Re: [Sketch-devel] Making 0 point objects

[Bernhard H. <bh...@in...>]

[[ CC to sketch-devel again ]]

Antoon Pardon <Ant...@re...> writes:
> Well  I didn't have printers in mind and that is why I inacuratly
> talked about one pixel. The standard says this:
> 
>  The marker type 'dot' is intended always to be displayed as  the
>  smallest visible point on the display surface at metafile inter­
>  pretation time. It is thus intended to behave as  a  "polypoint"
>  element.

What's a polypoint element in this context?

I'm not sure what would qualify as the "smallest visible point on the
display surface" in an import filter in Sketch. The document it creates
doesn't know about display surfaces it only knows about physical
coordinates on paper, basically. 

What would "metafile interpretation time" be here?

> So  as far as I understand this dot shouldn't scale when you show
> a magnified part of the drawing.

Hmm, should it stay the same size under simple zooming or when the
objects are resized? The latter could be achieved with a plugin object
which would simply override the transform method to turn the affine
transformation into the appropriate translation of the center point.

The former are more or less impossible as objects that are always drawn
at the same device dependent size regardless of zoom factor don't really
fit into Sketch's data model. The big question here would be how to
treat them when the document is rendered on a different devices.

A facility for marker objects might be interesting for some other
applications of Sketch. Geographic data may also contain point data --
in addition to polylines and polygons among others -- and there's no
good way to visualize point data in Sketch yet. Marker objects in this
sense, i.e. marking a certain point, should probably have a fixed
physical size so that the preview matches the printed output, for
instance, but they probably shouldn't scale or otherwise transform when
edited.


> I think zero width should be used in the same way  as  the  above
> dot  markers,  to  indicate the line should be drawn in the least
> visible width on the display and so should be of a constant width
> nomatter at what magnification you look at the drawing.

That's how they already behave, then :)

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