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Re: Extending the width of a glissando

From: Jean Abou Samra
Subject: Re: Extending the width of a glissando
Date: Tue, 21 Sep 2021 00:02:23 +0200
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Le 20/09/2021 à 23:55, David Kastrup a écrit :
Jean Abou Samra <> writes:

Le 20/09/2021 à 23:31, David Kastrup a écrit :
Jean Abou Samra <> writes:

Thoughts? One would have to look at the most typical use cases
to decide on an interface.
Anything wrong with using a ly:transform? type?  It's straightforward to
create and manipulate.
I had already forgotten about those. Given sufficient
documentation, it would probably work well.
I find in the IR:

  -- Function: ly:make-transform xx yx xy yy x0 y0
      Create a transform.  Without options, it is an identity transform.
      Given four arguments XX, YX, XY, and YY, it is a linear transform,
      given six arguments (with X0 and Y0 last), it is an affine
      transform.  Transforms can be called as functions on other
      transforms (concatening them) or on points given either as complex
      number or real number pair.  See also ‘ly:make-rotation’,
      ‘ly:make-scaling’, and ‘ly:make-translation’.

-- Function: ly:transform? x
      Is X a ‘Transform’ object?

  -- Function: ly:transform->list transform
      Convert a transform matrix to a list of six values.  Values are XX,
      YX, XY, YY, X0, Y0.

  -- Function: ly:make-translation x y
      Make a transform translating by X and Y.  If only X is given, it
      can also be a complex number or a pair of numbers indicating the
      offset to use.

  -- Function: ly:make-rotation angle center
      Make a transform rotating by ANGLE in degrees.  If CENTER is given
      as a pair of coordinates, it is the center of the rotation,
      otherwise the rotation is around (0 .  0).

  -- Function: ly:make-scaling scale scaley
      Create a scaling transform from argument SCALE and optionally
      SCALEY.  When both arguments are given, they must be real and give
      the scale in X and Y direction.  If only SCALE is given, it may
      also be complex to indicate a scaled rotation in the manner of
      complex number rotations, or a pair of reals for specifying
      different scales in X and Y direction like with the first calling

Sure, I didn't mean that transforms weren't well-documented.
I just suggest a paragraph of NR documentation, possibly linking
back to the IR, simply because the kind of technical language
we use in IR isn't obvious to understand for most users I would
guess (linear transform? complex number? number pair? etc.).

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