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# frozen_string_literal: true
require_relative 'bounding_box'
module Prawn
class Document # rubocop: disable Style/Documentation
# @group Experimental API
# A column box is a bounding box with the additional property that when
# text flows past the bottom, it will wrap first to another column on the
# same page, and only flow to the next page when all the columns are
# filled.
#
# `column_box` accepts the same parameters as {bounding_box}, as well as the
# number of `:columns` and a `:spacer` (in points) between columns. If
# resetting the top margin is desired on a new page (e.g. to allow for
# initial page wide column titles) the option `reflow_margins: true` can be
# set.
#
# @overload column_box(point, options = {})
# @param point [Array(Number, Number)]
# @param options [Hash{Symbol => any}]
# @option options :width [Number]
# width of the new column box, must be specified.
# @option options :height [Number]
# height of the new column box, stretchy box if omitted.
# @option options :hold_position [Boolean]
# whether to put cursor at the bottom of the column box.
# @option options :columns [Integer] (3)
# @option options :spacer [Number] (font_size)
# @option options :reflow_margins [Boolean] (false)
# @yieldparam parent_box [BoundingBox] parent bounding box
# @return [void]
def column_box(*args, &block)
init_column_box(block) do |parent_box|
map_to_absolute!(args[0])
@bounding_box = ColumnBox.new(self, parent_box, *args)
end
end
private
def init_column_box(user_block, options = {})
parent_box = @bounding_box
yield(parent_box)
self.y = @bounding_box.absolute_top
user_block.call
self.y = @bounding_box.absolute_bottom unless options[:hold_position]
@bounding_box = parent_box
end
# Implements the necessary functionality to allow {Document#column_box} to
# work.
#
class ColumnBox < BoundingBox
# @param point [Array(Number, Number)]
# @param options [Hash{Symbol => any}]
# @option options :width [Number]
# width of the new column box, must be specified.
# @option options :height [Number]
# height of the new column box, stretchy box if omitted.
# @option options :columns [Integer] (3)
# @option options :spacer [Number] (font_size)
# @option options :reflow_margins [Boolean] (false)
def initialize(document, parent, point, options = {})
super
@columns = options[:columns] || 3
@spacer = options[:spacer] || @document.font_size
@current_column = 0
@reflow_margins = options[:reflow_margins]
end
# The column width, not the width of the whole box, before left and/or
# right padding.
#
# @return [Number]
def bare_column_width
(@width - (@spacer * (@columns - 1))) / @columns
end
# The column width after padding. Used to calculate how long a line of
# text can be.
#
# @return [Number]
def width
bare_column_width - (@total_left_padding + @total_right_padding)
end
# Column width including the spacer.
#
# @return [Number]
def width_of_column
bare_column_width + @spacer
end
# x coordinate of the left edge of the current column.
#
# @return [Number]
def left_side
absolute_left + (width_of_column * @current_column)
end
# Relative position of the left edge of the current column.
#
# @return [Number]
def left
width_of_column * @current_column
end
# x coordinate of the right edge of the current column.
#
# @return [Number]
def right_side
columns_from_right = @columns - (1 + @current_column)
absolute_right - (width_of_column * columns_from_right)
end
# Relative position of the right edge of the current column.
#
# @return [Number]
def right
left + width
end
# Moves to the next column or starts a new page if currently positioned at
# the rightmost column.
#
# @return [void]
def move_past_bottom
@current_column = (@current_column + 1) % @columns
@document.y = @y
if @current_column.zero?
if @reflow_margins
@y = @parent.absolute_top
end
@document.start_new_page
end
end
# Override the padding functions so as not to split the padding amount
# between all columns on the page.
# @private
# @param left_padding [Number]
# @return [void]
def add_left_padding(left_padding)
@total_left_padding += left_padding
@x += left_padding
end
# @private
# @param left_padding [Number]
# @return [void]
def subtract_left_padding(left_padding)
@total_left_padding -= left_padding
@x -= left_padding
end
# @private
# @param right_padding [Number]
# @return [void]
def add_right_padding(right_padding)
@total_right_padding += right_padding
end
# @private
# @param right_padding [Number]
# @return [void]
def subtract_right_padding(right_padding)
@total_right_padding -= right_padding
end
end
end
end
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