Pixel engine: lifting pen should not "end the stroke"; "dry the paper" shortcut

Develop Feature Requests
1

Suppose I paint with opacity 50%, with the pixel engine (wash mode). As we know, until you lift the pen, drawing twice on the same pixel does not make it more opaque:

immagine

But as I lift the pen, if I draw over the old pixels, the overlap becomes visible:

immagine
immagine423×337 5.24 KB

So, lifting the pen has a very special meaning with the pixel engine.

Now, in order to better simulate watercolor style, I don’t want this behavior. I want no overlap even after I lift the pen :slight_smile: So I can build a single, trasparent shape with many strokes, with no overlap. And then I would need a shortcut, by which I could say “ok, now I’ve finished building my shape. Now it’s ok to start overlapping old pixels”. (Intuitively, the meaning of this shortcut is “dry the paper”.)

Is this very hard to implement?

Note: I could simulate this by creating a layer with 50% opacity, and then drawing with 100% opacity on this layer, and then , when I finished the shape, merging down the layer. But this is cumbersome. It would be much easier if the pen lifting stopped doing what it’s doing, and we had a shortcut to simulate lifting the pen. (“dry the paper”)

Thanks

2

Change the brush mode from build up to wash mode. Otherwise 50% opaque stroke plus another 50% opaque stroke will always end in a 100% opaque stroke.

3

Thanks but I’m already in wash mode. The problem is that wash mode behaves like buildup if I lift the pen :slight_smile:
I’d like it to continue as if I had not lifted the pen, until I press a key.

4

Have you tried the Greater blending mode yet? It only paints over if the new stroke is more opaque than what’s on the canvas.

By the way, the special meaning of lifting the pen is making Krita know that a brush stroke has ended.

5

Greater mode is interesting, but what do I do when I’ve finished the shape? When I’ve finished, I want to be able to draw a new shape over the previous one (with same 50% opacity)…

Greater mode would kind of work if I create a new layer, then paint, then when merge down when I have finished the shape. But then it requires layers…

6

yep. What I’m asking is for a way to make Krita believe the brush stroke hasn’t ended. Until I press a key which says “ok, now it’s ended”.

7

This would cause all sorts of problems because That’s pretty much the core functionality and Krita paints as long as the stroke continues.

You could edit the pressure curve of color rate so that it doesn’t paint at low rates of pressure but then you still had to keep the pen on the tablet the whole time.

I don’t know all the blending modes by heart so I can’t give you a better answer right now. There is a page in the manual listing them all with examples. Maybe something else is better suited.

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8

All the water color brushes I’ve seen so far use the masked brush feature, perhaps it’s worth looking into.

9

What about using “alpha darken” blending mode?

50% opaque over 50% opaque should end up mixing to 75% opaque if I’m not mistaken.

10

Thanks, but alpha darken doesn’t seem to be what I need. I need to keep 50% opacity even if I pass many times on the same pixels…

11

if you paint on a transparent layer with alpha darken and opacity = 50 then you won’t be able to paint more opaque than 50%, but you can still paint more transparent. It would be similar to your example with the layer opacity. In fact I think it is the mode used to mix the dabs in the stroke when using the wash mode.

If you paint on a opaque layer then the opacity information of the stroke is lost, the pixels on the layer will be 100% opaque, so it makes no sense to talk about a single transparent shape I think.

I think that concept of wet/dry layer requires more complex implementation.

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12

Yes, it is. It was developed for that mode.

13

Alpha darken is nice. It still requires me to create a layer and merge down when finished, but it’s nice.

14

I made a plugin to do just this! Here is a video to illustrate it: Demo watercolor etc with Krita plugin - YouTube

Basically it simulates wet paper. You have a shortcut (V) to dry the paper.

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15

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