ruby binding 追加

- FFI gem (libptouch)、exe ptouch-print-png（PNG のみ）
- ステータス 32 バイトを Hash に展開（parse_status / status_hash）
- CMake: libptouch 共有ライブラリ（ptouch_shared）
- RuboCop、gemspec（homepage / source_code_uri）

Made-with: Cursor

ruby/lib/libptouch/binding.rb

@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+require "ffi"
+
+module Libptouch
+  module Binding
+    extend FFI::Library
+
+    def self.library_files
+      list = []
+      env = ENV["LIBPTOUCH_LIB"]
+      list << env if env && !env.empty?
+      base = File.expand_path("../../..", __dir__)
+      %w[libptouch.so libptouch.dylib].each do |name|
+        path = File.join(base, "build", name)
+        list << path if File.file?(path)
+      end
+      list << "libptouch"
+      list
+    end
+
+    ffi_lib library_files
+
+    class RasterParams < FFI::Struct
+      layout :width_dots, :uint32,
+             :height_dots, :uint32,
+             :margin_mm, :uint8,
+             :_pad, [:uint8, 3]
+    end
+
+    class PngOptions < FFI::Struct
+      layout :threshold, :uint8
+    end
+
+    attach_function :libptouch_create, [], :pointer
+    attach_function :libptouch_destroy, [:pointer], :void
+    attach_function :libptouch_strerror, [:pointer], :string
+    attach_function :libptouch_last_error, [:pointer], :int
+    attach_function :libptouch_open_usb, [:pointer], :int
+    attach_function :libptouch_open_usb_vid_pid, %i[pointer uint16 uint16], :int
+    attach_function :libptouch_close, [:pointer], :void
+    attach_function :libptouch_check_raster, %i[pointer pointer size_t pointer], :int
+    attach_function :libptouch_print_raster, %i[pointer pointer size_t pointer], :int
+    attach_function :libptouch_png_file_to_raster,
+                    %i[pointer string pointer pointer pointer pointer], :int
+    attach_function :libptouch_free_raster, [:pointer], :void
+    attach_function :libptouch_get_status, %i[pointer pointer], :int
+  end
+end