def parse_transform_attribute(transform, space: :pdf)
matrix = Matrix.identity(3)
flip = space == :svg ? 1.0 : -1.0
parse_css_method_calls(transform).each do |name, arguments|
case name
when 'translate'
x, y = arguments
matrix *= translation_matrix(x_pixels(x.to_f), flip * y_pixels(y.to_f))
when 'translateX'
x = arguments.first
matrix *= translation_matrix(x_pixels(x.to_f), 0.0)
when 'translateY'
y = arguments.first
matrix *= translation_matrix(0.0, flip * y_pixels(y.to_f))
when 'rotate'
angle, x, y = arguments.collect(&:to_f)
angle = angle * Math::PI / 180.0
rotation = rotation_matrix(angle, space: space)
case arguments.length
when 1
matrix *= rotation
when 3
matrix *= translation_matrix(x_pixels(x.to_f), flip * y_pixels(y.to_f))
matrix *= rotation
matrix *= translation_matrix(-x_pixels(x.to_f), -flip * y_pixels(y.to_f))
else
warnings << "transform 'rotate' must have either one or three arguments"
end
when 'scale'
x_scale = arguments[0].to_f
y_scale = (arguments[1] || x_scale).to_f
matrix *= scale_matrix(x_scale, y_scale)
when 'skewX'
angle = arguments[0].to_f * Math::PI / 180.0
matrix *= Matrix[[1, flip * Math.tan(angle), 0], [0, 1, 0], [0, 0, 1]]
when 'skewY'
angle = arguments[0].to_f * Math::PI / 180.0
matrix *= Matrix[[1, 0, 0], [flip * Math.tan(angle), 1, 0], [0, 0, 1]]
when 'matrix'
if arguments.length == 6
a, b, c, d, e, f = arguments.collect(&:to_f)
matrix *= Matrix[[a, flip * c, e], [flip * b, d, flip * f], [0, 0, 1]]
else
warnings << "transform 'matrix' must have six arguments"
end
else
warnings << "Unknown/unsupported transformation '#{name}'; ignoring"
end
end
matrix
end