GRASS GIS 7 Programmer's Manual  7.7.svn(2018)-r73600
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rotate.c File Reference

GIS Library - rotate. More...

#include <math.h>
Include dependency graph for rotate.c:

Go to the source code of this file.

Macros

#define RpD   ((2 * M_PI) / 360.) /* radians/degree */
 
#define D2R(d)   (double)(d * RpD) /* degrees->radians */
 
#define R2D(d)   (double)(d / RpD) /* radians->degrees */
 

Functions

void G_rotate_around_point (double X0, double Y0, double *X1, double *Y1, double angle)
 Rotate point (double version) More...
 
void G_rotate_around_point_int (int X0, int Y0, int *X1, int *Y1, double angle)
 Rotate point (int version) More...
 

Detailed Description

GIS Library - rotate.

(C) 2001-2014 by the GRASS Development Team

This program is free software under the GNU General Public License (>=v2). Read the file COPYING that comes with GRASS for details.

Author
Hamish Bowman, Glynn Clements

Definition in file rotate.c.

Macro Definition Documentation

#define D2R (   d)    (double)(d * RpD) /* degrees->radians */

Definition at line 18 of file rotate.c.

Referenced by G_rotate_around_point().

#define R2D (   d)    (double)(d / RpD) /* radians->degrees */

Definition at line 19 of file rotate.c.

#define RpD   ((2 * M_PI) / 360.) /* radians/degree */

Definition at line 17 of file rotate.c.

Function Documentation

void G_rotate_around_point ( double  X0,
double  Y0,
double *  X1,
double *  Y1,
double  angle 
)

Rotate point (double version)

Given a point, angle, and origin, rotate the point around the origin by the given angle. Coordinates and results are double prec floating point.

Parameters
X0X component of origin (center of circle)
Y0Y component of origin (center of circle)
[out]X1X component of point to be rotated (variable is modified!)
[out]Y1Y component of point to be rotated (variable is modified!)
anglein degrees, measured CCW from east

Definition at line 35 of file rotate.c.

References D2R.

Referenced by G_rotate_around_point_int(), and stroke_chain().

void G_rotate_around_point_int ( int  X0,
int  Y0,
int X1,
int Y1,
double  angle 
)

Rotate point (int version)

Given a point, angle, and origin, rotate the point around the origin by the given angle. Coordinates are given in integer and results are rounded back to integer.

Parameters
X0X component of origin (center of circle)
Y0Y component of origin (center of circle)
[out]X1X component of point to be rotated (variable is modified!)
[out]Y1Y component of point to be rotated (variable is modified!)
anglein degrees, measured CCW from east

Definition at line 62 of file rotate.c.

References G_rotate_around_point(), int, and x.