//
// Copyright (c) 2001-2012 by PDFTron Systems Inc. All Rights Reserved.
//

using System;
using pdftron;
using pdftron.Common;
using pdftron.Filters;
using pdftron.SDF;
using pdftron.PDF;
using pdftron.PDF.OCG;

/// <summary>
//-----------------------------------------------------------------------------------
// This sample demonstrates how to create layers in PDF.
// The sample also shows how to extract and render PDF layers in documents 
// that contain optional content groups (OCGs)
//
// With the introduction of PDF version 1.5 came the concept of Layers. 
// Layers, or as they are more formally known Optional Content Groups (OCGs),
// refer to sections of content in a PDF document that can be selectively 
// viewed or hidden by document authors or consumers. This capability is useful 
// in CAD drawings, layered artwork, maps, multi-language documents etc.
//
// Notes: 
// ---------------------------------------
// - This sample is using CreateLayer() utility method to create new OCGs. 
//   CreateLayer() is relatively basic, however it can be extended to set 
//   other optional entries in the 'OCG' and 'OCProperties' dictionary. For 
//   a complete listing of possible entries in OC dictionary please refer to 
//   section 4.10 'Optional Content' in the PDF Reference Manual.
// - The sample is grouping all layer content into separate Form XObjects. 
//   Although using PDFNet is is also possible to specify Optional Content in 
//   Content Streams (Section 4.10.2 in PDF Reference), Optional Content in  
//   XObjects results in PDFs that are cleaner, less-error prone, and faster 
//   to process.
//-----------------------------------------------------------------------------------
/// </summary>
namespace PDFLayersTestCS
{
	class Class1 
	{			
		// Relative path to the folder containing test files.
		static string input_path =  "../../../../TestFiles/";
		static string output_path = "../../../../TestFiles/Output/";

		[STAThread]
		static void Main(string[] args)
		{
			PDFNet.Initialize();

			try
			{
				PDFDoc doc = new PDFDoc();

				// Create three layers...
				Group image_layer = CreateLayer(doc, "Image Layer");
				Group text_layer = CreateLayer(doc, "Text Layer");
				Group vector_layer = CreateLayer(doc, "Vector Layer");

				// Start a new page ------------------------------------
				Page page = doc.PageCreate();

				ElementBuilder builder = new ElementBuilder(); // ElementBuilder is used to build new Element objects
				ElementWriter writer = new ElementWriter(); // ElementWriter is used to write Elements to the page
				writer.Begin(page);	// begin writing to this page

				// Add new content to the page and associate it with one of the layers.
				Element element = builder.CreateForm(CreateGroup1(doc, image_layer.GetSDFObj()));
				writer.WriteElement(element);

				element = builder.CreateForm(CreateGroup2(doc, vector_layer.GetSDFObj()));
				writer.WriteElement(element);

				// Add the text layer to the page...
				if (false)  // set to 'true' to enable 'ocmd' example.
				{
					// A bit more advanced example of how to create an OCMD text layer that 
					// is visible only if text, image and path layers are all 'ON'.
					// An example of how to set 'Visibility Policy' in OCMD.
					Obj ocgs = doc.CreateIndirectArray();
					ocgs.PushBack(image_layer.GetSDFObj());
					ocgs.PushBack(vector_layer.GetSDFObj());
					ocgs.PushBack(text_layer.GetSDFObj());
					OCMD text_ocmd = OCMD.Create(doc, ocgs, OCMD.VisibilityPolicyType.e_AllOn);
					element = builder.CreateForm(CreateGroup3(doc, text_ocmd.GetSDFObj()));
				}
				else {
					element = builder.CreateForm(CreateGroup3(doc, text_layer.GetSDFObj()));
				}
				writer.WriteElement(element);

				// Add some content to the page that does not belong to any layer...
				// In this case this is a rectangle representing the page border.
				element = builder.CreateRect(0, 0, page.GetPageWidth(), page.GetPageHeight());
				element.SetPathFill(false);
				element.SetPathStroke(true);
				element.GetGState().SetLineWidth(40);
				writer.WriteElement(element);

				writer.End();  // save changes to the current page
				doc.PagePushBack(page);

				// Set the default viewing preference to display 'Layer' tab.
				PDFDocViewPrefs prefs = doc.GetViewPrefs();
				prefs.SetPageMode(PDFDocViewPrefs.PageMode.e_UseOC);

