ST_TransScale-PolarDB(PolarDB)-阿里云帮助中心

This topic describes the ST_TransScale function. This function translates and scales a meshgeom or sfmesh object based on given values.

Syntax

meshgeom ST_TransScale(meshgeomgeom, float Xoff, float Yoff, float XFactor, float YFactor);
sfmesh ST_TransScale(sfmeshsfmeshObject, float Xoff, float Yoff,  float XFactor, float YFactor);

Parameters

Parameter	Description
geom	The meshgeom object.
sfmeshObject	The sfmesh object.
Xoff	The offset value for the x-coordinate.
Yoff	The offset value for the y-coordinate.
XFactor	The scaling factor for the x-coordinate.
YFactor	The scaling factor for the y-coordinate.

Description

This function applies the following formulas to all coordinate points of a meshgeom or sfmesh object.

x' = XFactor *(x + Xoff) 
y' = XFactor *(y + Yoff)

Examples

select ST_asText(ST_TransScale('MESHGEOM(PATCH(INDEXSURFACE(VERTEX(0 0,0 10,10 10,10 0), INDEX((0,1,2),(1,2,3)))))'::meshgeom, 0.5, 0.8, 2.0,1.3));

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 MESHGEOM(PATCH(INDEXSURFACE(VERTEX(1 1.04,1 14.04,21 14.04,21 1.04),INDEX((0,1,2),(1,2,3)))))