module Gosu
  ##
  # The first component of the version.
  MAJOR_VERSION = :an_integer

  ##
  # The second component of the version.
  MINOR_VERSION = :an_integer

  ##
  # The third component of the version.
  POINT_VERSION = :an_integer

  ##
  # A version string of the form "0.1.2", "0.1.2.3" or "0.1.2pre4".
  VERSION = :a_string

  ##
  # A block of legal copy that your game is obliged to display somewhere.
  LICENSES = :a_string

  KB_0…KB_9 = :an_integer
  KB_A…KB_Z = :an_integer
  KB_APOSTROPHE = :an_integer
  KB_BACKSLASH = :an_integer
  KB_BACKSPACE = :an_integer
  KB_BACKTICK = :an_integer
  KB_COMMA = :an_integer
  KB_DELETE = :an_integer
  KB_DOWN = :an_integer
  KB_END = :an_integer

  KB_PRINT_SCREEN = :an_integer
  KB_SCROLL_LOCK = :an_integer
  KB_PAUSE = :an_integer

  ##
  # This is the key on the numpad.
  KB_ENTER = :an_integer

  KB_EQUALS = :an_integer
  KB_ESCAPE = :an_integer
  KB_F1…KB_F12 = :an_integer
  KB_HOME = :an_integer
  KB_INSERT = :an_integer
  KB_ISO = :an_integer
  KB_LEFT = :an_integer
  KB_LEFT_ALT = :an_integer
  KB_LEFT_BRACKET = :an_integer
  KB_LEFT_CONTROL = :an_integer
  KB_LEFT_META = :an_integer
  KB_LEFT_SHIFT = :an_integer
  KB_MINUS = :an_integer
  KB_NUMPAD_0…KB_NUMPAD_9 = :an_integer
  KB_NUMPAD_DELETE = :an_integer
  KB_NUMPAD_DIVIDE = :an_integer
  KB_NUMPAD_MINUS = :an_integer
  KB_NUMPAD_MULTIPLY = :an_integer
  KB_NUMPAD_PLUS = :an_integer
  KB_PAGE_DOWN = :an_integer
  KB_PAGE_UP = :an_integer
  KB_PERIOD = :an_integer

  ##
  # This is the key above the right shift key.
  KB_RETURN = :an_integer

  KB_RIGHT = :an_integer
  KB_RIGHT_ALT = :an_integer
  KB_RIGHT_BRACKET = :an_integer
  KB_RIGHT_CONTROL = :an_integer
  KB_RIGHT_META = :an_integer
  KB_RIGHT_SHIFT = :an_integer
  KB_SEMICOLON = :an_integer
  KB_SLASH = :an_integer
  KB_CAPS_LOCK = :an_integer
  KB_SPACE = :an_integer
  KB_TAB = :an_integer
  KB_UP = :an_integer

  MS_LEFT = :an_integer
  MS_MIDDLE = :an_integer
  MS_RIGHT = :an_integer
  MS_WHEEL_DOWN = :an_integer
  MS_WHEEL_UP = :an_integer
  MS_OTHER_0…MS_OTHER_7 = :an_integer

  GP_BUTTON_0…GP_BUTTON_15 = :an_integer
  GP_LEFT_STICK_X_AXIS = :an_integer
  GP_RIGHT_STICK_X_AXIS = :an_integer
  GP_LEFT_STICK_Y_AXIS = :an_integer
  GP_RIGHT_STICK_Y_AXIS = :an_integer
  GP_LEFT_TRIGGER_AXIS = :an_integer
  GP_RIGHT_TRIGGER_AXIS = :an_integer
  GP_DPAD_DOWN = :an_integer
  GP_DPAD_LEFT = :an_integer
  GP_DPAD_RIGHT = :an_integer
  GP_DPAD_UP = :an_integer
  GP_DOWN = :an_integer
  GP_LEFT = :an_integer
  GP_RIGHT = :an_integer
  GP_UP = :an_integer

  GP_0_BUTTON_0…GP_3_BUTTON_15 = :an_integer
  GP_0_LEFT_STICK_X_AXIS…GP_3_LEFT_STICK_X_AXIS = :an_integer
  GP_0_RIGHT_STICK_X_AXIS…GP_3_RIGHT_STICK_X_AXIS = :an_integer
  GP_0_LEFT_STICK_Y_AXIS…GP_3_LEFT_STICK_Y_AXIS = :an_integer
  GP_0_RIGHT_STICK_Y_AXIS…GP_3_RIGHT_STICK_Y_AXIS = :an_integer
  GP_0_LEFT_TRIGGER_AXIS…GP_3_LEFT_TRIGGER_AXIS = :an_integer
  GP_0_RIGHT_TRIGGER_AXIS…GP_3_RIGHT_TRIGGER_AXIS = :an_integer
  GP_0_DPAD_DOWN…GP_3_DPAD_DOWN = :an_integer
  GP_0_DPAD_LEFT…GP_3_DPAD_LEFT = :an_integer
  GP_0_DPAD_RIGHT…GP_3_DPAD_RIGHT = :an_integer
  GP_0_DPAD_UP…GP_3_DPAD_UP = :an_integer
  GP_0_DOWN…GP_3_DOWN = :an_integer
  GP_0_LEFT…GP_3_LEFT = :an_integer
  GP_0_RIGHT…GP_3_RIGHT = :an_integer
  GP_0_UP…GP_3_UP = :an_integer

  ##
  # Represents an ARGB color value with 8 bits for each channel. Colors can be used interchangeably with integer literals of the form 0xAARRGGBB in all Gosu APIs.
  class Color
    ##
    # @return [Integer] the color's alpha channel.
    attr_accessor :alpha

    ##
    # @return [Integer] the color's red channel.
    attr_accessor :red

    ##
    # @return [Integer] the color's green channel.
    attr_accessor :green

    ##
    # @return [Integer] the color's blue channel.
    attr_accessor :blue

    ##
    # @return [Float] the color's hue in the range [0.0; 360.0).
    attr_accessor :hue

    ##
    # @return [Float] the color's saturation in the range [0.0; 1.0].
    attr_accessor :saturation

    ##
    # @return [Float] the color's value in the range [0.0; 1.0].
    attr_accessor :value

    # @!group Creating colors.

    ##
    # @overload initialize(argb)
    #   @param argb [Integer] an integer of the form 0xAARRGGBB.
    #
    # @overload initialize(a, r, g, b)
    #   @param a [Integer] the color's alpha channel in the range [0; 255].
    #   @param r [Integer] the color's red channel in the range [0; 255].
    #   @param g [Integer] the color's green channel in the range [0; 255].
    #   @param b [Integer] the color's blue channel in the range [0; 255].
    #
    # @see from_hsv
    # @see from_ahsv
    # @see rgba
    # @see argb
    def initialize(*args); end

