#!/usr/bin/env ruby
# 
# Starter Graphics:
# Create some basic examples of vector graphics
#
# Stroke a line, curve, circle, arc, and rectangle using the current line width
# and stroke color. Stroke and fill a rectangle.
# Draw an arc segment by drawing a line and an arc, closing the path and
# filling and stroking it.
# Draw a rectangle and use it as the clipping a path. Draw and fill a circle
# using the clipping path defined.
#
# Required data: font

require 'PDFlib'

# This is where the data files are. Adjust if necessary.
searchpath = "../data"
outfile = "starter_graphics.pdf"

xt=20
x = 210
y=770
dy=90

begin
    p = PDFlib.new

    p.set_option("SearchPath={{" + searchpath +"}}")

    # This means we must check return values of load_font() etc.
    p.set_option("errorpolicy=return")

    if (p.begin_document(outfile, "") == -1)
        raise "Error: " + p.get_errmsg()
    end

    p.set_info("Creator", "PDFlib starter sample")
    p.set_info("Title", "starter_graphics")

    font = p.load_font("NotoSerif-Regular", "unicode", "")
    if font == -1
        raise "Error: " + p.get_errmsg + "\n"
    end

    # Start an A4 page
    p.begin_page_ext(0, 0, "width=a4.width height=a4.height")

    # Set the font
    p.setfont(font, 14)

    # Set the line width
    p.setlinewidth(2.0)

    # Set the stroke color
    p.set_graphics_option("strokecolor={rgb 0 0.5 0.5}")

    # Set the fill color
    p.set_graphics_option("fillcolor={rgb 0 0.85 0.85}")


    # -------------
    # Stroke a line
    # -------------


    # Set the current point for graphics output
    p.moveto(x, y)

    # Draw a line from the current point to the supplied point
    p.lineto(x+300, y+50)

    # Stroke the path using the current line width and stroke color, and
    # clear it

    p.stroke()

    # Output some descriptive black text
    p.fit_textline("lineto() and stroke()", xt, y, "fillcolor={gray 0}")


    # --------------
    # Stroke a curve
    # --------------


    # Set the current point for graphics output
    p.moveto(x, y-=dy)

    # Draw a B�zier curve from the current point to (x3, y3), using three
    # control points

    p.curveto(x+50, y+40, x+200, y+80, x+300, y+30)

    # Stroke the path using the current line width and stroke color, and
    # clear it

    p.stroke()

    # Output some descriptive black text
    p.fit_textline("curveto() and stroke()", xt, y, "fillcolor={gray 0}")


    # ---------------
    # Stroke a circle
    # ---------------


    # Draw a circle at position (x, y) with a radius of 40
    p.circle(x, y-=dy, 40)

    # Stroke the path using the current line width and stroke color, and
    # clear it

    p.stroke()

    # Output some descriptive black text
    p.fit_textline("circle() and stroke()", xt, y, "fillcolor={gray 0}")


    # ---------------------
    # Stroke an arc segment
    # ---------------------


    # Draw an arc segment counterclockwise at position (x, y) with a radius
    # of 40 starting at an angle of 90 degrees and ending at 180 degrees

    p.arc(x, y-=dy+20, 40, 90, 180)

    # Stroke the path using the current line width and stroke color, and
    # clear it

    p.stroke()

    # Output some descriptive black text
    p.fit_textline("arc() and stroke()", xt, y, "fillcolor={gray 0}")


    # ------------------
    # Stroke a rectangle
    # ------------------


    # Draw a rectangle at position (x, y) with a width of 200 and a height
    # of 50

    p.rect(x, y-=dy, 200, 50)

    # Stroke the path using the current line width and stroke color, and
    # clear it

    p.stroke()

    # Output some descriptive black text
    p.fit_textline("rect() and stroke()", xt, y, "fillcolor={gray 0}")


    # ----------------
    # Fill a rectangle
    # ----------------


    # Draw a rectangle at position (x, y) with a width of 200 and a height
    # of 50

    p.rect(x, y-=dy, 200, 50)

    # Fill the path using current fill color, and clear it
    p.fill()

    # Output some descriptive black text
    p.fit_textline("rect() and fill()", xt, y, "fillcolor={gray 0}")


    # ---------------------------
    # Fill and stroke a rectangle
    # ---------------------------


    # Draw a rectangle at position (x, y) with a width of 200 and a height
    # of 50

    p.rect(x, y-=dy, 200, 50)

    # Fill and stroke the path using the current line width, fill color,
    # and stroke color, and clear it

    p.fill_stroke()

    # Output some descriptive black text
    p.fit_textline("rect() and fill_stroke()", xt, y, "fillcolor={gray 0}")


    # -------------------------------------------------------------
    # Draw a line and an arc, close the path and fill and stroke it
    # -------------------------------------------------------------


    # Set the current point for graphics output
    p.moveto(x-40, y-=dy)

    # Draw a line from the current point to the supplied point
    p.lineto(x, y)

    # Draw an arc segment counterclockwise at position (x, y) with a radius
    # of 40 starting at an angle of 90 degrees and ending at 180 degrees

    p.arc(x, y, 40, 90, 180)

    # Close the path and stroke and fill it, i.e. close the current subpath
    # (add a straight line segment from the current point to the starting
    # point of the path), and stroke and fill the complete current path

    p.closepath_fill_stroke()

    # Output some descriptive black text
    p.fit_textline("lineto(), arc(), and", xt, y+20, "fillcolor={gray 0}")
    p.fit_textline("closepath_fill_stroke()", xt, y, "fillcolor={gray 0}")


    # -----------------------------------------------------------------
    # Draw a rectangle and use it as the clipping a path. Draw and fill
    # a circle and clip it according to the clipping path defined.
    # -----------------------------------------------------------------


    # Save the current graphics state including the current clipping
    # path which is set to the entire page by default

    p.save()

    # Draw a rectangle at position (x, y) with a width of 200 and a height
    # of 50

    p.rect(x, y-=dy, 200, 50)

    # Use the current path as the clipping path for subsequent operations

    p.clip()

    # Draw a circle at position (x, y) with a radius of 100
    p.circle(x, y, 80)

    # Fill the path with the current fill color and clear it

    p.fill()

    # Restore the graphics state which has been saved above
    p.restore()

    # Output some descriptive black text
    p.fit_textline("rect(), clip(),", xt, y+20, "fillcolor={gray 0}")
    p.fit_textline("circle(), and fill()", xt, y, "fillcolor={gray 0}")

    p.end_page_ext("")

    p.end_document("")

rescue  PDFlibException => pe
  print "PDFlib exception occurred:\n"
  print "[" + pe.get_errnum.to_s + "] " + pe.get_apiname + \
        ": " + pe.get_errmsg + "\n"
rescue  Exception => e
  print e.backtrace.join("\n") + "\n" + e.to_s
ensure
  p.delete() if p
end

# vim: sw=4
