add Dockerfile (based on Alpine)

.gitignore

@@ -6,4 +6,14 @@
 *.dwarf
 todo*
 AutoHotkey*.chm
-.vscode/.history
+.vscode/.history
+
+build/libxdo.so*
+build/libxkbcommon.so*
+build/libxkbcustom.a
+build/linuxdeploy-x86_64.AppImage
+build/linuxdeploy-plugin-gtk.sh
+build/*.AppImage*
+
+# for generating a .dockerignore based on .gitignore:
+.git

build/README.md

@@ -46,6 +46,16 @@ The released binaries are special because they need to be portable. We achieve t
 
 There's a script to call `./build.sh`, make a new release and publish it etc., it's `../release.sh`. You most likely can't run it yourself though.
 
+### Docker
+
+In the rare case that you want to use ahk_x11 containerized for headless purposes, you can find a working Dockerfile example in `./ahk_x11.alpine.Dockerfile`. Run it in the parent (main) directory like so:
+
+```bash
+cp .gitignore .dockerignore && \
+  docker build -t ahk_x11-alpine -f build/ahk_x11.alpine.Dockerfile . ; \
+  rm .dockerignore
+```
+
 ## Contributing
 
 If you feel like it, you are welcome to contribute! The language in use, Crystal, is resembling Ruby syntax and consequently also great for beginners.

build/ahk_x11.alpine.Dockerfile

@@ -0,0 +1,22 @@
+FROM alpine:latest as build-xdotool
+RUN apk add --no-cache alpine-sdk libxtst-dev libxinerama-dev libxkbcommon-dev libx11-dev
+RUN git clone --depth=1 https://github.com/jordansissel/xdotool /xdo
+WORKDIR /xdo
+RUN make WITHOUT_RPATH_FIX=1 libxdo.a
+
+FROM crystallang/crystal:latest-alpine AS build-ahkx11
+RUN apk add --no-cache gtk+3.0-dev gobject-introspection-dev libxtst-dev libnotify-dev
+RUN git clone --depth=1 https://github.com/phil294/ahk_x11 /ahk
+WORKDIR /ahk
+RUN shards install
+RUN bin/gi-crystal
+RUN sed -i -E 's/private getter xdo_p/getter xdo_p/' lib/x_do/src/x_do.cr
+RUN sed -i -E 's/GLib::String/::String/g' lib/gi-crystal/src/auto/gtk-3.0/gtk.cr
+RUN mkdir static
+COPY --from=build-xdotool /xdo/libxdo.a static
+RUN shards build -Dpreview_mt --link-flags="-L$PWD/static -lxdo -lxkbcommon -lXinerama -lXtst -lXi -lX11" --release
+
+FROM alpine:latest
+RUN apk add --no-cache libx11 libnotify gtk+3.0 libgcc
+COPY --from=build-ahkx11 /ahk/bin/ahk_x11 .
+CMD ["./ahk_x11"]