    ##
    # @return (see #initialize)
    #
    # @overload rgba(rgba)
    #   @param argb [Integer] an integer of the form 0xRRGGBBAA.
    #
    # @overload rgba(r, g, b, a)
    #   @param a [Integer] the color's alpha channel in the range [0; 255].
    #   @param r [Integer] the color's red channel in the range [0; 255].
    #   @param g [Integer] the color's green channel in the range [0; 255].
    #   @param b [Integer] the color's blue channel in the range [0; 255].
    #
    # @see #initialize
    # @see argb
    def self.rgba(*args); end

    # This method is equivalent to calling `Color.new`, but the name makes the parameter order explicit.
    #
    # @return (see #initialize)
    # @overload argb(argb)
    # @overload argb(a, r, g, b)
    #
    # @see #initialize
    # @see rgba
    def self.argb(*args); end

    # Converts an HSV triplet to an opaque color.
    #
    # @return [Color] a color corresponding to the HSV triplet.
    # @param h [Float] the color's hue in the range [0.0; 360.0).
    # @param s [Float] the color's saturation in the range [0.0; 1.0].
    # @param v [Float] the color's value in the range [0.0; 1.0].
    #
    # @see from_ahsv
    def self.from_hsv(h, s, v); end

    # Converts an HSV triplet to a color with the alpha channel set to a given value.
    #
    # @return (see from_hsv)
    # @param a [Integer] the color's opacity in the range [0; 255].
    # @param (see from_hsv)
    #
    # @see from_hsv
    def self.from_ahsv(a, h, s, v); end

    # @!endgroup

    ##
    # @return [Integer] a 32-bit representation of the color in 0xAARRGGBB format.
    def argb; end

    alias_method :to_i, :argb

    # Returns a 32-bit representation of the color suitable for use with OpenGL calls. This color is stored in a fixed format in memory and its integer value may vary depending on your system's byte order.
    #
    # @return [Integer] a 32-bit OpenGL color.
    def gl; end

    # Returns an OpenGL integer constant that identifies the RGBA color format that Gosu uses.
    GL_FORMAT = :some_integer

    ##
    # @return [Color] a copy of the color.
    def dup; end

    NONE    = Gosu::Color.argb(0x00_000000)
    BLACK   = Gosu::Color.argb(0xff_000000)
    GRAY    = Gosu::Color.argb(0xff_808080)
    WHITE   = Gosu::Color.argb(0xff_ffffff)
    AQUA    = Gosu::Color.argb(0xff_00ffff)
    RED     = Gosu::Color.argb(0xff_ff0000)
    GREEN   = Gosu::Color.argb(0xff_00ff00)
    BLUE    = Gosu::Color.argb(0xff_0000ff)
    YELLOW  = Gosu::Color.argb(0xff_ffff00)
    FUCHSIA = Gosu::Color.argb(0xff_ff00ff)
    CYAN    = Gosu::Color.argb(0xff_00ffff)
  end

  ##
  # A Font can be used to draw text on a Window object very flexibly.
  # Fonts are ideal for small texts that change regularly.
  # For large, static texts you should use {Gosu::Image#from_text}.
  class Font
    ##
    # The font's name. This may be the name of a system font or a filename.
    #
    # @return [String] the font's name.
    attr_reader :name

    ##
    # @return [Integer] the font's height in pixels.
    attr_reader :height

    ##
    # Load a font from the system fonts or a file.
    #
    # (Passing a Window reference is not necessary anymore, please use the first overload from now on.)
    #
    # @param height [Integer] the height of the font, in pixels.
    # @param [Hash] options
    # @option options [String] :name the name of a system font, or a path to a TrueType Font (TTF) file. A path must contain at least one '/' or '.' character to distinguish it from a system font.
    # @option options [bool] :bold (false)
    # @option options [bool] :italic (false)
    # @option options [bool] :underline (false)
    # @option options [bool] :retro (false) see Gosu::Image
    #
    # @overload initialize(height, options = {})
    # @overload initialize(window, font_name, height)
    def initialize(height, options = {}); end

    ##
    # Overrides the image for a character.
    #
    # @note For any given character, this method MUST NOT be called more than once, and MUST NOT be called if a string containing the character has already been drawn.
    #
    # @return [void]
    # @param character [String] the character to replace.
    # @param image [Image] the image to use for the character.
    def []=(character, image); end

    # @!group Drawing text

    ##
    # Draws a single line of text with its top left corner at (x, y).
    #
    # @return [void]
    # @param text [String]
    # @param x [Number] the X coordinate
    # @param y [Number] the Y coordinate
    # @param z [Number] the Z-order.
    # @param scale_x [Float] the horizontal scaling factor.
    # @param scale_y [Float] the vertical scaling factor.
    # @param color [Color, Integer]
    # @param mode [:default, :additive] the blending mode to use.
    #
    # @see #draw_rel
    # @see Gosu::Image.from_text
    # @see https://github.com/gosu/gosu/wiki/Basic-Concepts#drawing-with-colours Drawing with colors, explained in the Gosu Wiki
    # @see https://github.com/gosu/gosu/wiki/Basic-Concepts#z-ordering Z-ordering explained in the Gosu Wiki
    def draw_text(text, x, y, z, scale_x=1, scale_y=1, color=0xff_ffffff, mode=:default); end

    ##
    # Like {#draw_text}, but supports the following markup tags: `<b>bold</b>`, `<i>italic</i>`, `<c=rrggbb>colors</c>`.
    def draw_markup(markup, x, y, z, scale_x=1, scale_y=1, color=0xff_ffffff, mode=:default); end

    ##
    # Draws a single line of text relative to (x, y).
    #
    # The text is aligned to the drawing location according to the `rel_x` and `rel_y` parameters: a value of 0.0 corresponds to top and left, while 1.0 corresponds to bottom and right. A value of 0.5 naturally corresponds to the center of the text.
    #
    # All real numbers are valid alignment values and will be interpolated (or extrapolated) accordingly.
    #
    # @return [void]
    # @param rel_x [Float] the horizontal alignment.
    # @param rel_y [Float] the vertical alignment.
    # @param (see #draw)
    #
    # @see #draw
    # @see https://github.com/gosu/gosu/wiki/Basic-Concepts#drawing-with-colours Drawing with colors, explained in the Gosu Wiki
    # @see https://github.com/gosu/gosu/wiki/Basic-Concepts#z-ordering Z-ordering explained in the Gosu Wiki
    def draw_text_rel(text, x, y, z, rel_x, rel_y, scale_x=1, scale_y=1, color=0xff_ffffff, mode=:default); end

