[SOLVED] How to add ImageMagick/Magick++ to my c++ project with CMake?

Issue

I am new to CMake. I was trying to use ImageMagick's c++ api Magick++ in my code.

This is my whole directory structure:

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external/image_magick just contains the result of cloning the image magick library using: git submodule add https://github.com/ImageMagick/ImageMagick.git external/image_magick.

This is the top-level CMakeLists.txt ( the one in the pic above):

cmake_minimum_required (VERSION 3.22.1)
project(DEMO)
add_executable(${PROJECT_NAME} main.cpp)

This is main.cpp (it just crops the image magick image and saves it, just for the demo):

#include <iostream>

#include <Magick++.h>

using namespace std;

using namespace Magick;

int main()
{
    cout << "Hello World!" << endl;

    // Construct the image object. Seperating image construction from the
    // the read operation ensures that a failure to read the image file
    // doesn't render the image object useless.
    Image image;
    try
    {
        // Read a file into image object
        image.read("logo:");

        // Crop the image to specified size (width, height, xOffset, yOffset)
        image.crop(Geometry(100, 100, 100, 100));

        // Write the image to a file
        image.write("logo.png");
        printf("Image written to logo.png");
    }
    catch (Exception &error_)
    {
        cout << "Caught exception: " << error_.what() << endl;
        printf("Error: %s", error_.what());
        return 1;
    }

    return 0;
}

If I compile and run the app like this (as per image magick docs):

c++ main.cpp -o main.out `Magick++-config --cppflags --cxxflags --ldflags --libs`
./main.out

Then all is good and image is generated.

But I can't use the CMakeLists.txt to build and run like this:

cmake -S . -B out/build
cd out/build; make
cd out/build
./DEMO

Because the external/image_magick directory I cloned does not contain CMakeLists.txt. I tried searching inside that directory for the library file (something like libmagic++??) to use it like below in my top level CMakeLists.txt but I didn't know how to do it:

add_subdirectory(external/image_magick/Magick++)

target_include_directories(${PROJECT_NAME} 
    PUBLIC external/image_magick/
)
target_link_directories(${PROJECT_NAME} 
PRIVATE external/image_magick/Magick++
)
target_link_libraries(${PROJECT_NAME} 
    PUBLIC ${PROJECT_SOURCE_DIR}/Magick++
)
# DOES NOT WORK

So how to properly add this library to my app while keeping using CMAke?

Solution

According to this answer, the solution was to add the following to CMakeLists.txt:

#ImageMagick
add_definitions( -DMAGICKCORE_QUANTUM_DEPTH=16 )
add_definitions( -DMAGICKCORE_HDRI_ENABLE=0 )
find_package(ImageMagick COMPONENTS Magick++)
include_directories(${ImageMagick_INCLUDE_DIRS})
target_link_libraries(demo ${ImageMagick_LIBRARIES})

Answered By - Haidar

Answer Checked By - Robin (WPSolving Admin)