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# This Geometry class was yanked from RMagick. However, it lets ImageMagick handle the actual change_geometry.
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# Use #new_dimensions_for to get new dimensons
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# Used so I can use spiffy RMagick geometry strings with ImageScience
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class Geometry
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# ! and @ are removed until support for them is added
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FLAGS = ['', '%', '<', '>']#, '!', '@']
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RFLAGS = { '%' => :percent,
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'!' => :aspect,
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'<' => :>,
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'>' => :<,
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'@' => :area }
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attr_accessor :width, :height, :x, :y, :flag
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def initialize(width=nil, height=nil, x=nil, y=nil, flag=nil)
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# Support floating-point width and height arguments so Geometry
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# objects can be used to specify Image#density= arguments.
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raise ArgumentError, "width must be >= 0: #{width}" if width < 0
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raise ArgumentError, "height must be >= 0: #{height}" if height < 0
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@width = width.to_f
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@height = height.to_f
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@x = x.to_i
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@y = y.to_i
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@flag = flag
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end
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# Construct an object from a geometry string
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RE = /\A(\d*)(?:x(\d+))?([-+]\d+)?([-+]\d+)?([%!<>@]?)\Z/
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def self.from_s(str)
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raise(ArgumentError, "no geometry string specified") unless str
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if m = RE.match(str)
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new(m[1].to_i, m[2].to_i, m[3].to_i, m[4].to_i, RFLAGS[m[5]])
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else
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raise ArgumentError, "invalid geometry format"
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end
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end
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# Convert object to a geometry string
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def to_s
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str = ''
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str << "%g" % @width if @width > 0
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str << 'x' if (@width > 0 || @height > 0)
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str << "%g" % @height if @height > 0
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str << "%+d%+d" % [@x, @y] if (@x != 0 || @y != 0)
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str << FLAGS[@flag.to_i]
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end
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# attempts to get new dimensions for the current geometry string given these old dimensions.
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# This doesn't implement the aspect flag (!) or the area flag (@). PDI
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def new_dimensions_for(orig_width, orig_height)
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new_width = orig_width
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new_height = orig_height
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case @flag
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when :percent
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scale_x = @width.zero? ? 100 : @width
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scale_y = @height.zero? ? @width : @height
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new_width = scale_x.to_f * (orig_width.to_f / 100.0)
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new_height = scale_y.to_f * (orig_height.to_f / 100.0)
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when :<, :>, nil
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scale_factor =
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if new_width.zero? || new_height.zero?
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1.0
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else
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if @width.nonzero? && @height.nonzero?
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[@width.to_f / new_width.to_f, @height.to_f / new_height.to_f].min
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else
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@width.nonzero? ? (@width.to_f / new_width.to_f) : (@height.to_f / new_height.to_f)
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end
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end
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new_width = scale_factor * new_width.to_f
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new_height = scale_factor * new_height.to_f
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new_width = orig_width if @flag && orig_width.send(@flag, new_width)
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new_height = orig_height if @flag && orig_height.send(@flag, new_height)
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end
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[new_width, new_height].collect! { |v| v.round }
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end
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end
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class Array
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# allows you to get new dimensions for the current array of dimensions with a given geometry string
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#
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# [50, 64] / '40>' # => [40, 51]
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def /(geometry)
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raise ArgumentError, "Only works with a [width, height] pair" if size != 2
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raise ArgumentError, "Must pass a valid geometry string or object" unless geometry.is_a?(String) || geometry.is_a?(Geometry)
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geometry = Geometry.from_s(geometry) if geometry.is_a?(String)
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geometry.new_dimensions_for first, last
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end
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end
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