    ##
    # Like {#draw_text_rel}, but supports the following markup tags: `<b>bold</b>`, `<i>italic</i>`, `<c=rrggbb>colors</c>`.
    def draw_markup_rel(markup, x, y, z, rel_x, rel_y, scale_x=1, scale_y=1, color=0xff_ffffff, mode=:default); end

    # @!endgroup

    ##
    # Returns the width of a single line of text, in pixels, if it were drawn.
    #
    # @return [Integer] the width of the text, in pixels.
    # @param text [String]
    def text_width(text, scale_x=1); end

    ##
    # Like {#text_width}, but supports the following markup tags: `<b>bold</b>`, `<i>italic</i>`, `<c=rrggbb>colors</c>`.
    def markup_width(markup, scale_x=1); end
  end

  ##
  # Provides functionality for drawing rectangular images.
  class Image
    ##
    # @return [Integer] the image's width, in pixels.
    attr_reader :width

    ##
    # @return [Integer] the image's height, in pixels.
    attr_reader :height

    # @!group Creating and loading images

    ##
    # Loads an image from a file or an RMagick image.
    #
    # (Passing a Window reference is not necessary anymore, please use the first overload from now on.)
    #
    # @note For Windows Bitmap (BMP) images, magenta (FF00FF, often called "magic pink" in this context) is treated as a chroma key and all pixels of that color are automatically rendered fully transparent.
    #
    # @param [String, Magick::Image] source the filename or RMagick image to load from.
    # @param [Hash] options
    # @option options [true, false] :tileable (false) if true, the Image will not have soft edges when scaled
    # @option options [true, false] :retro (false) if true, the image will not be interpolated when it is scaled up or down. When :retro it set, :tileable has no effect.
    # @option options [Array] :rect ([0, 0, image_width, image_height]) the source rectangle in the image
    #
    # @overload initialize(source, options = {})
    # @overload initialize(window, source, tileable = false)
    # @overload initialize(window, source, tileable, left, top, width, height)
    #
    # @see load_tiles
    # @see from_text
    # @see https://github.com/gosu/gosu/wiki/Basic-Concepts#tileability Tileability explained in the Gosu Wiki
    def initialize(source, options = {}); end

    ##
    # Creates a new image with the given dimensions and RGBA pixel data.
    #
    # @param [Integer] width Width of the image in pixels.
    # @param [Integer] height Height of the image in pixels.
    # @param [String] rgba A string containing raw binary image data, with either one byte ('uint8') or four bytes ('float') per RGBA component.
    def self.from_blob(width, height, rgba = "\0\0\0\0" * (width * height)); end

    ##
    # Creates a reusable image from one or more lines of text.
    #
    # (Passing a Window reference is not necessary anymore, please use the first overload from now on.)
    #
    # @note The text is always rendered in white. To draw it in a different color, use the color parameter of {#draw}, et al.
    #
    # @overload from_text(text, line_height, options = {})
    # @overload from_text(window, text, font_name, line_height)
    # @overload from_text(window, text, font_name, line_height, line_spacing, width, align)
    #
    # @return [Gosu::Image]
    # @param [String] text
    # @param [Integer] line_height the line height, in pixels.
    # @param [Hash] options
    # @option options [String] :font (Gosu::default_font_name) the name of a system font, or a path to a TrueType Font (TTF) file. A path must contain at least one '/' character to distinguish it from a system font.
    # @option options [bool] :bold (false)
    # @option options [bool] :italic (false)
    # @option options [bool] :underline (false)
    # @option options [Integer] :width the width of the image, in pixels. Long lines will be automatically wrapped around to avoid overflow, but overlong words will be truncated. If this option is omitted, lines will not be wrapped, and :align and :spacing will be ignored as well.
    # @option options [Integer] :spacing (0) the spacing between lines, in pixels.
    # @option options [:left, :right, :center, :justify] :align (:left) the text alignment.
    # @option options [true, false] :retro (false) if true, the image will not be interpolated when it is scaled up or down.
    #
    # @see Gosu::Font
    # @see https://github.com/gosu/gosu/wiki/Basic-Concepts#drawing-with-colours Drawing with colors, explained in the Gosu Wiki
    def self.from_text(text, line_height, options = {}); end

    ##
    # Like {#from_text}, but supports the following markup tags: `<b>bold</b>`, `<i>italic</i>`, `<c=rrggbb>colors</c>`.
    def self.from_markup(markup, line_height, options = {}); end

    ##
    # Loads an image from a file or an RMagick image, then divides the image into an array of equal-sized tiles.
    #
    # @note For Windows Bitmap (BMP) images, magenta (FF00FF, often called "magic pink" in this context) is treated as a chroma key and all pixels of that color are automatically rendered fully transparent.
    #
    # @return [Array<Gosu::Image>]
    # @param source [String, Magick::Image]
    # @param tile_width [Integer] If positive, this is the width of the individual tiles; if negative, the image is divided into -tile_width columns.
    # @param tile_height [Integer] If positive, this is the height of the individual tiles; if negative, the image is divided into -tile_height rows.
    # @param [Hash] options
    # @option options [true, false] :tileable (false) if true, the Image will not have soft edges when scaled
    # @option options [true, false] :retro (false) if true, the image will not be interpolated when it is scaled up or down. When :retro it set, :tileable has no effect.
    #
    # @overload load_tiles(source, tile_width, tile_height, options = {})
    # @overload load_tiles(window, source, tile_width, tile_height, tileable)
    #
    # (Passing a Window reference is not necessary anymore, please use the first overload from now on.)
    #
    # @see https://github.com/gosu/gosu/wiki/Basic-Concepts#tileability Tileability explained in the Gosu Wiki
    def self.load_tiles(source, tile_width, tile_height, options = {}); end

    ##
    # Returns an image that is a smaller, rectangular view of this {Image}.
    #
    # This is a very fast operation, and no new textures will be allocated.
    # If you update this {Image} or the {#subimage} using {#insert}, the other {Image} will be affected as well.
    #
    # Caveats:
    # * If you stretch or rotate a {#subimage}, the pixels adjacent to it might bleed into it, as Gosu does not manage the 'tileability' of subimages.
    #
    # @return [Image?] an image that represents a portion of the containing image
    def subimage(left, top, width, height); end

