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

Modifier and Type	Method and Description
static double	angle(double x, double y) Returns the angle in degrees from the origin to the point (x , y).
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).
static double	cosDegrees(double angle) Returns the trigonometric cosine of its argument where angle is expressed in degrees.
static double	distance(double x, double y) Computes the distance between the origin and the point (x , y).
static double	distance(double x0, double y0, double x1, double y1) Computes the distance between the points (x0, y0) and (x1, y1).
static boolean	isBoolean(String s) Returns true if the given string could be interpreted as a boolean, such as "true" or "false".
static boolean	isChar(String s) Returns true if the given string could be interpreted as a char, such as "Q" or "\n".
static boolean	isDouble(String s) Returns true if the given string could be interpreted as a double, such as "123.45".
static boolean	isInteger(String s) Returns true if the given string could be interpreted as an integer, such as "12345".
static boolean	isLong(String s) Returns true if the given string could be interpreted as an long, such as "12345".
static int	round(double x) Rounds a double value to the nearest int.
static double	round(double x, int digitsAfterDecimal) Rounds a double value to the given number of decimal places.
static double	sinDegrees(double angle) Returns the trigonometric sine of its argument where angle is expressed in degrees.
static double	tanDegrees(double angle) Returns the trigonometric tangent of its argument where angle is expressed in degrees.
static double	toDegrees(double radians) Converts an angle from radians to degrees.
static double	toRadians(double degrees) Converts an angle from degrees to radians.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

isBoolean

public static boolean isBoolean(String s)

Returns true if the given string could be interpreted as a boolean, such as "true" or "false".

Parameters:

s - a string

isChar

public static boolean isChar(String s)

Returns true if the given string could be interpreted as a char, such as "Q" or "\n".

Parameters:

s - a string

isDouble

public static boolean isDouble(String s)

Returns true if the given string could be interpreted as a double, such as "123.45".

Parameters:

s - a string

isInteger

public static boolean isInteger(String s)

Returns true if the given string could be interpreted as an integer, such as "12345".

Parameters:

s - a string

isLong

public static boolean isLong(String s)

Returns true if the given string could be interpreted as an long, such as "12345".

Parameters:

s - a string

round

public static int round(double x)

Rounds a double value to the nearest int.

Parameters:

x - A double value

Returns:

The nearest int value

Usage:

int n = round(x);

round

public static double round(double x,
                           int digitsAfterDecimal)

Rounds a double value to the given number of decimal places. For example, round(3.141592, 2) returns 3.14.

Parameters:

x - A double value

digitsAfterDecimal - number of digits after decimal to keep

Returns:

The nearest int value

Usage:

double n = round(x, digits);

sinDegrees

public static double sinDegrees(double angle)

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

Parameters:

angle - An angle measured in degrees

Returns:

The trigonometric sine of the angle

Usage:

double s = sinDegrees(angle);

cosDegrees

public static double cosDegrees(double angle)

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

Parameters:

angle - An angle measured in degrees

Returns:

The trigonometric cosine of the angle

Usage:

double c = cosDegrees(angle);

tanDegrees

public static double tanDegrees(double angle)

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

Parameters:

angle - An angle measured in degrees

Returns:

The trigonometric tangent of the angle

Usage:

double t = tanDegrees(angle);

toDegrees

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.

Parameters:

radians - An angle measured in radians

Returns:

The equivalent angle in degrees

Usage:

double degrees = toDegrees(radians);

toRadians

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.

Parameters:

degrees - An angle measured in degrees

Returns:

The equivalent angle in radians

Usage:

double radians = toRadians(degrees);

distance

public static double distance(double x,
                              double y)

Computes the distance between the origin and the point (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)

Usage:

double d = distance(x, y);

distance

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

Computes the distance between the points (x0, y0) and (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)

Usage:

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

angle

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.

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

Usage:

double theta = angle(x, y);

angle

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).

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)

Usage:

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