Re: Arrow questions

On Thu, 4 Apr 2002, Cyrille Chepelov wrote:
Le Wed, Apr 03, 2002, à 05:52:15PM -0600, Lars Clausen a écrit:

Firstly, I notice explicit differences between hollow_ellipse and
filled_ellipse in whether to account for the line width.  Same for the
dots and boxes.  Shouldn't all of the account for the line width, so as
to line up nicely with the connection point?

This was mostly kept from the previous behaviour (I believe that Alex
wrote it that way). The current code is mostly mine, in a constant visual
aspect refactoring.

Ok, I shall redo them so they act somewhat more consistently.

Second, I notice you're using beziers rather than ellipses to draw the
round shapes.  Any particular reason for that?  Beziers are notoriously
difficult to translate into other formats, as they aren't really

non-horizontally aligned ellipses cause at least as many problems to
uncapable renderers than Beziers. For Beziers, the approximation problem
was already solved, so I re-used that code. And speed didn't seem to be
an issue here for anyone, so in hindsight, this wasn't a too bad

I see.  Since many of the arrows are horizontal or vertical, I'm thinking
using ellipses for those would improve rendering.  I guess a generic
draw_ellipse would be useful for the arrows.

Thirdly, I notice that the various objects have arrow information as
Arrow start_arrow, rather than Arrow *start_arrow.  Not only does that
waste some space, it also means that we can't add onto the Arrow
structure without causing binary incompatibilities.  Any reason to not
change that?

None ! (though I care about binary incompatibility as much as of my first

Uhm... how much do you care about your first cent?

Lastly, a general question.  With the upcoming arrow adjustment system,
it will be possible to have transparent arrowheads where the line
doesn't show through.  Is that desirable?  Better than the current
white-filled version?  Should we have both?

This sounds very cool !

We need to keep both versions, though: I can see areas where a hollow,
transparent triangle head where the line doesn't show through is useful,
as many as I can see areas where I'd want a bg-filled triangle head.


(do you have time to refactor the arrow selector code so that there is
only one arrow selector widget instead of two, and one which uses the
actual arrow-drawing code rather than custom, fixed-size code ? That'd
help cut down the amount of code in a very nice way !)

I was wondering why the toolbox arrow selector didn't have tooltips.  Yes,
they should be combined.  I shall look into that.  Don't know if using the
actual arrow-drawing code is the best solution, I may want to use pixmaps
for some of them.


Lars Clausen (| Hårdgrim of Numenor
"I do not agree with a word that you say, but I   |----------------------------
will defend to the death your right to say it."   | Where are we going, and
    --Evelyn Beatrice Hall paraphrasing Voltaire  | what's with the handbasket?

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