    # @!endgroup

    # @!group Drawing an image

    ##
    # Draws the image with its top left corner at (x, y).
    #
    # @return [void]
    # @param x [Float] the X coordinate.
    # @param y [Float] the Y coordinate.
    # @param z [Float] the Z-order.
    # @param scale_x [Float] the horizontal scaling factor.
    # @param scale_y [Float] the vertical scaling factor.
    # @param color [Gosu::Color, Integer]
    # @param mode [:default, :additive] the blending mode to use.
    #
    # @see #draw_rot
    # @see #draw_as_quad
    # @see https://github.com/gosu/gosu/wiki/Basic-Concepts#drawing-with-colours Drawing with colors, explained in the Gosu Wiki
    # @see https://github.com/gosu/gosu/wiki/Basic-Concepts#z-ordering Z-ordering explained in the Gosu Wiki
    def draw(x, y, z=0, scale_x=1, scale_y=1, color=0xff_ffffff, mode=:default); end

    ##
    # Draws the image rotated, with its rotational center at (x, y).
    #
    # @return [void]
    # @param angle [Float] the angle to rotate, in degrees.
    # @param center_x [Float] the relative horizontal rotation origin.
    # @param center_y [Float] the relative vertical rotation origin.
    # @param (see #draw)
    #
    # @see #draw
    # @see https://github.com/gosu/gosu/wiki/Basic-Concepts#drawing-with-colours Drawing with colors, explained in the Gosu Wiki
    # @see https://github.com/gosu/gosu/wiki/Basic-Concepts#z-ordering Z-ordering explained in the Gosu Wiki
    def draw_rot(x, y, z=0, angle=0, center_x=0.5, center_y=0.5, scale_x=1, scale_y=1, color=0xff_ffffff, mode=:default); end

    ##
    # Draws the image as an arbitrary quad. This method can be used for advanced non-rectangular drawing techniques, e.g., faking perspective or isometric projection.
    #
    # @return [void]
    # @param (see Gosu.draw_quad)
    #
    # @see #draw
    # @see Gosu.draw_quad
    # @see https://github.com/gosu/gosu/wiki/Basic-Concepts#drawing-with-colours Drawing with colors, explained in the Gosu Wiki
    # @see https://github.com/gosu/gosu/wiki/Basic-Concepts#order-of-corners The order of corners explained in the Gosu Wiki
    # @see https://github.com/gosu/gosu/wiki/Basic-Concepts#z-ordering Z-ordering explained in the Gosu Wiki
    def draw_as_quad(x1, y1, c1, x2, y2, c2, x3, y3, c3, x4, y4, c4, z, mode=:default); end

    # @!endgroup

    ##
    # Returns an object that holds information about the underlying OpenGL texture and UV coordinates of the image.
    #
    # @note Some images may be too large to fit on a single texture; this method returns nil in those cases.
    #
    # @return [Gosu::GLTexInfo?] information about the underlying OpenGL texture.
    #
    # @see Gosu::GLTexInfo
    def gl_tex_info; end

    ##
    # Returns the associated texture contents as binary string of packed RGBA values, useful for use with RMagick (Magick::Image.from_blob).
    #
    #    magick_image = Magick::Image.from_blob(image.to_blob) {
    #      self.format = "RGBA"
    #      self.size = "#{image.width}x#{image.height}"
    #      self.depth = 8
    #    }.first
    #
    # @return [String] a binary string of packed RGBA values.
    def to_blob; end

    ##
    # Overwrites part of the image with the contents of another. If the source image is partially out of bounds, it will be clipped to fit.
    #
    # This can be used to e.g. overwrite parts of a landscape.
    #
    # @return [void]
    # @param source [String, Magick::Image] the filename or RMagick image to load from.
    # @param x [Integer] the X coordinate of the top left corner.
    # @param y [Integer] the Y coordinate of the top left corner.
    def insert(source, x, y); end

    ##
    # Saves the image to a file. The file format is determined from the file extension.
    #
    # Useful for, e.g., pre-rendering text on a development machine where the necessary fonts are known to be available.
    #
    # @return [void]
    # @param filename [String] the path to save the file under.
    def save(filename); end
  end

  ##
  # A sample is a short sound that is completely loaded in memory, can be
  # played multiple times at once and offers very flexible playback
  # parameters. Use samples for everything that's not music.
  #
  # @see Gosu::Song
  class Sample
    ##
    # Loads a sample from a file.
    #
    # (Passing a Window reference is not necessary anymore, please use the first overload from now on.)
    #
    # @overload initialize(filename)
    # @overload initialize(window, filename)
    #
    # @param filename [String] the path to load the sample from.
    def initialize(filename); end

    ##
    # Plays the sample without panning.
    #
    # @return [Channel]
    # @param volume [Float] see {Channel#volume=}
    # @param speed [Float] see {Channel#speed=}
    # @param looping [true, false] whether the sample should play in a loop. If you pass true, be sure to store the return value of this method so that you can later stop the looping sound.
    #
    # @see #play_pan
    def play(volume=1, speed=1, looping=false); end

    ##
    # Plays the sample with panning.
    #
    # @return [Channel]
    # @param pan [Float] see {Channel#pan=}
    # @param volume [Float] see {Channel#volume=}
    # @param speed [Float] see {Channel#speed=}
    # @param looping [true, false] whether the sample should play in a loop. If you pass true, be sure to store the return value of this method so that you can later stop the looping sound.
    #
    # @see #play
    def play_pan(pan=0, volume=1, speed=1, looping=false); end
  end

  ##
  # {Sample#play} returns a Channel that represents the sound currently being played.
  #
  # This object can be used to stop sounds dynamically, or to check whether they have finished.
  class Channel
    ##
    # Sets the playback volume, in the range [0.0; 1.0], where 0 is completely silent and 1 is full volume. Values outside of this range will be clamped to [0.0; 1.0].
    # @param [Float]
    # @return [Float]
    attr_writer :volume

    ##
    # Sets the playback speed. A value of 2.0 will play the sample at 200% speed and one octave higher. A value of 0.5 will play the sample at 50% speed and one octave lower. The valid range of this property depends on the operating system, but values up to 8.0 should work.
    # @param [Float]
    # @return [Float]
    attr_writer :speed

    ##
    # Set the amount of panning, i.e. the position of the sound when using stereo speakers. 0.0 is the centre, negative values are to the left, positive values are to the right. If something happens on the edge of the screen, a good value for pan would be ±0.1.
    # @param [Float]
    # @return [Float]
    attr_writer :pan

    ##
    # Stops playback of this sample instance. After calling this method, the sample instance is useless and can be discarded.
    #
    # Calling `stop` after the sample has finished is harmless and has no effect.
    #
    # @return [void]
    def stop; end

    ##
    # Pauses the sample, to be resumed afterwards.
    #
    # @note The sample will still occupy a playback channel while paused.
    #
    # @return [void]
    def pause; end

