Method: HexaPDF::Content::Canvas#save_graphics_state

Defined in:

lib/hexapdf/content/canvas.rb

#save_graphics_state ⇒ Object

:call-seq:

canvas.save_graphics_state              => canvas
canvas.save_graphics_state { block }    => canvas

Saves the current graphics state and returns self.

If invoked without a block a corresponding call to #restore_graphics_state must be done to ensure proper nesting. Otherwise, i.e. when invoked with a block, the graphics state is automatically restored when the block is finished.

Any saved graphics states are also restored when the content stream associated with the canvas is serialized to ensure proper nesting.

Examples:

#>pdf
# With a block
canvas.save_graphics_state do
  canvas.stroke_color("hp-blue")             # After the block the color is reset
  canvas.line(20, 20, 70, 180).stroke
end
canvas.line(60, 20, 110, 180).stroke

# Same without a block
canvas.save_graphics_state.
  stroke_color("red").
  line(100, 20, 150, 180).stroke.
  restore_graphics_state
canvas.line(140, 20, 190, 180).stroke

See: PDF2.0 s8.4.2, #restore_graphics_state

# File 'lib/hexapdf/content/canvas.rb', line 360

def save_graphics_state
  raise_unless_at_page_description_level
  invoke0(:q)
  @font_stack.push(@font)
  if block_given?
    yield
    restore_graphics_state
  end
  self
end