imagedatafactory.java

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     *
     * <p>
     * The size of the returned image will be the size of the specified region
     * with the transform applied.  For example, if the region is
     * <code>100&nbsp;x&nbsp;50</code> pixels and the transform is
     * <code>TRANS_ROT90</code>, the
     * returned image will be <code>50&nbsp;x&nbsp;100</code> pixels.</p>
     *
     * <p><strong>Note:</strong> If all of the following conditions
     * are met, this method may
     * simply return the source <code>Image</code> without creating a
     * new one:</p>
     * <ul>
     * <li>the source image is immutable;</li>
     * <li>the region represents the entire source image; and</li>
     * <li>the transform is <code>TRANS_NONE</code>.</li>
     * </ul>
     *
     * @param dataSource the source image data to be copied from
     * @param x the horizontal location of the region to be copied
     * @param y the vertical location of the region to be copied
     * @param w the width of the region to be copied
     * @param h the height of the region to be copied
     * @param transform the transform to be applied to the region
     * @return the new, immutable image
     *
     * @throws NullPointerException if <code>image</code> is <code>null</code>
     * @throws IllegalArgumentException if the region to be copied exceeds
     * the bounds of the source image
     * @throws IllegalArgumentException if either <code>width</code> or
     * <code>height</code> is zero or less
     * @throws IllegalArgumentException if the <code>transform</code>
     * is not valid
     *
     */
    public ImageData createImmutableImageData(ImageData dataSource,
                                              int x, int y, int w, int h,
                                              int transform) {

        ImageData dataDest = null;

        if ((transform & Image.TRANSFORM_SWAP_AXIS) ==
            Image.TRANSFORM_SWAP_AXIS) {
            dataDest = new ImageData(h, w, false, false,
                                     dataSource.hasAlpha());
        } else {
            dataDest = new ImageData(w, h, false, false,
                                     dataSource.hasAlpha());
        }


        // Copy either the Java or romized data to its own array
        loadRegion(dataDest, dataSource, x, y, w, h, transform);

        return dataDest;
    }

    /**
     * Creates an immutable <code>ImageData</code>
     * from a sequence of ARGB values, specified
     * as <code>0xAARRGGBB</code>.
     * The ARGB data within the <code>rgb</code> array is arranged
     * horizontally from left to right within each row,
     * row by row from top to bottom.
     * If <code>processAlpha</code> is <code>true</code>,
     * the high-order byte specifies opacity; that is,
     * <code>0x00RRGGBB</code> specifies
     * a fully transparent pixel and <code>0xFFRRGGBB</code> specifies
     * a fully opaque
     * pixel.  Intermediate alpha values specify semitransparency.  If the
     * implementation does not support alpha blending for image rendering
     * operations, it must replace any semitransparent pixels with fully
     * transparent pixels.  (See <a href="#alpha">Alpha Processing</a>
     * for further discussion.)  If <code>processAlpha</code> is
     * <code>false</code>, the alpha values
     * are ignored and all pixels must be treated as fully opaque.
     *
     * <p>Consider <code>P(a,b)</code> to be the value of the pixel
     * located at column <code>a</code> and row <code>b</code> of the
     * Image, where rows and columns are numbered downward from the
     * top starting at zero, and columns are numbered rightward from
     * the left starting at zero. This operation can then be defined
     * as:</p>
     *
     * <TABLE BORDER="2">
     * <TR>
     * <TD ROWSPAN="1" COLSPAN="1">
     *    <pre><code>
     *    P(a, b) = rgb[a + b * width];    </code></pre>
     * </TD>
     * </TR>
     * </TABLE>
     * <p>for</p>
     *
     * <TABLE BORDER="2">
     * <TR>
     * <TD ROWSPAN="1" COLSPAN="1">
     *    <pre><code>
     *     0 &lt;= a &lt; width
     *     0 &lt;= b &lt; height    </code></pre>
     * </TD>
     * </TR>
     * </TABLE>
     * <p> </p>
     *
     * @param rgb an array of ARGB values that composes the image
     * @param width the width of the image
     * @param height the height of the image
     * @param processAlpha <code>true</code> if <code>rgb</code>
     * has an alpha channel,
     * <code>false</code> if all pixels are fully opaque
     * @return the created <code>ImageData</code>
     * @throws NullPointerException if <code>rgb</code> is <code>null</code>.
     * @throws IllegalArgumentException if either <code>width</code> or
     * <code>height</code> is zero or less
     * @throws ArrayIndexOutOfBoundsException if the length of
     * <code>rgb</code> is
     * less than<code> width&nbsp;*&nbsp;height</code>.
     *
     */
    public ImageData createImmutableImageData(int rgb[], int width, int height,
                                              boolean processAlpha) {
        ImageData data = new ImageData(width, height, false, false,
                                       processAlpha);
        loadRGB(data, rgb);