    ##
    # Resumes playback of the sample.
    #
    # @return [void]
    def resume; end

    ##
    # @return [true, false] whether the sample is paused.
    def paused?; end

    ##
    # @return [true, false] whether the sample is playing.
    def playing?; end
  end

  ##
  # Songs are less flexible than samples in that only one can be played at a time, with no panning or speed control.
  #
  # @see Gosu::Sample
  class Song
    class <<Song
      ##
      # Returns the song currently being played (even if it's paused), or nil if no song is playing.
      #
      # @return [Gosu::Song?] the currently playing song.
      attr_reader :current_song
    end

    ##
    # @return [Float] the song's playback volume.
    attr_accessor :volume

    ##
    # Loads a song from a file.
    #
    # (Passing a Window reference is not necessary anymore, please use the first overload instead.)
    #
    # @overload initialize(filename)
    # @overload initialize(window, filename)
    #
    # @param filename [String] the path to load the song from.
    def initialize(filename); end

    ##
    # Starts or resumes playback of the song.
    #
    # If another song is currently playing, it will be stopped and this song will be set as the current song.
    #
    # If `looping` is false, the current song will be set to `nil` when this song finishes.
    #
    # @return [void]
    # @param looping [true, false] whether the song should play in a loop.
    def play(looping=false); end

    ##
    # Pauses playback of the song. The current song is unchanged.
    #
    # @return [void]
    def pause; end

    # Returns true if this song is the current song and playback is paused.
    #
    # @return [true, false] whether the song is paused.
    def paused?; end

    ##
    # Stops playback if this song is the current song. The current song is set to `nil`.
    #
    # @return [void]
    def stop; end

    ##
    # @return [true, false] whether the song is playing.
    def playing?; end
  end

  ##
  # A TextInput is an invisible object that handles input using the operating system's input manager.
  #
  # At its most basic, you only need to set {Gosu::Window#text_input} to an instance of this class. The TextInput will then handle all keyboard input until {Gosu::Window#text_input} is set to `nil`. Any text the user has typed is available through {#text}.
  #
  # This class is purely back-end and does not come with a GUI; drawing the input field is up to you, the programmer. The best way to do that is left completely open. TextInput only aims to provide a foundation for you to build your own GUI.
  #
  # @see Gosu::Window#text_input
  # @see file:examples/TextInput.rb
  class TextInput
    ##
    # @return [String] the text that the user has typed.
    attr_accessor :text

    ##
    # @return [Integer] the position of the editing caret.
    attr_accessor :caret_pos

    ##
    # @return [Integer] the starting position of the currently selected text.
    attr_accessor :selection_start

    ##
    # This method is an overridable filter that is applied to all newly entered text. This allows for restricting input characters or format, automatic macro or abbreviation expansion and so on.
    #
    # The return value of this method will be inserted at the current caret position.
    #
    # The default implementation returns its argument unchanged.
    #
    # @return [String] the string to be inserted.
    # @param text_in [String] the text typed by the user.
    #
    # @example Forcing input to all uppercase, alphanumeric characters.
    #   input = TextInput.new
    #   def input.filter(text_in)
    #     text_in.upcase.gsub(/[^A-Z0-9]/, '')
    #   end
    def filter; end

    ##
    # Replaces the current selection (if any) and inserts the given string at the current caret position.
    # The filter method will not be applied before appending the string.
    def insert_text(str); end

    ##
    # Deletes the current selection, if any, or the next character.
    def delete_forward; end

    ##
    # Deletes the current selection, if any, or the previous character.
    def delete_backward; end
  end

  ##
  # Main class that serves as the foundation of a standard
  # Gosu application. Manages initialization of all of Gosu's core components
  # and provides timing functionality.
  #
  # Note that all coordinates, even the mouse position, are in client coordinates, relative to the window’s top left corner.
  # This means that the mouse position can be negative or larger than the window size.
  #
  # @note There should really only be one instance of this class at a time. This may or may not change later.
  class Window
    ##
    # @return [String] the window's caption, usually displayed in the title bar.
    attr_accessor :caption

    ##
    # @return [Float] the mouse pointer's window-based X coordinate.
    attr_accessor :mouse_x

    ##
    # @return [Float] the mouse pointer's window-based Y coordinate.
    attr_accessor :mouse_y

    ##
    # The currently active {TextInput}. If not nil, all keyboard input will be handled by this object.
    #
    # @return [TextInput?] the currently active text input, if any.
    attr_accessor :text_input

    ##
    # The window's width, in pixels. This only counts the drawable area and does not include any borders or decorations added by the window manager.
    #
    # @return [Integer] the window's width, in pixels.
    attr_accessor :width

    ##
    # The window's height, in pixels. This only counts the drawable area and does not include any borders or decorations added by the window manager.
    #
    # @return [Integer] the window's height, in pixels.
    attr_accessor :height

    ##
    # @return [true, false] whether this is a fullscreen window.
    def fullscreen?; end

    ##
    # Toggles between windowed mode and fullscreen.
    attr_writer :fullscreen

    ##
    # @return [true, false] whether this window is resizable.
    def resizable?; end

    ##
    # Toggles between resizable and fixed modes.
    attr_writer :resizable

    ##
    # @return [true, false] whether this window is borderless.
    def borderless?; end

    ##
    # Toggles between borderless mode and having window chrome.
    attr_writer :borderless

    ##
    # @return [Float] the interval between calls to {#update}, in milliseconds.
    attr_accessor :update_interval

    ##
    # Creates a new window with the requested size.
    #
    # Resizable fullscreen windows always use the full desktop resolution.
    # Windows that are larger than the desktop resolution will be shrunk.
    #
    # @overload initialize(width, height, options = {})
    # @overload initialize(width, height, fullscreen, update_interval = 16.666666)
    #
    # @param width [Integer] the desired window width.
    # @param height [Integer] the desired window height.
    # @param [Hash] options
    # @option options [true, false] :fullscreen (false) whether to present the window in fullscreen mode.
    # @option options [true, false] :resizable (false) whether the window can be resized by the user. Not useful if the window is either fullscreen or borderless.
    # @option options [true, false] :borderless (false) whether the window should hide all its window chrome. Does not affect fullscreen windows.
    # @option options [Float] :update_interval (16.666666) the interval between frames, in milliseconds.
    def initialize(width, height, options); end

    ##
    # Enters a modal loop where the Window is visible on screen and receives calls to draw, update etc.
    #
    # @return [void]
    def show; end

