slint.h not found when building with platformio

[pej-p]

I'm trying to upload the slint-cpp-template to an esp32 using platformio, but I'm receiving the following error;

-------------------------------------------------------------------------
Verbose mode can be enabled via `-v, --verbose` option
CONFIGURATION: https://docs.platformio.org/page/boards/espressif32/lilygo-t-display-s3.html
PLATFORM: Espressif 32 (6.2.0) > LilyGo T-Display-S3
HARDWARE: ESP32S3 240MHz, 320KB RAM, 16MB Flash
DEBUG: Current (cmsis-dap) External (cmsis-dap, esp-bridge, esp-builtin, esp-prog, iot-bus-jtag, jlink, minimodule, olimex-arm-usb-ocd, olimex-arm-usb-ocd-h, olimex-arm-usb-tiny-h, olimex-jtag-tiny, tumpa)
PACKAGES: 
 - tool-esptoolpy @ 1.40501.0 (4.5.1) 
 - tool-openocd-esp32 @ 2.1100.20220706 (11.0) 
 - toolchain-riscv32-esp @ 8.4.0+2021r2-patch5 
 - toolchain-xtensa-esp32s3 @ 8.4.0+2021r2-patch5
LDF: Library Dependency Finder -> https://bit.ly/configure-pio-ldf
LDF Modes: Finder ~ chain, Compatibility ~ soft
Found 0 compatible libraries
Scanning dependencies...
No dependencies
Building in release mode
Compiling .pio/build/ui/src/main.o
In file included from src/main.cpp:1:
src/../build/main.h:5:10: fatal error: slint.h: No such file or directory

***************************************************************
* Looking for slint.h dependency? Check our library registry!
*
* CLI  > platformio lib search "header:slint.h"
* Web  > https://registry.platformio.org/search?q=header:slint.h
*
***************************************************************

 #include <slint.h>
          ^~~~~~~~~
compilation terminated.
*** [.pio/build/ui/src/main.o] Error 1
====================== [FAILED] Took 0.42 seconds ======================

This surprises me since I can build the template via cli just fine.
CMakeLists.txt;

cmake_minimum_required(VERSION 3.21)
project(ui LANGUAGES CXX)

find_package(Slint QUIET)
if (NOT Slint_FOUND)
  message("Slint could not be located in the CMake module search path. Downloading it from Git and building it locally")
  include(FetchContent)
  FetchContent_Declare(
    Slint
    GIT_REPOSITORY https://github.com/slint-ui/slint.git
    # `release/1` will auto-upgrade to the latest Slint >= 1.0.0 and < 2.0.0
    # `release/1.0` will auto-upgrade to the latest Slint >= 1.0.0 and < 1.1.0
    GIT_TAG release/1
    SOURCE_SUBDIR api/cpp
  )
  FetchContent_MakeAvailable(Slint)
endif (NOT Slint_FOUND)

add_executable(ui src/main.cpp)
slint_target_sources(ui src/main.slint)
target_link_libraries(ui PRIVATE Slint::Slint)
# On Windows, copy the Slint DLL next to the application binary so that it's found.
if (WIN32)
    add_custom_command(TARGET ui POST_BUILD COMMAND ${CMAKE_COMMAND} -E copy $<TARGET_RUNTIME_DLLS:ui> $<TARGET_FILE_DIR:ui> COMMAND_EXPAND_LISTS)
endif()

platformio.ini;

[env:ui]
build_flags = -D ui -DARDUINO_USB_MODE=1
platform = espressif32
board = lilygo-t-display-s3
upload_port = usb
upload_protocol = custom 
upload_flags =
    -C
    ${platformio.packages_dir}/espressif/toolchain-xtensa-esp32
    -P
    $UPLOAD_PORT
upload_command = avrdude $UPLOAD_FLAGS -U flash:w:$SOURCE:i

[ogoffart]

I am not familiar with platformio.

It looks like the include paths are not set correctly.
Normally, this line in the CMakeLists.txt: target_link_libraries(ui PRIVATE Slint::Slint) should tell cmake to pass the right include path.

Maybe you can pass the -v flag and it will probably show the include path and commands that it uses, and we can debug from there.

[pej-p]

I confused something - platformio currently doesn't even generate the appwindow.h. I only got to the error message above, because I had built it with cmake before. And I'm not sure how to configure the platformio.ini so it'll work with .slint files. Also while I managed to fix the include errors by now, it just led to another bunch of error messages, so I think it might be better to just stay with cmake for now.

[gkoh]

I've managed to make some progress on esp-idf + platformio + slint-ui.
In general, platformio appears to mostly disregard the esp-idf build system, preferring to manage its own model of dependencies, using esp-idf only to generate the initial build configuration.

I was able to get the basic app-window example building by doing the following:

• use extra_scripts to add a custom target that generates the slint outputs
• invoke the custom target before the usual pio build

Add pre_slint.py to the root directory:

Import("env")

platform = env.PioPlatform()

build_dir = env.subst('$BUILD_DIR')
ninja_exe = "{:s}/ninja".format(platform.get_package_dir("tool-ninja"))

env.AddCustomTarget(
        name="slint",
        dependencies=None,
        actions=[
          "cd {:s} && {:s} esp-idf/main/app-window.h".format(build_dir, ninja_exe),
            ],
        title="Slint Build",
        description="Generate Slint UI sources and build")

Modify platformio.ini to add the slint generation target and link the nightly prebuilt slint static library:

build_flags = -L$BUILD_DIR/slint-prebuilt/Slint-cpp-nightly-xtensa-esp32-none-elf/lib -lslint_cpp
extra_scripts = pre:pre_slint.py

And with the following invocation:

$ platformio run -t slint
$ platformio run

I can produce an esp32 binary that loads and kinda runs.
Unfortunately I get runtime crashes, but that is due to unmatched hardware requirements on my end.

There's a handful of hardcoded paths that will need adjustment for other projects, however I hope this helps someone else.