prawnpdf/prawn

# frozen_string_literal: true

require 'prawn/manual_builder'

Prawn::ManualBuilder::Chapter.new do
  title 'Gradients'

  text do
    prose <<~TEXT
      Note that because of the way PDF renders radial gradients in order to get
      solid fill your start circle must be fully inside your end circle.
      Otherwise you will get triangle fill like illustrated in the example
      below.
    TEXT
  end

  example new_page: true do
    self.line_width = 10

    # Linear Gradients
    fill_gradient [0, 250], [100, 150], 'ff0000', '0000ff'
    fill_rectangle [0, 250], 100, 100

    stroke_gradient [150, 150], [250, 250], '00ffff', 'ffff00'
    stroke_rectangle [150, 250], 100, 100

    fill_gradient [300, 250], [400, 150], 'ff0000', '0000ff'
    stroke_gradient [300, 150], [400, 250], '00ffff', 'ffff00'
    fill_and_stroke_rectangle [300, 250], 100, 100

    rotate 45, origin: [500, 200] do
      stops = { 0 => 'ff0000', 0.6 => '999900', 0.8 => '00cc00', 1 => '4444ff' }
      fill_gradient from: [460, 240], to: [540, 160], stops: stops
      fill_rectangle [460, 240], 80, 80
    end

    # Radial gradients
    fill_gradient [50, 50], 0, [50, 50], 70.71, 'ff0000', '0000ff'
    fill_rectangle [0, 100], 100, 100

    stroke_gradient [200, 50], 45, [200, 50], 70.71, '00ffff', 'ffff00'
    stroke_rectangle [150, 100], 100, 100

    stroke_gradient [350, 50], 45, [350, 50], 70.71, '00ffff', 'ffff00'
    fill_gradient [350, 50], 0, [350, 50], 70.71, 'ff0000', '0000ff'
    fill_and_stroke_rectangle [300, 100], 100, 100

    fill_gradient [500, 100], 50, [500, 0], 0, 'ff0000', '0000ff'
    fill_rectangle [450, 100], 100, 100
  end
end