I have a problem and can not solve in my application. The application performs operations on images like PNG, the image is convert in a byte array , then a piece from this array of bytes is performed on bitwise operations , the problem is the new series of new bitmap format byte is always null. I just do not understand why the new bitmap, from new array byte, is always null and not know how to fix it this bug.
// GetByte method from Image
private byte[] getByteImageData(String filePath) {
/*
Bitmap bitmap = BitmapFactory.decodeFile(filePath);
Bitmap mutable = bitmap.copy(Bitmap.Config.RGB_565, true);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
mutable.compress(Bitmap.CompressFormat.PNG, 100, baos);
return baos.toByteArray();
*/
byte[] _imagebytedata = new byte[1024];
InputStream _input = null;
try {
if (filePath != null && (filePath.length() > 0)) {
// Create a file for image
File _fileimage = new File(filePath);
if (_fileimage.exists()) {
// Get the byte from file image
_input = new BufferedInputStream(new FileInputStream(
_fileimage));
_imagebytedata = new byte[(int) _fileimage.length()];
_input.read(_imagebytedata, 0, (int) _fileimage.length());
_input.close();
}
}
} catch (Exception e) {
}
// Bitwise operations
private byte[] Text(byte[] imagedata, byte[] textmess, int offset) {
for (int i = 0; i < textmess.length; ++i) {
int add = textmess[i];
for (int bit = 7; bit >= 0; --bit, ++offset) {
int b = (add >>> bit) & 1;
imagedata[offset] = (byte) ((imagedata[offset] & 0xFE) |b);
}
}
return imagedata;
}
//Save image from new byte array
private boolean saveImage(String pathFile,byte[] encodedimage) {
OutputStream _output = null;
File _newFileImage = new File(pathFile);
byte[] _encodedimage = encodedimage;
//Bitmap _imagebitmap = BitmapFactory.decodeByteArray(encodedimage, 0, encodedimage.length);
if (_newFileImage.exists()) {
try {
_output = new BufferedOutputStream(new FileOutputStream(
_newFileImage));
_output.write(_encodedimage, 0, _encodedimage.length);
_output.flush();
_output.close();
return true;
} catch (Exception e) {
}
;
}// _newFileImage.exists()
return false;
}
public boolean encodeTextInFile(String filepath, String text) {
byte[] _newimagebytedata;
byte[] _imagebytedata = getByteImageData(filepath);
byte[] _textbytedata = text.getBytes();
byte[] _lengthbytedata = byteConversion(text.length());
Bitmap _bitmapunu = BitmapFactory.decodeByteArray(_imagebytedata, 0, _imagebytedata.length);
_newimagebytedata = Text(_imagebytedata, _lengthbytedata, 33);
Bitmap _bitmapdoi = BitmapFactory.decodeByteArray(_newimagebytedata, 0, _newimagebytedata.length);
// The value of variable _bitmapdoi is null
_newimagebytedata = Text(_imagebytedata, _textbytedata, 65);
return saveImage(filepath, _newimagebytedata);
}
It looks as if you are trying to encode a text message in the lower bits of the image (if I understand your code correctly). I actually used this as a christmas card for fellow geeks this year.
ReplyDeleteHowever, when you create Text you encode the text into the byte[] of the image file thus probably destroying the image (unless you are very lucky). You probably want your addition of the text bytes to be on the decoded image (Bitmap _bitmapunu).
The javadoc for Bitmap.decodeByteArray says that it will return null if the image can not be decoded.
This is what you need to do:
Read the image bytes from the file, say fileArray.
Decode the fileArray into actual pixels, imageArray
Manipulate the pixels in imageArray
Encode the pixels into a image format again (such as png), say newFileArray.
Store the newFileArray to a file.
What you seem to be doing is trying to manipulate the bytes in fileArray directly, thus breaking the file format and making it impossible to decode the bytes into pixels.