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RenderableImageOp.javaAPI DocJava SE 5 API12919Fri Aug 26 14:56:56 BST 2005java.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.

Fields Summary
ParameterBlock
paramBlock
A ParameterBlock containing source and parameters.
ContextualRenderedImageFactory
myCRIF
The associated ContextualRenderedImageFactory.
Rectangle2D
boundingBox
The bounding box of the results of this RenderableImageOp.
Constructors Summary
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.

param
CRIF a ContextualRenderedImageFactory object
param
paramBlock a ParameterBlock containing this operation's source images and other parameters necessary for the operation to run.

        this.myCRIF = CRIF;
        this.paramBlock = (ParameterBlock) paramBlock.clone();
    
Methods Summary
public java.awt.image.RenderedImagecreateDefaultRendering()
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.

return
a RenderedImage containing the rendered data.

        AffineTransform usr2dev = new AffineTransform(); // Identity
        RenderContext newRC = new RenderContext(usr2dev);
        return createRendering(newRC);
    
public java.awt.image.RenderedImagecreateRendering(java.awt.image.renderable.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.

param
renderContext The RenderContext to use to perform the rendering.
return
a RenderedImage containing the desired output image.

        RenderedImage image = null;
        RenderContext rcOut = null;

        // Clone the original ParameterBlock; if the ParameterBlock
        // contains RenderableImage sources, they will be replaced by
        // RenderedImages.
        ParameterBlock renderedParamBlock = (ParameterBlock)paramBlock.clone();
        Vector sources = getRenderableSources();

        try {
            // This assumes that if there is no renderable source, that there
            // is a rendered source in paramBlock
            
            if (sources != null) {
                Vector renderedSources = new Vector();
                for (int i = 0; i < sources.size(); i++) {
                    rcOut = myCRIF.mapRenderContext(i, renderContext,
                                                    paramBlock, this);
                    RenderedImage rdrdImage =
                       ((RenderableImage)sources.elementAt(i)).createRendering(rcOut);
                    if (rdrdImage == null) {
                        return null;
                    }
                    
                    // Add this rendered image to the ParameterBlock's
                    // list of RenderedImages.
                    renderedSources.addElement(rdrdImage);
                }
                
                if (renderedSources.size() > 0) {
                    renderedParamBlock.setSources(renderedSources);
                }
            }

            return myCRIF.create(renderContext, renderedParamBlock);
        } catch (ArrayIndexOutOfBoundsException e) {
            // This should never happen
            return null;
        }
    
public java.awt.image.RenderedImagecreateScaledRendering(int w, int h, java.awt.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.

param
w the width of rendered image in pixels, or 0.
param
h the height of rendered image in pixels, or 0.
param
hints a RenderingHints object containg hints.
return
a RenderedImage containing the rendered data.

        // DSR -- code to try to get a unit scale
        double sx = (double)w/getWidth();
        double sy = (double)h/getHeight();
        if (Math.abs(sx/sy - 1.0) < 0.01) {
            sx = sy;
        }
        AffineTransform usr2dev = AffineTransform.getScaleInstance(sx, sy);
        RenderContext newRC = new RenderContext(usr2dev, hints);
        return createRendering(newRC);
    
public floatgetHeight()
Gets the height in user coordinate space. By convention, the usual height of a RenderedImage is equal to 1.0F.

return
the height of the image in user coordinates.

        if (boundingBox == null) {
            boundingBox = myCRIF.getBounds2D(paramBlock);
        }
        return (float)boundingBox.getHeight();
    
public floatgetMinX()
Gets the minimum X coordinate of the rendering-independent image data.

        if (boundingBox == null) {
            boundingBox = myCRIF.getBounds2D(paramBlock);
        }
        return (float)boundingBox.getMinX();
    
public floatgetMinY()
Gets the minimum Y coordinate of the rendering-independent image data.

        if (boundingBox == null) {
            boundingBox = myCRIF.getBounds2D(paramBlock);
        }
        return (float)boundingBox.getMinY();
    
public java.awt.image.renderable.ParameterBlockgetParameterBlock()
Returns a reference to the current parameter block.

return
the ParameterBlock of this RenderableImageOp.
see
#setParameterBlock(ParameterBlock)

        return paramBlock;
    
public java.lang.ObjectgetProperty(java.lang.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.

param
name the name of the property to get, as a String.
return
a reference to the property Object, or the value java.awt.Image.UndefinedProperty.

        return myCRIF.getProperty(paramBlock, name);
    
public java.lang.String[]getPropertyNames()
Return a list of names recognized by getProperty.

return
a list of property names.

        return myCRIF.getPropertyNames();
    
private java.util.VectorgetRenderableSources()

        Vector sources = null;

        if (paramBlock.getNumSources() > 0) {
            sources = new Vector();
            int i = 0;
            while (i < paramBlock.getNumSources()) {
                Object o = paramBlock.getSource(i);
                if (o instanceof RenderableImage) {
                    sources.add((RenderableImage)o);
                    i++;
                } else {
                    break;
                }
            }
        }
        return sources;
    
public java.util.VectorgetSources()
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.

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

        return getRenderableSources();
    
public floatgetWidth()
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).

return
the width of the image in user coordinates.

        if (boundingBox == null) {
            boundingBox = myCRIF.getBounds2D(paramBlock);
        }
        return (float)boundingBox.getWidth();
    
public booleanisDynamic()
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.

return
true if successive renderings with the same arguments might produce different results; false otherwise.

        return myCRIF.isDynamic();
    
public java.awt.image.renderable.ParameterBlocksetParameterBlock(java.awt.image.renderable.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.

param
paramBlock the new ParameterBlock.
return
the old ParameterBlock.
see
#getParameterBlock

        ParameterBlock oldParamBlock = this.paramBlock;
        this.paramBlock = (ParameterBlock)paramBlock.clone();
        return oldParamBlock;