compute Bitmap Sample Size - Android Graphics

Android examples for Graphics:Bitmap Size

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Description

compute Bitmap Sample Size

Demo Code

import android.graphics.BitmapFactory;

public class Main {
  public static int computeSampleSize(BitmapFactory.Options options, int minSideLength, int maxNumOfPixels) {
    int initialSize = computeInitialSampleSize(options, minSideLength, maxNumOfPixels);

    int roundedSize;
    if (initialSize <= 8) {
      roundedSize = 1;/*  ww  w .j a v a  2s. c o m*/
      while (roundedSize < initialSize) {
        roundedSize <<= 1;
      }
    } else {
      roundedSize = (initialSize + 7) / 8 * 8;
    }

    return roundedSize;
  }

  private static int computeInitialSampleSize(BitmapFactory.Options options, int minSideLength, int maxNumOfPixels) {
    double w = options.outWidth;
    double h = options.outHeight;

    int lowerBound = (maxNumOfPixels < 0) ? 1 : (int) Math.ceil(Math.sqrt(w * h / maxNumOfPixels));
    int upperBound = (minSideLength < 0) ? 128
        : (int) Math.min(Math.floor(w / minSideLength), Math.floor(h / minSideLength));

    if (upperBound < lowerBound) {
      // return the larger one when there is no overlapping zone.
      return lowerBound;
    }

    if (maxNumOfPixels < 0 && minSideLength < 0) {
      return 1;
    } else if (minSideLength < 0) {
      return lowerBound;
    } else {
      return upperBound;
    }
  }
}

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