Technical question about control points

[Gare]

There was a time when I was certain of the number and location of control poiunts in a given character in a typeface I'd use, because Program X or Program Y flashed a little thing on its splash screen "reading font metrics"...

Does Xara even read font metrics at all?

The reason I ask it that frequently I need to modify a glyph to make a logo or something. And Xara Designer 11 produces way more control points than I'd expect or want whenever I do the Ctrl+Shift+S thing:



This is a fair comparison above: Here'a glyph shown with its original control points in FontLab (a font editor), at bottom. And then there's the glyph (top) when reduced to a path in Xara.


Why? And is there a way to curtail this excessive control point thing?

TIA,

Gary

[mwenz]

Metrics? Yes, to a point (no pun intended). I don't think that control points are part of a font's metrics. Maybe, but I have never thought of them that way.

Fundamentally, unless an application actually can utilize and draw curves according to whether a font is TT or OT, I think that the addition/subtraction of curves are needed. I would be extremely happy if application X would implement the control nodes as smooth curves where appropriate instead of cusps when type is converted to curves.

I also think that this may be character related. In the screen shot below the on-curve points line up fairly well and the cusp handle adjustments match the off-curve points well.



Mike

[Gare]

Mike, you're saying that the conversion from glyph to path involves absolutely no culling of control point info?

Seems bass-ackwards to me when the data is already mapped out in the file.

Thanks, though.

Life sucks sometimes...

-g

[mwenz]

No, I didn't mean that. In my example, the on-curve points as shown in my editor and the cusp points from XDP'S conversion literally are aligned (some are simply very close). The off-curve points from the font editor are still seen when they are outside curves.

Techically in my example, XDP has about 30% fewer points than the font editor if the on- and off-curve points are added together. XDP has 50 some points on the same character as in my font editor, which has 95 points.

What I was getting at, in my example XDP converted that A character with fewer points than are in the font editor. Your example has more points than your font editor. So perhaps it all depends on what character is converted to curves. Maybe even whether it is a TT or OT, seeing how technically they are different types of curves.

[Gare]

Thanks for your explanation, Mike.

However, I still do not understand—and the lack of understanding is my own problem—why, if a program can "see", parse, understand a curve, why it doesn't see the tension and bias values of bounding control points and just use them when a gylph is "decompiled into a simpler vector form.

In any event, it's a chore to eliminate unnecessary control points!

My Best,

Gary

[mwenz]

Dunno the answer, Gary.

It works in the reverse--I can go from XDP or AI or CD and the on-curve control points are near identical in my font editor. So I think it can be done. That said, most of the characters I tried other than that 'A' convert fairly well.

What font are you using in your example?

[Gare]

Okay, I did what should have been obvious from the get-go: it's no secret that Adobe Illustrator "pre-rolls" font data so there's not wait when the program loads, so you can get down to work, unlike Photoshop.

I used a glyph from Zapf Dingbats. I think based on simplifying the glyph in Xara and in Illustrator, that Xara doesn't read all the font set data. Why else would Illustrator show a decompiled glyph as being node-for-node the same as it was designed (in the FontLab view)?

I'm not trying to give the programmers at Xara a hard time. I know how to be a jerk using far less energy than here!




I'd love to know the secret recipe Illustrator uses and see if it can't be applied to Xara. I'm having a devil of a time manually reworking glyph are so I can use fewer control points (thus fewer bumps in smooth "knots") in certain Xara pieces of Art and outlnes for modeling.

Sigh,

Gare

[mwenz]

This is what I get in XDPX11 when that character is converted to shapes/curves:

[Gare]

...so this exercise can be repeated with consistency, mwenz! This is exactly my result.

Which is an exact, inexact replica of the structure of the glyph.

The reason I'm harping on this is that for the most part, modeling programs tend to put a kink in the outline of a 3D extruded shape when the control point isn't flawless, the number of control points are succinct) and the properties of a curve are correct.



The fewer connections I have, the less of a chance I fnd a bum one, as shown above.

And all of these excessive son-of-a-guns have cusp, not smooth connections, if you or anyone else can confirm.

Harumph. And it's only Tuesday!

:)

-g

[mwenz]

I think my screen shot shows the control points as per AI, not your screen shot of what your XDP is doing.

To edit...yes, they are cups and not smooth points. I think I have mentioned that above. That is the only improvement I think is needed. At least in my conversion of type to curves.