acm.graphics
Class GMath

java.lang.Object
  acm.graphics.GMath

public class GMath
extends Object

This class defines a variety of static mathematical methods that are useful for the acm.graphics package.

Method Summary

double	angle(double x, double y) Returns the angle in degrees from the origin to the point (x, y).
double	angle(double x0, double y0, double x1, double y1) Computes the angle in degrees formed by a line segment from the point (x0, y0) and (x1, y1).
double	cosDegrees(double angle) Returns the trigonometric cosine of its argument where angle is expressed in degrees.
double	distance(double x, double y) Computes the distance between the origin and the point (x, y).
double	distance(double x0, double y0, double x1, double y1) Computes the distance between the points (x0, y0) and (x1, y1).
int	round(double x) Rounds a double value to the nearest int.
double	sinDegrees(double angle) Returns the trigonometric sine of its argument where angle is expressed in degrees.
double	tanDegrees(double angle) Returns the trigonometric tangent of its argument where angle is expressed in degrees.
double	toDegrees(double radians) Converts an angle from radians to degrees.
double	toRadians(double degrees) Converts an angle from degrees to radians.

Method Detail

public static double angle(double x, double y)

Returns the angle in degrees from the origin to the point (x, y). This method is easier to use than atan2 because it specifies the displacements in the usual x/y order and because it takes care of the fact that the Java coordinate system is flipped. The point (0, 0) is arbitrarily defined to be at angle 0.

Usage:

double theta = angle(x, y);

Parameters:

x	The x-coordinate of the point
y	The y-coordinate of the point

Returns:

The angle from the origin to the point (x, y) measured in degrees counterclockwise from the +x axis

public static double angle(double x0, double y0, double x1, double y1)

Computes the angle in degrees formed by a line segment from the point (x0, y0) and (x1, y1).

Usage:

double theta = angle(x0, y0, x1, y1);

Parameters:

x0	The x-coordinate of one point
y0	The y-coordinate of that point
x1	The x-coordinate of the other point
y1	The y-coordinate of that point

Returns:

The angle formed by the line segment from (x0, y0) to (x1, y1)

public static double cosDegrees(double angle)

Returns the trigonometric cosine of its argument where angle is expressed in degrees.

Usage:

double c = cosDegrees(angle);

Parameter:

angle

An angle measured in degrees

Returns:

The trigonometric cosine of the angle

public static double distance(double x, double y)

Computes the distance between the origin and the point (x, y).

Usage:

double d = distance(x, y);

Parameters:

x	The x-coordinate of the point
y	The y-coordinate of the point

Returns:

The distance from the origin to the point (x, y)

public static double distance(double x0, double y0, double x1, double y1)

Computes the distance between the points (x0, y0) and (x1, y1).

Usage:

double d = distance(x0, y0, x1, y1);

Parameters:

x0	The x-coordinate of one point
y0	The y-coordinate of that point
x1	The x-coordinate of the other point
y1	The y-coordinate of that point

Returns:

The distance between the points (x0, y0) and (x1, y1)

public static int round(double x)

Rounds a double value to the nearest int.

Usage:

int n = round(x);

Parameter:

x	A double value

Returns:

The nearest int value

public static double sinDegrees(double angle)

Returns the trigonometric sine of its argument where angle is expressed in degrees.

Usage:

double s = sinDegrees(angle);

Parameter:

angle

An angle measured in degrees

Returns:

The trigonometric sine of the angle

public static double tanDegrees(double angle)

Returns the trigonometric tangent of its argument where angle is expressed in degrees.

Usage:

double t = tanDegrees(angle);

Parameter:

angle

An angle measured in degrees

Returns:

The trigonometric tangent of the angle

public static double toDegrees(double radians)

Converts an angle from radians to degrees. This method is defined in the Math class, but was added only in JDK1.2, which is not supported in all browsers.

Usage:

double degrees = toDegrees(radians);

Parameter:

radians

An angle measured in radians

Returns:

The equivalent angle in degrees

public static double toRadians(double degrees)

Converts an angle from degrees to radians. This method is defined in the Math class, but was added only in JDK1.2, which is not supported in all browsers.

Usage:

double radians = toRadians(degrees);

Parameter:

degrees

An angle measured in degrees

Returns:

The equivalent angle in radians