#!/usr/bin/env ruby
# 
# Starter layer:
# Define several layers, output images and text to them and define
# particular layers to be visible when opening the document
#
# Define two layers for RGB or Grayscale images and two layers for English or
# German image captions. Output images and text on the various layers and
# open the document with the RGB images and English captions visible.
#
# Required data: grayscale and RGB images

require 'PDFlib'

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

rgb = "nesrin.jpg"
gray = "nesrin_gray.jpg"

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")

    # Open the document with the "Layers" navigation tab visible
    if (p.begin_document(outfile, "openmode=layers") == -1)
        raise "Error: " + p.get_errmsg()
    end

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

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

    # Load the Grayscale image
    imageGray = p.load_image("auto", gray, "")
    if imageGray == -1
        raise "Error: " + p.get_errmsg + "\n"
    end

    # Load the RGB image
    imageRGB = p.load_image("auto", rgb, "")
    if imageRGB == -1
        raise "Error: " + p.get_errmsg + "\n"
    end

    #
    # Define all layers which will be used, and their relationships.
    # This should be done before the first page if the layers are
    # used on more than one page.


    # Define the layer "RGB"
    layerRGB = p.define_layer("RGB", "")

    # Define the layer "Grayscale" which is hidden when opening the
    # document or printing it.
    layerGray = p.define_layer("Grayscale",
        "initialviewstate=false initialprintstate=false")

    # At most one of the "Grayscale" and "RGB" layers should be visible 
    p.set_layer_dependency("Radiobtn", "group={" + layerGray.to_s + " " + \
        layerRGB.to_s + "}")

    # Define the layer "English"
    layerEN = p.define_layer("English", "")

    # Define the layer "German" which is hidden when opening the document
    # or printing it.
    layerDE = p.define_layer("German",
        "initialviewstate=false initialprintstate=false")

    # At most one of the "English" and "German" layers should be visible
    p.set_layer_dependency("Radiobtn", "group={" + layerEN.to_s + " " + \
        layerDE.to_s + "}")

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

    # Place the RGB image on the layer "RGB"
    p.begin_layer(layerRGB)
    p.fit_image(imageRGB, 100, 400, "boxsize={400 300} fitmethod=meet")

    # Place the Grayscale image on the layer "Grayscale"
    p.begin_layer(layerGray)
    p.fit_image(imageGray, 100, 400, "boxsize={400 300} fitmethod=meet")

    # Place an English image caption on the layer "English"
    p.begin_layer(layerEN)
    p.fit_textline("This is the Nesrin image.", 100, 370, "font=" + \
        font.to_s + " fontsize=20")

    # Place a German image caption on the layer "German" 
    p.begin_layer(layerDE)
    p.fit_textline("Das ist das Nesrin-Bild.", 100, 370, "font=" + \
        font.to_s + " fontsize=20")

    p.end_layer()

    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
