I have an image captured by a camera, in RAW BGRA format (byte array).
How can I save it to disk, as a JPG/PNG file?
I've tried with ImageIO.write from Java API, but I got error IllegalArgumentException (image = null)
CODE:
try
{
InputStream input = new ByteArrayInputStream(img);
BufferedImage bImageFromConvert = ImageIO.read(input);
String path = "D:/image.jpg";
ImageIO.write(bImageFromConvert, "jpg", new File(path));
}
catch(Exception ex)
{
System.out.println(ex.toString());
}
Note that "img" is the RAW byte array, and that is NOT null.
The problem is that ImageIO.read does not support raw RGB (or BGRA in your case) pixels. It expects a file format, like BMP, PNG or JPEG, etc.
In your code above, this causes bImageFromConvert to become null, and this is the reason for the error you see.
If you have a byte array in BGRA format, try this:
// You need to know width/height of the image
int width = ...;
int height = ...;
int samplesPerPixel = 4;
int[] bandOffsets = {2, 1, 0, 3}; // BGRA order
byte[] bgraPixelData = new byte[width * height * samplesPerPixel];
DataBuffer buffer = new DataBufferByte(bgraPixelData, bgraPixelData.length);
WritableRaster raster = Raster.createInterleavedRaster(buffer, width, height, samplesPerPixel * width, samplesPerPixel, bandOffsets, null);
ColorModel colorModel = new ComponentColorModel(ColorSpace.getInstance(ColorSpace.CS_sRGB), true, false, Transparency.TRANSLUCENT, DataBuffer.TYPE_BYTE);
BufferedImage image = new BufferedImage(colorModel, raster, colorModel.isAlphaPremultiplied(), null);
System.out.println("image: " + image); // Should print: image: BufferedImage#<hash>: type = 0 ...
ImageIO.write(image, "PNG", new File(path));
Note that JPEG is not a good format for storing images with alpha channel. While it is possible, most software will not display it properly. So I suggest using PNG instead.
Alternatively, you could remove the alpha channel, and use JPEG.
With Matlab you can convert all types of images with 2 lines of code:
img=imread('example.CR2');
imwrite(img,'example.JPG');
Related
I have raw grayscale image pixels represented by short[]. I would like to create BufferedImage from it and save it as PNG.
Since there is no TYPE_SHORT_GRAY defined for BufferedImage I'm creating one myself this way:
short[] myRawImageData;
// Create signed 16 bit data buffer, and compatible sample model
DataBuffer dataBuffer = new DataBufferShort(myRawImageData, w * h);
SampleModel sampleModel = new ComponentSampleModel(DataBuffer.TYPE_SHORT, w, h, 1, w, new int[] {0});
// Create a raster from sample model and data buffer
WritableRaster raster = Raster.createWritableRaster(sampleModel, dataBuffer, null);
// Create a 16 bit signed gray color model
ColorSpace colorSpace = ColorSpace.getInstance(ColorSpace.CS_GRAY);
ColorModel colorModel = new ComponentColorModel(colorSpace, false, false, Transparency.OPAQUE, DataBuffer.TYPE_SHORT);
// Finally create the signed 16 bit image
BufferedImage image = new BufferedImage(colorModel, raster, colorModel.isAlphaPremultiplied(), null);
try (FileOutputStream fos = new FileOutputStream("/tmp/tst.png")) {
ImageIO.write(image, "png", fos);// <--- Here goes the exception
} catch (Exception ex) {
ex.printStackTrace();
}
So far so good but when I'm trying to use ImageIO.write to save it as PNG I'm getting ArrayIndexOutOfBoundsException.
Your code works fine for me, the only way I got your error was when I changed the bandOffsets. Could you give us more of your code?
EDIT
If you have negative data in your dataset, you should probably be using ushort instead of short.
int h = 64, w = 64;
short[] myRawImageData = new short[4096];
for (int i = 0; i < 4096; i++){
//this rolls over into negative numbers
myRawImageData[i] = (short) (i * 14);
}
// Create signed 16 bit data buffer, and compatible sample model
DataBuffer dataBuffer = new DataBufferUShort(myRawImageData, w * h);
SampleModel sampleModel = new ComponentSampleModel(DataBuffer.TYPE_USHORT, w, h, 1, w, new int[] {0});
// Create a raster from sample model and data buffer
WritableRaster raster = Raster.createWritableRaster(sampleModel, dataBuffer, null);
// Create a 16 bit signed gray color model
ColorSpace colorSpace = ColorSpace.getInstance(ColorSpace.CS_GRAY);
ColorModel colorModel = new ComponentColorModel(colorSpace, false, false, Transparency.OPAQUE, DataBuffer.TYPE_USHORT);
// Finally create the signed 16 bit image
BufferedImage image = new BufferedImage(colorModel, raster, colorModel.isAlphaPremultiplied(), null);
try (FileOutputStream fos = new FileOutputStream("/tmp/tst.png")) {
ImageIO.write(image, "png", fos);// <--- Here goes the exception
} catch (Exception ex) {
ex.printStackTrace();
}
This is assuming you expect negative values to be the brighter half of the gamut.