    ##
    # EXPERIMENTAL - MAY DISAPPEAR WITHOUT WARNING.
    #
    # Performs a single step in the main loop.
    # This can be useful for integrating Gosu with other libraries that have their own main loop, e.g. Ruby/Tk.
    #
    # See: https://www.libgosu.org/cgi-bin/mwf/topic_show.pl?tid=1218
    #
    # If you find a good way to use {#tick}, please let us know on the forum and we can make this a part of Gosu's stable interface.
    # Thank you!
    #
    # @return [true, false] whether the {Window} should still be shown after this tick
    def tick; end

    ##
    # Tells the window to end the current run loop as soon as possible.
    #
    # @return [void]
    def close!; end

    # @!group Callbacks

    ##
    # This method is called once every {#update_interval} milliseconds while the window is being shown. Your application's main logic should go here.
    #
    # @return [void]
    def update; end

    ##
    # This method is called after every update and whenever the OS wants the window to repaint itself. Your application's rendering code should go here.
    #
    # @return [void]
    #
    # @see #needs_redraw?
    def draw; end

    ##
    # This method can be overridden to give the game a chance to opt out of a call to {#draw}; however, the operating system can still force a redraw for any reason.
    #
    # @return [true, false] whether the window needs to be redrawn.
    #
    # @see #draw
    def needs_redraw?; end

    ##
    # This method can be overridden to control the visibility of the system cursor over your window.
    # The base class implementation returns true.
    #
    # @return [true, false] whether the system cursor should be shown.
    def needs_cursor?; end

    ##
    # This method is called whenever the user tries to close the window, e.g. by clicking the [x]
    # button in the window's title bar.
    # If you do not want the window to close immediately, you should override this method and
    # call the {#close!} when needed.
    #
    # @return [bool]
    def close; end

    ##
    # This method is called before {#update} if a button is pressed while the window has focus.
    #
    # By default, this will toggle fullscreen mode if the user presses Alt+Enter (Windows,
    # Linux), cmd+F (macOS), or F11 (on all operating systems).
    # To support these shortcuts in your application, make sure to call super in your
    # implementation.
    #
    # @return [void]
    # @param id [Integer] the button's platform-defined id.
    #
    # @see #button_up
    # @see Gosu.button_down?
    def button_down(id); end

    ##
    # This method is called before {#update} if a button is released while the window has focus.
    #
    # @return [void]
    # @param (see #button_down)
    #
    # @see #button_down
    # @see Gosu.button_down?
    def button_up(id); end

    ##
    # Called when a file is dropped onto the window.
    #
    # @param filename [String] the filename of the dropped file. When multiple files are dropped, this method will be called several times.
    def drop(filename); end

    ##
    # Called when a gamepad is connected.
    # If a gamepad is momentarily disconnected and then reconnected, before another gamepad, it will have the same index.
    #
    # @param index [integer] index for looking up gamepad.
    #
    # @see Gosu.gamepad_name
    def gamepad_connected(index); end

    ##
    # Called when a gamepad is disconnected.
    #
    # @param index [integer] index for looking up gamepad.
    #
    # @see #gamepad_connected
    # @see Gosu.gamepad_name
    def gamepad_disconnected(index); end

    ##
    # Called when the window gains focus
    def gain_focus; end

    ##
    # Called when the windows loses focus
    def lose_focus; end

    # @!endgroup
  end

  ##
  # Holds information about the underlying OpenGL texture and UV coordinates of an image.
  #
  # Can be retrieved from some images to use them in OpenGL operations.
  #
  # @see Gosu::Image#gl_tex_info
  class GLTexInfo
    ##
    # @return [Integer] OpenGL texture id
    attr_reader :tex_name

    ##
    # @return [Float] the U coordinate of the left edge of the image.
    attr_reader :left

    ##
    # @return [Float] the U coordinate of the right edge of the image.
    attr_reader :right

    ##
    # @return [Float] the V coordinate of the top edge of the image.
    attr_reader :top

    ##
    # @return [Float] the V coordinate of the bottom edge of the image.
    attr_reader :bottom
  end

  class << self
    ##
    # Returns whether the button `id` is currently pressed. Button states are updated once per tick, so repeated calls during the same tick will always yield the same result.
    #
    # @return [true, false] whether the button is currently pressed.
    # @param (see #button_down)
    #
    # @see Window#button_down
    # @see Window#button_up
    def button_down?(id); end

    ##
    # Returns the name of a Gosu::KB_{*} constant. Returns nil if no name is found.
    #
    # @example
    #   Gosu.button_name(Gosu::KB_SPACE) #=> "Space"
    #
    # @return [String, nil]
    # @param id [Integer]
    #
    def button_name(id); end

    ##
    # Returns the name for gamepad at `index` or nil if there is no connected at the specified index.
    #
    # @example
    #   Gosu.gamepad_name(0) #=> "PS4 Controller"
    #
    # @return [String, nil]
    # @param index [Integer]
    def gamepad_name(index); end

    ##
    # Returns the value for the specified gamepad axis in the range -1.0..1.0 for joysticks and 0.0..1.0 for triggers.
    #
    # @example
    #   Gosu.axis(Gosu::GP_0_LEFT_STICK_Y_AXIS) #=> 0.75
    #
    # @return [Float]
    # @param id [Integer]
    #
    def axis(id); end

    ##
    # Returns the contents of the clipboard as plain text, or an empty string if none is available.
    #
    # @return [String]
    def clipboard(); end

    ##
    # Replaces the contents of the clipboard with the given string.
    #
    # @return [nil]
    def clipboard=(text); end


    # @!group Drawing primitives

    ##
    # Draws a line from one point to another---inconsistently.
    #
    # @note OpenGL lines are not reliable at all and may have a missing pixel at the start or end point. Relying on your machine's behavior can only end in tears. Recommended for debugging purposes only.
    #
    # @return [void]
    # @param x1 [Float] the X coordinate of the start point.
    # @param y1 [Float] the Y coordinate of the start point.
    # @param c1 [Gosu::Color] the color of the start point.
    # @param x2 [Float] the X coordinate of the end point.
    # @param y2 [Float] the Y coordinate of the end point.
    # @param c2 [Gosu::Color] the color of the end point.
    # @param z [Float] the Z-order.
    # @param mode [:default, :additive] the blending mode to use.
    #
    # @see draw_triangle
    # @see draw_quad
    # @see https://github.com/gosu/gosu/wiki/Basic-Concepts#drawing-with-colours Drawing with colors, explained in the Gosu Wiki
    # @see https://github.com/gosu/gosu/wiki/Basic-Concepts#z-ordering Z-ordering explained in the Gosu Wiki
    def draw_line(x1, y1, c1, x2, y2, c2, z=0, mode=:default); end

