Hello, I would like to know how to convert an image that is on my memory card into hexadecimal.
I have an application that prints a receipt through a thermal printer, it prints some information like date, time, name, value, etc.
And I need in the header to print the company logo.
The printer I use to print for it to understand the image and to be able to print it the image must be in hexadecimal format.
First you must convert it to an array of bytes, then convert this byte array to hex.
Make sure this function helps you:
final protected static char[] hexArray = "0123456789ABCDEF".toCharArray();
public static String bytesToHex(byte[] bytes) {
char[] hexChars = new char[bytes.length * 2];
for ( int j = 0; j < bytes.length; j++ ) {
int v = bytes[j] & 0xFF;
hexChars[j * 2] = hexArray[v >>> 4];
hexChars[j * 2 + 1] = hexArray[v & 0x0F];
}
return new String(hexChars);
}
Check the discussion here
First you should read the file (image) and convert it to an array of bytes:
public byte[] ler_ficheiro(String path)
{
File file = new File(path);
if (file.exists())
{
FileInputStream fis = new FileInputStream(file);
byte[] data = new byte[(int) file.length()];
fis.read(data);
fis.close();
return data;
} else
{
return null;
}
}
Then convert this byte array to hex.
private String bytesToHex(byte[] bytes)
{
StringBuffer sb = new StringBuffer();
for (byte b : bytes)
{
sb.append(String.format("%02X", b));
}
return sb.toString();
}
In summary you should proceed to these steps:
String imagem=...;
byte[] imagem_byte=ler_ficheiro(imagem);
if(imagem_byte!=null)
{
String imagem_hex=bytesToHex(imagem_byte);
}