Crystal Bindings to Qt 5 Beta
Bindings for the Qt5 Framework using bindgen.
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Ready-to-use Qt versions: 5.5 to 5.10
- Just Works™ - Drop the dependency into a project, and use it.
- Providing an API that feels native to Crystal
- Focus on the GUI components (That is,
Add this to your application's
dependencies: qt5: github: Papierkorb/qt5.cr branch: master-ready-to-use
Your users will require the Qt5 libraries on their system.
Additional development dependencies
Using your systems package manager:
pacman -S qt5-base
apt-get install qtbase5-dev
apt-get install qtbase5-dev
Have a look in samples/!
A short Hello World snippet looks like this:
require "qt5" # Require it! qApp = Qt::Application.new # Create the application # Display something on the screen label = Qt::Label.new "Hello from Crystal/Qt!" label.show Qt::Application.exec # And run it!
A note on Qt's license
A common misconception is that you have to pay for Qt to use it in closed-source applications.
This project assumes you'll link to Qt dynamically. In this case, you can use Qt free of charge including for closed-source, commercial applications under the terms of the LGPL.
You can build closed-source applications using Crystal, this shard, and Qt for free.
Note: This section is to combat this misconception, the authors of
are in no way responsible to check if the same terms apply in your jurisdiction.
Generating the bindings
If you want to work on
qt5.cr itself, or have a custom build of Qt you want to
use, you'll have to generate the bindings yourself.
These steps can be followed from a project using
qt5.cr, or from within
qt5.cr itself. For the latter, just check out the
master branch instead
of changing a
Important: For this you'll also have to meet the dependencies of bindgen.
qt5.cr supports many different versions of Qt on different platforms,
generated bindings follow a naming scheme. The scheme is as follows:
KERNELis the OS kernel, e.g.
LIB_Cis the lib C name, e.g.
ARCHis the architecture, e.g.
VERSIONis the Qt version, e.g.
The naming scheme is not strictly enforced. However, it should always end with
Generating all binding versions
master-ready-to-use branch is built using this method:
- Change into the
- If you want to change which bindings to generate, edit
The script will automatically download, unpack, build and generate all
configured versions of Qt. It'll store the Qt5 versions in a directory called
download_cache/. Subsequent invocations of that script will use these cached
assets. The first run may take a long time.
Generating a specific binding version
- Use the
crystal depsto download dependencies
- Decide which version of Qt to use, and build the scheme (See above)
- Export the binding scheme:
- If you're not using your systems Qt:
- Run bindgen:
lib/bindgen/tool.sh qt.yml --stats
Future things to do
qHash()of wrapped types (to
- Integration with LibEvent: Right now, Qt blocks the whole thread.
- The rest of the billion Qt classes of interest
- Everything in the to be done category
- Integration for the
Qt DesignerUI designer
- Integration for
- Localization/Translation for your applications!
- UI test library, with adapter for
- Also, actual tests - Let's catch whacko bugs right in the CI!
- Automated copy (and adaption) of the Qt documentation, for easy Crystal-specific docs
- The Qt Docs license should allow this if done correctly
- Talk to
#crystal-langabout what you're gonna do.
- You got the go-ahead? The project's in an early state: Things may change without notice under you.
- Then do the rest, PR and all. You know the drill.
The Qt bindings, including the generated and manually-written parts, are subject
to the MPL-2 license. You can find a copy attached of the full license text in
This project claims no copyright on the
Qt framework or of any of its
trademarks, source, or any other assets.
Questions? Contact Papierkorb.
- Papierkorb Stefan Merettig - creator, maintainer