NinePatchData.java 文件源码

/**
 * Attempts to decode 9-patch data from a {@link Bitmap}.
 * @param bitmap The {@link Bitmap} to check.
 * @return       An instance of {@link NinePatchData} representing the 9-patch information
 *               encoded in {@code bitmap} or {@code null} if the {@link Bitmap} wasn't a
 *               9-patch.
 */
public static NinePatchData create(Bitmap bitmap) {
    if (bitmap == null) return null;

    try {
        byte[] chunk = bitmap.getNinePatchChunk();
        if (chunk == null || !NinePatch.isNinePatchChunk(chunk)) return null;

        ByteBuffer buffer = ByteBuffer.wrap(chunk).order(ByteOrder.nativeOrder());

        // int8_t wasDeserialized
        if (buffer.get() == 0) return null;

        // int8_t numXDivs
        int numDivX = buffer.get();
        if (numDivX == 0 || (numDivX & 0x01) != 0) return null;

        // int8_t numYDivs
        int numDivY = buffer.get();
        if (numDivY == 0 || (numDivY & 0x01) != 0) return null;

        // int8_t numColors
        buffer.get();

        // uint32_t xDivsOffset
        buffer.getInt();

        // uint32_t yDivsOffset
        buffer.getInt();

        Rect padding = new Rect();

        // uint32_t paddingLeft
        padding.left = buffer.getInt();

        // uint32_t paddingRight
        padding.right = buffer.getInt();

        // uint32_t paddingTop
        padding.top = buffer.getInt();

        // uint32_t paddingBottom
        padding.bottom = buffer.getInt();

        // uint32_t colorsOffset
        buffer.getInt();

        // uint32_t uint32_t uint32_t ...
        int[] divX = new int[numDivX];
        for (int i = 0; i < numDivX; i++) divX[i] = buffer.getInt();

        // uint32_t uint32_t uint32_t ...
        int[] divY = new int[numDivY];
        for (int i = 0; i < numDivY; i++) divY[i] = buffer.getInt();

        return new NinePatchData(bitmap.getWidth(), bitmap.getHeight(), padding, divX, divY);
    } catch (BufferUnderflowException ex) {
        return null;
    }
}