[[https://www.qt.io/qt-features-libraries-apis-tools-and-ide|QT Creator]] is a cross-platform IDE designed to build Qt applications. The Qt Creator IDE is currently the preferred choice to build and run custom qt applications on the reMarkable tablet.
===== Installation =====
==== Ubuntu ====
$ sudo apt install qtcreator
Note: On Linux Mint the qtcreator package is outdated. Please install the Qt Creator IDE via the [[https://www.qt.io/download-qt-installer?hsCtaTracking=99d9dd4f-5681-48d2-b096-470725510d34%7C074ddad0-fdef-4e53-8aa8-5e8a876d6ab4 | Qt Online Installer]].
==== Arch Linux ====
# pacman -S qtcreator
==== Fedora ====
# yum install qt-creator
For other Linux distributions, please refer to the distribution specific package manager and package list. Optionally, or if your distribution does not provide a qt-creator package, you may follow [[http://doc.qt.io/qtcreator/ |the official Qt Creator Manual]] and build Qt Creator from source.
===== Toolchain =====
For applications to be able to run on the reMarkable, they must be compiled for the ARM architecture
using a toolchain. (See [[toolchain]] for ways to download the official toolchain and for information about alternative toolchains.)
In the following, it is assumed that you downloaded the official toolchain installer to a file named ''install-toolchain.sh''.
Before executing the toolchain installer, ensure that ''bsdtar'' is installed. Then execute the toolchain installer:
$ chmod +x install-toolchain.sh
$ ./install-toolchain
You will be prompted to specify an installation path. It is highly recommended to use the default SDK path as it is used through out this article.
===== Configuring QT Creator =====
The QT Creator IDE must first be configured to support cross-compiling for the reMarkable tablet. It is assumed that the toolchain has been installed to ''/usr/local/oecore-x86_64''
Open the options menu under ''Tools'' > ''Options'' > ''Kits'' and follow the latter steps
==== QT Version ====
Under the QT Versions tab, click on ''Add...'' and select the qmake binary located in ''/usr/local/oecore-x86_64/sysroots/x86_64-oesdk-linux/usr/bin/qmake''. Set the Version name to reMarkable 5.11.3 to follow up with this guide.
==== Compiler ====
Under the compilers tab, click ''Add'' > ''GCC''. From there you'll have to add a C and C++ compiler.
Set the path of both compilers to ''/usr/local/oecore-x86_64/sysroots/x86_64-oesdk-linux/usr/bin/arm-oe-linux-gnueabi/arm-oe-linux-gnueabi-gcc'' and name them reMarkable GCC each and keep the ABI settings at ''arm-linux-generic-elf-32bit''.
==== Debugger ====
Under the debuggers tab, click ''Add'' and set the path to ''/usr/local/oecore-x86_64/sysroots/x86_64-oesdk-linux/usr/bin/arm-oe-linux-gnueabi/arm-oe-linux-gnueabi-gdb''.
Set the name to reMarkable GDB
==== QT Kit ====
Under the kits tab, click ''Add''. From there ensure all properties are set as shown in the following table :
^ Property ^ Value ^
| File system name | |
| Device Type | Generic Linux Device |
| Device | |
| Sysroot | /usr/local/oecore-x86_64/sysroots/cortexa9hf-neon-oe-linux-gnueabi|
| Compiler (C) | reMarkable GCC |
| Compiler (C++) | reMarkable GCC |
| Environment | No changes to apply. |
| Debugger | reMarkable GDB |
| Qt version | reMarkable 5.11.3 |
| Qt mkspec | linux-oe-g++ |
CMake related properties have been left out from the table as they should remain unmodified. Should Qt creator report that the Qt Version already exists, simply alter the name to something different.
===== Adding your device =====
Qt has to be able to establish connection to your device for it to directly install and execute code on it.
Add an entry for your reMarkable tablet under ''Tools'' > ''Options'' > ''Devices''. From there go to the ''Devices'' tab and click ''Add'' > ''Generic Linux Device''.
Set a name for the device, such as reMarkable, and specify the necessary [[http://remarkablewiki.com/index.php?title=Methods_of_access#SSH|SSH credentials]] to access your device.
===== After Configuration =====
After all steps above have been completed, close the current Qt Creator session and source the toolchain environment:
$ source /usr/local/oecore-x86_64/environment-setup-cortexa9hf-neon-oe-linux-gnueabi
Then start Qt creator from the same sh session:
$ qtcreator
**On every new shell session, the toolchain environment must be sourced before Qt Creator has been opened.***
At this point, Qt Creator should be able to build and execute code on your reMarkable tablet as long as it's unlocked and connected (via SSH) to the host machine.
**Tip:**
The device's graphical interface, [[tech:xochitl]], may undesirably interfere and overlap with the executed Qt Application. To stop this behavior from reoccurring, stop the xochitl service on your reMarkable trough systemctl:
remarkable: ~/ systemctl stop xochitl
To start the GUI again, either restart the device or start xochitl from systemctl:
remarkable: ~/ systemctl start xochitl
===== Remarkable 2 =====
For running your apps on the remarkable 2, you must have [[https://github.com/ddvk/remarkable2-framebuffer|rm2fb]] installed (possible from toltec) and run your apps with LD_PRELOAD=/opt/lib/librm2fb_client.so.1.0.0/librm2fb_client.so.1.0.0 . You can add this in qtcreator by going to Projects > Build & Run > Remarkable > Run > Run environment and add here the key LD_PRELOAD and value /opt/lib/librm2fb_client.so.1.0.0 (or where you've installed rm2fb).