Trail: 2D Graphics
Lesson: Working with Images
Creating and Drawing to an Image
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Creating and Drawing to an Image

We already know how to load an existing image, which was created and stored in your system or in any network location. But, you probably would like also to create an new image as a pixel data buffer.

In this case, you can create a BufferedImage object manually, using three constructors of this class:

On the other hand, we can use methods of the Component class. These methods can analyze the display resolution for the given Component or GraphicsConfiguration and create an image of an appropriate type.

GraphicsConfiguration returns an object of BufferedImage type, but the Component returns an object of Image type, if you need a BufferedImage object instead then you can perform an instanceof and cast to a BufferedImage in your code.

As was already mentioned in the previous lessons, we can render images not only on screen. An images itself can be considered as a drawing surface. You can use a createGraphics() method of the BufferedImage class for this purpose:

...

BufferedImage off_Image =
  new BufferedImage(100, 50,
                    BufferedImage.TYPE_INT_ARGB);

Graphics2D g2 = off_Image.createGraphics();

Another interesting use of offscreen images is an automaticdouble buffering. This feature allows to avoid flicker in animated images by drawing an image to a back buffer and then copying that buffer onto the screen instead of drawing directly to the screen.

Java 2D also allows access to hardware acceleration for offscreen images, which can provide the better performance of rendering to and copying from these images. You can get the benefit of this functionality by using the following methods of the Image class:


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