Kotlin Thursdays: Image Processing in Kotlin Part 2

Welcome to Kotlin Thursdays!  Last week, we were able to render an image with TornadoFX and even manipulate its pixels.  Today, we will go over Pixel Math!

Resources

Think of these resources as supplemental if you happen to be more curious.  We always encourage looking into documentation for things you use!

• Project Github Repository: https://github.com/Kotlin-Thursdays/Image-Processing-in-Kotlin
• Installing Java with Oracle:  https://www.oracle.com/technetwork/java/javase/downloads/jdk8-downl...
• Kotlin: https://kotlinlang.org/docs/reference/
• TornadoFX: https://edvin.gitbooks.io/tornadofx-guide/content/

Binary Operations

Last week, we got the hang of how to grab these pixels and do something with them.  Today, we're going to expand by creating our own filters using operational pixel manipulation.

For all practical purposes, we're going to be talking about monochromatic images. If we try to write filters using colored pixels, it will prove a lot more difficult to work with RGB values as opposed to just black or white.  

Best we learn to walk before we start trying to fly!  

In order to create our own image filters, we need to have a solid understanding of pixel math, or binary operations.

Binary operations are the bread and butter of computers! You can compute operations on binary values 1 and 0.   

AND - both inputs must be true for the output to be true

0 && 0 = 0

0 && 1 = 0

1 && 0 = 0

1 && 1 = 1

OR - one or both inputs must be true for the output to be true

0 || 0 = 0

0 || 1 = 1

1 || 0 = 1

1 || 1 = 1

NOT - inverse result

!0 = 1

!1 = 0

!(0 && 0) = 1

!(1 || 1) = 0

Likewise, if we assign the color BLACK to 1 and the color WHITE to 0, we can easily apply binary operations to to the binary values black and white.  Working with colors gets significantly more difficult when there are RGB values to consider. There are other binary operations like XANDS, XORS, and XNORS, but for now, let's just focus on the first three.

Implementing Primitive Filters

Now that we understand how OR, AND, and NOT works, let's implement these functions with colors.

Conclusion

You'll notice that these functions are for pixel colors only.  Next week, we look into higher-order functions in Kotlin to learn how we can pass functions as a parameter - but you'll welcome to check out the video to see how we can apply one of these primitive filters to our images! See you next week :)