Books have prefaces, but since this is a website it has a readme file instead.
This is an online textbook on basic optics and visual optics (that is, optics applied to the eye). But it's an interactive textbook. Many of the figures can be manipulated by you, the reader, to gain additional insight into the optical principles being talked about. That means, though, that you, the reader, need to engage with the book just a little more than you would a regular textbook.
Or you can just play with them.
The simplest sort of interaction, or toy, is a slideshow. A slideshow looks like a regular image, except it has arrowheads to the left or right. If you click on these arrows, you will move the slideshow forwards or back. The caption might change as well.
The other sort of image is fully interactive. These images have an icon like this
beside them. If you touch or click on the icon, the parts of the image that you can move or drag are lit up. Try it on the image below:
Figure 2 Parts of this picture can be dragged around. You can see which parts by holding down the finger icon to the right hand side of the picture: red arrows appear around the white arrowhead, showing that it can be dragged around. As well as that, checkboxes (and sliders if present) can be checked or slid. The checkboxes add por remove components of the image.
This picture is taken from Chapter 6
If you ever want to get back to the original state of an interactive image, you have to refresh the page.
This book is released under the Creative Commons Attribution-NonCommercial-ShareAlike License. In summary, this means you can
The sole author is me (see below), but I had help from some great software:
processing
language, used to create the diagrams and interactive figures.If you have any questions or suggestions for improvement, please email me