# skewy.rb

    #!/usr/local/bin/ruby18 -w
    require 'RMagick'

    imgl = Magick::ImageList.new
    imgl.new_image(250, 250, Magick::HatchFill.new('white','lightcyan2'))

    gc = Magick::Draw.new

    # Move the origin to the center.
    gc.translate(125, 125)
    max_x = imgl.columns/2
    max_y = imgl.rows/2

    # Skew y 30 degrees
    gc.skewy(30)

    # Draw down-pointing arrow
    gc.fill('gray50')
    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.stroke('red')
    gc.stroke_width(3)
    gc.line(-max_x+10, 0, max_x-10,   0)
    gc.line( max_x-10, 0, max_x-20, -10)
    gc.line( max_x-10, 0, max_x-20,  10)

    gc.draw(imgl)

    # Add labels
    gc = Magick::Draw.new
    gc.pointsize(14)
    gc.font_weight(Magick::NormalWeight)
    gc.font_style(Magick::NormalStyle)
    gc.stroke('transparent')
    gc.gravity(Magick::CenterGravity)
    gc.text(15, 0, "'0,0'")
    gc.gravity(Magick::EastGravity)
    gc.text(10, 0, "'+x'")
    gc.gravity(Magick::SouthGravity)
    gc.text(10, 20, "'+y'")
    gc.draw(imgl)

    imgl.border!(1,1, 'lightcyan2')
    imgl.write("skewy.gif")

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