ImageUtils.java

/* Copyright 2015 Google Inc. All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
==============================================================================*/

package org.tensorflow.demo.env;

import android.graphics.Bitmap;
import android.os.Environment;

import java.io.File;
import java.io.FileOutputStream;

/**
 * Utility class for manipulating images.
 **/
public class ImageUtils {
  @SuppressWarnings("unused")
  private static final Logger LOGGER = new Logger();

  /**
   * Utility method to compute the allocated size in bytes of a YUV420SP image
   * of the given dimensions.
   */
  public static int getYUVByteSize(final int width, final int height) {
    // The luminance plane requires 1 byte per pixel.
    final int ySize = width * height;

    // The UV plane works on 2x2 blocks, so dimensions with odd size must be rounded up.
    // Each 2x2 block takes 2 bytes to encode, one each for U and V.
    final int uvSize = ((width + 1) / 2) * ((height + 1) / 2) * 2;

    return ySize + uvSize;
  }

  /**
   * Saves a Bitmap object to disk for analysis.
   *
   * @param bitmap The bitmap to save.
   */
  public static void saveBitmap(final Bitmap bitmap) {
    final String root =
        Environment.getExternalStorageDirectory().getAbsolutePath() + File.separator + "tensorflow";
    LOGGER.i("Saving %dx%d bitmap to %s.", bitmap.getWidth(), bitmap.getHeight(), root);
    final File myDir = new File(root);

    if (!myDir.mkdirs()) {
      LOGGER.i("Make dir failed");
    }

    final String fname = "preview.png";
    final File file = new File(myDir, fname);
    if (file.exists()) {
      file.delete();
    }
    try {
      final FileOutputStream out = new FileOutputStream(file);
      bitmap.compress(Bitmap.CompressFormat.PNG, 99, out);
      out.flush();
      out.close();
    } catch (final Exception e) {
      LOGGER.e(e, "Exception!");
    }
  }

  /**
   * Converts YUV420 semi-planar data to ARGB 8888 data using the supplied width
   * and height. The input and output must already be allocated and non-null.
   * For efficiency, no error checking is performed.
   *
   * @param input The array of YUV 4:2:0 input data.
   * @param output A pre-allocated array for the ARGB 8:8:8:8 output data.
   * @param width The width of the input image.
   * @param height The height of the input image.
   * @param halfSize If true, downsample to 50% in each dimension, otherwise not.
   */
  public static native void convertYUV420SPToARGB8888(
      byte[] input, int[] output, int width, int height, boolean halfSize);

  /**
   * Converts YUV420 semi-planar data to ARGB 8888 data using the supplied width
   * and height. The input and output must already be allocated and non-null.
   * For efficiency, no error checking is performed.
   *
   * @param y
   * @param u
   * @param v
   * @param uvPixelStride
   * @param width The width of the input image.
   * @param height The height of the input image.
   * @param halfSize If true, downsample to 50% in each dimension, otherwise not.
   * @param output A pre-allocated array for the ARGB 8:8:8:8 output data.
   */
  public static native void convertYUV420ToARGB8888(
      byte[] y,
      byte[] u,
      byte[] v,
      int[] output,
      int width,
      int height,
      int yRowStride,
      int uvRowStride,
      int uvPixelStride,
      boolean halfSize);

  /**
   * Converts YUV420 semi-planar data to RGB 565 data using the supplied width
   * and height. The input and output must already be allocated and non-null.
   * For efficiency, no error checking is performed.
   *
   * @param input The array of YUV 4:2:0 input data.
   * @param output A pre-allocated array for the RGB 5:6:5 output data.
   * @param width The width of the input image.
   * @param height The height of the input image.
   */
  public static native void convertYUV420SPToRGB565(
      byte[] input, byte[] output, int width, int height);

  /**
   * Converts 32-bit ARGB8888 image data to YUV420SP data.  This is useful, for
   * instance, in creating data to feed the classes that rely on raw camera
   * preview frames.
   *
   * @param input An array of input pixels in ARGB8888 format.
   * @param output A pre-allocated array for the YUV420SP output data.
   * @param width The width of the input image.
   * @param height The height of the input image.
   */
  public static native void convertARGB8888ToYUV420SP(
      int[] input, byte[] output, int width, int height);

  /**
   * Converts 16-bit RGB565 image data to YUV420SP data.  This is useful, for
   * instance, in creating data to feed the classes that rely on raw camera
   * preview frames.
   *
   * @param input An array of input pixels in RGB565 format.
   * @param output A pre-allocated array for the YUV420SP output data.
   * @param width The width of the input image.
   * @param height The height of the input image.
   */
  public static native void convertRGB565ToYUV420SP(
      byte[] input, byte[] output, int width, int height);
}