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# encoding: utf-8
# patterns.rb : Implements axial & radial gradients
#
# Originally implemented by Wojciech Piekutowski. November, 2009
# Copyright September 2012, Alexander Mankuta. All Rights Reserved.
#
# This is free software. Please see the LICENSE and COPYING files for details.
#
module Prawn
module Graphics
module Patterns
# @group Stable API
# Sets the fill gradient from color1 to color2.
# old arguments: point, width, height, color1, color2, options = {}
# new arguments: from, to, color1, color1
# or from, r1, to, r2, color1, color2
def fill_gradient(*args)
set_gradient(:fill, *args)
end
# Sets the stroke gradient from color1 to color2.
# old arguments: point, width, height, color1, color2, options = {}
# new arguments: from, to, color1, color2
# or from, r1, to, r2, color1, color2
def stroke_gradient(*args)
set_gradient(:stroke, *args)
end
private
def set_gradient(type, *grad)
patterns = page.resources[:Pattern] ||= {}
registry_key = gradient_registry_key grad
if patterns["SP#{registry_key}"]
shading = patterns["SP#{registry_key}"]
else
unless shading = gradient_registry[registry_key]
shading = gradient(*grad)
gradient_registry[registry_key] = shading
end
patterns["SP#{registry_key}"] = shading
end
operator = case type
when :fill
'scn'
when :stroke
'SCN'
else
raise ArgumentError, "unknown type '#{type}'"
end
set_color_space type, :Pattern
renderer.add_content "/SP#{registry_key} #{operator}"
end
def gradient_registry_key(gradient)
if gradient[1].is_a?(Array) # axial
[
map_to_absolute(gradient[0]),
map_to_absolute(gradient[1]),
gradient[2], gradient[3]
]
else # radial
[
map_to_absolute(gradient[0]),
gradient[1],
map_to_absolute(gradient[2]),
gradient[3],
gradient[4], gradient[5]
]
end.hash
end
def gradient_registry
@gradient_registry ||= {}
end
def gradient(*args)
if args.length != 4 && args.length != 6
raise ArgumentError, "Unknown type of gradient: #{args.inspect}"
end
color1 = normalize_color(args[-2]).dup.freeze
color2 = normalize_color(args[-1]).dup.freeze
if color_type(color1) != color_type(color2)
raise ArgumentError, "Both colors must be of the same color space: #{color1.inspect} and #{color2.inspect}"
end
process_color color1
process_color color2
shader = ref!({
:FunctionType => 2,
:Domain => [0.0, 1.0],
:C0 => color1,
:C1 => color2,
:N => 1.0,
})
shading = ref!({
:ShadingType => args.length == 4 ? 2 : 3, # axial : radial shading
:ColorSpace => color_space(color1),
:Coords => args.length == 4 ?
[0, 0, args[1].first - args[0].first, args[1].last - args[0].last] :
[0, 0, args[1], args[2].first - args[0].first, args[2].last - args[0].last, args[3]],
:Function => shader,
:Extend => [true, true],
})
ref!({
:PatternType => 2, # shading pattern
:Shading => shading,
:Matrix => [1, 0,
0, 1] + map_to_absolute(args[0]),
})
end
end
end
end
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