Feature Request: New Vector drawing mode "Spiro"

[remi]

Hi John,

this algorithm draws beautiful lines.
Automatically.
Easier.

See the video.

Remi

[RTK]

I must be missing something.

Yes, that is obvious...

Risto

[BobInce]

I always wondered if there was known maths behind the idea of interpolating curvature instead of position (as beziers do), since I've always suspected that the constant change in curvature should result in prettier curves. Looks like yes!

I don't think the implementation (in Inkscape and the other dev tools using libspiro) is quite how I'd like though... whilst it's fun to play with you have to give up all control and let the spiro decide what the tangents at each point are going to be, even which way round the line is going to go, which can get wacky when you're dragging the points around and Inkscape decides the only way to make a spiro fit is to take a detour round miles of looping weirdness. Altering one control point has the ripple-through effect on the line tangent at all contiguous control points, which could also be impractical.

And I don't really like having to switch spiros on and off as a property of the line... can't I have an uber-path-tool that lets me drop straight line, bezier and spiro segments into the same object? hmmmm.

[remi]

...and let the spiro decide what the tangents at each point are going to be, even which way round the line is going to go, which can get wacky...

Sure, it can get wacky and it could be impractical. But a control point of a Bezier spline can also get wacky and the tool can be impractical - it depends on the practice (in both cases).

And I don't really like having to switch spiros on and off as a property of the line... can't I have an uber-path-tool that lets me drop straight line, bezier and spiro segments into the same object? hmmmm.

I think, you are right: It could be possible to implement the spiro points within a normal path. In the end it's a path with different types of points (PT_LINETO for straight lines, PT_BEZIERTO for spline curves and a new type PT_SPIROTO for spiro curves).

Remi

[MarkMyWords]

Spiro clearly gives a much more 'elegant' line than can easily be achieved without it, sorry John, your 'S' doesn't come close to the quality of a Spiro line. I had always thought the B-Spline tool in Expression gave the best possible curves, but Spiro is even better. As for the stretching an object along a path, isn't that the way the stroke/line-shape already work? If so how much more difficult could it be to allow custom shapes?

This is now top of my wish-list for new tools and coming close second are Live path effects.

[Penny O'Rorke]

Thanks Remi. I used the spiral generator from Dimitry a bit, but mostly done with Freehand tool (maximum smoothing) plus node pushing and pulling.
Penny

[jclements]

Very nice!

How much extra time is spent tweeking node handles; especially when hand tracing bitmaps. The "Fluidiity" of the curves is extremely nice.

I also like the way the "brushes" have implimented the use of the clipboard of load the stroke. How simple.


Thanks for posting the video.

John

[raynerj1]

I still don't see what is so great about this. I can do the same quickly with Xpro. My "s" took less than 1 minute, including the opening time for Xpro. If I spent a little more time on the "s" it might have been prettier. I didn't set out to draw a perfect s-curve, just to get a quick wag.

[covoxer]

I didn't set out to draw a perfect s-curve, just to get a quick wag.

Exactly. I guess the point is that any quick wag with the "Spiro" gives you a kind of "perfect" curve (whatever that means) unlike Beziers.

[steve.ledger]

I still don't see what is so great about this.

Then you will have absolutely no use for it