    ##
    # Draws a triangle.
    #
    # @return [void]
    # @param x1 [Float] the X coordinate of the first vertex.
    # @param y1 [Float] the Y coordinate of the first vertex.
    # @param c1 [Gosu::Color] the color of the first vertex.
    # @param x2 [Float] the X coordinate of the second vertex.
    # @param y2 [Float] the Y coordinate of the second vertex.
    # @param c2 [Gosu::Color] the color of the second vertex.
    # @param x3 [Float] the X coordinate of the third vertex.
    # @param y3 [Float] the Y coordinate of the third vertex.
    # @param c3 [Gosu::Color] the color of the third vertex.
    # @param z [Float] the Z-order.
    # @param mode [:default, :additive] the blending mode to use.
    #
    # @see draw_line
    # @see draw_rect
    # @see draw_quad
    # @see https://github.com/gosu/gosu/wiki/Basic-Concepts#drawing-with-colours Drawing with colors, explained in the Gosu Wiki
    # @see https://github.com/gosu/gosu/wiki/Basic-Concepts#z-ordering Z-ordering explained in the Gosu Wiki
    def draw_triangle(x1, y1, c1, x2, y2, c2, x3, y3, c3, z=0, mode=:default); end

    ##
    # Draws a rectangle (actually a quad, or two triangles).
    #
    # @return [void]
    # @param x [Float] the X coordinate of the rectangle’s top left corner.
    # @param y [Float] the Y coordinate of the rectangle’s top left corner.
    # @param width [Float] the width of the rectangle.
    # @param height [Float] the height of the rectangle.
    # @param c [Gosu::Color] the color of the rectangle.
    # @param z [Float] the Z-order.
    # @param mode [:default, :additive] the blending mode to use.
    #
    # @see draw_line
    # @see draw_triangle
    # @see draw_quad
    # @see https://github.com/gosu/gosu/wiki/Basic-Concepts#drawing-with-colours Drawing with colors, explained in the Gosu Wiki
    # @see https://github.com/gosu/gosu/wiki/Basic-Concepts#order-of-corners The order of corners explained in the Gosu Wiki
    # @see https://github.com/gosu/gosu/wiki/Basic-Concepts#z-ordering Z-ordering explained in the Gosu Wiki
    def draw_rect(x, y, width, height, c, z=0, mode=:default); end

    ##
    # Draws a quad (actually two triangles).
    #
    # @return [void]
    # @param x1 [Float] the X coordinate of the first vertex.
    # @param y1 [Float] the Y coordinate of the first vertex.
    # @param c1 [Gosu::Color] the color of the first vertex.
    # @param x2 [Float] the X coordinate of the second vertex.
    # @param y2 [Float] the Y coordinate of the second vertex.
    # @param c2 [Gosu::Color] the color of the second vertex.
    # @param x3 [Float] the X coordinate of the third vertex.
    # @param y3 [Float] the Y coordinate of the third vertex.
    # @param c3 [Gosu::Color] the color of the third vertex.
    # @param x4 [Float] the X coordinate of the fourth vertex.
    # @param y4 [Float] the Y coordinate of the fourth vertex.
    # @param c4 [Gosu::Color] the color of the fourth vertex.
    # @param z [Float] the Z-order.
    # @param mode [:default, :additive] the blending mode to use.
    #
    # @see draw_line
    # @see draw_triangle
    # @see draw_rect
    # @see https://github.com/gosu/gosu/wiki/Basic-Concepts#drawing-with-colours Drawing with colors, explained in the Gosu Wiki
    # @see https://github.com/gosu/gosu/wiki/Basic-Concepts#order-of-corners The order of corners explained in the Gosu Wiki
    # @see https://github.com/gosu/gosu/wiki/Basic-Concepts#z-ordering Z-ordering explained in the Gosu Wiki
    def draw_quad(x1, y1, c1, x2, y2, c2, x3, y3, c3, x4, y4, c4, z=0, mode=:default); end

    # @!endgroup
    # @!group Manipulating the current drawing context

    ##
    # Flushes all drawing operations to OpenGL so that Z-ordering can start anew. This is useful for drawing multiple layers that may not have knowledge of each other's Z-ordering, e.g., drawing a HUD on top of the game world or ensuring that a custom cursor is always drawn above everything else.
    #
    # @return [void]
    def flush; end

    ##
    # Runs the block in a clean OpenGL environment.
    #
    # If a Z-order is given, the block will be scheduled to run between Gosu drawing operations as normal; otherwise, all prior drawing operations will be flushed and the block will be executed immediately.
    #
    # @note Gosu does not provide access to the underlying OpenGL APIs. A gem like ruby-opengl is required to use custom OpenGL drawing code.
    #
    # @note Gosu rendering functions MUST NOT be used within the block, and {gl} MUST be used only within the call tree of {Window#draw}.
    #
    # @return [void]
    # @param z [Float] the Z-order.
    # @yield OpenGL code.
    #
    # @see Window#draw
    # @see file:reference/Z-Ordering
    def gl(z=nil); end

    ##
    # Masks the drawing area inside the block.
    #
    # @return [void]
    # @param x [Float] the X coordinate of the top left corner,.
    # @param y [Float] the Y coordinate of the top left corner.
    # @param w [Float] the width of the clipping area.
    # @param h [Float] the height of the clipping area.
    # @yield rendering code.
    #
    # @see Window#draw
    def clip_to(x, y, w, h); end

    ##
    # Records all drawing operations inside the block as a macro (a special {Gosu::Image}) that can be reused later on.
    # This is useful for rendering larger groups of images (e.g. a tiled map in a game) and then rendering this group with a single call to {Gosu::Image#draw}.
    #
    # @note Because the returned object is not backed by a bitmap texture, there are restrictions on how it can be used. For example, you can not use any color other than {Gosu::Color#WHITE} when drawing the image.
    #
    # @note The width and height of the returned image will be the values you passed to {record}, regardless of the area you draw on.
    # It is important to pass accurate values if you plan on calling {Gosu::Image#draw_as_quad} or {Gosu::Image#draw_rot} on the result later.
    #
    # @return [Gosu::Image] the recorded drawing operations.
    # @param width [Integer] the width of the recorded image.
    # @param height [Integer] the height of the recorded image.
    # @yield rendering code.
    #
    # @see Window#render
    # @see Gosu::Image
    def record(width, height); end

    ##
    # Records all drawing operations inside the block and returns the result as a new {Gosu::Image}.
    #
    # @return [Gosu::Image] the rendered drawing operations.
    # @param width [Integer] the width of the recorded image.
    # @param height [Integer] the height of the recorded image.
    # @param [Hash] options
    # @option options [true, false] :retro (false) if true, the resulting image will not be interpolated when it is scaled up or down.
    # @yield rendering code.
    #
    # @see Window#record
    # @see Gosu::Image
    def render(width, height); end

