package org.imaginer.scol;

import android.graphics.ImageFormat;
import android.graphics.Rect;
import android.media.Image;
import java.nio.ByteBuffer;

abstract public class FormatConverter {
    public static byte[] YUV420toNV21(Image image, byte[] data)
    {
        Rect crop = image.getCropRect();
        int format = image.getFormat();
        int width = crop.width();
        int height = crop.height();
        Image.Plane[] planes = image.getPlanes();
        if (data == null)
            data = new byte[width * height * ImageFormat.getBitsPerPixel(format) / 8];

        byte[] rowData = new byte[planes[0].getRowStride()];

        int channelOffset = 0;
        int outputStride = 1;
        for (int i = 0; i < planes.length; i++)
        {
            switch (i)
            {
                case 0:
                    channelOffset = 0;
                    outputStride = 1;
                    break;
                case 1:
                    channelOffset = width * height + 1;
                    outputStride = 2;
                    break;
                case 2:
                    channelOffset = width * height;
                    outputStride = 2;
                    break;
            }

            ByteBuffer buffer = planes[i].getBuffer();
            int rowStride = planes[i].getRowStride();
            int pixelStride = planes[i].getPixelStride();

            int shift = (i == 0) ? 0 : 1;
            int w = width >> shift;
            int h = height >> shift;
            buffer.position(rowStride * (crop.top >> shift) + pixelStride * (crop.left >> shift));
            for (int row = 0; row < h; row++)
            {
                int length;
                if (pixelStride == 1 && outputStride == 1)
                {
                    length = w;
                    buffer.get(data, channelOffset, length);
                    channelOffset += length;
                }
                else
                {
                    length = (w - 1) * pixelStride + 1;
                    buffer.get(rowData, 0, length);
                    for (int col = 0; col < w; col++)
                    {
                        data[channelOffset] = rowData[col * pixelStride];
                        channelOffset += outputStride;
                    }
                }
                if (row < h - 1)
                    buffer.position(buffer.position() + rowStride - length);
            }
        }
        return data;
    }
}