PaletteFactory
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Object
public class PaletteFactory
A factory for index color models created from RGB values listed
in files. The palette definition files are text files containing an arbitrary number of lines,
each line containing RGB components ranging from 0 to 255 inclusive. An optional fourth column
may be provided for alpha components. Empty lines and lines starting with the '#'
character are ignored. Example:
The number of RGB codes doesn't have to match the target color map size. RGB codes will be automatically interpolated as needed. For example it is legal to declare only 2 colors, blue and red for instance. If an image needs 256 colors, then all needed colors will be interpolated from blue to red, with blue at index 0 and red at index 255.# RGB codes for SeaWiFs images # (chlorophylle-a concentration) 033 000 096 032 000 097 031 000 099 030 000 101 029 000 102 028 000 104 026 000 106 025 000 107 etc...
The default instance provides the following color palettes. More details about those palettes are provided in this page.
Adding custom palettes
To add custom palettes, create a subclass of PaletteFactory like below:
public class MyPalettes extends PaletteFactory {
public MyPalettes() {
// The call below uses the default options for convenience,
// but we could use an other constructor with more parameters.
super();
}
}
// Optionally, we could override getResourceAsStream(String) if we wanted
// to fetch the color codes from a custom source (e.g. from a database).MyPalettes.class file, create a "colors"
sub-directory and put the palette definitions (as text files with the ".pal" suffix)
in that directory. The directory and the file suffix can be changed using one of the
constructors expecting arguments.
Finally, declare the fully-qualified name of MyPalettes in the following file:
META-INF/services/org.geotoolkit.image.io.PaletteFactory
| coverage/geotk-coverage (download) | View source code for this class |
| Field Summary | |
|---|---|
protected WeakHashSet<Palette> |
palettes
The set of palettes already created and not yet garbage-collected. |
| Constructor Summary | |
|---|---|
protected |
PaletteFactory()
Constructs a default palette factory using this object class for loading palette definition files. |
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PaletteFactory(File directory,
String extension,
Charset charset,
Locale locale)
Constructs a palette factory which will load the palette definition files from the specified directory. |
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PaletteFactory(PaletteFactory fallback,
Class<?> loader,
File directory,
String extension,
Charset charset,
Locale locale)
Constructs a palette factory using an optional class for loading palette definition files. |
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PaletteFactory(PaletteFactory fallback,
ClassLoader loader,
File directory,
String extension,
Charset charset,
Locale locale)
Constructs a palette factory using an optional class loader for loading palette definition files. |
| Method Summary | |
|---|---|
Set<String> |
getAvailableNames()
Returns the set of available palette names. |
Color[] |
getColors(String name)
Loads colors from a definition file. |
Palette |
getContinuousPalette(String name,
float minimum,
float maximum,
int dataType,
int numBands,
int visibleBand)
Creates a palette suitable for floating point values. |
static PaletteFactory |
getDefault()
Gets the default palette factory. |
Palette |
getPalette(String name,
int size)
Returns the palette of the specified name and size. |
Palette |
getPalette(String name,
int lower,
int upper,
int size,
int numBands,
int visibleBand)
Returns the palette of the specified name and size. |
Palette |
getPalettePadValueFirst(String name,
int size)
Returns a palette with a pad value at index 0. |
Palette |
getPalettePadValueLast(String name,
int size)
Returns a palette with pad value at the last index. |
protected InputStream |
getResourceAsStream(String name)
Returns an input stream for reading the specified resource. |
Locale |
getWarningLocale()
Returns the locale set by the last invocation to setWarningLocale(Locale)
in the current thread. |
static void |
scanForPlugins(ClassLoader loader)
Lookups for custom palette factories on the classpath. |
void |
setWarningLocale(Locale warningLocale)
Sets the locale to use for formatting warning or error messages. |
| Methods inherited from class Object |
|---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Field Detail |
|---|
protected final WeakHashSet<Palette> palettes
getPalette
method implementations shall return unique Palette
instances as below:
public Palette getPalette(...) {
Palette palette = ...;
palette = palettes.unique(palette); // Ensure that the instance is unique.
return palette;
}ColorModel instances when possible, since they
may be big (up to 256 kilobytes for an IndexColorModel with 16 bits integers).
This mechanism works provided that Palette.createImageTypeSpecifier() lazily
create the color model only when first invoked.
| Constructor Detail |
|---|
protected PaletteFactory()
"colors" relative to
the directory of the subclass extending this class. The character encoding is ISO-8859-1
and the locale is US.
This constructor is protected because is it merely a convenience for subclasses registering themselves as a service in the following file (see class javadoc for more details):
Users should invokeMETA-INF/services/org.geotoolkit.image.io.PaletteFactory
getDefault() instead, which will return a shared instance
of this class together with any custom factories found on the class path.
public PaletteFactory(File directory,
String extension,
Charset charset,
Locale locale)
directory - The base directory for palette definition files relative to current
directory, or null for ".".extension - File name extension, or null if there is no extension
to add to filename. If non-null, this extension will be automatically
appended to filename. It should starts with the '.' character.charset - The charset to use for parsing files, or null for the default.locale - The locale to use for parsing files, or null for the default.
public PaletteFactory(PaletteFactory fallback,
ClassLoader loader,
File directory,
String extension,
Charset charset,
Locale locale)
loader is non-null, the definitions
will be read using ClassLoader.getResource(String), which imply that the
directory argument is relative to the root packages on the classpath.
fallback - An optional fallback factory, or null if there is none. The fallback
factory will be queried if a palette was not found in the current factory.loader - An optional class loader to use for loading the palette definition files.