				// Calling Dispose() on ElementReader/Writer/Builder can result in increased performance and lower memory consumption.
				builder.Dispose();
				writer.Dispose();

				doc.Save(output_path + "pdf_layers.pdf", SDFDoc.SaveOptions.e_linearized);
				doc.Close();
				Console.WriteLine("Done.");
			}
			catch (PDFNetException e)
			{
				Console.WriteLine(e.Message);
			}

			// The following is a code snippet shows how to selectively render 
			// and export PDF layers.
			try  
			{	 
				PDFDoc doc = new PDFDoc(output_path + "pdf_layers.pdf");
				doc.InitSecurityHandler();

				if (!doc.HasOC()) 
				{
					Console.WriteLine("The document does not contain 'Optional Content'");
				}
				else 
				{
					Config init_cfg = doc.GetOCGConfig();
					Context ctx = new Context(init_cfg);

					PDFDraw pdfdraw = new PDFDraw();
					pdfdraw.SetImageSize(1000, 1000);
					pdfdraw.SetOCGContext(ctx); // Render the page using the given OCG context.

					Page page = doc.GetPage(1); // Get the first page in the document.
					pdfdraw.Export(page, output_path + "pdf_layers_default.png");

					// Disable drawing of content that is not optional (i.e. is not part of any layer).
					ctx.SetNonOCDrawing(false);

					// Now render each layer in the input document to a separate image.
					Obj ocgs = doc.GetOCGs(); // Get the array of all OCGs in the document.
					if (ocgs != null) 
					{
						int i, sz = ocgs.Size();
						for (i=0; i<sz; ++i) 
						{
							Group ocg = new Group(ocgs.GetAt(i));
							ctx.ResetStates(false);
							ctx.SetState(ocg, true);
							string fname = output_path + "pdf_layers_" + ocg.GetName() + ".png";
							Console.WriteLine(fname);
							pdfdraw.Export(page, fname);
						}
					}

					// Now draw content that is not part of any layer...
					ctx.SetNonOCDrawing(true);
					ctx.SetOCDrawMode(Context.OCDrawMode.e_NoOC);
					pdfdraw.Export(page, output_path + "pdf_layers_non_oc.png");

					pdfdraw.Dispose();  // Calling Dispose() on PDFDraw when it is not anymore in use can result in increased performance and lower memory consumption.
					doc.Close();
					Console.WriteLine("Done.");
				}
			}
			catch (PDFNetException e)
			{
				Console.WriteLine(e.Message);
			}


			PDFNet.Terminate();
		}

		// A utility function used to add new Content Groups (Layers) to the document.
		static Group CreateLayer(PDFDoc doc, String layer_name)
		{
			Group grp = Group.Create(doc, layer_name);
			Config cfg = doc.GetOCGConfig();
			if (cfg == null) 
			{
				cfg = Config.Create(doc, true);
				cfg.SetName("Default");
			}

			// Add the new OCG to the list of layers that should appear in PDF viewer GUI.
			Obj layer_order_array = cfg.GetOrder();
			if (layer_order_array == null) 
			{
				layer_order_array = doc.CreateIndirectArray();
				cfg.SetOrder(layer_order_array);
			}
			layer_order_array.PushBack(grp.GetSDFObj());

			return grp;
		}

		// Creates some content (3 images) and associate them with the image layer
		static Obj CreateGroup1(PDFDoc doc, Obj layer)
		{
			ElementWriter writer = new ElementWriter();
			writer.Begin(doc);

			// Create an Image that can be reused in the document or on the same page.		
			Image img = Image.Create(doc.GetSDFDoc(), (input_path + "peppers.jpg"));

			ElementBuilder builder = new ElementBuilder();
			Element element = builder.CreateImage(img, new Matrix2D(img.GetImageWidth()/2, -145, 20, img.GetImageHeight()/2, 200, 150));
			writer.WritePlacedElement(element);

			GState gstate = element.GetGState();	// use the same image (just change its matrix)
			gstate.SetTransform(200, 0, 0, 300, 50, 450);
			writer.WritePlacedElement(element);

			// use the same image again (just change its matrix).
			writer.WritePlacedElement(builder.CreateImage(img, 300, 600, 200, -150));

			Obj grp_obj = writer.End();	

			// Calling Dispose() on ElementReader/Writer/Builder can result in increased performance and lower memory consumption.
			builder.Dispose();
			writer.Dispose();

			// Indicate that this form (content group) belongs to the given layer (OCG).
			grp_obj.PutName("Subtype","Form");
			grp_obj.Put("OC", layer);	
			grp_obj.PutRect("BBox", 0, 0, 1000, 1000);  // Set the clip box for the content.

