Now that you know an image is just a grid of integers, it's not too difficult to create them. Of course you're not going to programmatically draw the Mona Lisa, but you might draw the Mandelbrot set or other pictures that can be created algorithmically.
There are a number of different ways to create an
Image object from raw bytes. The easiest is with the
java.awt.image.MemoryImageSource class. This class
implements the java.awt.image.ImageProducer interface
as will all classes that create images.
public MemoryImageSource(int width, int height, int[] pixels, int offset, int scan)
public MemoryImageSource(int width, int height, ColorModel cm, byte[] pixels,
int offset, int scan)
public MemoryImageSource(int width, int height, ColorModel cm, byte[] pixels,
int offset, int scan, Hashtable props)
public MemoryImageSource(int width, int height, ColorModel cm, int[] pixels,
int offset, int scan)
public MemoryImageSource(int width, int height, ColorModel cm, int[] pixels,
int offset, int scan, Hashtable properties) There are five different constructors in the
MemoryImageSource class. for now let's concentrate on the
first:
public MemoryImageSource(int width, int height, int[]
pixels, int offset, int scan)
width is the width of the image in pixels.
height is the height of the image in pixels.
pixels is an int array that contains the actual
image data. Each int in the array is a 32-bit quantity
containing the RGB-transparency value for one pixel.
offset is the index in the array where the image data
starts. scan is the number of pixels in each line of
the array. Most of the time this is the same as
width.
To create an image you first fill an array with the data for the
image, then use that array to construct a new
MemoryImageSource. Then you pass the
MemoryImageSource to the createImage() method
of the Component class to actually produce an
Image object.