# Qt5 module

The Qt5 module provides tools to automatically deal with the various
tools and steps required for Qt. The module has two methods.

## preprocess

This method takes the following keyword arguments:
 - `moc_headers`, `moc_sources`, `ui_files`, `qresources`, which define the files that require preprocessing with `moc`, `uic` and `rcc`
 - `include_directories`, the directories to add to header search path for `moc` (optional)
 - `moc_extra_arguments`, any additional arguments to `moc` (optional). Available since v0.44.0.
 - `uic_extra_arguments`, any additional arguments to `uic` (optional). Available since v0.49.0.
 - `rcc_extra_arguments`, any additional arguments to `rcc` (optional). Available since v0.49.0.
 - `dependencies`, dependency objects needed by moc. Available since v0.48.0.

It returns an opaque object that should be passed to a main build target.

## compile_translations (since v0.44.0)

This method generates the necessary targets to build translation files with lrelease, it takes the following keyword arguments:
 - `ts_files`, the list of input translation files produced by Qt's lupdate tool.
 - `install` when true, this target is installed during the install step (optional).
 - `install_dir` directory to install to (optional).
 - `build_by_default` when set to true, to have this target be built by default, that is, when invoking `meson compile`; the default value is false (optional).
 - `qresource` rcc source file to extract ts_files from; cannot be used with ts_files kwarg. Available since v0.56.0.
 - `rcc_extra_arguments`, any additional arguments to `rcc` (optional), when used with `qresource. Available since v0.56.0.

Returns either: a list of custom targets for the compiled
translations, or, if using a `qresource` file, a single custom target
containing the processed source file, which should be passed to a main
build target.

## has_tools

This method returns `true` if all tools used by this module are found,
`false` otherwise.

It should be used to compile optional Qt code:
```meson
qt5 = import('qt5')
if qt5.has_tools(required: get_option('qt_feature'))
  moc_files = qt5.preprocess(...)
  ...
endif
```

This method takes the following keyword arguments:
- `required`: by default, `required` is set to `false`. If `required` is set to
  `true` or an enabled [`feature`](Build-options.md#features) and some tools are
  missing Meson will abort.
- `method`: method used to find the Qt dependency (`auto` by default).

*Since: 0.54.0*

## Dependencies

See [Qt dependencies](Dependencies.md#qt4-qt5)

The 'modules' argument is used to include Qt modules in the project.
See the Qt documentation for the [list of
modules](http://doc.qt.io/qt-5/qtmodules.html).

The 'private_headers' argument allows usage of Qt's modules private
headers. (since v0.47.0)

## Example
A simple example would look like this:

```meson
qt5 = import('qt5')
qt5_dep = dependency('qt5', modules: ['Core', 'Gui'])
inc = include_directories('includes')
moc_files = qt5.preprocess(moc_headers : 'myclass.h',
                           moc_extra_arguments: ['-DMAKES_MY_MOC_HEADER_COMPILE'],
                           include_directories: inc,
                           dependencies: qt5_dep)
translations = qt5.compile_translations(ts_files : 'myTranslation_fr.ts', build_by_default : true)
executable('myprog', 'main.cpp', 'myclass.cpp', moc_files,
           include_directories: inc,
           dependencies : qt5_dep)
```

Sometimes, translations are embedded inside the binary using qresource
files. In this case the ts files do not need to be explicitly listed,
but will be inferred from the built qm files listed in the qresource
file. For example:

```meson
qt5 = import('qt5')
qt5_dep = dependency('qt5', modules: ['Core', 'Gui'])
lang_cpp = qt5.compile_translations(qresource: 'lang.qrc')
executable('myprog', 'main.cpp', lang_cpp,
           dependencies: qt5_dep)
```