Example usage for javax.imageio ImageWriteParam getSourceXSubsampling

Introduction

In this page you can find the example usage for javax.imageio ImageWriteParam getSourceXSubsampling.

Prototype

public int getSourceXSubsampling() 

Source Link

Document

Returns the number of source columns to advance for each pixel.

Usage

From source file:ch5ImageWriter.java

/**
 * write out the output image specified by index imageIndex using the
 * parameters specified by the ImageWriteParam object param
 *///from ww w  . jav  a 2  s  . c o  m
public void write(IIOMetadata metadata, IIOImage iioimage, ImageWriteParam param) {
    Node root = null;
    Node dimensionsElementNode = null;

    if (iioimage.getRenderedImage() != null)
        raster = iioimage.getRenderedImage().getData();
    else
        raster = iioimage.getRaster();

    /*
     * since this format allows you to write multiple images, the
     * streamMetadataWritten variable makes sure the stream metadata is
     * written only once
     */
    if (streamMetadataWritten == false) {
        if (metadata == null)
            metadata = getDefaultStreamMetadata(param);
        root = metadata.getAsTree("ch5.imageio.ch5stream_1.00");
        dimensionsElementNode = root.getFirstChild();
        Node numberImagesAttributeNode = dimensionsElementNode.getAttributes().getNamedItem("numberImages");
        String numberImages = numberImagesAttributeNode.getNodeValue();
        try {
            ios.writeBytes("5\n");
            ios.writeBytes(numberImages);
            ios.flush();
        } catch (IOException ioe) {
            System.err.println("IOException " + ioe.getMessage());
        }
        streamMetadataWritten = true;
    }

    String widthString;
    String heightString;
    IIOMetadata imageMetadata = (ch5ImageMetadata) iioimage.getMetadata();
    /*
     * don't really need image metadata object here since raster knows
     * necessary information
     */
    if (imageMetadata == null)
        imageMetadata = getDefaultImageMetadata(null, param);

    root = imageMetadata.getAsTree("ch5.imageio.ch5image_1.00");
    dimensionsElementNode = root.getFirstChild();

    Node widthAttributeNode = dimensionsElementNode.getAttributes().getNamedItem("imageWidth");
    widthString = widthAttributeNode.getNodeValue();

    Node heightAttributeNode = dimensionsElementNode.getAttributes().getNamedItem("imageHeight");
    heightString = heightAttributeNode.getNodeValue();

    int sourceWidth = Integer.parseInt(widthString);
    int sourceHeight = Integer.parseInt(heightString);
    int destinationWidth = -1;
    int destinationHeight = -1;
    int sourceRegionWidth = -1;
    int sourceRegionHeight = -1;
    int sourceRegionXOffset = -1;
    int sourceRegionYOffset = -1;
    int xSubsamplingFactor = -1;
    int ySubsamplingFactor = -1;

    if (param == null)
        param = getDefaultWriteParam();

    /*
     * get Rectangle object which will be used to clip the source image's
     * dimensions.
     */
    Rectangle sourceRegion = param.getSourceRegion();
    if (sourceRegion != null) {
        sourceRegionWidth = (int) sourceRegion.getWidth();
        sourceRegionHeight = (int) sourceRegion.getHeight();
        sourceRegionXOffset = (int) sourceRegion.getX();
        sourceRegionYOffset = (int) sourceRegion.getY();

        /*
         * correct for overextended source regions
         */
        if (sourceRegionXOffset + sourceRegionWidth > sourceWidth)
            destinationWidth = sourceWidth - sourceRegionXOffset;
        else
            destinationWidth = sourceRegionWidth;

        if (sourceRegionYOffset + sourceRegionHeight > sourceHeight)
            destinationHeight = sourceHeight - sourceRegionYOffset;
        else
            destinationHeight = sourceRegionHeight;
    } else {
        destinationWidth = sourceWidth;
        destinationHeight = sourceHeight;
        sourceRegionXOffset = sourceRegionYOffset = 0;
    }
    /*
     * get subsampling factors
     */
    xSubsamplingFactor = param.getSourceXSubsampling();
    ySubsamplingFactor = param.getSourceYSubsampling();

    destinationWidth = (destinationWidth - 1) / xSubsamplingFactor + 1;
    destinationHeight = (destinationHeight - 1) / ySubsamplingFactor + 1;

    byte[] sourceBuffer;
    byte[] destinationBuffer = new byte[destinationWidth];

    try {
        ios.writeBytes(new String("\n"));
        ios.writeBytes(new String(destinationWidth + "\n"));
        ios.writeBytes(new String(destinationHeight + "\n"));

        int jj;
        int index;
        for (int j = 0; j < sourceWidth; j++) {
            sourceBuffer = (byte[]) raster.getDataElements(0, j, sourceWidth, 1, null);
            jj = j - sourceRegionYOffset;
            if (jj % ySubsamplingFactor == 0) {
                jj /= ySubsamplingFactor;
                if ((jj >= 0) && (jj < destinationHeight)) {
                    for (int i = 0; i < destinationWidth; i++) {
                        index = sourceRegionXOffset + i * xSubsamplingFactor;
                        destinationBuffer[i] = sourceBuffer[index];
                    }
                    ios.write(destinationBuffer, 0, destinationWidth);
                    ios.flush();
                }
            }
        }
    } catch (IOException e) {
        System.err.println("IOException: " + e.getMessage());
    }
}

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