Kinda tempted to start playing dwarf fortress, but at the same time it’s 30 past midnight, and I know I’ll be facing crashes and bugs…
Crossposted from http://wolthera.info/?p=726
HSI and HSY for Krita’s advanced colour selector.
So, in the past few weeks, I spent some time hacking a new feature into Krita that I had wanted for a long time, and this monday I actually commited it. So, I figured it be best to make a little post about the new functionality.
The inspiration, no doubt, was a combination of MyPaint’s HCY’ and the artistic colour selector’s HSI and HSY.
Yes, that’s right, the artistic colour selector had these features al ready. However, the artistic colour selector did not update.
What is HSI and HSY’/HCY.
We’ll borrow an image from Wikipedia for this:
Image B, the HSV, we all know: The most colorfull colour is equal to white in this system. It more or less seems a definition of how bright a given pixel-component is shining.
This is not a great system to use for artists. It you want to make a tone ramp from black to blue to white, you first need to only adjust the value slider, until you hit blue, and from there you need to adjust the saturation till you hit white.
No, much more comfortable is image C, HSL. In this system you can adjust the lightness slider only to have a black-to-colour-to-white tone ramp. Saturation in this case is only reserved for going from a colorfull colour to grey.
But there’s still something weird about HSL: If you have yellow, which need both the red and green lights to be fully lit, and blue, which only need the blue light to be fully lit, then one is obviously brighter than the other? Yet, HSL sets both at 50% lightness.
So we get to our next system, the first of the added options:
Image A, component avarage, or HSI. This determines the Intensity of a colour by adding up all the components. So white(r+g+b) is lighter than yellow(r+g) is lighter than blue(b), which in turn is lighter than black(everthing at zero).
This also results in slightly more intuitive colour picking. But. It’s still a little weird.
Once you start to do measurements of how bright certain colours are, you end up with yellow being even brighter than it is in intensity. When doing so, you get Luminosity(Y). However, unless you have your screen fully colour managed, you can not really use this information: The RGB of your screen does not know where it is in the full extent of visible colour. To map this knowledge to RGB space anyway, image D, HSY’, Luma(Y’) was designed. Luma takes the components, and weights them before adding up.
This makes it even more intuitive than HSI. Though not as powerful as a system that maps to luminance correctly. Such a system, commonly LCH, can be made at this time, but to genuinely give proper feedback, we’ll need to implement colour-management aware colour mixing, also known as perceptual gradients. This will take a lot of work, so until now we stop right here.
Note of HSY: This is exactly the same as MyPaint’s HCY’. The difference between using C(chroma) or S(saturation) is not very clear to me. Officially, Chroma the colourful need relative to the lightning, and our cylindrical HSY’ formula would be justified in being called a HCY’ formula in that case. However, some say that only conical formulas are allowed to use Chroma. To explain, we needed to convert the conical formula to a cylindrical one so the colour selection would actually make sense. In the end I went with the artistic colour selector’s convention.
So what is the point?
If you followed the previous explaination, you should have a vague idea what it’s about.
But I’ll show you anyway:
The above shows the difference between colours at the same hue as two reds. Where in HSL the colours remain the most colourful colour possible in that hue, in HSI and HSY, the shifts try to maintain the relative lightness of a colour in exchange for it’s saturation being different. As humans are more sensitive to lightness contrasts than colourful-ness contrasts, these selectors are much more intuitive to use when painting.
So where can I find them?
In the advanced colour selector options:
Right now it’s a little difficult to figure out which is which, hence the little guide above. There will be a better choosing system in the future, but for now this works.
Triangle, here, is named wildcard, because while internally it maps to HSL, it is, in fact for all shapes the same! To have a difference between HSL, HSI and HSY’ triables, you’d need to dynamically change the proportions per hue.
You can also find them in the mypaint shade selector, which before could only do HSV. This is partially because it was the easiest place to implement them, but also because it is actually pretty useful to use the shade selector in these colour models.
I hope you will be able to enjoy the new selector options as much as I do!
It may not seem much, but I’m really proud of the above :3
Basically, it’s some code added to Krita to make for neater colour selectors. I’ll be writing a better explaination soonish.
Demo of the new Stablizer Smoothing option.
Another new thing in the build I just linked to… A new brush stabilizer algorithm, by Juan Luis Boya García. As demoed by Wolthera, one of our resident artists:
Try out the feature with the new build here: https://www.kickstarter.com/projects/krita/krita-open-source-digital-painting-accelerate-deve/posts/878909
Running a kickstarter campaign can be quite exhausting! But that doesn&#039;t mean that coding stops — here is one new Krita 2.9 feature that we prep…
After the successful release of Krita 2.8, the advanced open source digital painting application, the we’re kicking off the work on the next release with a kickstarter campaign!
Krita 2.8, released on Linux and Windows, has been a very successful release, with hundreds of thousands of downloads. The buzz has simply been insane! And of course, Krita 2.8 really was a very good release, polished, full of productivity enhancing features.
Part of the secret was Dmitry Kazakov’s full-time work sponsored by the Krita Foundation which provided Krita with an insane number of productivie and innovative features.
So for Krita 2.9, we are going for a repeat performance! And we’re going to try and double it, too, and have two people work on Krita full-time. Next to Dmitry, there’s Sven, who’s just finished university. Sven’s been working on Krita for about ten years now. That’s the first stretch goal.
And as a super-stretch goal, we intend to port Krita to OS X, too!
Together with our artist community we created a set of goals to work on, ranging from improved compatibility with Photoshop to making the transform tool the most awesome ever seen. Check out the work package for Krita 2.9 on the kickstarter campaign page.
Maastricht makes me feel like I’m stuck in a Layton game…
Right now, those huge clouds you see(which are genuinely green, my camera didn’t believe me so I tried to correct it) are flooding the streets. It’s literally raining so hard that the drainage pipes can’t keep up. There’s pink lighting everywhere.
Now that huge tower over there? That’s the Maastricht University faculty of Law. It’s really towering in real life, but because my compositionskills are shitty or because my lens is too generic, it doesn’t come across that way here, but it really is towering and big. I’ve been staring at it all day trying to figure out how they got that flag up there.
Now here’s the real kicker:
At the base of that tower, is a statue of a distant uncle of mine(different branch, long dead), we call him “Uncle Mustache” in the family. Family crest and everything.
And there’s pink lightning flashing behind that tower now.
I’m stuck in a Layton game.
is witnessing the most gorgeous pink lightning on green skies rainstorm right now.
seimeinotaka, no It’s not Mahoney(Espella in the translations), but you’re on the money with Barnham(Knight dude).
I am seriously puzzled as to why they aren’t releasing it over there. I mean, they have the translations already(English, French, Italian, German, Spanish… They even have a Dutch translation, like what the hell?). And they’ve released all other Layton and Ace Attorney games… To top it all off, the biggest spoiler in the games is that Maya is Phoenix’s assistant.
Oh, of course, they need to redub Layton and Luke’s lines. Actual British accents can’t be understood by americans, you see.