        return data;
    }

    /**
     * Function to decode an <code>ImageData</code> from romized data.
     *
     * @param imageDataArrayPtr native pointer to image data as Java int
     * @param imageDataArrayLength length of image data array
     * @return <code>ImageData</code> created from romized data.
     * @throws IllegalArgumentException if the id is invalid
     */
    public ImageData createImmutableImageData(int imageDataArrayPtr,
            int imageDataArrayLength) {

        ImageData data = new ImageData();
        if (!loadRomizedImage(data, imageDataArrayPtr,
                    imageDataArrayLength)) {
            throw new IllegalArgumentException();
        }
        return data;
    }

    /**
     * Creates an immutable image from decoded image data obtained from an
     * <code>InputStream</code>.  This method blocks until all image data has
     * been read and decoded.  After this method completes (whether by
     * returning or by throwing an exception) the stream is left open and its
     * current position is undefined.
     *
     * @param stream the name of the resource containing the image data
     * in one of the supported image formats
     *
     * @return the created image
     * @throws NullPointerException if <code>stream</code> is <code>null</code>
     * @throws java.io.IOException if an I/O error occurs, if the image data
     * cannot be loaded, or if the image data cannot be decoded
     *
     */
    public ImageData createImmutableImageData(InputStream stream)
        throws IOException {

        ImageData data = new ImageData();
        createImageFromStream(data, stream);
        return data;
    }

    /**
     * Populates an immutable <code>ImageData</code>
     * from decoded data obtained from an <code>InputStream</code>.
     * This method blocks until all image data has
     * been read and decoded.  After this method completes (whether by
     * returning or by throwing an exception) the stream is left open and its
     * current position is undefined.
     *
     * @param data The <code>ImageData</code> to be populated
     * @param stream the name of the resource containing the image data
     * in one of the supported image formats
     *
     * @throws NullPointerException if <code>stream</code> is <code>null</code>
     * @throws java.io.IOException if an I/O error occurs, if the image data
     * cannot be loaded, or if the image data cannot be decoded
     *
     */
    private void createImageFromStream(ImageData data, InputStream stream)
        throws java.io.IOException {

        if (stream == null) {
            throw new java.io.IOException();
        } else {
            /*
             * Allocate an array assuming available is correct.
             * Only reading an EOF is the real end of file
             * so allocate an extra byte to read the EOF into.
             * If available is incorrect, increase the buffer
             * size and keep reading.
             */
            int l = stream.available();
            byte[] buffer = new byte[l+1];
            int length = 0;

            // TBD: Guard against an implementation with incorrect available
            while ((l = stream.read(buffer, length, buffer.length-length))
                   != -1) {
                length += l;
                if (length == buffer.length) {
                    byte[] b = new byte[buffer.length + 4096];
                    System.arraycopy(buffer, 0, b, 0, length);
                    buffer = b;
                }
            }

            stream.close();

            try {
                decode(data, buffer, 0, length);
            } catch (IllegalArgumentException e) {
                throw new java.io.IOException();
            }
        }
    }

    /**
     * Load an <code>ImageData</code> from cache. The real work is done in
     * the native function.
     *
     * @param   imageData The <code>ImageData</code> to be populated
     * @param   resName  Image resource name
     * @return  true if image was loaded and created, false otherwise
     */
    private boolean loadCachedImage(ImageData imageData,
                                    String resName) {
        return imageCache.loadAndCreateImmutableImageData(imageData, 
                                                            resName);
    }

    /**
     * Function to decode an <code>ImageData</code> from PNG data.
     *
     * @param imageData the <code>ImageData</code> to be populated
     * @param imageBytes the array of image data in a supported image format
     * @param imageOffset the offset of the start of the data in the array
     * @param imageLength the length of the data in the array
     */
    private void decodePNG(ImageData imageData,
                           byte[] imageBytes,
                           int imageOffset, int imageLength) {
        // find the format of the image data
        if (imageLength < pngHeader.length + 8) {
            throw new IllegalArgumentException();