[23_27] Change std-arc to counterclockwise

[Oyyko]

What

Change the arc direction of std-arc to counterclockwise

Why

It's more common for math workers.

How to test your changes?

Use mogan's arc drawing function

[Oyyko]

Maybe useful reference: #1038

[da-liii]

Here is the test doc, with or without this pull request, the rendering of the arc is different. Please think about compatibility!

Must we break the compatibility?

<TeXmacs|2.1.2>

<style|<tuple|generic|no-page-numbers|chinese>>

<\body>
  <with|gr-mode|<tuple|edit|point>|gr-frame|<tuple|scale|1cm|<tuple|0.5gw|0.5gh>>|gr-geometry|<tuple|geometry|1par|0.6par>|gr-grid|<tuple|empty>|gr-edit-grid-aspect|<tuple|<tuple|axes|none>|<tuple|1|none>|<tuple|10|none>>|gr-edit-grid|<tuple|empty>|gr-arrow-end|\<gtr\>|gr-grid-old|<tuple|cartesian|<point|0|0>|2>|gr-edit-grid-old|<tuple|cartesian|<point|0|0>|1>|<graphics||<with|arrow-end|\<gtr\>|<std-arc|<point|0|0>|<point|0.0|2.0>|<point|2.0|0.0>>>>>
</body>

<\initial>
  <\collection>
    <associate|page-medium|paper>
    <associate|page-screen-margin|false>
  </collection>
</initial>

[Oyyko]

Here is the test doc, with or without this pull request, the rendering of the arc is different. Please think about compatibility!

Must we break the compatibility?

<TeXmacs|2.1.2>

<style|<tuple|generic|no-page-numbers|chinese>>

<\body>
  <with|gr-mode|<tuple|edit|point>|gr-frame|<tuple|scale|1cm|<tuple|0.5gw|0.5gh>>|gr-geometry|<tuple|geometry|1par|0.6par>|gr-grid|<tuple|empty>|gr-edit-grid-aspect|<tuple|<tuple|axes|none>|<tuple|1|none>|<tuple|10|none>>|gr-edit-grid|<tuple|empty>|gr-arrow-end|\<gtr\>|gr-grid-old|<tuple|cartesian|<point|0|0>|2>|gr-edit-grid-old|<tuple|cartesian|<point|0|0>|1>|<graphics||<with|arrow-end|\<gtr\>|<std-arc|<point|0|0>|<point|0.0|2.0>|<point|2.0|0.0>>>>>
</body>

<\initial>
  <\collection>
    <associate|page-medium|paper>
    <associate|page-screen-margin|false>
  </collection>
</initial>

One solution is to introduce a new data type, for example we can name it std2-arc. std-arc is clockwise, and std2-arc is counterclockwise. Then in the new version we can generate std2-arc by default when drawing an arc. This is a solution. I'm wondering if there is a better solution.

[Oyyko]

@da-liii I add a new type called std-arc-counterclockwise. And we will use this for drawing an arc by default in this PR. The old document with std-arc type can also be drawed correctly. So we maintained the compatibility.

[da-liii]

Is there a better and shorter name for std-arc-counterclockwise to express the same idea?

[Oyyko]

I've abstracted the common part into a helper function.

[Oyyko]

@da-liii I've added sector counterclockwise.

[da-liii]

Tested on Linux