# KDDockWidgets

[![Build Status](https://travis-ci.com/KDAB/KDDockWidgets.svg?branch=master)](https://travis-ci.com/KDAB/KDDockWidgets)

> ⚠️⚠️: 2.0 is under development, there might be API breaks before release.
> Stick with version 1.6 if you're using QtWidgets. However, if you're using
> QtQuick it's better to base on 2.0, as 1.6 won't be receiving much QtQuick development.

`KDDockWidgets` is a Qt dock widget library written by KDAB, suitable for replacing
`QDockWidget` and implementing advanced functionalities missing in Qt.

Although `KDDockWidgets` is ready to be used out of the box, it can also be seen
as a framework to allow building very tailored custom docking systems. It tries
to expose every internal widget and every knob for the app developer to tune.

## Motivation

Throughout the years KDAB contributed and funded bug fixes and features to `QDockWidget`.
Sadly, this was very painful. Each bug fix or feature took many days of implementation,
and an equal number of days just to fix dozens of regressions.

`QDockWidget` mixes GUI code with logic with state, making it very hard
to move forward with new features. Furthermore, our customers were getting more
creative with their requests, so it was clear we needed a better docking framework.

You will find more information in these places:

- [our official home page](https://www.kdab.com/development-resources/qt-tools/kddockwidgets)
- [online detailed browsable API reference](https://docs.kdab.com/kddockwidgets)
- [our example programs](examples/)

We also have an [in browser demo](https://demos.kdab.com/wasm/kddockwidgets/dockwidgets.html). Note
however that this demo isn't fully featured, as it's running on Qt for WebAssembly.

## Features

- Provide advanced docking that QDockWidget doesn't support
  - Native window resize on Windows (allowing for Aero-snap even with custom title bar decorations)
  - Arrow drop indicators for great drop precision
  - Allow for totally different, user provided, drop indicator types
  - Nesting dock widgets in a floating window and docking that group back to main window
  - Docking to any main window, not only to the parent main window
  - Docking to center of main window, or simply removing the concept of "central widget"
  - Main window supporting detachable tabs in center widget
  - Detaching arbitrary tabs from a tab bar into a dock area
  - Supporting more than 1 main window
  - Support for affinities, making some dock widgets only dockable on certain main windows
  - Allow to hide TitleBar and just show tabs. Allows dragging via the tab bar.
  - Exposing inner helper widgets so the user can customize them or provide his own
    - Customize tab widgets
    - Customize title bars
    - Customize window frames
    - Custom widget separators
- Cross-platform (macOS, Linux, Windows, WebAssembly, Wayland, X11/XCB, EGLFS are working)
  See README-Wayland.md and README-WASM.md for platform specific information.
- Layouting engine honouring min/max size constraints and some size policies
- PySide2 bindings
- Clean codebase
  - Not mixing GUI with state with logic with animations
  - Great test coverage, even the GUI and DnD operations are tested. 200 tests currently.
  - Fuzzer for doing random testing and finding bugs
- Lazy separator resize
- Reordering tabs with mouse
- Partial layout save/restore, affecting only a chosen sub-set
- Double click on title bar to maximize
- Double click on separator to distribute equally
- Show close button on tabs
- Allow to make a dock widget non-closable and/or non-dockable
- Optional minimize and maximize button on the title bar
- FloatingWindows can be utility windows or full native

## Screen capture

![Screen capture](./screencap.gif?raw=true "The docking system in action")

## Building and requirements

To build KDDockWidgets you'll need:

- CMake
- Qt 5.15.x or Qt6 >= 6.2
- Ninja (Other generators might work but are untested)
- C++17 capable compiler. Minimum VS2019 on Windows.
- Qt Widgets module
- Qt X11Extras module if on Linux/X11
- Qt Quick and QuickControls2 modules if using the QtQuick support
- Qt private development headers, for instance, for Qt5:
  - SUSE: libqt5-qtbase-private-headers-devel
  - Ubuntu, debian-based: qtbase5-private-dev
  - Fedora, redhat-based: qt5-qtbase-private-devel
  - others: consult your distro

Open a terminal capable of building Qt applications.
Make sure you have cmake, ninja, compiler, Qt, etc in PATH.

Adapt the instructions to suit your cmake generator and operating system.

```bash
    cmake -G Ninja -DCMAKE_INSTALL_PREFIX=/path/where/to/install ../path/to/kddockwidgets
    cmake --build .
    cmake --build . --target install
```

Now build and run the example:

```bash
    cd path/to/kddockwidgets/examples/dockwidgets/
    cmake -G Ninja -DCMAKE_PREFIX_PATH=/path/where/to/install
    cmake --build .
    ./bin/examples/qtwidgets_dockwidgets
```

The installation directory defaults to `c:\KDAB\KDDockWidgets-<version>` on Windows
and `/usr/local/KDAB/KDDockWidgets-<version>` on non-Windows.

