wamr-app-framework/samples/gui.

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 user clicks 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

./configure C_FLAGS=-m32 CXX_FLAGS=-m32 LD_FLAGS=-m32
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

    sudo make install

Build and Run

  • Build


    All binaries are in "out", which contains "host_tool", "ui_decrease.wasm", "ui_increase.wasm" and "wasm_runtime_wgl".

  • Run WASM VM Linux applicaton & install WASM APP First start wasm_runtime_wgl in server mode.

    ./wasm_runtime_wgl -s

Then install wasm APP by using host tool.

./host_tool -i inc -f ui_increase.wasm
# or
./host_tool -i dec -f ui_decrease.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.

    west init zephyrproject
    cd zephyrproject/zephyr
    git checkout zephyr-v2.3.0
    cd ..
    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 ../../../../
cmake -GNinja -DBOARD=nucleo_f767zi ..
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.

    sudo ./host_tool -D /dev/ttyUSBXXX -i inc -f ui_increase.wasm
    # /dev/ttyUSBXXX is the UART device, e.g. /dev/ttyUSB0
  • Install AOT version WASM application

    wamrc --target=thumbv7 --target-abi=eabi --cpu=cortex-m7 -o ui_app.aot ui_increase.wasm
    ./host_tool -D /dev/ttyUSBXXX -i inc -f ui_app.aot

The graphic user interface demo photo:

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