How can I save BufferedImage with TYPE_INT_ARGB to jpg?
Program generates me that image:
And it's OK, but when I save it in that way:
ByteArrayOutputStream byteStream = new ByteArrayOutputStream();
BufferedOutputStream bos = new BufferedOutputStream(byteStream);
try {
ImageIO.write(buffImg, "jpg", bos);
// argb
byteStream.flush();
byte[] newImage = byteStream.toByteArray();
OutputStream out = new BufferedOutputStream(new FileOutputStream("D:\\test.jpg"));
out.write(newImage);
out.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
The result is:
Understand that this is due to the alpha layer, but don't know how to fix it. Png format does not suit me, need jpg.
OK!
I've solved it.
Everything was pretty easy. Don't know is it a good decision and how fast it is. I have not found any other.
So.. everything we need is define new BufferedImage.
BufferedImage buffImg = new BufferedImage(getWidth(), getHeight(), BufferedImage.TYPE_INT_ARGB);
Graphics2D g2 = buffImg.createGraphics();
// ... other code we need
BufferedImage img= new BufferedImage(buffImg.getWidth(), buffImg.getHeight(), BufferedImage.TYPE_INT_RGB);
Graphics2D g2d = img.createGraphics();
g2d.drawImage(buffImg, 0, 0, null);
g2d.dispose();
If there any ideas to improve this method, please, your welcome.
Images having 4 color channels should not be written to a jpeg file. We can convert between ARGB and RGB images without duplicating pixel values. This comes in handy for large images. An example:
int a = 10_000;
BufferedImage im = new BufferedImage(a, a, BufferedImage.TYPE_INT_ARGB);
Graphics2D g = im.createGraphics();
g.setColor(Color.RED);
g.fillRect(a/10, a/10, a/5, a*8/10);
g.setColor(Color.GREEN);
g.fillRect(a*4/10, a/10, a/5, a*8/10);
g.setColor(Color.BLUE);
g.fillRect(a*7/10, a/10, a/5, a*8/10);
//preserve transparency in a png file
ImageIO.write(im, "png", new File("d:/rgba.png"));
//pitfall: in a jpeg file 4 channels will be interpreted as CMYK... this is no good
ImageIO.write(im, "jpg", new File("d:/nonsense.jpg"));
//we need a 3-channel BufferedImage to write an RGB-colored jpeg file
//we can make up a new image referencing part of the existing raster
WritableRaster ras = im.getRaster().createWritableChild(0, 0, a, a, 0, 0, new int[] {0, 1, 2}); //0=r, 1=g, 2=b, 3=alpha
ColorModel cm = new BufferedImage(1, 1, BufferedImage.TYPE_INT_RGB).getColorModel(); //we need a proper ColorModel
BufferedImage imRGB = new BufferedImage(cm, ras, cm.isAlphaPremultiplied(), null);
//this image we can encode to jpeg format
ImageIO.write(imRGB, "jpg", new File("d:/rgb1.jpg"));
I need to convert a BufferedImage to a BufferedImage indexed type to extract the indices of the colors data and the 256 color palette.
i think that i am doing right the conversion of a BufferedImage to indexed mode and then extracting the color indices with the next code:
BufferedImage paletteBufferedImage=new BufferedImage(textureInfoSubFile.getWidth(), textureInfoSubFile.getHeight(),BufferedImage.TYPE_BYTE_INDEXED);
paletteBufferedImage.getGraphics().drawImage(originalBufferedImage, 0, 0, null);
// puts the image pixeldata into the ByteBuffer
byte[] pixels = ((DataBufferByte) paletteBufferedImage.getRaster().getDataBuffer()).getData();
My problem now is that i need to know the ARGB values of each color index( the palette) to put them into an array. i have been reading about ColorModel and ColorSpace but i don´t find some methods to do what i need.
I think your code is good (except that you don't "put" any data into anything, you merely reference the data buffer's backing array, meaning changes in pixels will reflect to paletteBufferedImage and vice versa).
