Re: Implementing SVG attribute "stroke-miterlimit" ( tdf#48066)

Hi Regina,

Am 24.03.2016 um 16:35 schrieb Regina Henschel:
> Hi Armin,
>
> I need an advice/opinion _where_ to hold the information:

Definitely in drawinglayer::attribute::LineAttribute, same place where 
basegfx::B2DLineJoin is held. A double, defaulted to 15.0 and read 
access will be fine. For setting it, add a 5th parameter to the 
constructor, defaulted to 15.0. The LineAttribute is a read-only, not 
later changeable class to keep things simple. It is better/safer to 
create another one when a value needs to be changed than starting to 
keep track of changes and add notification or other stuff.

HTH!

Regards,
Armin

> I cannot calculate whether to exchange 'miter' with 'bevel' directly 
> in svgreader, because there only properties for the whole path are 
> handled, but such exchange only happens for a single line pair of the 
> path. So I think, the exchange needs to be in createAreaGeometry part 
> //check and create linejoin. Is that right?
>
> createAreaGeometry gets all needed information already in distinct 
> parameters. The division in single parameters is done inside 
> PolygonStrokePrimitive2D::create2DDecomposition part // create fat 
> line data. There I need access to 'miterlimit'. How should I hold this 
> information? Should I extend LineAttribute, or somethink else?
>
> Kind regards
> Regina
>
> Armin Le Grand schrieb:
> > Hi Regina,
> >
> > AFAIK it is partially used, but not completely. I know of some cases in
> > renderers where today a fixed default of 15.0 is used. Various
> > GraphicSystems use various definitions for it, take care. It would be
> > necessary to define a definition for it for LO, import where available
> > and use where available. Some sub-systems can use it, e.g. Gdiplus or
> > cairo, export to SVG, but no tMetafile (at least not ours). There is
> > definitely no UI for it.
> >
> > HTH!
> > Regards,
> > Armin
> >
> > Am 24.03.2016 um 01:39 schrieb Regina Henschel:
> > > Hi all,
> > >
> > > the following is, what I have found so far, but it might have errors.
> > > So please correct me.
> > >
> > > If two lines build a corner, the corner-style can be None, Rounded,
> > > Beveled or Mitered. That is the property "draw:stroke-linejoin" in ODF
> > > and "stroke-linejoin" in SVG. But SVG has the additional property
> > > "stroke-miterlimit". Using it, the author can determine how sharp the
> > > corner can be before it is turned into kind Beveled. I see no such
> > > property in ODF. LibreOffice turns automatically to kind Bevel using
> > > the default value of svg:stroke-miterlimit.
> > >
> > > The API has the struct "StrokeAttributes" in css::rendering. It has
> > > the element "MiterLimit". I do not know any UI for it and don't know,
> > > if and how it is usable at all. The service "LineProperties" in
> > > css::drawing does not provide such property.
> > >
> > > In OOXML it is the attribute "lim" in element a:miter (20.1.8.43).
> > >
> > >
> > > This svg-attribute is read on SVG import. And it could be evaluated by
> > > the method basegfx::tools::createAreaGeometry(), if it got a value
> > > into the already prepared parameter. But between these two ends there
> > > is currently no way to transport the information. The line properties
> > > Width, Color, LineCap and LineJoin are transported via class
> > > "LineAttribute".
> > >
> > > So my question is, how to transport the "Miterlimit"-information?
> > > Add a member to class LineAttribute?
> > > Add a member to PolygonStrokePrimitive2D and an additional new
> > > parameter into the chain of calls and constructions?
> > > Only fix svg-import or care for other things too? What would I have to
> > > consider?
> > >
> > > Kind regards
> > > Regina
> > >
> > >
> > >
> > >
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>
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