java.awt.image.renderable
Class RenderableImageOp

java.lang.Object
  |
  +--java.awt.image.renderable.RenderableImageOp

public class RenderableImageOp

extends Object

implements RenderableImage

This class handles the renderable aspects of an operation with help from its associated instance of a ContextualRenderedImageFactory.

Constructor Summary

RenderableImageOp(ContextualRenderedImageFactory CRIF, ParameterBlock paramBlock)
Constructs a RenderedImageOp given a ContextualRenderedImageFactory object, and a ParameterBlock containing RenderableImage sources and other parameters.

Method Summary

RenderedImage	createDefaultRendering() Gets a RenderedImage instance of this image with a default width and height in pixels.
RenderedImage	createRendering(RenderContext renderContext) Creates a RenderedImage which represents this RenderableImageOp (including its Renderable sources) rendered according to the given RenderContext.
RenderedImage	createScaledRendering(int w, int h, RenderingHints hints) Creates a RenderedImage instance of this image with width w, and height h in pixels.
float	getHeight() Gets the height in user coordinate space.
float	getMinX() Gets the minimum X coordinate of the rendering-independent image data.
float	getMinY() Gets the minimum Y coordinate of the rendering-independent image data.
ParameterBlock	getParameterBlock() Returns a reference to the current parameter block.
Object	getProperty(String name) Gets a property from the property set of this image.
String[]	getPropertyNames() Return a list of names recognized by getProperty.
Vector	getSources() Returns a vector of RenderableImages that are the sources of image data for this RenderableImage.
float	getWidth() Gets the width in user coordinate space.
boolean	isDynamic() Returns true if successive renderings (that is, calls to createRendering() or createScaledRendering()) with the same arguments may produce different results.
ParameterBlock	setParameterBlock(ParameterBlock paramBlock) Change the current ParameterBlock of the operation, allowing editing of image rendering chains.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RenderableImageOp

public RenderableImageOp(ContextualRenderedImageFactory CRIF,
                         ParameterBlock paramBlock)

Constructs a RenderedImageOp given a ContextualRenderedImageFactory object, and a ParameterBlock containing RenderableImage sources and other parameters. Any RenderedImage sources referenced by the ParameterBlock will be ignored.

Parameters:

CRIF - a ContextualRenderedImageFactory object

paramBlock - a ParameterBlock containing this operation's source images and other parameters necessary for the operation to run.

Method Detail

getSources

public Vector getSources()

Returns a vector of RenderableImages that are the sources of image data for this RenderableImage. Note that this method may return an empty vector, to indicate that the image has no sources, or null, to indicate that no information is available.

Specified by:

getSources in interface RenderableImage

Returns:

a (possibly empty) Vector of RenderableImages, or null.

getProperty

public Object getProperty(String name)

Gets a property from the property set of this image. If the property name is not recognized, java.awt.Image.UndefinedProperty will be returned.

Specified by:

getProperty in interface RenderableImage

Parameters:

name - the name of the property to get, as a String.

Returns:

a reference to the property Object, or the value java.awt.Image.UndefinedProperty.

getPropertyNames

public String[] getPropertyNames()

Return a list of names recognized by getProperty.

Specified by:

getPropertyNames in interface RenderableImage

isDynamic

public boolean isDynamic()

Returns true if successive renderings (that is, calls to createRendering() or createScaledRendering()) with the same arguments may produce different results. This method may be used to determine whether an existing rendering may be cached and reused. The CRIF's isDynamic method will be called.

Specified by:

isDynamic in interface RenderableImage

getWidth

public float getWidth()

Gets the width in user coordinate space. By convention, the usual width of a RenderableImage is equal to the image's aspect ratio (width divided by height).

Specified by:

getWidth in interface RenderableImage

Returns:

the width of the image in user coordinates.

getHeight

public float getHeight()

Gets the height in user coordinate space. By convention, the usual height of a RenderedImage is equal to 1.0F.

Specified by:

getHeight in interface RenderableImage

Returns:

the height of the image in user coordinates.

getMinX

public float getMinX()

Gets the minimum X coordinate of the rendering-independent image data.

Specified by:

getMinX in interface RenderableImage

getMinY

public float getMinY()

Gets the minimum Y coordinate of the rendering-independent image data.

Specified by:

getMinY in interface RenderableImage

setParameterBlock

public ParameterBlock setParameterBlock(ParameterBlock paramBlock)

Change the current ParameterBlock of the operation, allowing editing of image rendering chains. The effects of such a change will be visible when a new rendering is created from this RenderableImageOp or any dependent RenderableImageOp.

Parameters:

paramBlock - the new ParameterBlock.

Returns:

the old ParameterBlock.

getParameterBlock

public ParameterBlock getParameterBlock()

Returns a reference to the current parameter block.

createScaledRendering

public RenderedImage createScaledRendering(int w,
                                           int h,
                                           RenderingHints hints)

Creates a RenderedImage instance of this image with width w, and height h in pixels. The RenderContext is built automatically with an appropriate usr2dev transform and an area of interest of the full image. All the rendering hints come from hints passed in.

If w == 0, it will be taken to equal Math.round(h*(getWidth()/getHeight())). Similarly, if h == 0, it will be taken to equal Math.round(w*(getHeight()/getWidth())). One of w or h must be non-zero or else an IllegalArgumentException will be thrown.

The created RenderedImage may have a property identified by the String HINTS_OBSERVED to indicate which RenderingHints were used to create the image. In addition any RenderedImages that are obtained via the getSources() method on the created RenderedImage may have such a property.

Specified by:

createScaledRendering in interface RenderableImage

Parameters:

w - the width of rendered image in pixels, or 0.

h - the height of rendered image in pixels, or 0.

hints - a RenderingHints object containg hints.

Returns:

a RenderedImage containing the rendered data.

createDefaultRendering

public RenderedImage createDefaultRendering()

Gets a RenderedImage instance of this image with a default width and height in pixels. The RenderContext is built automatically with an appropriate usr2dev transform and an area of interest of the full image. All the rendering hints come from hints passed in. Implementors of this interface must be sure that there is a defined default width and height.

Specified by:

createDefaultRendering in interface RenderableImage

Returns:

a RenderedImage containing the rendered data.

createRendering

public RenderedImage createRendering(RenderContext renderContext)

Creates a RenderedImage which represents this RenderableImageOp (including its Renderable sources) rendered according to the given RenderContext.

This method supports chaining of either Renderable or RenderedImage operations. If sources in the ParameterBlock used to construct the RenderableImageOp are RenderableImages, then a three step process is followed:

1. mapRenderContext() is called on the associated CRIF for each RenderableImage source;
2. createRendering() is called on each of the RenderableImage sources using the backwards-mapped RenderContexts obtained in step 1, resulting in a rendering of each source;
3. ContextualRenderedImageFactory.create() is called with a new ParameterBlock containing the parameters of the RenderableImageOp and the RenderedImages that were created by the createRendering() calls.

If the elements of the source Vector of the ParameterBlock used to construct the RenderableImageOp are instances of RenderedImage, then the CRIF.create() method is called immediately using the original ParameterBlock. This provides a basis case for the recursion.

The created RenderedImage may have a property identified by the String HINTS_OBSERVED to indicate which RenderingHints (from the RenderContext) were used to create the image. In addition any RenderedImages that are obtained via the getSources() method on the created RenderedImage may have such a property.

Specified by:

createRendering in interface RenderableImage

Parameters:

renderContext - The RenderContext to use to perform the rendering.

Returns:

a RenderedImage containing the desired output image.