Change the installation location by passing the option `-DCMAKE_INSTALL_PREFIX=/install/path` to CMake.

## Trying out the examples

A full demo that showcases most of the features lives in [examples/dockwidgets](examples/dockwidgets).

A simpler example can be found in [examples/minimal](examples/minimal),
which might be more indicated to learn the API, as it's less overwhelming than the full demo.

To build and run the example:

```bash
    cd path/to/kddockwidgets/examples/dockwidgets/
    cmake -G Ninja -DCMAKE_PREFIX_PATH=/path/where/kddw/is/installed
    cmake --build .
    ./kddockwidgets_example
```

## Using

From your CMake Qt5 project, add

```cmake
    find_package(KDDockWidgets CONFIG)
```

or for Qt6

```cmake
    find_package(KDDockWidgets-qt6 CONFIG)
```

and link to the imported target `KDAB::kddockwidgets`.
That's all you need to do (the imported target also brings in the include directories)

You may also need to modify the `CMAKE_PREFIX_PATH` environment variable depending
on where you installed KDDockWidgets.

## Python Bindings

Please refer to [README-bindings.md](README-bindings.md).

## Versioning

New features go to master while the stable branch only accepts non-intrusive bug fixes.

We'll try to remain source and binary compatible across versions. API will get
a deprecation notice before being removed in the next version. Note that this
compatibility effort is only for the public API. Private API (headers ending
in _p.h) might change so you shouldn't depend on them. Private API is only
exposed so more advanced users can override, for example `paintEvent()`, and
not so they can change internal business logic.

We don't promise or test binary compatibility. It's advised that you recompile
your application whenever updating KDDW.

## Styling

Almost all private widgets used by KDDW can be derived by the user to give them
a custom look. That's done by providing your own ViewFactory. Run
"examples/qtwidgets_dockwidgets -p" to see that in action.

Qt StyleSheets are not, and will not, be supported. See the comments in
`examples/dockwidgets/MyTitleBar_CSS.h` for why. You can however use some minimal
CSS, as shown in that example, just don't report bugs about it.

Warning: When using private headers, be sure to rebuild your application whenever you
update to a new KDDW version. Binary compatibility is only kept when using public
headers.

## Licensing

KDDockWidgets is (C) 2019-2022, Klarälvdalens Datakonsult AB, and is licensed according to
the terms of the [GPL 2.0](LICENSES/GPL-2.0-only.txt) or [GPL 3.0](LICENSES/GPL-3.0-only.txt).

Contact KDAB at <info@kdab.com> to inquire about commercial licensing.

## Get Involved

Please submit your issue reports to our GitHub space at <https://github.com/KDAB/KDDockWidgets>.

When reporting bugs please make it easy for the maintainer to reproduce it. Use `examples/minimal/`
or `examples/dockwidgets/` for reproducing the problem. If you did modifications to the example
in order to reproduce then please attach the *patch* and not a picture of your changes. You can
get a patch by doing `git diff > repro.diff` at the repo root.

Also state which KDDW sha1, branch or version you're using, and which operating system.

KDAB will happily accept external contributions; however, **all** contributions require a
signed [Copyright Assignment Agreement](docs/KDDockWidgets-CopyrightAssignmentForm.pdf).

This is needed so we can continue to dual-license it.

Contact info@kdab.com for more information.

Thanks to our [contributors](CONTRIBUTORS.txt).

## About KDAB

KDDockWidgets is supported and maintained by Klarälvdalens Datakonsult AB (KDAB).

The KDAB Group is the global No.1 software consultancy for Qt, C++ and
OpenGL applications across desktop, embedded and mobile platforms.

The KDAB Group provides consulting and mentoring for developing Qt applications
from scratch and in porting from all popular and legacy frameworks to Qt.
We continue to help develop parts of Qt and are one of the major contributors
to the Qt Project. We can give advanced or standard trainings anywhere
around the globe on Qt as well as C++, OpenGL, 3D and more.

Please visit <https://www.kdab.com> to meet the people who write code like this.

Stay up-to-date with KDAB product announcements:

- [KDAB Newsletter](https://news.kdab.com)
- [KDAB Blogs](https://www.kdab.com/category/blogs)
- [KDAB on Twitter](https://twitter.com/KDABQt)
