Programmer Guide/Command Reference/EVAL/pgtrans: Difference between revisions
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Shift, scale and/or rotate a polygon. | Shift, scale and/or rotate a polygon. | ||
;Usage: | ;Usage: | ||
:<code>pgtrans(<var>X</var>, <var>IX</var> {, <var>DX</var>, <var>DY</var> | :<code>pgtrans(<var>X</var>, <var>IX</var> {, <var>DX</var>, <var>DY</var>, <var>KX</var>, <var>KY</var>, <var>A</var>})</code> | ||
:;<var>X</var>:a [[../#polygons|closed point-list]] or a [[../#polygons|polygon-stream]] defining one or more polygons. | :;<var>X</var>:a [[../#polygons|closed point-list]] or a [[../#polygons|polygon-stream]] defining one or more polygons. | ||
:;<var>IX</var>:The index of the polygon of ''X'' to be tested; 0 <= <var>IX</var> < <code>[[../pgget|pgget]](''X'')</code> | :;<var>IX</var>:The index of the polygon of ''X'' to be tested; 0 <= <var>IX</var> < <code>[[../pgget|pgget]](''X'')</code> |
Revision as of 10:19, 20 April 2011
Shift, scale and/or rotate a polygon.
- Usage
pgtrans(X, IX {, DX, DY, KX, KY, A})
- X
- a closed point-list or a polygon-stream defining one or more polygons.
- IX
- The index of the polygon of X to be tested; 0 <= IX <
pgget(X)
- DX, DY
- shift values for x and y (default=0, no shift)
- shift the center point
<xc,yc>
of XIX
<x[i] , y[i]> -> <x[i]+DX , y[i]+DY>
- shift the center point
- KX, KY
- scaling factors; both factors must be greater than zero (default=1, no scaling)
- scale the distances of corners of XIX to the center point
<x[i] , y[i]> -> <(x[i]-xc)*KX+xc , (y[i]-yc)*KY'+yc>
- A
- rotation angle in degree (default=0, no rotation); a scaling factors (default=1)
- rotate the polygon around the center point