drawcmd.rb

drawcmd.rb

if ARGV.size != 1
  warn "Usage: ruby #$0 <image file>"
  exit
end
image_file = ARGV.shift.encode("utf-16le")


require "fiddle/import"

module Kernel32
  extend Fiddle::Importer
  dlload "kernel32.dll"

  extern "int GetLastError()"
  extern "intptr_t GetConsoleWindow()"
  extern "int GetConsoleScreenBufferInfo(intptr_t, void *)"
  extern "int GetCurrentConsoleFont(intptr_t, int, void *)"
  extern "intptr_t CreateFile(void *, unsigned int, unsigned int, void *, unsigned int, unsigned int, intptr_t)"
  extern "int CloseHandle(intptr_t)"

  GENERIC_READ = 0x80000000
  GENERIC_WRITE = 0x40000000
  OPEN_EXISTING = 3

  CONSOLE_SCREEN_BUFFER_INFO = struct([
    "short width",
    "short height",
    "short x",
    "short y",
    "unsigned short wAttribute",
    "short left",
    "short top",
    "short right",
    "short bottom",
    "short maxWidth",
    "short maxHeight",
  ])

  CONSOLE_FONT_INFO = struct([
    "unsigned int nFont",
    "short width",
    "short height",
  ])
end

module User32
  extend Fiddle::Importer
  dlload "user32.dll"

  extern "intptr_t GetDC(intptr_t)"
  extern "int ReleaseDC(intptr_t, intptr_t)"
  extern "int GetClientRect(intptr_t, void *)"

  RECT = struct([
    "int left",
    "int top",
    "int right",
    "int bottom",
  ])
end

module GdiPlus
  extend Fiddle::Importer
  dlload "gdiplus.dll"

  extern "int GdiplusStartup(void *, void *, void *)"
  extern "int GdiplusShutdown(void *)"
  extern "int GdipCreateFromHWND(intptr_t, void *)"
  extern "int GdipDeleteGraphics(void *)"
  extern "int GdipLoadImageFromFile(void *, void *)"
  extern "int GdipDrawImageI(void *, void *, int, int)"
  extern "int GdipDrawImageRectI(void *, void *, int, int, int, int)"
  extern "int GdipDisposeImage(void *)"
  extern "int GdipGetImageWidth(void *, void *)"
  extern "int GdipGetImageHeight(void *, void *)"

  Pointer = struct([
    "void *ptr"
  ])
  UInt = struct([
    "unsigned int value"
  ])
  StartupInput = struct([
    "unsigned int GdiPlusVersion",
    "void *DebugEventCallback",
    "int SuppressBackgroundThread",
    "int SuppressExternalCodecs",
  ])

  def self.method_missing(name, *args)
    meth = ("Gdip" + name.to_s).to_sym
    unless respond_to?(meth)
      meth = ("Gdiplus" + name.to_s).to_sym
    end
    raise NoMethodError, "No such method: `#{name}'" unless respond_to?(meth)
    status = __send__(meth, *args)
    if status != 0
      raise "GDI error: #{status}"
    end
    0
  end
end


hcon = Kernel32.CreateFile("CONOUT$", Kernel32::GENERIC_READ | Kernel32::GENERIC_WRITE, 0, nil, Kernel32::OPEN_EXISTING, 0, 0)
raise "Cannot get console output handle" if hcon == -1

begin
  fontinfo = Kernel32::CONSOLE_FONT_INFO.malloc
  if Kernel32.GetCurrentConsoleFont(hcon, 0, fontinfo) == 0
    raise "Cannot get console screen buffer info"
  end

  hwnd = Kernel32.GetConsoleWindow
  raise "Cannot get console window handle" if hwnd == -1

  tokenbuf = GdiPlus::Pointer.malloc
  gsi = GdiPlus::StartupInput.malloc
  gsi.GdiPlusVersion = 1
  gsi.DebugEventCallback = nil
  gsi.SuppressBackgroundThread = 0
  gsi.SuppressExternalCodecs = 0
  GdiPlus.Startup(tokenbuf, gsi, nil)

  begin
    grbuf = GdiPlus::Pointer.malloc
    GdiPlus.CreateFromHWND(hwnd, grbuf)

    begin
      imagebuf = GdiPlus::Pointer.malloc
      GdiPlus.LoadImageFromFile(image_file, imagebuf)

      begin
        buf = GdiPlus::UInt.malloc
        GdiPlus.GetImageWidth(imagebuf.ptr, buf)
        w = buf.value
        GdiPlus.GetImageHeight(imagebuf.ptr, buf)
        h = buf.value
        rect = User32::RECT.malloc
        if User32.GetClientRect(hwnd, rect) == 0
          raise "cannot call GetClientRect"
        end
        cw = rect.right - rect.left
        ch = rect.bottom - rect.top - fontinfo.height
        if w > cw
          h = cw*h/w
          w = cw
        end
        if h > ch
          w = w*ch/h
          h = ch
        end
        n = h / fontinfo.height
        n.times do
          puts
        end
        coninfo = Kernel32::CONSOLE_SCREEN_BUFFER_INFO.malloc
        if Kernel32.GetConsoleScreenBufferInfo(hcon, coninfo) == 0
          raise "Cannot get console screen buffer info"
        end
        y = ((coninfo.y - n) - coninfo.top) * fontinfo.height
        GdiPlus.DrawImageRectI(grbuf.ptr, imagebuf.ptr, 0, y, w, h)
      ensure
        GdiPlus.DisposeImage(imagebuf.ptr)
      end
    ensure
      GdiPlus.DeleteGraphics(grbuf.ptr)
    end
  ensure
    GdiPlus.Shutdown(tokenbuf.ptr)
  end
ensure
  Kernel32.CloseHandle(hcon)
end

https://github.com/mattn/drawcmd のドキュメントだけ読んで「なるほど」と思って雑に書いてみたもの。
コードは読まなかったので、同じことをやってるのか、とか、同じ機能を満たしてるのか、とかは未確認。