org.apache.pdfbox.pdmodel.graphics.xobject
Class CompositeImage

java.lang.Object
  org.apache.pdfbox.pdmodel.graphics.xobject.CompositeImage

public class CompositeImage
extends Object

This class is responsible for combining a base image with an SMask-based transparency image to form a composite image. See section 11.5 of the pdf specification for details on Soft Masks.

Briefly however, an Smask is a supplementary greyscale image whose RGB-values define a transparency mask which, when combined appropriately with the base image, allows per-pixel transparency to be applied.

Note that Smasks are not required for any image and if the smask is not present in the pdf file, the image will have no transparent pixels.

Author:

Neil McErlean

Constructor Summary

CompositeImage(BufferedImage baseImage, BufferedImage smaskImage)
Standard constructor.

Method Summary

BufferedImage

createMaskedImage(COSArray decodeArray) This method applies the specified transparency mask to a given image and returns a new BufferedImage whose alpha values are computed from the transparency mask (smask) image.

Methods inherited from class java.lang.Object

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

Constructor Detail

CompositeImage

public CompositeImage(BufferedImage baseImage,
                      BufferedImage smaskImage)

Standard constructor.

Parameters:

baseImage - the base Image.

smaskImage - the transparency image.

Method Detail

createMaskedImage

public BufferedImage createMaskedImage(COSArray decodeArray)
                                throws IOException

This method applies the specified transparency mask to a given image and returns a new BufferedImage whose alpha values are computed from the transparency mask (smask) image.

Throws:

IOException