Android Open Source - AndroidCameraUtil Bitmap Helper

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Back to project page AndroidCameraUtil.

License

The source code is released under:

Apache License

Java Source Code

package de.ecotastic.android.camerautil.util;
//from   w ww  .  ja v  a  2  s  .  c  om
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;

import android.content.Context;
import android.content.Intent;
import android.content.res.AssetFileDescriptor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.net.Uri;
import android.os.Environment;

/**
 * A helper class to conveniently alter Bitmap data
 * 
 * @author Ralf Gehrer <ralf@ecotastic.de>
 */
public class BitmapHelper {

  /**
     * Converts a Bitmap to a byteArray.
     * @param Bitmap
     * @return byteArray
     */
    public static byte[] bitmapToByteArray(Bitmap bitmap) {
        ByteArrayOutputStream stream = new ByteArrayOutputStream();
        bitmap.compress(Bitmap.CompressFormat.PNG, 100, stream);
        return stream.toByteArray();
    }

    /**
     * Converts a byteArray to a Bitmap object
     * @param byteArray
     * @return Bitmap
     */
    public static Bitmap byteArrayToBitmap(byte[] byteArray) {
        if (byteArray == null) {
            return null;
        } else {
            return BitmapFactory.decodeByteArray(byteArray, 0, byteArray.length);
        }
    }

    /**
     * Shrinks and a passed Bitmap.
     * 
     * @param bm
     * @param maxLengthOfEdge
     * @return Bitmap
     */
    public static Bitmap shrinkBitmap(Bitmap bm, int maxLengthOfEdge) {
        return shrinkBitmap(bm, maxLengthOfEdge, 0);
    }

    /**
     * Shrinks and rotates (if necessary) a passed Bitmap.
     * 
     * @param bm
     * @param maxLengthOfEdge
     * @param rotateXDegree
     * @return Bitmap
     */
    public static Bitmap shrinkBitmap(Bitmap bm, int maxLengthOfEdge, int rotateXDegree) {
        if (maxLengthOfEdge > bm.getWidth() && maxLengthOfEdge > bm.getHeight()) {
            return bm;
        } else {
            // shrink image
            float scale = (float) 1.0;
            if (bm.getHeight() > bm.getWidth()) {
                scale = ((float) maxLengthOfEdge) / bm.getHeight();
            } else {
                scale = ((float) maxLengthOfEdge) / bm.getWidth();
            }
            // CREATE A MATRIX FOR THE MANIPULATION
            Matrix matrix = new Matrix();
            // RESIZE THE BIT MAP
            matrix.postScale(scale, scale);
            matrix.postRotate(rotateXDegree);

            // RECREATE THE NEW BITMAP
            bm = Bitmap.createBitmap(bm, 0, 0, bm.getWidth(), bm.getHeight(),
                    matrix, false);

            matrix = null;
            System.gc();

            return bm;
        }
    }

    /**
     * Reads a Bitmap from an Uri.
     * 
     * @param context
     * @param selectedImage
     * @return Bitmap
     */
    public static Bitmap readBitmap(Context context, Uri selectedImage) {
        Bitmap bm = null;
        BitmapFactory.Options options = new BitmapFactory.Options();
        options.inPreferredConfig = Bitmap.Config.RGB_565;
        options.inScaled = false;
//      options.inSampleSize = 3;
        AssetFileDescriptor fileDescriptor = null;
        try {
            fileDescriptor = context.getContentResolver().openAssetFileDescriptor(selectedImage, "r");
        } catch (FileNotFoundException e) {
            return null;
        } finally {
            try {
                bm = BitmapFactory.decodeFileDescriptor(
                        fileDescriptor.getFileDescriptor(), null, options);
                fileDescriptor.close();
            } catch (IOException e) {
                return null;
            }
        }
        return bm;
    }

    /**
     * Clears all Bitmap data, that is, recycles the Bitmap and 
     * triggers the garbage collection.
     * 
     * @param bm
     */
    public static void clearBitmap(Bitmap bm) {
        bm.recycle();
        System.gc();
    }  
    
    
    /**
     * Deletes an image given its Uri and refreshes the gallery thumbnails.
     * @param cameraPicUri
     * @param context
     * @return true if it was deleted successfully, false otherwise.
     */
  public static boolean deleteImageWithUriIfExists(Uri cameraPicUri, Context context) {
    try {
      if (cameraPicUri != null) {
        File fdelete = new File(cameraPicUri.getPath());
            if (fdelete.exists()) {
                if (fdelete.delete()) {
                  refreshGalleryImages(context, fdelete);
                  return true;
                }
            }  
      }
    } catch (Exception e) {
    }
    return false;
  }

  /**
   * Forces the Android gallery to  refresh its thumbnail images.
   * @param context
   * @param fdelete
   */
  private static void refreshGalleryImages(Context context, File fdelete) {
    try {
        context.sendBroadcast(new Intent(Intent.ACTION_MEDIA_MOUNTED, Uri.parse("file://" +  Environment.getExternalStorageDirectory())));
      } catch (Exception e1) {
        try {
            Intent mediaScanIntent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
              Uri contentUri = Uri.fromFile(fdelete);
              mediaScanIntent.setData(contentUri);
              context.sendBroadcast(mediaScanIntent);
        } catch (Exception e2) {
        }
      }    
  }
}

Java Source Code List

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