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kotlinlang

Screenshot_20230125-200309~2.png

How does one draw `Path`s like this?
i.e. how to change stroke width during the path?

(Notice the line being thicker at the beginning)

I only see one `style` for the whole path

`drawPath(path, color, style)`

_Is this even a `Path`? could it maybe be `drawPoints` with changed size per point?_ 

Unfortunately you cannot do this with the `Path` APIs. It’s something that would have to be built and exposed as a `PathEffect`. To achieve what you want you could indeed draw points of varying size, or stamp a bitmap brush along a path, varying its scale (and you’d have to be careful if you ever need to use translucent colors since overlapping points/brushes won’t do what you want)

would drawing points captured from drag events be enough though? 
currently I'm only drawing lines with `path.lineTo` and sometimes it is possible to see the individual segments .. so should I maybe interpolate until it's contiguous at all times? or go the path effect way?

And to be clear, you can’t build a `PathEffect` for this unfortunately. What I meant is that *we* (Android team) would have to add a new `PathEffect` API in the platform

Both on how to smooth the curves by using Bézier segments instead of `lineTo` and how to achieve the variable width: <https://developer.squareup.com/blog/smoother-signatures/>

(which they do with points :slightly_smiling_face:

I would do it slightly differently and not use a fixed `drawSteps` like they do

But use the length of each curve to figure that out

btw when samsung are having drawing apps for their stylus, what do you think is the thing that modulates the width around "loops" or however you say it in english :grinning: when writing in cursive

is it velocity?

It’s usually a mix of velocity and angle of the stylus (when available)

Sometimes also the “local turn radius”

in android that is VelocityTracker right?

also, If I could ask, how can a stylus tell its angle? by the area of the tip touching?

Our signature pad has seen two or three rewrites since that post. No idea what they do today.

but that is their thing? or with say `pointerInput` can I tell the area of the finger?

I remember it being quite the rabbit hole

There are entire apps built around this (Procreate for instance)

<@U9DPCUAB0> There would be an API telling you the tilt angle

You could also use pressure (<https://developer.android.com/reference/android/view/MotionEvent#getPressure(int)>) to vary the stroke width

Btw how do you like finger signing/annotating screenshots as a user? I could never like the end result :grinning: I was wondering why is it so hard to sign nicely.. maybe offset the "cursor" so its not drawing directly under a finger where I cannot see it?

Latency is part of it but it’s gotten a lot better. It’s also precision

I'm already looking into it, thank you so much