Module: Prawn::TransformationStack

Included in:
Document
Defined in:
lib/prawn/transformation_stack.rb

Overview

Stores the transformations that have been applied to the document.

Instance Method Summary collapse

Instance Method Details

#add_to_transformation_stack(a, b, c, d, e, f) ⇒ void

This method returns an undefined value.

Add transformation to the stack.

Parameters:

  • a (Number)
  • b (Number)
  • c (Number)
  • d (Number)
  • e (Number)
  • f (Number) 


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# File 'lib/prawn/transformation_stack.rb', line 20

def add_to_transformation_stack(a, b, c, d, e, f)
  @transformation_stack ||= [[]]
  @transformation_stack.last.push([a, b, c, d, e, f].map { |i| Float(i) })
end

#current_transformation_matrix_with_translation(x = 0, y = 0) ⇒ Array(Number, Number, Number, Number, Number, Number)

Get current transformation matrix. It’s a result of multiplication of the whole transformation stack with additional translation.

Parameters:

  • x (Number) (defaults to: 0)
  • y (Number) (defaults to: 0)

Returns:

  • (Array(Number, Number, Number, Number, Number, Number)) 


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# File 'lib/prawn/transformation_stack.rb', line 48

def current_transformation_matrix_with_translation(x = 0, y = 0)
  transformations = (@transformation_stack || [[]]).last

  matrix = Matrix.identity(3)

  transformations.each do |a, b, c, d, e, f|
    matrix *= Matrix[[a, c, e], [b, d, f], [0, 0, 1]]
  end

  matrix *= Matrix[[1, 0, x], [0, 1, y], [0, 0, 1]]

  matrix.to_a[0..1].transpose.flatten
end

#restore_transformation_stack ⇒ void

This method returns an undefined value.

Restore previous transformation.

Effectively pops the last transformation off of the transformation stack.



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# File 'lib/prawn/transformation_stack.rb', line 38

def restore_transformation_stack
  @transformation_stack&.pop
end

#save_transformation_stack ⇒ void

This method returns an undefined value.

Save transformation stack.



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# File 'lib/prawn/transformation_stack.rb', line 28

def save_transformation_stack
  @transformation_stack ||= [[]]
  @transformation_stack.push(@transformation_stack.last.dup)
end