If null, loading will occurs from the system current working
directory.directory - The base directory for palette definition files. It may be a Java package
if a loader were specified. If null, then "." is
assumed.extension - File name extension, or null if there is no extension
to add to filename. If non-null, this extension will be automatically
appended to filename. It should starts with the '.' character.charset - The charset to use for parsing files, or null for the default.locale - The locale to use for parsing files, or null for the default.
public PaletteFactory(PaletteFactory fallback,
Class<?> loader,
File directory,
String extension,
Charset charset,
Locale locale)
loader is non-null, the definitions will be read
using Class.getResource(String), which imply that the directory argument
is relative to the package of the PaletteFactory subclass.
Using a class instead of a class loader can
avoid security issue on some platforms (some platforms do not allow to load resources
from a ClassLoader because it would make possible to load from the root package).
fallback - An optional fallback factory, or null if there is none. The fallback
factory will be queried if a palette was not found in the current factory.loader - An optional class to use for loading the palette definition files.
If null, loading will occurs from the system current working
directory.directory - The base directory for palette definition files. It may be a Java package
if a loader were specified. If null, then "." is
assumed.extension - File name extension, or null if there is no extension
to add to filename. If non-null, this extension will be automatically
appended to filename. It should starts with the '.' character.charset - The charset to use for parsing files, or null for the default.locale - The locale to use for parsing files. or null for the default.| Method Detail |
|---|
public static PaletteFactory getDefault()
Note:
The scan for custom factories is performed only when this method is first invoked. If
a new scan is desired (for example because new JAR files are added on the classpath,
then scanForPlugins(null) should be invoked explicitly.
If custom factories are found and if they define some palettes of the same name than the
ones provided by the build-in factory, then the custom palettes have precedence over the
build-in ones.
public static void scanForPlugins(ClassLoader loader)
getDefault() and doesn't need to be invoked explicitly, unless
new JAR files have been added on the classpath or unless some specific class loader
needs to be used.
Custom factories shall be declared in the following file:
Newly discovered factories have precedence over the old ones.META-INF/services/org.geotoolkit.image.io.PaletteFactory
loader - The class loader to use, or null for the default one.public void setWarningLocale(Locale warningLocale)
This method sets the locale for the current thread only. It is safe to use this palette factory concurrently in many threads, each with their own locale.
warningLocale - The locale for warning or error messages, or null for the
default locale.public Locale getWarningLocale()
setWarningLocale(Locale)
in the current thread.
protected InputStream getResourceAsStream(String name)
Class or
ClassLoader getResourceAsStream(String)
method, depending on the type of the loader argument given to the constructor.
Subclasses may override this method if a more elaborated mechanism is wanted for fetching
resources. This is sometime required in the context of applications using particular class
loaders.
name - The name of the resource to load, constructed as directory + name
+ extension where directory and extension were
specified to the constructor, while name was given to the
getPalette(java.lang.String, int) method.
null if the resources was not found.public Set<String> getAvailableNames()
getPalette(String, int) method.
If this method can not infer the names of available palettes, then it returns null.
Note that this is not the same than an empty set, which means "there is no palette". The
null return value means that the set is unknown.
null if this method
is unable to fetch this information.
public Color[] getColors(String name)
throws IOException
Special case for single color
If the given name starts with the '#' character, then the string is decoded as
a color using the Color.decode(String) method (i.e., the string is interpreted
as a hexadecimal RGB value) and the decoded color is returned in an array of length 1.
name - The name of the palette to load.
null if no palette was found for the given name.
IOException - if an error occurs during reading.
public Palette getPalette(String name,
int size)
This method does not test the validity of thereturn getPalette(name, 0, size, size, 1, 0);
name argument. If there is
no palette for the given name, then a FileNotFoundException will
be thrown by the getter methods in the returned palette.
name - The name of the palette to load.size - The index color model size.
public Palette getPalettePadValueFirst(String name,
int size)
This method does not test the validity of thereturn getPalette(name, 1, size, size, 1, 0);
name argument. If there is
no palette for the given name, then a FileNotFoundException will
be thrown by the getter methods in the returned palette.
name - The name of the palette to load.size - The index color model size.
public Palette getPalettePadValueLast(String name,
int size)
This method does not test the validity of thereturn getPalette(name, 0, size-1, size, 1, 0);
name argument. If there is
no palette for the given name, then a FileNotFoundException will
be thrown by the getter methods in the returned palette.
name - The name of the palette to load.size - The index color model size.
public Palette getPalette(String name,
int lower,
int upper,
int size,
int numBands,
int visibleBand)
lower inclusive to upper exclusive. Remaining pixel values
(if any) will be left to a black or transparent color by default.
This method does not test the validity of the name argument. If there is
no palette for the given name, then a FileNotFoundException will
be thrown by the getter methods in the returned palette.
name - The name of the palette to load.lower - Index of the first valid element (inclusive) in the
index color model to be created.upper - Index of the last valid element (exclusive) in the
index color model to be created.size - The size of the index color model to be created.
This is the value to be returned by IndexColorModel.getMapSize().numBands - The number of bands (usually 1).visibleBand - The band to use for color computations (usually 0).
public Palette getContinuousPalette(String name,
float minimum,
float maximum,
int dataType,
int numBands,
int visibleBand)
name - The palette name.minimum - The minimal sample value expected.maximum - The maximal sample value expected.dataType - The data type as a DataBuffer.TYPE_INT,
DataBuffer.TYPE_FLOAT or
DataBuffer.TYPE_DOUBLE constant.numBands - The number of bands (usually 1).visibleBand - The band to use for color computations (usually 0).
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