Missing cairo.h when trying to build OpenFPGA with GUI enabled

[MidsummerNight]

Sorry if this turns out to be a low level mistake on my part, but when following the How to Compile instructions on enabling the GUI ("VPR’s GUI requires gtk-3, and can be enabled with cmake .. -DVPR_USE_EZGL=on"), I modified /OpenFPGA/Makefile like this:

# Makefile

ifeq ($(origin CMAKE_COMMAND),undefined)
CMAKE_COMMAND := cmake
else
CMAKE_COMMAND := ${CMAKE_COMMAND}
endif

.PHONY: all checkout compile

all: checkout
    mkdir -p build && cd build && $(CMAKE_COMMAND) ${CMAKE_FLAGS} .. -DVPR_USE_EZGL=on
    cd build && $(MAKE)

checkout: 
    git submodule init
    git submodule update --init --recursive

compile:
    mkdir -p build && cd build && $(CMAKE_COMMAND) ${CMAKE_FLAGS} .. -DVPR_USE_EZGL=on
    cd build && $(MAKE)

clean:
    rm -rf build

build/Makefile:
    make checkout

.PHONY: Makefile

%: build/Makefile
    cd build && $(MAKE) $@

Then executed make all, and everything went well until this:

......<left out previous output results>......
make[3]: Leaving directory '/home/my_machine/OpenFPGA/build'
[  3%] Built target libtatum
make[3]: Entering directory '/home/my_machine/OpenFPGA/build'
Scanning dependencies of target ezgl
make[3]: Leaving directory '/home/my_machine/OpenFPGA/build'
make[3]: Entering directory '/home/my_machine/OpenFPGA/build'
[  3%] Building CXX object libs/EXTERNAL/libezgl/CMakeFiles/ezgl.dir/src/application.cpp.o
In file included from /home/my_machine/OpenFPGA/libs/EXTERNAL/libezgl/include/ezgl/canvas.hpp:24,
                 from /home/my_machine/OpenFPGA/libs/EXTERNAL/libezgl/include/ezgl/application.hpp:22,
                 from /home/my_machine/OpenFPGA/libs/EXTERNAL/libezgl/src/application.cpp:19:
/home/my_machine/OpenFPGA/libs/EXTERNAL/libezgl/include/ezgl/graphics.hpp:27:10: fatal error: cairo.h: No such file or directory
   27 | #include <cairo.h>
      |          ^~~~~~~~~
compilation terminated.
make[3]: *** [libs/EXTERNAL/libezgl/CMakeFiles/ezgl.dir/build.make:63: libs/EXTERNAL/libezgl/CMakeFiles/ezgl.dir/src/application.cpp.o] Error 1
make[3]: Leaving directory '/home/my_machine/OpenFPGA/build'
make[2]: *** [CMakeFiles/Makefile2:980: libs/EXTERNAL/libezgl/CMakeFiles/ezgl.dir/all] Error 2
make[2]: Leaving directory '/home/my_machine/OpenFPGA/build'
make[1]: *** [Makefile:141: all] Error 2
make[1]: Leaving directory '/home/my_machine/OpenFPGA/build'
make: *** [Makefile:13: all] Error 2

To be honest I didn't really understand how to cmake .. -DVPR_USE_EZGL=on exactly, so I took a guess and added the flag inside the Makefile. Is this not the proper way and the reason of my error? Or did I mishandle something else? Many thanks!

[tangxifan]

@MidsummerNight

From the log file, I think you missed a package:

https://github.com/lnis-uofu/OpenFPGA/blob/4e50644ea866e30ea8dadb67d127a27f8fa6375a/.github/workflows/install_dependencies_build.sh#L17

[MidsummerNight]

@tangxifan Yeah I noticed that right after posting, sorry my fault. But is adding -DVPR_USE_EZGL=on directly inside the Makefile the proper way to enable the GUI?

[MidsummerNight]

Update:

The same issue persists even after installing the packages listed in OpenFPGA/.github/workflows/install_dependencies_build.sh. Strangely -- EZGL: graphics enabled is always displayed before cd build && make, regardless of whether -DVPR_USE_EZGL=on is in Makefile or not, and the build process succeeded after I installed libgtk-3-dev.

[tangxifan]

@MidsummerNight In general, you do not need to specify the -DVPR_USE_EZGL=on using Cmake options. The Cmakefile is designed to automatically detect your packages, if the packages are all installed, if will enable GUI. Otherwise it will not.

Regarding libgtk-3-dev, it is not in our dependency list. It seems that on Github runners, it is preinstalled. If you are trying a different machine that our Github runners, you may expect differences in preinstalled packages.

[MidsummerNight]

In the end, my issue was solved by installing libgtk-3-dev, whatever the reason. This is indeed quite strange since I recall successfully building OpenFPGA back in September without libgtk-3-dev. I'll close this issue now, hopefully my experience would be helpful to future troubled users.