lib/prawn/grid.rb
# frozen_string_literal: true
module Prawn
class Document # rubocop: disable Style/Documentation
# @group Experimental API
# Defines the grid system for a particular document. Takes the number of
# rows and columns and the width to use for the gutter as the
# keys :rows, :columns, :gutter, :row_gutter, :column_gutter
#
# @note A completely new grid object is built each time `define_grid`
# is called. This means that all subsequent calls to grid() will use
# the newly defined Grid object -- grids are not nestable like
# bounding boxes are.
#
# @param options [Hash{Symbol => any}]
# @option options :columns [Integer] Number of columns in the grid.
# @option options :rows [Integer] Number of rows in the grid.
# @option options :gutter [Number] Gutter size. `:row_gutter` and
# `:column_gutter` are ignored if specified.
# @option options :row_gutter [Number] Row gutter size.
# @option options :column_gutter [Number] Column gutter size.
# @return [Grid]
def define_grid(options = {})
@boxes = nil
@grid = Grid.new(self, options)
end
# A method that can either be used to access a particular grid on the page
# or work with the grid system directly.
#
# @overload grid
# Get current grid.
#
# @return [Grid]
#
# @overload grid(row, column)
# Get a grid box.
#
# @param row [Integer]
# @param column [Integer]
# @return [GridBox]
#
# @overload grid(box1, box2)
# Get a grid multi-box.
#
# @param box1 [Array(Integer, Integer)] Start box coordinates.
# @param box2 [Array(Integer, Integer)] End box coordinates.
# @return [MultiBox]
def grid(*args)
@boxes ||= {}
@boxes[args] ||=
if args.empty?
@grid
else
g1, g2 = args
if g1.is_a?(Array) && g2.is_a?(Array) &&
g1.length == 2 && g2.length == 2
multi_box(single_box(*g1), single_box(*g2))
else
single_box(g1, g2)
end
end
end
# A Grid represents the entire grid system of a Page and calculates
# the column width and row height of the base box.
#
# @group Experimental API
class Grid
# @private
# @return [Prawn::Document]
attr_reader :pdf
# Number of columns in the grid.
# @return [Integer]
attr_reader :columns
# Number of rows in the grid.
# @return [Integer]
attr_reader :rows
# Gutter size.
# @return [Number]
attr_reader :gutter
# Row gutter size.
# @return [Number]
attr_reader :row_gutter
# Column gutter size.
# @return [Number]
attr_reader :column_gutter
# @param pdf [Prawn::Document]
# @param options [Hash{Symbol => any}]
# @option options :columns [Integer] Number of columns in the grid.
# @option options :rows [Integer] Number of rows in the grid.
# @option options :gutter [Number] Gutter size. `:row_gutter` and
# `:column_gutter` are ignored if specified.
# @option options :row_gutter [Number] Row gutter size.
# @option options :column_gutter [Number] Column gutter size.
def initialize(pdf, options = {})
valid_options = %i[columns rows gutter row_gutter column_gutter]
Prawn.verify_options(valid_options, options)
@pdf = pdf
@columns = options[:columns]
@rows = options[:rows]
apply_gutter(options)
end
# Calculates the base width of boxes.
#
# @return [Float]
def column_width
@column_width ||= subdivide(pdf.bounds.width, columns, column_gutter)
end
# Calculates the base height of boxes.
#
# @return [Float]
def row_height
@row_height ||= subdivide(pdf.bounds.height, rows, row_gutter)
end
# Diagnostic tool to show all of the grid boxes.
#
# @param color [Color]
# @return [void]
def show_all(color = 'CCCCCC')
rows.times do |row|
columns.times do |column|
pdf.grid(row, column).show(color)
end
end
end
private
def subdivide(total, num, gutter)
(Float(total) - (gutter * Float((num - 1)))) / Float(num)
end
def apply_gutter(options)
if options.key?(:gutter)
@gutter = Float(options[:gutter])
@row_gutter = @gutter
@column_gutter = @gutter
else
@row_gutter = Float(options[:row_gutter])
@column_gutter = Float(options[:column_gutter])
@gutter = 0
end
end
end
# A Box is a class that represents a bounded area of a page.
# A Grid object has methods that allow easy access to the coordinates of
# its corners, which can be plugged into most existing Prawn methods.
#
# @group Experimental API
class GridBox
# @private
attr_reader :pdf
def initialize(pdf, rows, columns)
@pdf = pdf
@rows = rows
@columns = columns
end
# Mostly diagnostic method that outputs the name of a box as
# col_num, row_num
#
# @return [String]
def name
"#{@rows},#{@columns}"
end
# @private
def total_height
Float(pdf.bounds.height)
