installation/SDL2: one single page (instead of one by platform)

Author: vindarel

content/en/installation/ncurses/_index.md

@@ -140,3 +140,12 @@ $ ros follow-dependency=t install lem-project/lem
 ```
 export PATH=$PATH:~/.roswell/bin
 ```
+
+## Japanese Industrial Standard keyboard layout
+
+If your keyboard is a JIS layout, you need to put the following settings in `$HOME/.lem/init.lisp`
+
+```common-lisp
+#+lem-sdl2
+(lem-sdl2:set-keyboard-layout :jis)
+```

content/en/installation/sdl2/_index.md

@@ -3,3 +3,132 @@ title: Lem SDL2
 weight: -20
 geekdocCollapseSection: true
 ---
+
+> **Note:** the SDL2 UI is deprecated in favor of the Webview one. It won't receive updates.
+
+
+## Using the binary
+
+[Lem has nightly releases](https://github.com/lem-project/lem/releases) (Linux AppImages, MacOS and Windows binaries), but not for the SDL2 GUI.
+
+
+## Installation from scratch
+
+Dependencies:
+
+- [sbcl](https://www.sbcl.org/)
+- [sdl2](https://www.libsdl.org/)
+- [qlot](https://github.com/fukamachi/qlot)
+- [git](https://git-scm.com/)
+
+### Install SBCL and SDL2 libraries
+
+- Debian-like distro
+
+```
+sudo apt install sbcl build-essential libsdl2-dev libsdl2-image-dev libsdl2-ttf-dev fd-find
+```
+
+- Fedora-like distro
+
+```
+sudo dnf install sbcl SDL2-devel SDL2_image-devel SDL2_ttf-devel fd-find
+sudo dnf group install c-development development-tools
+```
+
+### Install qlot
+
+- Automatic installer
+
+```
+curl -L https://qlot.tech/installer | bash
+```
+
+> **Note:** For an alternative installation, see https://github.com/fukamachi/qlot#installation
+
+### Download and install
+
+There are two ways to install Lem:
+
+**1. Local installation:**
+
+```
+mkdir $HOME/common-lisp
+cd $HOME/common-lisp
+git clone https://github.com/lem-project/lem.git
+cd lem && make sdl2
+```
+
+> **Note:** You can also run `make sdl2-ncurses` to build Lem with both the SDL2 and ncurses interfaces. You can then choose the interface at startup with `-i / --interface`, either "sdl2" or "ncurses".
+
+Then add the executable to your PATH by adding this line to your `~/.bashrc`:
+
+```
+export PATH="$HOME/common-lisp/lem:$PATH"
+```
+
+**2. System-wide installation:**
+
+```
+git clone https://github.com/lem-project/lem.git
+cd lem
+```
+
+First ensure qlot is installed for the root user:
+```
+sudo bash -c "curl -L https://qlot.tech/installer | bash"
+```
+
+Then install Lem:
+```
+sudo make install
+```
+
+This will:
+
+- Build Lem with both SDL2 and ncurses interfaces
+- Install the executable system-wide
+- Add a desktop entry file with relevant file associations
+- Configure SDL2 as the default interface
+
+You can still switch between interfaces using the `-i / --interface` option when launching Lem.
+
+## MacOS
+
+### How to Fix “App Is Damaged and Can’t Be Opened” on OSX
+Copy the app file to the applications folder and type the following in your terminal:
+```
+xattr -d com.apple.quarantine /Applications/lem.app
+```
+### Make it an Application
+
+To create an executable that you can run as a GUI you will need to use Automator.
+
+- Launch Automator
+- Choose 'Application' as the type for your document
+
+You should now see three columns. In the second column there will be a collection of actions
+that you can run in this 'application'. Scroll down until you see `Run Shell Script`. Double click
+on this and on the right you should now see a text box where you can enter your script:
+
+Replace the contents of this shell script with the following:
+
+```zsh
+source ~/.zshrc
+cd ~/common-lisp/lem
+./lem -i sdl2 &
+exit 0
+```
+
+Save this as an application (this should be the default) with the name `Lem` to `\Applications`.
+
+You should now be abel to run this as an application from the Applications folder.
+
+## Japanese Industrial Standard keyboard layout
+
+If your keyboard is a JIS layout, you need to put the following settings in `$HOME/.lem/init.lisp`
+
+```common-lisp
+#+lem-sdl2
+(lem-sdl2:set-keyboard-layout :jis)
+```