NanoGUI
========================================================================================
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    :alt: Docs

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.. begin_brief_description

NanoGUI is a minimalistic cross-platform widget library for OpenGL 3.x or higher. It
supports automatic layout generation, stateful C++11 lambdas callbacks, a variety of
useful widget types and Retina-capable rendering on Apple devices thanks to NanoVG_ by
Mikko Mononen. Python bindings of all functionality are provided using pybind11_.

.. _NanoVG: https://github.com/memononen/NanoVG
.. _pybind11: https://github.com/wjakob/pybind11

.. end_brief_description

- `Documentation <https://nanogui.readthedocs.io>`_

.. contents:: Contents
   :local:
   :backlinks: none

Example screenshot
----------------------------------------------------------------------------------------

.. image:: https://github.com/wjakob/nanogui/raw/master/resources/screenshot.png
   :alt: Screenshot of Example 1.
   :align: center

Description
----------------------------------------------------------------------------------------

.. begin_long_description

NanoGUI builds on GLFW_ for cross-platform OpenGL context creation and event handling,
GLAD_ to use OpenGL 3.x or higher Windows, Eigen_ for basic vector types, and NanoVG_ to
draw 2D primitives.

Note that the dependency library NanoVG already includes some basic example code to draw
good-looking static widgets; what NanoGUI does is to flesh it out into a complete GUI
toolkit with event handling, layout generation, etc.

NanoGUI currently works on Mac OS X (Clang) Linux (GCC or Clang) and Windows (Visual
Studio ≥ 2015); it requires a recent C++11 capable compiler. All dependencies are
jointly built using a CMake-based build system.

.. _GLFW: http://www.glfw.org/
.. _GLAD: https://github.com/Dav1dde/glad
.. _Eigen: http://eigen.tuxfamily.org/index.php?title=Main_Page

.. end_long_description

Creating widgets
----------------------------------------------------------------------------------------

NanoGUI makes it easy to instantiate widgets, set layout constraints, and
register event callbacks using high-level C++11 code. For instance, the
following two lines from the included example application add a new button to
an existing window `window` and register an event callback.

.. code-block:: cpp

   Button *b = new Button(window, "Plain button");
   b->setCallback([] { cout << "pushed!" << endl; });


The following lines from the example application create the coupled
slider and text box on the bottom of the second window (see the screenshot).

.. code-block:: cpp

   /* Create an empty panel with a horizontal layout */
   Widget *panel = new Widget(window);
   panel->setLayout(new BoxLayout(BoxLayout::Horizontal, BoxLayout::Middle, 0, 20));

   /* Add a slider and set defaults */
   Slider *slider = new Slider(panel);
   slider->setValue(0.5f);
   slider->setFixedWidth(80);

   /* Add a textbox and set defaults */
   TextBox *textBox = new TextBox(panel);
   textBox->setFixedSize(Vector2i(60, 25));
   textBox->setValue("50");
   textBox->setUnits("%");

   /* Propagate slider changes to the text box */
   slider->setCallback([textBox](float value) {
       textBox->setValue(std::to_string((int) (value * 100)));
   });


The Python version of this same piece of code looks like this:

.. code-block:: py

   # Create an empty panel with a horizontal layout
   panel = Widget(window)
   panel.setLayout(BoxLayout(BoxLayout.Horizontal, BoxLayout.Middle, 0, 20))

   # Add a slider and set defaults
   slider = Slider(panel)
   slider.setValue(0.5f)
   slider.setFixedWidth(80)

   # Add a textbox and set defaults
   textBox = TextBox(panel)
   textBox.setFixedSize(Vector2i(60, 25))
   textBox.setValue("50")
   textBox.setUnits("%")

   # Propagate slider changes to the text box
   def cb(value):
       textBox.setValue("%i" % int(value * 100))
   slider.setCallback(cb)

"Simple mode"
----------------------------------------------------------------------------------------

Christian Schüller contributed a convenience class that makes it possible to
create AntTweakBar-style variable manipulators using just a few lines of code.
For instance, the source code below was used to create the following example
application.

.. image:: https://github.com/wjakob/nanogui/raw/master/resources/screenshot2.png
   :alt: Screenshot
   :align: center


.. code-block:: cpp

   /// dvar, bar, strvar, etc. are double/bool/string/.. variables

   FormHelper *gui = new FormHelper(screen);
   ref<Window> window = gui->addWindow(Eigen::Vector2i(10, 10), "Form helper example");
   gui->addGroup("Basic types");
   gui->addVariable("bool", bvar);
   gui->addVariable("string", strvar);

   gui->addGroup("Validating fields");
   gui->addVariable("int", ivar);
   gui->addVariable("float", fvar);
   gui->addVariable("double", dvar);

   gui->addGroup("Complex types");
   gui->addVariable("Enumeration", enumval, enabled)
      ->setItems({"Item 1", "Item 2", "Item 3"});
   gui->addVariable("Color", colval);

   gui->addGroup("Other widgets");
   gui->addButton("A button", [](){ std::cout << "Button pressed." << std::endl; });

   screen->setVisible(true);
   screen->performLayout();
   window->center();

Compiling
----------------------------------------------------------------------------------------

Clone the repository and all dependencies (with ``git clone --recursive``),
run CMake to generate Makefiles or CMake/Visual Studio project files, and
the rest should just work automatically.

On Debian/Ubuntu, make sure that you have installed the following packages

.. code-block:: bash

   $ apt-get install cmake xorg-dev libglu1-mesa-dev

To also get the Python bindings, you'll need to run

.. code-block:: bash

   $ apt-get install python-dev

On RedHat/Fedora, make sure that you have installed the following packages

.. code-block:: bash

   $ sudo dnf install cmake mesa-libGLU-devel libXi-devel libXcursor-devel libXinerama-devel libXrandr-devel xorg-x11-server-devel

To also get the Python bindings, you'll need to run

.. code-block:: bash

   $ sudo dnf install python3-devel

License
----------------------------------------------------------------------------------------

.. begin_license

NanoGUI is provided under a BSD-style license that can be found in the LICENSE_
file. By using, distributing, or contributing to this project, you agree to the
terms and conditions of this license.

.. _LICENSE: https://github.com/wjakob/nanogui/blob/master/LICENSE.txt

NanoGUI uses Daniel Bruce's `Entypo+ <http://www.entypo.com/>`_ font for the
icons used on various widgets.  This work is licensed under a
`CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0/>`_ license.
Commercial entities using NanoGUI should consult the proper legal counsel for
how to best adhere to the attribution clause of the license.

.. end_license
