CMake based build system
============================

The file contains the instruction to build Hugin with CMake.

1. DEPENDENCIES

Hugin depends on the following packages. 

1.1. Build-Time Dependencies

Users compiling Hugin from source will need:

    A C++compiler which supports OpenMP and C++17.
        * OpenMP support is not required. But when compiling
          without OpenMP nona and cpfind (and some other
          algorithm) are running only with one thread, 
          which is slower.
    CMake (the build system), version >=3.15
    The wxWidgets GUI toolkit version >=3.2.0.
    libtiff the TIFF library with LZW support.
    libpano13 version >=2.9.19
    libopenexr the OpenEXR library
    libvigra the VIGRA libray, header files and impex library (>=1.9)
    Exiv2 Image metadata library
    GLEW the OpenGL Extension Wrangler Library or libepoxy (see BUILD_WITH_EPOXY switch below)
    gettext
    sqlite3, the SQL database backend for the lens database
    littlecms2, little cms color engine
    optionally, lapack
    optionally, libfftw3
    on Unix you need also
        libGLU the OpenGL utility library
        libxi
        libxmu
    on Windows you need
        HTML Help Workshop for generating compiled HTML help file
    on Mac OS you need
        freeglut or glut, the OpenGL utility toolkit
    for the optional Python Scripting Interface (currently functional and tested only on Linux and Windows)
        Python version >=3.0
        Python package setuptools only with Python >=3.12
        SWIG >=2.0.4 
    when building a static version
        libjpg the JPEG library
        libpng the PNG library
    Hugin can be compiled with gcc, as well as with MSVC.
    The build process requires CMake version >=3.15

If cmake fails to pick up some dependencies, make sure you have
the corresponding development packages installed (often named:
libtiff-dev and so on).

Notes: 
When using wxWidgets 3.0.x series Hugin does not run native on Wayland. A workaround is to use the
XWayland emulation layer. This has be activated during building by adding -DUSE_GDKBACKEND_X11=on 
to the CMake command line. (This is not necessary when compiling against wxWidgets 3.2.x or later).

On Linux wxWidgets 3.1.5 and later is by default compiled with EGL support for the wxGLCanvas class. 
In this case you need to activate EGL support explicitly also in GLEW, otherwise there are crashes when
intializing the wxGLCanvas. Alternatively you can also use the epoxy library instead of GLEW, which does
the detection at run time. To build with epoxy add -DBUILD_WITH_EPOXY=on to the CMake command line.

1.2. At runtime

During runtime of Hugin the following programs are needed:

    enblend >= 3.2 is required.
    Exiftool, version >=9.09 is required to support GPano tags. Otherwise they are ignored.
    
    Optionally Python argparse command-line parsing library for the Python scripts. 

2. COMPILING
=======================================

First, create a build directory and change into it:
$ mkdir mybuild
$ cd mybuild

Then call CMake from this build directory and point to the *root* directory of the 
extracted Hugin sources. (Don't specify the src subdirectory in the Hugin sources.)
CMake can also create install package. Depending on the format of your packages
call for a Debian package
$ cmake -DCMAKE_INSTALL_PREFIX=/usr/local -DCPACK_BINARY_DEB:BOOL=ON /PATH/HUGIN_SOURCE
or for a rpm package
$ cmake -DCMAKE_INSTALL_PREFIX=/usr/local -DCPACK_BINARY_RPM:BOOL=ON /PATH/HUGIN_SOURCE
(for other formats see CMake documentation)

Build the package
$ make package
and install the package with your package manager

The build process can be configured with different switches. These variables
can be set with the -D command line parameter. Important variables include:

CMAKE_INSTALL_PREFIX  Destination directory of make install
                      (default: /usr/local)
CMAKE_BUILD_TYPE      Specify the build type (Release (Default) or Debug)
HUGIN_SHARED          set to 0 to disable build shared libraries for internal
                      functions.
BUILD_HSI=on          Set to on to build with Python scripting support
USE_GDKBACKEND_X11=on Set to on to enforce using X11 as GDKBACKEND.
                      This is needed for Wayland, because wxWidgets wxGLCanvas
                      does not support Wayland at the moment.
BUILD_WITH_EGL=on     When set to on it uses EGL to initialize OpenGL context
                      in nona instead of X windows functions.
BUILD_WITH_EPOXY=on   Use libepoxy instead of GLEW for handling OpenGL function 
                      pointers
ENABLE_LAPACK=on      Use LAPACK based solver, otherwise a builtin LU based
                      solver is used for photometric optimizer.
                      The LAPACK solver could be more stable, but no extensive
                      comparison was done.

MAC_SELF_CONTAINED_BUNDLE=1 Configures hugin for a fully bundled version, where
                      all required programs (nona, enblend, HuginStitchProject,
                      etc.) are embedded in the bundle.
                      Without this switch, hugin will behave just like on
                      any other unix platform and depend on resources
                      outside the bundle (translations, data files etc.).
UNIX_SELF_CONTAINED_BUNDLE=on Configure hugin for building a fully bundled 
                      AppImage version, where all dependencies are embedded in 
                      the bundle.

CMake offers also a GUI which makes setting these variables and checking the paths
to the dependencies easier.


3. FURTHER REMARKS
=======================================

3.1 Fedora's rpmbuild
=====================
If using Fedora's rpmbuild to build an rpm package, the recommended procedure 
is similar to the above.
$ cd hugin
$ mkdir mybuild
$ cd mybuild
$ cmake ..
$ make package_source
copy, or move the selected source archive (.bz2 or .gz) from your mybuild dir to your rpmbuild
SOURCE dir, generate or edit your .spec file, and build your package.

3.2 For distributors
====================
CMake supports the DESTDIR variable during make install, this
might be helpful to install into a temporary directory during
package creation

$ make install DESTDIR=mytmp_package_dir



Please report any problems to the hugin-ptx group at google:
http://groups.google.com/group/hugin-ptx
