ChunkyPNG - the pure ruby library to access PNG files.
The ChunkyPNG module defines some constants that are used in the PNG specification, specifies some exception classes, and serves as a namespace for all the other modules and classes in this library.
{ChunkyPNG::Image}: | class to represent PNG images, including metadata. |
{ChunkyPNG::Canvas}: | class to represent the image‘s canvas. |
{ChunkyPNG::Color}: | module to work with color values. |
{ChunkyPNG::Palette}: | represents the palette of colors used on a {ChunkyPNG::Canvas}. |
{ChunkyPNG::Datastream}: | represents the internal structure of a PNG {ChunkyPNG::Image}. |
{ChunkyPNG::Color}: | represents one chunk of data within a {ChunkyPNG::Datastream}. |
{ChunkyPNG::Point}: | geometry helper class representing a 2-dimensional point. |
{ChunkyPNG::Dimension}: | geometry helper class representing a dimension (i.e. width x height). |
{ChunkyPNG::Vector}: | geometry helper class representing a series of points. |
@author Willem van Bergen
VERSION | = | "1.2.0" | The current version of ChunkyPNG. This value will be updated automatically by them gem:release rake task. | |
COLOR_GRAYSCALE | = | 0 | Indicates that the PNG image uses grayscale colors, i.e. only a single teint channel. @private | |
COLOR_TRUECOLOR | = | 2 | Indicates that the PNG image uses true color, composed of a red green and blue channel. @private | |
COLOR_INDEXED | = | 3 | Indicates that the PNG image uses indexed colors, where the values point to colors defined on a palette. @private | |
COLOR_GRAYSCALE_ALPHA | = | 4 | Indicates that the PNG image uses grayscale colors with opacity, i.e. a teint channel with an alpha channel. @private | |
COLOR_TRUECOLOR_ALPHA | = | 6 | Indicates that the PNG image uses true color with opacity, composed of a red, green and blue channel, and an alpha value. @private | |
COMPRESSION_DEFAULT | = | 0 | Indicates that the PNG specification‘s default compression method is used (Zlib/Deflate) @private | |
INTERLACING_NONE | = | 0 | Indicates that the image does not use interlacing. @private | |
INTERLACING_ADAM7 | = | 1 | Indicates that the image uses Adam7 interlacing. @private | |
FILTERING_DEFAULT | = | 0 | Indicates that the PNG specification‘s default filtering are being used in the image. @private | |
FILTER_NONE | = | 0 | Indicates that no filtering is used for the scanline. @private | |
FILTER_SUB | = | 1 | Indicates that SUB filtering is used for the scanline. @private | |
FILTER_UP | = | 2 | Indicates that UP filtering is used for the scanline. @private | |
FILTER_AVERAGE | = | 3 | Indicates that AVERAGE filtering is used for the scanline. @private | |
FILTER_PAETH | = | 4 | Indicates that PAETH filtering is used for the scanline. @private | |
EMPTY_BYTEARRAY | = | String.method_defined?(:force_encoding) ? "".force_encoding('ASCII-8BIT').freeze : "".freeze | Empty byte array. This basically is an empty string, but with the encoding set correctly to ASCII-8BIT (binary) in Ruby 1.9. @return [String] An empty string, with encoding set to binary in Ruby 1.9 @private | |
EXTRA_BYTE | = | String.method_defined?(:force_encoding) ? "\0".force_encoding('ASCII-8BIT') : "\0" | Null-byte, with the encoding set correctly to ASCII-8BIT (binary) in Ruby 1.9. @return [String] A binary string, consisting of one NULL-byte. @private |
Factory method to return a color value, based on the arguments given.
@overload Color(r, g, b, a)
@param (see ChunkyPNG::Color.rgba) @return [Integer] The rgba color value.
@overload Color(r, g, b)
@param (see ChunkyPNG::Color.rgb) @return [Integer] The rgb color value.
@overload Color(hex_value, opacity = nil)
@param (see ChunkyPNG::Color.from_hex) @return [Integer] The hex color value, with the opacity applied if one was given.
@overload Color(color_name, opacity = nil)
@param (see ChunkyPNG::Color.html_color) @return [Integer] The hex color value, with the opacity applied if one was given.
@overload Color(color_value, opacity = nil)
@param [Integer, :to_i] The color value. @return [Integer] The color value, with the opacity applied if one was given.
@return [Integer] The determined color value as RGBA integer. @raise [ArgumentError] if the arguments weren‘t understood as a color. @see ChunkyPNG::Color @see ChunkyPNG::Color.parse
# File lib/chunky_png/color.rb, line 29 29: def self.Color(*args) 30: case args.length 31: when 1; ChunkyPNG::Color.parse(args.first) 32: when 2; (ChunkyPNG::Color.parse(args.first) & 0xffffff00) | args[1].to_i 33: when 3; ChunkyPNG::Color.rgb(*args) 34: when 4; ChunkyPNG::Color.rgba(*args) 35: else raise ArgumentError, "Don't know how to create a color from #{args.inspect}!" 36: end 37: end
Creates a {ChunkyPNG::Dimension} instance using arguments that can be interpreted as width and height.
@overload Dimension(width, height)
@param [Integer] width The width-component of the dimension. @param [Integer] height The height-component of the dimension. @return [ChunkyPNG::Dimension] The instantiated dimension.
@overload Dimension(string)
@param [String] string A string from which a width and height value can be parsed, e.g. <tt>'10x20'</tt> or <tt>'[10, 20]'</tt>. @return [ChunkyPNG::Dimension] The instantiated dimension.
