Java Reference
In-Depth Information
Finally,the
color model
interpretsapixel'ssamplesasacoloraccordingtoaspecific
Whenyouinvoke
getRGB()
toobtainapixel'sred,green,blue,and(possibly)alpha
components(dependingonthebuffer'stype),thismethodtellstherastertoobtainpixel
samples,therastertellsthesamplemodeltofindthesamples,thesamplemodelfetches
the samples from the data buffer and passes them to the raster, which passes them to
getRGB()
. At this point,
getRGB()
tells the color model to convert the samples to
colorinformation.Thecolormodelusesthecolorspacetohelpitperformthisconver-
sion.
Whenyouinvoke
setRGB()
tosetapixel'scolorcomponents,thismethodtellsthe
color model to obtain sample values corresponding to the color components, and then
tells the raster to store these samples. The raster tells the sample model to store the
pixel's samples, and the sample model stores these samples in the data buffer.
Note
Therasterandcolormodelneedtobecompatible.Inotherwords,thenumber
of samples (per pixel) must equal the number of color model components.
The
java.awt.image
package contains a concrete
Raster
class for describing
read-only rasters, an abstract
DataBuffer
class for describing data buffers, an ab-
stract
SampleModel
class for describing sample models, and an abstract
Color-
Model
class for describing color models. The
java.awt.color
package contains
anabstract
ColorSpace
classfordescribingcolorspaces.ConsulttheJavadocument-
ation to learn more about these classes and their subclasses (e.g.,
Raster
's
Writ-
ableRaster
subclass).
Buffered Image Processing
Image processing
is a form of signal processing (
http://en.wikipedia.org/
wiki/Signal_processing
) where mathematical transformations convert digital
images into other digital images. Transformations exist to blur, sharpen, colorize, em-
boss, sepia tone, and apply other kinds of operations to images.
Java 2D lets you process buffered images or their rasters by providing the
java.awt.image.BufferedImageOp
and
java.awt.image.RasterOp
in-
terfaces.Althoughtheseinterfacesaresimilar(e.g.,eachinterfacedeclaresfivemethods
thatperformequivalenttasks),theydifferinthat
BufferedImageOp
canaccessthe
bufferedimage'scolormodel,whereas
RasterOp
cannotaccessthecolormodel.Also,
RasterOp
issomewhatmoreperformantthan
BufferedImageOp
,butisabitmore
involved to work with.
