Added first tutorial

core/tutorial/01_imageio.md

@@ -1 +1,42 @@
 # Tutorial 01 - Basic Image I/O Operations
+
+In this first tutorial you will learn how to read and write image files and how images are represented in NICE.
+
+## Prerequisites
+If you need support for a specific image file format other than PGM/PPM, you have to compile nice-core yourself and add the necessary libraries and CMake flags.
+
+The sample code for this tutorial does not have any dependencies other than nice-core. You can find it in the tutorial/progs subfolder.
+
+## Images in memory
+NICE provides a common generic interface for grayscale and multi-channel images. The corresponding classes are _ImageT_ and _ColorImageT_, both subclasses of _GrayColorImageCommonImplementationT_ which contains the most basic image access methods. Those are used by many of the other modules. You can find typical use cases in the next tutorials.
+
+## Image files
+In NICE, instances of _ImageT_ or _ColorImageT_ do not have to exist on disk. Files are different, completely independent objects. The _ImageFile_ class serves as a pointer to a file in the file system.
+
+An instance of _ImageFile_ can be read from or written to, but it does not modify the file in any way unless you call those methods.
+
+Constructing an _ImageFile_ is simple:
+
+```c++
+ImageFile file("path/to/file.pgm");
+```
+
+This does not touch the file at all and it doesn't need to exist. If it does exist, you can read the image file into memory like this:
+
+```c++
+Image image_in_memory;
+file.reader(&image_in_memory);
+```
+
+After making our changes to the image (in memory), we can write them to the file:
+```c++
+file.writer(&image_in_memory);
+```
+
+## Header information
+Sometimes it can be useful to access metadata without reading the whole image into memory. _ImageFile_ provides the __getHeader__ method for this. It reads the file and returns an instance of _Header_ with the fields __width__, __height__, __bitdepth__, __channel__.
+
+## Formats
+Note that _ImageFile_ attemtps to determine the file format by looking at the file name. You can override this behaviour by providing the __type__ parameter using the _Format_ enumeration.
+
+Supported file formats include PGM/PPM out of the box and those provided by libpng, libjpeg and libimagemagick++.

core/tutorial/progs/01_imageio.cpp

@@ -8,9 +8,37 @@
  * @author Clemens-A. Brust
  */
 
+#include <iostream>
+#include <string>
+#include <core/image/ImageT.h>
+
 /*
  * Entry point
  */
 int main(int argc, char** argv) {
+	// Check if enough parameters were supplied
+	if (argc < 3) {
+		std::cout << "USAGE: " << argv[0] << " <input image> <output image>\n";
+		return -1;
+	}	
+
+	// These are our file names
+	std::string input_path(argv[1]);
+	std::string output_path(argv[2]);
+
+	// Read file header and display header information
+	NICE::ImageFile source_file(input_path);
+	NICE::ImageFile::Header source_header = source_file.getHeader();
+
+	std::cout << "Source image dimensions: " << source_header.width << " x " << source_header.height;
+	std::cout << " (" << source_header.channel << " channels, " << source_header.bitdepth << " bpp)\n";
+
+	// Read image into memory
+	NICE::ColorImage source_image;
+	source_file.reader(&source_image);
+
+	// Write image to disk
+	NICE::ImageFile dest_image(output_path);
+	dest_image.writer(&source_image);
 	return 0;
 }