us.zuercher.gpx2map.plotter
Class Color

java.lang.Object
  us.zuercher.gpx2map.plotter.Color

public class Color
extends Object

Color represents an RGB color. The static getColor(String) and getColors() methods obtain the default set of colors from a copy of rgb.txt taken from Netpbm 10.29.

The rgb.txt file may contain multiple names for a given RGB triplet. For example, "Black", "Gray0", and "Grey0" all map to (0, 0, 0). Also, rgb.txt sometimes contains multiple RGB triplets for a single color name. Examples include "Black" which appears twice as (0, 0, 0) and "Navy" which appears first as (0, 0, 142) and again as (0, 0, 128).

The static internal mapping of color name to Color object maintained by this class uses the first appearance of each color name, so requests for the color "Navy" will return a Color with an RGB value of (0, 0, 142). However, Color also maintains a static internal mapping of RGB value to Color objects. Both versions of "Navy" appear in this map.

Author:

Stephan Zuercher

Field Summary

private int	blue Blue value.
private String	colorName Color's name.
private static Map<String,Color>	colors Map of color names to Colors.
private static Map<Integer,Color>	colorsByValue Map of color values to Colors.
private int	green Green value.
private int	red Red value.

Constructor Summary

private

Color(String colorName, int red, int green, int blue) Constructs a new Color object.

Method Summary

boolean	equalByColorValue(Color other) Tests to see if this Color has the same color value as another Color.
boolean	equals(Object other) Tests to see if this Color is the same as another Color by both name and RGB value.
int	getBlue() Returns the color's blue value.
static Color	getColor(String colorName) Returns the Color associated with the given name.
String	getColorName() Returns the Color's name.
static Collection<Color>	getColors() Returns an unordered collection of all known Color objects.
int	getGreen() Returns the color's green value.
int	getRed() Returns the color's red value.
int	hashCode() Computes the hashcode of the color's name.
private static void	loadColors() Load the standard color name/value to Color mappings.
private static int	makeColorValueKey(int red, int green, int blue) Computes a "color value key" for a given RGB value.
static void	resetColors() Resets the color name/value to Color mappings to their startup defaults.
String	toString() Returns the color's name.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

colors

private static Map<String,Color> colors

Map of color names to Colors.

colorsByValue

private static Map<Integer,Color> colorsByValue

Map of color values to Colors.

colorName

private final String colorName

Color's name.

red

private final int red

Red value.

green

private final int green

Green value.

blue

private final int blue

Blue value.

Constructor Detail

Color

private Color(String colorName,
              int red,
              int green,
              int blue)

Constructs a new Color object. See the static initializer block.

Parameters:

colorName - color's name

red - red value

green - green value

blue - blue value

Method Detail

getColors

public static Collection<Color> getColors()
                                   throws ColorDataError

Returns an unordered collection of all known Color objects.

Returns:

an unordered collection of all known Color objects.

Throws:

ColorDataError - if there's an error loading color data from rgb.txt (only on first call or after resetColors())

getColor

public static Color getColor(String colorName)
                      throws ColorDataError

Returns the Color associated with the given name. The color's name is not case sensitive. If the color's name is in the form "#rrggbb", where rr, gg, and bb are hexadecimal values, the normal search by name occurs. If it fails, a search of existing Colors by RGB value is performed. If an existing Color is found with the provided RGB values, it is returned. Finally, if no existing Color is found by RGB value, a new Color object is constructed with the given name ("#rrggbb") and parsed RGB values.

Example results, assuming that getColor(String) is called repeatedly with each name. Note the unexpected behavior with respect to "Navy" in the last three examples (see class description for an explanation).

Name	Result
Red	rgb.txt Color("Red", 255, 0, 0)
red	rgb.txt Color("Red", 255, 0, 0)
#ff0000	rgb.txt Color("Red", 255, 0, 0)
#FF0000	rgb.txt Color("Red", 255, 0, 0)
#00008D	new Color ("#00008D", 0, 0, 141)
#00008d	Color("#00008D", 0, 0, 141)
Navy	rgb.txt Color("Navy", 0, 0, 142)
#00008e	rgb.txt Color("Navy", 0, 0, 142)
#000080	rgb.txt Color("Navy", 0, 0, 128)

Parameters:

colorName - case-insensitive color name

Returns:

the associated Color or null if not found

Throws:

ColorDataError - if there's an error loading color data from rgb.txt (only on first call or after resetColors())

getColorName

public String getColorName()

Returns the Color's name.

Returns:

the Color's name.

getRed

public int getRed()

Returns the color's red value.

Returns:

the color's red value.

getGreen

public int getGreen()

Returns the color's green value.

Returns:

the color's green value.

getBlue

public int getBlue()

Returns the color's blue value.

Returns:

the color's blue value.

toString

public String toString()

Returns the color's name.

Overrides:

toString in class Object

Returns:

the color's name.

hashCode

public int hashCode()

Computes the hashcode of the color's name.

Overrides:

hashCode in class Object

Returns:

a hashcode of the color's name.

equals

public boolean equals(Object other)

Tests to see if this Color is the same as another Color by both name and RGB value. Note that two Colors with the same RGB values, but different names are not considered equal.

Overrides:

equals in class Object

Parameters:

other - another Color object

Returns:

true if the objects are equal (see above)

Throws:

ClassCastException - if other is not a Color

See Also:

equalByColorValue(Color)

equalByColorValue

public boolean equalByColorValue(Color other)

Tests to see if this Color has the same color value as another Color. The Colors' names are irrelevant for this comparison. This method returns true if the RGB values of this are identical to those of the other color.

Parameters:

other - another Color

Returns:

true if the RGB values are the same

resetColors

public static void resetColors()

Resets the color name/value to Color mappings to their startup defaults. In practice, the color mappings are not reloaded until getColor(String) or getColors() is called.

makeColorValueKey

private static int makeColorValueKey(int red,
                                     int green,
                                     int blue)

Computes a "color value key" for a given RGB value. Color value keys are used as a key into the map of Colors by color value.

Parameters:

red - red value

green - green value

blue - blue value

Returns:

the color value key for the given RGB triplet.

loadColors

private static void loadColors()
                        throws ColorDataError

Load the standard color name/value to Color mappings.

Throws:

ColorDataError - if there's an error loading Color data.