@overload Dimension(ary)
@param [Array] ary An array with the desired width as first element and the desired height as second element, e.g. <tt>[10, 20]</tt>. @return [ChunkyPNG::Dimension] The instantiated dimension.
@overload Dimension(hash)
@param [Hash] hash An hash with a <tt>'height'</tt> or <tt>:height</tt> key for the desired height and with a <tt>'width'</tt> or <tt>:width</tt> key for the desired width. @return [ChunkyPNG::Dimension] The instantiated dimension.
@return [ChunkyPNG::Dimension] The dimension created by this factory method. @raise [ArgumentError] If the argument(s) given where not understood as a dimension. @see ChunkyPNG::Dimension
# File lib/chunky_png/dimension.rb, line 30 30: def self.Dimension(*args) 31: 32: case args.length 33: when 2; ChunkyPNG::Dimension.new(*args) 34: when 1; case source = args.first 35: when ChunkyPNG::Dimension; source 36: when ChunkyPNG::Point; ChunkyPNG::Dimension.new(source.x, source.y) 37: when Array; ChunkyPNG::Dimension.new(source[0], source[1]) 38: when Hash; ChunkyPNG::Dimension.new(source[:width] || source['width'], source[:height] || source['height']) 39: when ChunkyPNG::Dimension::DIMENSION_REGEXP; ChunkyPNG::Dimension.new($1, $2) 40: else 41: if source.respond_to?(:width) && source.respond_to?(:height) 42: ChunkyPNG::Dimension.new(source.width, source.height) 43: else 44: raise ArgumentError, "Don't know how to construct a point from #{source.inspect}!" 45: end 46: end 47: else raise ArgumentError, "Don't know how to construct a point from #{args.inspect}!" 48: end 49: end
Factory method to create {ChunkyPNG::Point} instances.
This method tries to be as flexible as possible with regards to the given input: besides explicit coordinates, this method also accepts arrays, hashes, strings, {ChunkyPNG::Dimension} instances and anything that responds to :x and :y.
@overload Point(x, y)
@param [Integer, :to_i] x The x-coordinate @param [Integer, :to_i] y The y-coordinate @return [ChunkyPNG::Point] The instantiated point.
@overload Point(array)
@param [Array<Integer>] array A two element array which represent the x- and y-coordinate. @return [ChunkyPNG::Point] The instantiated point.
@overload Point(hash)
@param [Hash] array A hash with the <tt>:x</tt> or <tt>'x'</tt> and <tt>:y</tt> or <tt>'y'</tt> keys set, which will be used as coordinates. @return [ChunkyPNG::Point] The instantiated point.
@overload Point(string)
@param [String] string A string that contains the coordinates, e.g. <tt>'0, 4'</tt>, <tt>'(0 4)'</tt>, <tt>[0,4}'</tt>, etc. @return [ChunkyPNG::Point] The instantiated point.
@return [ChunkyPNG::Point] @raise [ArgumentError] if the arguments weren‘t understood. @see ChunkyPNG::Point
# File lib/chunky_png/point.rb, line 31 31: def self.Point(*args) 32: case args.length 33: when 2; ChunkyPNG::Point.new(*args) 34: when 1; case source = args.first 35: when ChunkyPNG::Point; source 36: when ChunkyPNG::Dimension; ChunkyPNG::Point.new(source.width, source.height) 37: when Array; ChunkyPNG::Point.new(source[0], source[1]) 38: when Hash; ChunkyPNG::Point.new(source[:x] || source['x'], source[:y] || source['y']) 39: when ChunkyPNG::Point::POINT_REGEXP; ChunkyPNG::Point.new($1.to_i, $2.to_i) 40: else 41: if source.respond_to?(:x) && source.respond_to?(:y) 42: ChunkyPNG::Point.new(source.x, source.y) 43: else 44: raise ArgumentError, "Don't know how to construct a point from #{source.inspect}!" 45: end 46: end 47: else raise ArgumentError, "Don't know how to construct a point from #{args.inspect}!" 48: end 49: end
Factory method for {ChunkyPNG::Vector} instances.
@overload Vector(x0, y0, x1, y1, x2, y2, …)
Creates a vector by parsing two subsequent values in the argument list as x- and y-coordinate of a point. @return [ChunkyPNG::Vector] The instantiated vector.
@overload Vector(string)
Creates a vector by parsing coordinates from the input string. @return [ChunkyPNG::Vector] The instantiated vector.
@overload Vector(pointlike, pointlike, pointlike, …)
Creates a vector by converting every argument to a point using {ChunkyPNG.Point}. @return [ChunkyPNG::Vector] The instantiated vector.
@return [ChunkyPNG::Vector] The vector created by this factory method. @raise [ArgumentError] If the given arguments could not be understood as a vector. @see ChunkyPNG::Vector
# File lib/chunky_png/vector.rb, line 19 19: def self.Vector(*args) 20: 21: return args.first if args.length == 1 && args.first.kind_of?(ChunkyPNG::Vector) 22: 23: if args.length == 1 && args.first.respond_to?(:scan) 24: ChunkyPNG::Vector.new(ChunkyPNG::Vector.multiple_from_string(args.first)) # e.g. ['1,1 2,2 3,3'] 25: else 26: ChunkyPNG::Vector.new(ChunkyPNG::Vector.multiple_from_array(args)) # e.g. [[1,1], [2,2], [3,3]] or [1,1,2,2,3,3] 27: end 28: end