#!/usr/bin/env ruby -w
require 'rmagick'

imgl = Magick::ImageList.new
imgl.new_image(200, 200, Magick::HatchFill.new('white','lightcyan2'))

gc = Magick::Draw.new

# Move the origin to the center.
gc.translate(100, 100)
max_x = imgl.columns/2
max_y = imgl.rows/2

# Rotate 45 degrees
gc.rotate(45)

gc.stroke('red')
gc.stroke_width(3)

# Draw down-pointing arrow
gc.line(0, -max_y,   0, max_y)
gc.line(0,  max_y,  10, max_y-10)
gc.line(0,  max_y, -10, max_y-10)

# Draw right-pointing arrow
gc.line(-max_x, 0, max_x,     0)
gc.line( max_x, 0, max_x-10, -10)
gc.line( max_x, 0, max_x-10,  10)

# Add labels
gc.font_weight(Magick::NormalWeight)
gc.font_style(Magick::NormalStyle)
gc.fill('black')
gc.stroke('transparent')

gc.text(8, 15, "'0,0'")
gc.text(110, 16, 'x')
gc.text(12, 115, 'y')

gc.draw(imgl)

imgl.border!(1,1, 'lightcyan2')

imgl.write('rotate.gif')