//
// Copyright (c) 2001-2019 by PDFTron Systems Inc. All Rights Reserved.
//

using System;
using System.Drawing;
using System.Drawing.Imaging;

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

namespace ImageExtractTestCS
{
	class Class1
	{
		private static pdftron.PDFNetLoader pdfNetLoader = pdftron.PDFNetLoader.Instance();
		static Class1() { }

		static int image_counter = 0;

		// Relative path to the folder containing test files.
		static string input_path = "../../../../TestFiles/";
		static string output_path = @"D:\Ryan\clients\serrala\20947\";

		static void ImageExtract(PDFDoc doc, ElementReader reader)
		{
			Element element;
			while ((element = reader.Next()) != null)
			{
				switch (element.GetType())
				{
					case Element.Type.e_image:
					case Element.Type.e_inline_image:
						{
							Console.WriteLine("--> Image: {0}", ++image_counter);
							Console.WriteLine("    Width: {0}", element.GetImageWidth());
							Console.WriteLine("    Height: {0}", element.GetImageHeight());
							Console.WriteLine("    BPC: {0}", element.GetBitsPerComponent());

							Matrix2D ctm = element.GetCTM();
							double x2 = 1, y2 = 1, y1 = ctm.m_v;
							ctm.Mult(ref x2, ref y2);
							// Write the coords to 3 decimal places.
							Console.WriteLine("    Coords: x1={0:N2}, y1={1:N2}, x2={2:N2}, y2={3:N2}", ctm.m_h, ctm.m_v, x2, y2);
							pdftron.PDF.Image image = null;
							if (element.GetType() == Element.Type.e_image)
							{
								image = new pdftron.PDF.Image(element.GetXObject());
							}
							else // inline image
							{
								if (y1 > y2)
								{
									byte[] flipped_image = FlipImage(element);
									image = pdftron.PDF.Image.Create(doc, flipped_image, element.GetImageWidth(), element.GetImageHeight(), 8, ColorSpace.CreateDeviceRGB());
								}
								else
								{
									Image2RGB image2rgb = new Image2RGB(element);
									FilterReader image_reader = new FilterReader(image2rgb);
									image = pdftron.PDF.Image.Create(doc, image_reader, element.GetImageWidth(), element.GetImageHeight(), 8, ColorSpace.CreateDeviceRGB());
								}
							}
							string fname = output_path + "image_extract1_" + image_counter.ToString();
							pdftron.Filters.MemoryFilter mf = new pdftron.Filters.MemoryFilter(0, false); // zero, since we don't know how big the TIFF will be, and false = sink
							FilterWriter fw = new FilterWriter(mf);
							int imageType = image.Export(fw);
							if(imageType == 0)
                            {
								fname += ".png";
                            }
							else if(imageType == 1)
                            {
								fname += ".tif";
							}
							else if (imageType == 2)
							{
								fname += ".jpg";
							}
							else
                            {
								throw new Exception("Unknown image type");
                            }
							mf.SetAsInputFilter(); // switch the MemoryFilter to a source
							FilterReader filterReader = new FilterReader(mf);
							byte[] buffer = new byte[1024]; // 1KiB buffer
							using (FileStream ostm = new FileStream(fname, FileMode.Create, FileAccess.Write))
							{
								int bytesRead = filterReader.Read(buffer);
								while (bytesRead > 0)
								{
									// for demo purpose, now write to disk, but this can be any stream/buffer
									ostm.Write(buffer, 0, bytesRead);
									bytesRead = filterReader.Read(buffer);
								}
							}
							

							//mf.WriteToFile(fname, false); // for demo purpose write to disk
							// See here for another example reading MemoryFilter

							break;
						}
					case Element.Type.e_form: // Process form XObjects
						{
							reader.FormBegin();
							ImageExtract(doc, reader);
							reader.End();
							break;
						}
				}
			}
		}

		static byte[] FlipImage(Element element)
		{
			Image2RGB image2rgb = new Image2RGB(element);
			int width = element.GetImageWidth();
			int height = element.GetImageHeight();
			int out_data_sz = width * height * 3;
			int stride = width * 3;
			FilterReader reader = new FilterReader(image2rgb);
			byte[] image_data = new byte[out_data_sz];
			byte[] flipped_data = new byte[out_data_sz];
			reader.Read(image_data);
			for (int row = 0; row < height; ++row)
			{
				Buffer.BlockCopy(image_data, row * stride, flipped_data, out_data_sz - (stride * (row + 1)), stride);
			}
			return flipped_data;
		}

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

			// Example 1: 
			// Extract images by traversing the display list for 
			// every page. With this approach it is possible to obtain 
			// image positioning information and DPI.
			try
			{
				using (PDFDoc doc = new PDFDoc(your_pdf))
				using (ElementReader reader = new ElementReader())
				{
					doc.InitSecurityHandler();

					PageIterator itr;
					for (itr = doc.GetPageIterator(); itr.HasNext(); itr.Next())
					{
						reader.Begin(itr.Current());
						ImageExtract(doc, reader);
						reader.End();
					}

					Console.WriteLine("Done.");
				}
			}
			catch (PDFNetException e)
			{
				Console.WriteLine(e.Message);
			}

			Console.WriteLine("----------------------------------------------------------------");
		}
	}
}