get_multiline_type_metrics.rb

# frozen_string_literal: true

require 'rmagick'

TEXT = 'get\nmultiline\ntype\nmetrics'

background = Magick::Image.new(200, 200)
gc = Magick::Draw.new

# Draw the text centered on the background
gc.annotate(background, 0, 0, 0, 0, TEXT) do |options|
  options.font_family = 'Verdana'
  options.pointsize = 36
  options.gravity = Magick::CenterGravity
  options.stroke = 'none'
end

# Get the metrics
metrics = gc.get_multiline_type_metrics(background, TEXT)

# Compute the corners for a rectangle surrounding the text
x = (background.columns - metrics.width) / 2
y = (background.rows - metrics.height) / 2

# Draw 2 rectangles over the text.
gc = Magick::Draw.new
gc.stroke('red')
gc.stroke_width(5)
gc.stroke_linejoin('round')
gc.fill('cyan')
gc.fill_opacity(0.10)
gc.rectangle(x, y, x + metrics.width, y + metrics.height)

gc.stroke('white')
gc.stroke_width(1)
gc.fill('none')
gc.rectangle(x, y, x + metrics.width, y + metrics.height)
gc.draw(background)

background.border!(1, 1, 'blue')

background.write('get_multiline_type_metrics.gif')