def self.layout(images, options = {})
width = options[:width]
height = options[:height]
hpadding = options[:hpadding] || 0
vpadding = options[:vpadding] || 0
hmargin = options[:hmargin] || 0
vmargin = options[:vmargin] || 0
max_width = width || (2 * (hpadding + hmargin) + images.map{|i| i[:width]}.max)
y = 0
images.each do |i|
if width
i[:cssw] = width
i[:cssx] = 0
i[:x] = 0 + (width - i[:width]) / 2
else
i[:cssw] = i[:width] + (2 * hpadding)
i[:cssx] = (max_width - i[:cssw]) / 2
i[:x] = i[:cssx] + hpadding
end
if height
i[:cssh] = height
i[:cssy] = y
i[:y] = y + (height - i[:height]) / 2
else
i[:cssh] = i[:height] + (2 * vpadding)
i[:cssy] = y + vmargin
i[:y] = i[:cssy] + vpadding
end
y += i[:cssh] + 2 * vmargin
end
{ :width => max_width, :height => y }
end