			// As an example of further configuration, set the image layer to
			// be visible on screen, but not visible when printed...

			// The AS entry is an auto state array consisting of one or more usage application 
			// dictionaries that specify how conforming readers shall automatically set the 
			// state of optional content groups based on external factors.
			Obj cfg = doc.GetOCGConfig().GetSDFObj();
			Obj auto_state = cfg.FindObj("AS");
			if (auto_state == null) auto_state = cfg.PutArray("AS");
			Obj print_state = auto_state.PushBackDict();
			print_state.PutArray("Category").PushBackName("Print");
			print_state.PutName("Event", "Print");
			print_state.PutArray("OCGs").PushBack(layer);

			Obj layer_usage = layer.PutDict("Usage");

			Obj view_setting = layer_usage.PutDict("View");
			view_setting.PutName("ViewState", "ON");

			Obj print_setting = layer_usage.PutDict("Print");
			print_setting.PutName("PrintState", "OFF");

			return grp_obj;
		}

		// Creates some content (a path in the shape of a heart) and associate it with the vector layer
		static Obj CreateGroup2(PDFDoc doc, Obj layer)
		{
			ElementWriter writer = new ElementWriter();
			writer.Begin(doc);

			// Create a path object in the shape of a heart.
			ElementBuilder builder = new ElementBuilder();
			builder.PathBegin();		// start constructing the path
			builder.MoveTo(306, 396);
			builder.CurveTo(681, 771, 399.75, 864.75, 306, 771);
			builder.CurveTo(212.25, 864.75, -69, 771, 306, 396);
			builder.ClosePath();
			Element element = builder.PathEnd(); // the path geometry is now specified.

			// Set the path FILL color space and color.
			element.SetPathFill(true);
			GState gstate = element.GetGState();
			gstate.SetFillColorSpace(ColorSpace.CreateDeviceCMYK()); 
			gstate.SetFillColor(new ColorPt(1, 0, 0, 0));  // cyan

			// Set the path STROKE color space and color.
			element.SetPathStroke(true); 
			gstate.SetStrokeColorSpace(ColorSpace.CreateDeviceRGB()); 
			gstate.SetStrokeColor(new ColorPt(1, 0, 0));  // red
			gstate.SetLineWidth(20);

			gstate.SetTransform(0.5, 0, 0, 0.5, 280, 300);

			writer.WriteElement(element);

			Obj grp_obj = writer.End();	

			// Calling Dispose() on ElementReader/Writer/Builder can result in increased performance and lower memory consumption.
			builder.Dispose();
			writer.Dispose();

			// Indicate that this form (content group) belongs to the given layer (OCG).
			grp_obj.PutName("Subtype","Form");
			grp_obj.Put("OC", layer);
			grp_obj.PutRect("BBox", 0, 0, 1000, 1000); 	// Set the clip box for the content.

			return grp_obj;
		}

		// Creates some text and associate it with the text layer
		static Obj CreateGroup3(PDFDoc doc, Obj layer)
		{
			ElementWriter writer = new ElementWriter();
			writer.Begin(doc);

			// Create a path object in the shape of a heart.
			ElementBuilder builder = new ElementBuilder();

			// Begin writing a block of text
			Element element = builder.CreateTextBegin(Font.Create(doc, Font.StandardType1Font.e_times_roman), 120);
			writer.WriteElement(element);

			element = builder.CreateTextRun("A text layer!");

			// Rotate text 45 degrees, than translate 180 pts horizontally and 100 pts vertically.
			Matrix2D transform = Matrix2D.RotationMatrix(-45 *  (3.1415/ 180.0));
			transform.Concat(1, 0, 0, 1, 180, 100);  
			element.SetTextMatrix(transform);

			writer.WriteElement(element);
			writer.WriteElement(builder.CreateTextEnd());

			Obj grp_obj = writer.End();	

			// Calling Dispose() on ElementReader/Writer/Builder can result in increased performance and lower memory consumption.
			builder.Dispose();
			writer.Dispose();

			// Indicate that this form (content group) belongs to the given layer (OCG).
			grp_obj.PutName("Subtype","Form");
			grp_obj.Put("OC", layer);
			grp_obj.PutRect("BBox", 0, 0, 1000, 1000); 	// Set the clip box for the content.

			return grp_obj;
		}
	}
}