end
# Width of a box.
#
# @return [Float]
def width
Float(grid.column_width)
end
# Height of a box.
#
# @return [Float]
def height
Float(grid.row_height)
end
# Width of the gutter.
#
# @return [Float]
def gutter
Float(grid.gutter)
end
# x-coordinate of left side.
#
# @return [Float]
def left
@left ||= (width + grid.column_gutter) * Float(@columns)
end
# x-coordinate of right side.
#
# @return [Float]
def right
@right ||= left + width
end
# y-coordinate of the top.
#
# @return [Float]
def top
@top ||= total_height - ((height + grid.row_gutter) * Float(@rows))
end
# y-coordinate of the bottom.
#
# @return [Float]
def bottom
@bottom ||= top - height
end
# x,y coordinates of top left corner.
#
# @return [Array(Float, Float)]
def top_left
[left, top]
end
# x,y coordinates of top right corner.
#
# @return [Array(Float, Float)]
def top_right
[right, top]
end
# x,y coordinates of bottom left corner.
#
# @return [Array(Float, Float)]
def bottom_left
[left, bottom]
end
# x,y coordinates of bottom right corner.
#
# @return [Array(Float, Float)]
def bottom_right
[right, bottom]
end
# Creates a standard bounding box based on the grid box.
#
# @yield
# @return [void]
def bounding_box(&blk)
pdf.bounding_box(top_left, width: width, height: height, &blk)
end
# Drawn the box. Diagnostic method.
#
# @param grid_color [Color]
# @return [void]
def show(grid_color = 'CCCCCC')
bounding_box do
original_stroke_color = pdf.stroke_color
pdf.stroke_color = grid_color
pdf.text(name)
pdf.stroke_bounds
pdf.stroke_color = original_stroke_color
end
end
private
def grid
pdf.grid
end
end
# A MultiBox is specified by 2 Boxes and spans the areas between.
#
# @group Experimental API
class MultiBox
def initialize(pdf, box1, box2)
@pdf = pdf
@boxes = [box1, box2]
end
# @private
attr_reader :pdf
# Mostly diagnostic method that outputs the name of a box.
#
# @return [String]
def name
@boxes.map(&:name).join(':')
end
# @private
def total_height
@boxes[0].total_height
end
# Width of a box.
#
# @return [Float]
def width
right_box.right - left_box.left
end
# Height of a box.
#
# @return [Float]
def height
top_box.top - bottom_box.bottom
end
# Width of the gutter.
#
# @return [Float]
def gutter
@boxes[0].gutter
end
# x-coordinate of left side.
#
# @return [Float]
def left
left_box.left
end
# x-coordinate of right side.
#
# @return [Float]
def right
right_box.right
end
# y-coordinate of the top.
#
# @return [Float]
def top
top_box.top
end
# y-coordinate of the bottom.
#
# @return [Float]
def bottom
bottom_box.bottom
end
# x,y coordinates of top left corner.
#
# @return [Array(Float, Float)]
def top_left
[left, top]
end
# x,y coordinates of top right corner.
#
# @return [Array(Float, Float)]
def top_right
[right, top]
end
# x,y coordinates of bottom left corner.
#
# @return [Array(Float, Float)]
def bottom_left
[left, bottom]
end
# x,y coordinates of bottom right corner.
#
# @return [Array(Float, Float)]
def bottom_right
[right, bottom]
end
# Creates a standard bounding box based on the grid box.
#
# @yield
# @return [void]
def bounding_box(&blk)
pdf.bounding_box(top_left, width: width, height: height, &blk)
end
# Drawn the box. Diagnostic method.
#
# @param grid_color [Color]
# @return [void]
def show(grid_color = 'CCCCCC')
bounding_box do
original_stroke_color = pdf.stroke_color
pdf.stroke_color = grid_color
pdf.text(name)
pdf.stroke_bounds
pdf.stroke_color = original_stroke_color
end
end
private
def left_box
@left_box ||= @boxes.min_by(&:left)
end
def right_box
@right_box ||= @boxes.max_by(&:right)
end
def top_box
@top_box ||= @boxes.max_by(&:top)
end
def bottom_box
@bottom_box ||= @boxes.min_by(&:bottom)
end
end
private
def single_box(rows, columns)
GridBox.new(self, rows, columns)
end
def multi_box(box1, box2)
MultiBox.new(self, box1, box2)
end
end
end