Codetown ::: a software developer's community
Part 1: https://codetown.com/group/kotlin/forum/topics/kotlin-thursdays-ima...
Part 2: https://codetown.com/group/kotlin/forum/topics/kotlin-thursdays-ima...
Welcome to Kotlin Thursdays! Last week, we figured out how to write primitive filters and apply them to our images with the or function. This week, we look at refactoring with higher-order functions.
Think of these resources as supplemental if you happen to be more curious. We always encourage looking into documentation for things you use!
We could continue to write individual functions that feeds 2 images and a particular function, but in Kotlin, we have the ability to use a single function that accepts 2 images and a function with the help of higher order functions. Below, you can see how similar our orFilter function and makeDuller function is.
In programming, programs may take data as parameters and pass those parameters into the function to return a different output or alter the behavior of a program. Kotlin is a functional language, and one characteristic of a functional language is that functions are also able to treat functions as data. You can pass a function as a parameter, which is really powerful!
A higher-order function is a function that may take functions as parameters. You can pass a function with double-colon (::). Double-colon (::) is used to get function (callable) reference in Kotlin.
Ruby facilitates higher order functions with yield, which involves passing a block to a method.
Like Ruby, Kotlin treats functions as first-class citizens, which is a pillar of functional programming. In Kotlin, the equivalent of block code is known as lambda functions, indicated by the pattern:
Instead of passing the object as an argument, you invoke the lambda variable as it if were an extension function. Haskell also has higher order functions which can designate the kinds of parameters a function may take within a function.
In this case, we are going to work with a general function, as opposed to an extension function that is invoked with a qualifer.
The function we write will take a filter function and 2 pixelReaders. Our function parameter, in particular, will only accept functions that take 2 Color parameters and returns a Color.
So here, the input function that accepts the 2 parameters is the receiver type, the output Color receiver object.
fun applyFilter (filter: (Color, Color) --> Color, a: PixelReader, b: PixelReader): PixelWriter {
for (x in 0 until width) {
for (y in 0 until height) {
resultWriter.setColor(x, y, filter(a.getColor(x, y), b.getColor(x, y))
}
}
return resultWriter
}
I hope you all had fun learning a little bit about image processing! Keep exploring and creating new image filters and maybe even as a challenge, think about how you might implement an RGB system to create image filters for colors. Until next time :)
Tags:
Codetown is a social network. It's got blogs, forums, groups, personal pages and more! You might think of Codetown as a funky camper van with lots of compartments for your stuff and a great multimedia system, too! Best of all, Codetown has room for all of your friends.
Created by Michael Levin Dec 18, 2008 at 6:56pm. Last updated by Michael Levin May 4, 2018.
Check out the Codetown Jobs group.
More projects from the CNCF incubated level are preparing to graduate for an ever-widening cloud native ecosystem. The Backstage community has worked on a more robust architecture, and Crossplane aimed to improve its developer DX. KubeFlow and Volcano, both tools promising to improve AI adoption within the Kubernetes ecosystem, are working on easier installation and more features, respectively.
By Olimpiu PopAccording to Marijn Huizenveld, discipline is key to preventing accumulating technical debt. In order to be disciplined you should make it difficult to ignore the debt. Heuristics like fixing small issues immediately, agreeing on a timebox for improvement, and making messy things look messy, can help tame technical debt.
By Ben LindersElon Musk announced that xAI would make its AI chatbot Grok open source, and now the release is accessible on GitHub and Hugging Face. This move enables researchers and developers to expand upon the model, influencing how xAI evolves Grok in the face of competition from tech giants like OpenAI, Meta, Google, Microsoft, and others.
By Daniel DominguezWilliam Chen discusses the importance of trimming your computational graph, storing data in multiple formats, leveraging open source, and considering multiple dimensions of modularization.
By William ChenRedis has recently announced a change in their license by transitioning from the open-source BSD to the more restrictive Server Side Public License (SSPLv1). The move has promptly led to a fork initiated by former maintainers and reignited discussions surrounding the sustainability of open-source initiatives.
By Renato Losio© 2024 Created by Michael Levin. Powered by