#!/home/software/ruby-1.8.7/bin/ruby -w
require 'RMagick'
imgl = Magick::ImageList.new
imgl.new_image(390, 240, Magick::HatchFill.new('white','lightcyan2'))
gc = Magick::Draw.new
# Draw path
gc.fill_opacity 0
gc.stroke 'red'
gc.stroke_width 3
gc.path "M20,120 C20,20 170,20 170,120 S320,220 320,120"
# Annotate
# Show end points
gc.fill_opacity 0
gc.stroke 'gray50'
gc.stroke_width 1
gc.circle 20,120, 23, 123
gc.circle 170,120, 173, 123
gc.circle 320,120, 323, 123
# Show control points
gc.fill_opacity 1
gc.circle 20, 20, 23, 23
gc.circle 170, 20, 173, 23
gc.circle 320,220, 323, 223
# Show connector lines
gc.line 20,120, 20, 20
gc.line 170, 20, 170,220
gc.line 320,220, 320,120
# Show auto control point
gc.fill_opacity 0
gc.stroke 'blue'
gc.stroke_width 3
gc.circle 170,220, 173,223
# Add labels
gc.font_weight Magick::NormalWeight
gc.font_style Magick::NormalStyle
gc.stroke "none" # unset stroke color
gc.fill 'black'
# Add end point labels
gc.text 30,125, "'20,120'"
gc.text 180,125, "'170,120'"
gc.text 330,125, "'320,120'"
# Add control point labels
gc.text 30, 25, "'20,20'"
gc.text 180, 25, "'170,20'"
gc.text 330,225, "'320,220'"
# Add auto control point label
gc.text 180,225, "'auto ctl point'"
gc.draw imgl
imgl.border!(1,1, 'lightcyan2')
imgl.write 'path.gif'