Bringing command 'arcangleto' (G) to ODF
rb.henschel at t-online.de
Thu Jan 24 23:16:26 UTC 2019
some years ago Radek Doulik has implemented a commant 'G' for the
enhanced-path of a custom shape. Such path is written in drawooo
namespace. I have not found any documentation about it and it is not
You know, that I'm hesitant to bring something new to ODF. But in this
case the new command seems to be useful. You will find the draft for a
proposal below. Because the lack of any documentation (and my problems
with English) it would be nice, if you look whether I have got it correct.
PowerPoint restricts the swing angle to [-360°;360°], but I do not find
any such restriction in the OOXML spec. What to do for ODF about this?
Currently it is not restricted in my proposal draft.
Parameters (wR hR st sw) +
Draws an arc of an ellipse. The ellipse is specified by the width 2*wR,
and the hight 2*hR. The arc is specifies by the start angle st in
degrees and the swing angle sw in degrees. The ellipse is positioned so
that the current point is the start point of the arc. The arc is drawn
so that sw is the central angle of the arc. If sw is positive, the arc
is drawn clockwise; if sw is negative, the arc is drawn
counter-clockwise. The endpoint of the arc becomes the new current point.
In case the path is filled, the filling is drawn as ellipse sector.
The swing angle may be greater as 360° and may be smaller than -360°. In
that cases filling will overlap.
This command is needed for interoperability with the OOXML standard and
its attribute "arcTo", see ECMA-376 Part 1 section 20.1.94. With the
current commands A, B, U, T, V and W only one direction of the arc is
possible, either clockwise or counter-clockwise. The new command G
allows to specify the arc direction depending on a parameter. Such
parameter can be calculated from a formula or adjustment value, so the
direction is not predefined.
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