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Hello, I wonder how to convert an image that is on my memory card in 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 out so she can understand the image and print it out needs to be in hexadecimal format.
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First you must convert it to an array of bytes, then convert that array of bytes to hexadecimal.
Check if 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
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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 that byte array to hexadecimal.
private String bytesToHex(byte[] bytes)
{
StringBuffer sb = new StringBuffer();
for (byte b : bytes)
{
sb.append(String.format("%02X", b));
}
return sb.toString();
}
In short you should proceed to these steps:
String imagem=...;
byte[] imagem_byte=ler_ficheiro(imagem);
if(imagem_byte!=null)
{
String imagem_hex=bytesToHex(imagem_byte);
}
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Look, there’s a gambit. If you have a project open in the Sublime Text 2 editor and in this project there is an image, if you click it, it shows the image Hex.
– dsantoro
Are you sure it needs to be sent in hexadecimal? You could add the relevant instruction in the printer manual (and/or model) to make the question more complete?
– Bacco