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Overview
| Comment: | In the GeoPoly documentation, mention that geopoly_ccw() can be used to correct vertex order after geopoly_xform(). |
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| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA3-256: |
bfc897c9c02eebf5321dc7c222fabb56 |
| User & Date: | drh 2018-11-24 20:58:44 |
Context
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2018-11-26
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| 12:01 | Merge typo fix from the 3.25 branch. check-in: 121aeee579 user: drh tags: trunk | |
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2018-11-24
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| 20:58 | In the GeoPoly documentation, mention that geopoly_ccw() can be used to correct vertex order after geopoly_xform(). check-in: bfc897c9c0 user: drh tags: trunk | |
| 20:24 | Minor enhancements and updates to various documents. check-in: 9e12c649c9 user: drh tags: trunk | |
Changes
Changes to pages/geopoly.in.
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<p> To rotate a polygon by R radians around the point 0, 0: <codeblock> geopoly_xform($polygon, cos($R), sin($R), -sin($R), cos($R), 0, 0) </codeblock> <tcl>hd_fragment regpoly geopoly_regular</tcl> <h2>The geopoly_regular(X,Y,R,N) Function</h2> <p> The geopoly_regular(X,Y,R,N) function returns a convex, simple, regular, equilateral, equiangular polygon with N sides, centered at X,Y, and with |
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<p> To rotate a polygon by R radians around the point 0, 0: <codeblock> geopoly_xform($polygon, cos($R), sin($R), -sin($R), cos($R), 0, 0) </codeblock> <p> Note that a transformation that flips the polygon might cause the order of vertexes to be reversed. In other words, the transformation might cause the vertexes to circulate in clockwise order instead of counter-clockwise. This can be corrected by sending the result through the [geopoly_ccw()] function after transformation. <tcl>hd_fragment regpoly geopoly_regular</tcl> <h2>The geopoly_regular(X,Y,R,N) Function</h2> <p> The geopoly_regular(X,Y,R,N) function returns a convex, simple, regular, equilateral, equiangular polygon with N sides, centered at X,Y, and with |