To get the ARGB values for the indices in pixels:
IndexColorModel indexedCM = (IndexColorModel) paletteBufferedImage.getColorModel(); // cast is safe for TYPE_BYTE_INDEXED
int[] palette = new int[indexedCM.getMapSize()]; // Allocate array
indexedCM.getRGBs(palette); // Copy palette to array (ARGB values)
For more information, see the IndexColorModel class documentation.
Finally i solve it with this code:
public static BufferedImage rgbaToIndexedBufferedImage(BufferedImage sourceBufferedImage) {
// With this constructor, we create an indexed buffered image with the same dimension and with a default 256 color model
BufferedImage indexedImage = new BufferedImage(sourceBufferedImage.getWidth(), sourceBufferedImage.getHeight(), BufferedImage.TYPE_BYTE_INDEXED);
ColorModel cm = indexedImage.getColorModel();
IndexColorModel icm = (IndexColorModel) cm;
int size = icm.getMapSize();
byte[] reds = new byte[size];
byte[] greens = new byte[size];
byte[] blues = new byte[size];
icm.getReds(reds);
icm.getGreens(greens);
icm.getBlues(blues);
WritableRaster raster = indexedImage.getRaster();
int pixel = raster.getSample(0, 0, 0);
IndexColorModel icm2 = new IndexColorModel(8, size, reds, greens, blues, pixel);
indexedImage = new BufferedImage(icm2, raster, sourceBufferedImage.isAlphaPremultiplied(), null);
indexedImage.getGraphics().drawImage(sourceBufferedImage, 0, 0, null);
return indexedImage;
}
I have this method here, which converts an image to a byte array.
public byte[] imageToCompressedByteArray(Image image) throws IOException {
//load the image
String f = "C:\\Users\\mamed\\Documents\\NetBeansProjects\\Main\\src\\resources\\accept.png";
image = ImageIO.read(new FileInputStream(new File(f)));
// get image size
int width = image.getWidth(null);
int height = image.getHeight(null);
try {
int[] imageSource = new int[width * height];
PixelGrabber pg = new PixelGrabber(image, 0, 0, width, height, imageSource, 0, width);
pg.grabPixels();
ByteArrayOutputStream byteStream = new ByteArrayOutputStream();
GZIPOutputStream zippedStream = new GZIPOutputStream(byteStream);
ObjectOutputStream objectStream = new ObjectOutputStream(zippedStream);
objectStream.writeShort(width);
objectStream.writeShort(height);
objectStream.writeObject(imageSource);
objectStream.flush();
objectStream.close();
return byteStream.toByteArray();
}
catch (Exception e) {
throw new IOException("Error storing image in object: " + e);
}
}
However, i can't get this to work, i mean, it can't load the image and convert it, and i don't have an idea what the problem can be.
Are you sure the image path is correct and the loaded image is not corrupted image.
I not modified your code and I can see 1778416 byes its read from the image file.
I do not see anything wrong with the program. Maybe your image file is corrupted or image path is not correct.
I have 16-bit per pixel grayscale BufferedImage created from an array of shorts:
private BufferedImage get16bitImage(short[] pixels) {
ColorModel colorModel = new ComponentColorModel(
ColorSpace.getInstance(ColorSpace.CS_GRAY),
new int[]{16},
false,
false,
Transparency.OPAQUE,
DataBuffer.TYPE_USHORT);
DataBufferUShort db = new DataBufferUShort(pixels, pixels.length);
WritableRaster raster = Raster.createInterleavedRaster(
db,
imgD.width,
imgD.height,
imgD.width,
1,
new int[1],
null);
return new BufferedImage(colorModel, raster, false, null);
}
When trying to save it:
ImageIO.write(img, "PNG", new File(resultImgNamePNG)); // works fine
ImageIO.write(img, "BMP", new File(resultImgNameBMP)); // doesn't work, returns false
ImageIO.write(img, "JPEG", new File(resultImgNameJPEG)); // doesnt work, returns false
I tried using JAI:
public void writeImageToJPEG(File out, BufferedImage image, float quality) throws IOException {
JPEGEncodeParam param = new JPEGEncodeParam();
param.setQuality(quality);
ImageEncoder encoder = ImageCodec.createImageEncoder("JPEG", new FileOutputStream(out), param);
encoder.encode(image);
}
encoder.encode(image) throws java.lang.RuntimeException: Only 1, or 3-band byte data may be written.
I think you have to convert it to 8-bit first. If this is used for display purposes, java converts it to 8-bit bit before display anyways.
You can do something that I've seen sometimes actually improve the displayed image which is doing non-linear scaling of the values (using a log scale for example) such detail depends on the image you are generating ofcourse.
More on such effect here: http://www.java.net/external?url=http://www.cs.unm.edu/~brayer/vision/perception.html