I am wanting to convert any file to a PNG and also reverse the process, all in Java.
I want to use an int-RGB form for the image, and have bytes from the file be a byte in the RGB integer. This should produce an image.
I've gotten this to work by only storing the bytes in the red color, but I can't figure out how to also use green and blue.
This is the code I use at the moment, which only uses red, and it works fine:
public static void fileToImage(String sourceFile, String imageFile) throws IOException {
DataInputStream dis = new DataInputStream(new FileInputStream(sourceFile));
int size = ((int) Math.sqrt(dis.available())) + 2;
BufferedImage image = new BufferedImage(size,size, BufferedImage.TYPE_INT_RGB);
for (int y = 0; y < size; y++) {
for (int x = 0; x < size; x++) {
int red = dis.read(); // I'm using only red
int green = 0; // default
int blue = 0; // default
int rgb = (0xFF << 24) | ((red & 0xFF) << 16) | ((green & 0xFF) << 8) | (blue & 0xFF);
image.setRGB(x, y, rgb);
}
}
dis.close();
ImageIO.write(image, "png", new File(imageFile));
}
public static void imageToFile(String imageFile, String outputFile) throws IOException {
BufferedImage image = ImageIO.read(new File(imageFile));
DataOutputStream dos = new DataOutputStream(new FileOutputStream(outputFile));
for (int y = 0; y < image.getHeight(); y++) {
for (int x = 0; x < image.getWidth(); x++) {
int rgb = image.getRGB(x, y);
int red = (rgb >> 16) & 0xFF;
int green = (rgb >> 8) & 0xFF;
int blue = rgb & 0xFF;
dos.write(red); // I'm using only red
}
}
dos.close();
}
EDIT: Okay, so I have modified the code, here it is:
public static void fileToImage(String sourceFile, String imageFile) throws IOException {
DataInputStream dis = new DataInputStream(new FileInputStream(sourceFile));
int size = ((int) Math.sqrt(dis.available())) + 2;
BufferedImage image = new BufferedImage(size,size, BufferedImage.TYPE_INT_RGB);
for (int y = 0; y < size; y++) {
for (int x = 0; x < size; x++) {
int red = dis.read();
int green = dis.read();
int blue = dis.read();
int rgb = (0xFF << 24) | ((red & 0xFF) << 16) | ((green & 0xFF) << 8) | (blue & 0xFF);
image.setRGB(x, y, rgb);
}
}
dis.close();
ImageIO.write(image, "png", new File(imageFile));
}
public static void imageToFile(String imageFile, String outputFile) throws IOException {
BufferedImage image = ImageIO.read(new File(imageFile));
DataOutputStream dos = new DataOutputStream(new FileOutputStream(outputFile));
for (int y = 0; y < image.getHeight(); y++) {
for (int x = 0; x < image.getWidth(); x++) {
int rgb = image.getRGB(x, y);
int red = (rgb >> 16) & 0xFF;
int green = (rgb >> 8) & 0xFF;
int blue = rgb & 0xFF;
dos.write(red);
dos.write(green);
dos.write(blue);
}
}
dos.close();
}
This does "work", but not exactly as expected. There's a whole lot of black space in the produced PNG, because I believe the "size" of the image is wrong. Because of this, when translating the PNG back into the original file, it becomes much larger than originally.
EDIT: The issue I am now having is this: For example, if I turn a text file with the following content to a PNG using the fileToImage method: hello world! Then I use imageToFile to convert it back, the output is: hello world!SSSSSSSSSSSSSSS (S stands for "space", there are 15)
EDIT: Still can't figure this out. Here's what I'm using:
private static final int NAN = -1;
private static int readByte(DataInputStream dis) throws IOException {
int b;
try {
b = dis.readByte();
} catch (EOFException e) {
b = NAN;
}
return b;
}
public static void fileToImage(String sourceFile, String imageFile) throws IOException {
DataInputStream dis = new DataInputStream(new FileInputStream(sourceFile));
int size = ((int) Math.sqrt(dis.available())) + 2;
BufferedImage image = new BufferedImage(size, size, BufferedImage.TYPE_INT_RGB);
for (int y = 0; y < size; y++) {
boolean finished = false;
for (int x = 0; x < size; x++) {
int alpha = 3;
int red = readByte(dis);
int green = readByte(dis);
int blue = readByte(dis);
if (red == NAN) {
alpha--;
red = 0;
}
if (green == NAN) {
alpha--;
green = 0;
}
if (blue == NAN) {
alpha--;
blue = 0;
}
int rgb = ((alpha & 0xFF) << 24) | ((red & 0xFF) << 16) | ((green & 0xFF) << 8) | (blue & 0xFF);
image.setRGB(x, y, rgb);
if (alpha < 3) {
finished = true;
break;
}
}
if (finished) break;
}
dis.close();
ImageIO.write(image, "png", new File(imageFile));
}
public static void imageToFile(String imageFile, String outputFile) throws IOException {
BufferedImage image = ImageIO.read(new File(imageFile));
DataOutputStream dos = new DataOutputStream(new FileOutputStream(outputFile));
for (int y = 0; y < image.getHeight(); y++) {
boolean finished = false;
for (int x = 0; x < image.getWidth(); x++) {
int rgb = image.getRGB(x, y);
int alpha = (rgb >> 24) & 0xFF;
int red = (rgb >> 16) & 0xFF;
int green = (rgb >> 8) & 0xFF;
int blue = rgb & 0xFF;
if (alpha == 0) {
finished = true;
break;
}
if (alpha >= 1) dos.write(red);
if (alpha >= 2) dos.write(green);
if (alpha == 3) dos.write(blue);
}
if (finished) break;
}
dos.close();
}
I think you just need to adjust the inner loops slightly. A small helper method will make this thing easier to use, thought I'm sure my sketch is a bit ugly:
int myReadByte(DataInputStream dis) {
int b;
try {
b = dis.readByte():
} catch (EOFException e) {
b = 0;
}
return b;
}
Now with this helper...
for (int x = 0; x < size; x++) {
int red = myReadByte(dis);
int green = myReadByte(dis);
int blue = myReadByte(dis);
int rgb = (0xFF << 24) | ((red & 0xFF) << 16) | ((green & 0xFF) << 8) | (blue & 0xFF);
image.setRGB(x, y, rgb);
and
for (int x = 0; x < image.getWidth(); x++) {
int rgb = image.getRGB(x, y);
int red = (rgb >> 16) & 0xFF;
int green = (rgb >> 8) & 0xFF;
int blue = rgb & 0xFF;
dos.write(red);
dos.write(green);
dos.write(blue);
}