org.exoplatform.imageio.plugins.common
Class ReaderUtil

java.lang.Object
  org.exoplatform.imageio.plugins.common.ReaderUtil

public class ReaderUtil
extends Object

version: openjdk-7-ea-src-b35-11_sep_2008 This class contains utility methods that may be useful to ImageReader plugins. Ideally these methods would be in the ImageReader base class so that all subclasses could benefit from them, but that would be an addition to the existing API, and it is not yet clear whether these methods are universally useful, so for now we will leave them here.

Constructor Summary

ReaderUtil()

Method Summary

static int[]

computeUpdatedPixels(Rectangle sourceRegion, Point destinationOffset, int dstMinX, int dstMinY, int dstMaxX, int dstMaxY, int sourceXSubsampling, int sourceYSubsampling, int passXStart, int passYStart, int passWidth, int passHeight, int passPeriodX, int passPeriodY) A utility method that computes the exact set of destination pixels that will be written during a particular decoding pass.

Methods inherited from class java.lang.Object

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

Constructor Detail

ReaderUtil

public ReaderUtil()

Method Detail

computeUpdatedPixels

public static int[] computeUpdatedPixels(Rectangle sourceRegion,
                                         Point destinationOffset,
                                         int dstMinX,
                                         int dstMinY,
                                         int dstMaxX,
                                         int dstMaxY,
                                         int sourceXSubsampling,
                                         int sourceYSubsampling,
                                         int passXStart,
                                         int passYStart,
                                         int passWidth,
                                         int passHeight,
                                         int passPeriodX,
                                         int passPeriodY)

A utility method that computes the exact set of destination pixels that will be written during a particular decoding pass. The intent is to simplify the work done by readers in combining the source region, source subsampling, and destination offset information obtained from the ImageReadParam with the offsets and periods of a progressive or interlaced decoding pass.

Parameters:

sourceRegion - a Rectangle containing the source region being read, offset by the source subsampling offsets, and clipped against the source bounds, as returned by the getSourceRegion method.

destinationOffset - a Point containing the coordinates of the upper-left pixel to be written in the destination.

dstMinX - the smallest X coordinate (inclusive) of the destination Raster.

dstMinY - the smallest Y coordinate (inclusive) of the destination Raster.

dstMaxX - the largest X coordinate (inclusive) of the destination Raster.

dstMaxY - the largest Y coordinate (inclusive) of the destination Raster.

sourceXSubsampling - the X subsampling factor.

sourceYSubsampling - the Y subsampling factor.

passXStart - the smallest source X coordinate (inclusive) of the current progressive pass.

passYStart - the smallest source Y coordinate (inclusive) of the current progressive pass.

passWidth - the width in pixels of the current progressive pass.

passHeight - the height in pixels of the current progressive pass.

passPeriodX - the X period (horizontal spacing between pixels) of the current progressive pass.

passPeriodY - the Y period (vertical spacing between pixels) of the current progressive pass.

Returns:

an array of 6 ints containing the destination min X, min Y, width, height, X period and Y period of the region that will be updated.