1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
|
/* Copyright (C) 2000 Free Software Foundation
This file is part of libgcj.
This software is copyrighted work licensed under the terms of the
Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
details. */
package gnu.awt.j2d;
import java.awt.image.WritableRaster;
import java.awt.image.ColorModel;
/* The raster and associated properties of a mapped screen region.
* The compositing capabilities of backends are often insufficient.
* The backend may not support alpha blending, or may not support some
* other special compositing rule. This means that compositing must
* sometimes be done within the rendering pipeline. The general
* compositing operation consists of combining new color and alpha
* values with existing color values on the drawing surface, to find
* the new color values for the drawing surface. The way the values
* are combined, determines what kind of compositing operation that is
* performed. The default compositing operation is alpha compositing.
*
* <p>In order to perform alpha compositing and other compositing
* operations, we need access to the color values of the imagery that
* has already been drawn on the drawing surface. The
* DirectRasterGraphics interface must therefore contain methods that
* makes it possible to gain access to the pixel values of the drawing
* surface. The methods are modeled after the POSIX mmap() and
* munmap() functions. But, instead of mapping and unmapping portions
* of data from a file descriptor to memory, the methods in
* DirectRasterGraphics maps and unmaps portions of the drawing
* surface to data arrays within writable raster objects. A call to
* mapRaster() will return a writable raster object, encapsulating the
* image data of the drawing surface in the requested domain. The data
* encapsulated by this raster object can be modified using the
* WritableRaster API, or the data buffers can be retrieved from the
* raster, so that the data arrays can be manipulated directly. When
* the raster image has been modified as desired, the data can be
* resynchronized with the drawing surface by calling mapRaster().
*
* <p>As with mmap() and munmap() the methods may work by direct
* manipulation of shared memory, (i.e. the raster object directly
* wraps the actual image data of the drawing surface), or may make a
* private copy that is resynched when the raster is unmapped. The
* backend may choose to implement either mechanism, and the pipeline
* code should not care what mechanism is actually used. This design
* allows us to make full use of speedups such as X shared memory
* extentions when available.
*/
public class MappedRaster
{
WritableRaster raster;
ColorModel cm;
public MappedRaster(WritableRaster raster, ColorModel cm)
{
this.raster = raster;
this.cm = cm;
}
public final WritableRaster getRaster()
{
return raster;
}
public final ColorModel getColorModel()
{
return cm;
}
}
|
