Re: Bug in 5.4.rc2

[Ethan A M. <me...@uw...>]

On Friday, 26 June 2020 02:21:58 PDT Dima Kogan wrote:
> Ethan A Merritt <me...@uw...> writes:
> 
> > Sounds like your plot wants to use "with ellipses".
> 
> OK, I'm using ellipses now. It does what I want. I just hit a corner
> case, however that did a surprising thing. The corner case is this:
> 
>   plot '-' notitle with ellipses
>   0 0 0 0
> 
> I'm plotting an ellipse at the origin with axis lengths 0. The
> previously stated purpose was to draw an ellipse with the described
> geometry against the graph coordinates, instead of drawing an abstract
> symbol, like "with circles" does.

I do not recognize that description.  Abstract symbol?
Sounds like a bug.  There is no special code in plot_circles() to
do something other than draw an arc of a circle.
What exactly did you provide as a plot command, and what did
the symbol look like?

> Thus here I would expect nothing
> drawn, or maybe just a single dot drawn. Instead it draws an ellipse of
> some arbitrary size, independent of the zoom level: it's an abstract
> symbol.

I can see why you would expect the size to go to zero or a dot if
the axis length values reach 0.  That would be reasonable, but currently
it interprets that as a request to use the default properties set by
      set style ellipse ...
which also seem reasonable.  Did it do something else?

> Proposal: ellipses with axis lengths >= 0 are not abstract symbols, and
> are drawn as the data dictates. axis lengths < 0 may be rendered as
> symbols.
> 
> Reasonable?

Currently the code uses the absolute value of the axis lengths,
so negative values have no special meaning.
What kind of symbols are you proposing,
and when would you use this rather than plotting `with points`?

	Ethan

	Ethan