Module: AspectRatio

Defined in:
lib/aspect_ratio.rb

Class Method Summary collapse

Class Method Details

.crop(x, y, r) ⇒ Object 



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# File 'lib/aspect_ratio.rb', line 24

def self.crop(x, y, r)
  orient = r.split('!')[1]
  ratio  = r.split('!')[0].split(':').sort.map { |r| BigDecimal(r) }

  vertical = y > x
  rotate = y > x && orient == 'h' || x > y && orient == 'v'

  if (vertical || rotate) && !(vertical && rotate)
    x = x + y
    y = x - y
    x = x - y
  end

  xʹ = x
  yʹ = x * (ratio[1] / ratio[0])

  if (yʹ > y) || rotate && (yʹ > x)
    yʹ = y
    xʹ = y * (ratio[1] / ratio[0])

    if xʹ > x
      xʹ = x
      yʹ = x * (ratio[0] / ratio[1])
    end
  end

  Δx = ((x - xʹ) / 2).to_f.floor
  Δy = ((y - yʹ) / 2).to_f.floor

  if (vertical || rotate) && !(vertical && rotate)
    [
      Δy,         # crop top left x
      Δx,         # crop top left y
      y - Δy * 2, # crop width
      x - Δx * 2  # crop height
    ]
  else
    [
      Δx.to_f,    # crop top left x
      Δy,         # crop top left y
      x - Δx * 2, # crop width
      y - Δy * 2  # crop height
    ]
  end
end

.resize(x, y, x_max = nil, y_max = nil) ⇒ Object 



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# File 'lib/aspect_ratio.rb', line 4

def self.resize(x, y, x_max = nil, y_max = nil)
  x = BigDecimal(x)
  y = BigDecimal(y)

  if x_max && y_max
    # Maximum values of height and width given, aspect ratio preserved.
    if y > x
      return [(y_max * x / y).round, y_max]
    else
      return [x_max, (x_max * y / x).round]
    end
  elsif x_max
    # Width given, height automagically selected to preserve aspect ratio.
    return [x_max, (x_max * y / x).round]
  else
    # Height given, width automagically selected to preserve aspect ratio.
    return [(y_max * x / y).round, y_max]
  end
end