    ##
    # Rotates all drawing operations inside the block.
    #
    # @return [void]
    # @param angle [Float] the rotation angle.
    # @param around_x [Float] the X coordinate of the rotation origin.
    # @param around_y [Float] the Y coordinate of the rotation origin.
    # @yield rendering code.
    #
    # @see Window#draw
    # @see scale
    # @see translate
    # @see transform
    def rotate(angle, around_x=0, around_y=0); end

    ##
    # Scales all drawing operations inside the block.
    #
    # @overload scale(scale_x, scale_y = scale_x) { ... }
    # @overload scale(scale_x, scale_y, around_x, around_y) { ... }
    #
    # @return [void]
    # @param scale_x [Float] the horizontal scaling factor.
    # @param scale_y [Float] the vertical scaling factor.
    # @param around_x [Float] the X coordinate of the scaling origin.
    # @param around_y [Float] the Y coordinate of the scaling origin.
    # @yield rendering code.
    #
    # @see Window#draw
    # @see rotate
    # @see translate
    # @see transform
    def scale(scale_x, scale_y, around_x, around_y); end

    ##
    # Offsets all drawing operations inside the block.
    #
    # @return [void]
    # @param x [Float] the X offset.
    # @param y [Float] the Y offset.
    # @yield rendering code.
    #
    # @see Window#draw
    # @see rotate
    # @see scale
    # @see transform
    def translate(x, y); end

    ##
    # Applies a free-form matrix transformation to everything drawn in the block.
    #
    # @return [void]
    # @param m0 [Float]
    # @param m1 [Float]
    # @param m2 [Float]
    # @param m3 [Float]
    # @param m4 [Float]
    # @param m5 [Float]
    # @param m6 [Float]
    # @param m7 [Float]
    # @param m8 [Float]
    # @param m9 [Float]
    # @param m10 [Float]
    # @param m11 [Float]
    # @param m12 [Float]
    # @param m13 [Float]
    # @param m14 [Float]
    # @param m15 [Float]
    # @yield rendering code.
    #
    # @see Window#draw
    # @see rotate
    # @see scale
    # @see translate
    def transform(m0, m1, m2, m3, m4, m5, m6, m7, m8, m9, m10, m11, m12, m13, m14, m15); end

    # @!endgroup

    ##
    # Returns the character a button usually produces, if any.
    #
    # @note For real text input, look at {TextInput} instead.
    #
    # @return [String?] the character the button usually produces.
    # @param id [Integer] the button's platform-defined id.
    #
    # @see char_to_button_id
    # @see Window#text_input
    # @see TextInput
    def button_id_to_char(id); end

    ##
    # Returns the button that usually produces a character, if any.
    #
    # @return [Integer?] the button that usually produces the character.
    # @param char [String] the character to query.
    #
    # @see button_id_to_char
    # @see Window#text_input
    # @see TextInput
    def char_to_button_id(char); end

    ##
    # @return [Float] a random number in the range [min; max).
    # @param min [Float] the minimum value, inclusive.
    # @param max [Float] the maximum value, exclusive.
    def random(min, max); end

    ##
    # @return [Float] the X component of a vector of angle theta and magnitude r, or the horizontal distance covered by moving r pixels in the direction given by theta.
    # @param theta [Float]
    # @param r [Float]
    def offset_x(theta, r); end

    ##
    # @return [Float] the Y component of a vector of angle theta and magnitude r, or the vertical distance covered by moving r pixels in the direction given by theta.
    # @param theta [Float]
    # @param r [Float]
    def offset_y(theta, r); end

    ##
    # @return [Float] the angular distance from (x1, y1) to (x1, y2) in degrees, where 0.0 is up. Returns 0 if both points are equal.
    # @param x1 [Float]
    # @param y1 [Float]
    # @param x2 [Float]
    # @param y2 [Float]
    def angle(x1, y1, x2, y2); end

    ##
    # @return [Float] the shortest angular distance from angle1 to angle2. This can be negative if counter-clockwise rotation would yield a shorter distance.
    # @param angle1 [Float]
    # @param angle2 [Float]
    def angle_diff(angle1, angle2); end

    ##
    # @return [Float] the distance from (x1, y1) to (x2, y2).
    # @param x1 [Float]
    # @param y1 [Float]
    # @param x2 [Float]
    # @param y2 [Float]
    def distance(x1, y1, x2, y2); end

    ##
    # @note For long-running games, this counter will eventually wrap around to 0 again.
    #
    # @return [Integer] the number of milliseconds elapsed.
    def milliseconds(); end

    ##
    # @return [Integer] the current framerate, in frames per second.
    def fps(); end

    # @return [String] the name of a neutral font that is available on the current platform.
    #
    # @see Gosu::Font
    # @see Gosu::Image#from_text
    def default_font_name(); end

    ##
    # @return [Integer] the width (in pixels) of a screen.
    # @param window [Gosu::Window] The result describes the screen on which the window is shown, or the primary screen if no window is given.
    def screen_width(window = nil); end

    # @return [Integer] the height (in pixels) of a screen.
    # @param window [Gosu::Window] The result describes the screen on which the window is shown, or the primary screen if no window is given.
    def screen_height(window = nil); end

    ##
    # @return [Integer] the maximum width (in 'points') that is available for a non-fullscreen Window.
    # All windows larger than this size will automatically be shrunk to fit.
    def available_width(window = nil); end

    # @return [Integer] the maximum height (in 'points') that is available for a non-fullscreen Window.
    # All windows larger than this size will automatically be shrunk to fit.
    def available_height(window = nil); end

    ##
    # Returns the language code for the user's preferred language.
    # Expect return values such as 'en_US', 'de_DE.UTF-8', 'ja', 'zh-Hans', etc.
    # You can rely only the first two letters being a language abbreviation.
    #
    # @return [String] the user's preferred language.
    def language(); end
  end
end

##
# Small additions to Numeric to make it easier to integrate Gosu with
# libraries that use radians, like Chipmunk.
class ::Numeric
  ##
  # Converts radians to a Gosu-compatible angle using the formula <tt>self * 180.0 / Math::PI + 90</tt>.
  #
  # @return [Float] degrees.
  def radians_to_gosu(); end

  ##
  # Converts a Gosu-compatible angle to radians using the formula <tt>(self - 90) * Math::PI / 180.0</tt>.
  #
  # @return [Float] radians.
  def gosu_to_radians(); end

  ##
  # Converts degrees to radians.
  #
  # @return [Float] radians.
  def degrees_to_radians(); end

  ##
  # Converts radians to degrees.
  #
  # @return [Float] degrees.
  def radians_to_degrees(); end
end
