AnimatedDrawableUtil.java

/*
 * Copyright (c) 2015-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 */

package com.facebook.imagepipeline.animated.util;

import java.util.Arrays;

import android.annotation.SuppressLint;
import android.graphics.Bitmap;
import android.os.Build;

import com.facebook.imagepipeline.animated.base.AnimatedDrawable;

/**
 * Utility methods for {@link AnimatedDrawable}.
 */
public class AnimatedDrawableUtil {

  // See comment in fixFrameDurations below.
  private static final int MIN_FRAME_DURATION_MS = 11;
  private static final int FRAME_DURATION_MS_FOR_MIN = 100;

  public void appendMemoryString(StringBuilder sb, int bytes) {
    int kbUsed = bytes / 1024;
    if (kbUsed < 1024) {
      sb.append(kbUsed);
      sb.append("KB");
    } else {
      int mbUsed = kbUsed / 1024;
      int mbUsedDecimal = (kbUsed % 1024) / 100;
      sb.append(mbUsed);
      sb.append(".");
      sb.append(mbUsedDecimal);
      sb.append("MB");
    }
  }

  /**
   * Adjusts the frame duration array to respect logic for minimum frame duration time.
   *
   * @param frameDurationMs the frame duration array
   */
  public void fixFrameDurations(int[] frameDurationMs) {
    // We follow Chrome's behavior which comes from Firefox.
    // Comment from Chrome's ImageSource.cpp follows:
    // We follow Firefox's behavior and use a duration of 100 ms for any frames that specify
    // a duration of <= 10 ms. See <rdar://problem/7689300> and <http://webkit.org/b/36082>
    // for more information.
    for (int i = 0; i < frameDurationMs.length; i++) {
      if (frameDurationMs[i] < MIN_FRAME_DURATION_MS) {
        frameDurationMs[i] = FRAME_DURATION_MS_FOR_MIN;
      }
    }
  }

  /**
   * Gets the total duration of an image by summing up the duration of the frames.
   *
   * @param frameDurationMs the frame duration array
   * @return the total duration in milliseconds
   */
  public int getTotalDurationFromFrameDurations(int[] frameDurationMs) {
    int totalMs = 0;
    for (int i = 0; i < frameDurationMs.length; i++) {
      totalMs += frameDurationMs[i];
    }
    return totalMs;
  }

  /**
   * Given an array of frame durations, generate an array of timestamps corresponding to when each
   * frame beings.
   *
   * @param frameDurationsMs an array of frame durations
   * @return an array of timestamps
   */
  public int[] getFrameTimeStampsFromDurations(int[] frameDurationsMs) {
    int[] frameTimestampsMs = new int[frameDurationsMs.length];
    int accumulatedDurationMs = 0;
    for (int i = 0; i < frameDurationsMs.length; i++) {
      frameTimestampsMs[i] = accumulatedDurationMs;
      accumulatedDurationMs += frameDurationsMs[i];
    }
    return frameTimestampsMs;
  }

  /**
   * Gets the frame index for specified timestamp.
   *
   * @param frameTimestampsMs an array of timestamps generated by {@link #getFrameForTimestampMs)}
   * @param timestampMs the timestamp
   * @return the frame index for the timestamp or the last frame number if the timestamp is outside
   *    the duration of the entire animation
   */
  public int getFrameForTimestampMs(int frameTimestampsMs[], int timestampMs) {
    int index = Arrays.binarySearch(frameTimestampsMs, timestampMs);
    if (index < 0) {
      return -index - 1 - 1;
    } else {
      return index;
    }
  }

  @SuppressLint("NewApi")
  public int getSizeOfBitmap(Bitmap bitmap) {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
      return bitmap.getAllocationByteCount();
    } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB_MR1) {
      return bitmap.getByteCount();
    } else {
      // Estimate for earlier platforms.
      return bitmap.getWidth() * bitmap.getHeight() * 4;
    }
  }

  /**
   * Checks whether the specified frame number is outside the range inclusive of both start and end.
   * If start <= end, start is within, end is within, and everything in between is within.
   * If start > end, start is within, end is within, everything less than start is within and
   * everything greater than end is within. This behavior is useful for handling the wrapping case.
   *
   * @param startFrame the start frame
   * @param endFrame the end frame
   * @param frameNumber the frame number
   * @return whether the frame is outside the range of [start, end]
   */
  public static boolean isOutsideRange(int startFrame, int endFrame, int frameNumber) {
    if (startFrame == -1 || endFrame == -1) {
      // This means nothing should pass.
      return true;
    }
    boolean outsideRange;
    if (startFrame <= endFrame) {
      outsideRange = frameNumber < startFrame || frameNumber > endFrame;
    } else {
      // Wrapping
      outsideRange = frameNumber < startFrame && frameNumber > endFrame;
    }
    return outsideRange;
  }
}