This question already has answers here:
Converting `BufferedImage` to `Mat` in OpenCV
(9 answers)
Closed 6 years ago.
I've tried this link and have the code below. My program imports images in a BufferedImage format and then displays it to the users. I'm using the matchingTemplate function in OpenCV which requires me to convert it to a Mat format.
The code works if I import the image -> convert it to Mat then save the image using imwrite. The program also allows the user to crop an image and then use the Template matching to compare it to another image. The issue come when I tried to convert the cropped image to Mat I need to convert it from Int to Byte using this code:
im = new BufferedImage(im.getWidth(), im.getHeight(),BufferedImage.TYPE_3BYTE_BGR);
This however results in a black image. But if I get rid of it it only works with imported images and not cropped. What is going on here? I'm certain it is something to do with the coversion process as I have tested the template matching function using read in images.
// Convert image to Mat
public Mat matify(BufferedImage im) {
// Convert INT to BYTE
//im = new BufferedImage(im.getWidth(), im.getHeight(),BufferedImage.TYPE_3BYTE_BGR);
// Convert bufferedimage to byte array
byte[] pixels = ((DataBufferByte) im.getRaster().getDataBuffer())
.getData();
// Create a Matrix the same size of image
Mat image = new Mat(im.getHeight(), im.getWidth(), CvType.CV_8UC3);
// Fill Matrix with image values
image.put(0, 0, pixels);
return image;
}
You can try this method, to actually convert the image to TYPE_3BYTE_BGR (your code simply created a blank image of the same size, that is why it was all black).
Usage:
// Convert any type of image to 3BYTE_BGR
im = toBufferedImageOfType(im, BufferedImage.TYPE_3BYTE_BGR);
// Access pixels as in original code
And the conversion method:
public static BufferedImage toBufferedImageOfType(BufferedImage original, int type) {
if (original == null) {
throw new IllegalArgumentException("original == null");
}
// Don't convert if it already has correct type
if (original.getType() == type) {
return original;
}
// Create a buffered image
BufferedImage image = new BufferedImage(original.getWidth(), original.getHeight(), type);
// Draw the image onto the new buffer
Graphics2D g = image.createGraphics();
try {
g.setComposite(AlphaComposite.Src);
g.drawImage(original, 0, 0, null);
}
finally {
g.dispose();
}
return image;
}
Related
How to save image in java as java.awt.image.IndexColorModel PNG? I'm loading indexed color png with ImageIO, manipulate it with Catalino library which unfortunately converts the color space to java.awt.image.DirectColorModel.
Now I want to save the result in the exactly same format as the original image. I tried the following snippet of code.
private static void testIndexedColor() throws IOException {
FastBitmap input = new FastBitmap("test.png");
BufferedImage bi = new BufferedImage(input.getWidth(), input.getHeight(), BufferedImage.TYPE_BYTE_INDEXED);
bi.getGraphics().drawImage(input.toBufferedImage(), 0, 0, null);
ImageIO.write(bi, "PNG", new File("test_result.png"));
}
But in the result weird light gray pixel artifacts appeared in the white background, and PPI decreased . How to correctly convert back to indexed color mode without quality loss and distortion?
Assuming I'm correct about the Catalano framework, you should be able to re-write your methods as this:
private static void testIndexedColor() throws IOException {
BufferedImage bi = ImageIO.read(new File("test.png"));
FastBitmap input = new FastBitmap(bi);
Graphics2D g = bi.createGraphics();
try {
g.drawImage(input.toBufferedImage(), 0, 0, null);
}
finally {
g.dispose(); // Good practice ;-)
}
ImageIO.write(bi, "PNG", new File("test_result.png"));
}
At least you should get away with the fixed palette and the artifacts.
However, this will likely still modify the PPI (but this won't affect the pixels). And even in some cases the image might be written back as a non-palette PNG.
Update: It seems the PNGImageWriter (through the PNGMetadata) actually re-writes an IndexColorModel containing a perfect grayscale, to a grayscale PNG by default. This is normally a good idea, as you reduce file size by not writing the PLTE chunk. You should be able to get around this, by passing the metadata from the original, along with the image pixel data, to instruct the writer to keep the IndexColorModel (ie. write PLTE chunk):
private static void testIndexedColor() throws IOException {
File in = new File("test.png");
File out new File("test_result.png");
try (ImageInputStream input = ImageIO.createImageInputStream(in);
ImageOutputStream output = ImageIO.createImageOutputStream(out)) {
ImageReader reader = ImageIO.getImageReaders(input).next(); // Will fail if no reader
reader.setInput(input);
ImageWriter writer = ImageIO.getImageWriter(reader); // Will obtain a writer that understands the metadata from the reader
writer.setOutput(output); // Will fail if no writer
// Now, the important part, we'll read the pixel AND metadata all in one go
IIOImage image = reader.readAll(0, null); // PNGs only have a single image, so index 0 is safe
// You can now access and modify the image data using:
BufferedImage bi = (BufferedImage) image.getRenderedImage();
FastBitmap fb = new FastBitmap(bi);
// ...do stuff...
Graphics2D g = bi.createGraphics();
try {
g.drawImage(fb.toBufferedImage(), 0, 0, null);
}
finally {
g.dispose();
}
// Write pixel and metadata back
writer.write(null, image, writer.getDefaultWriteParam());
}
}
This should (as a bonus) also keep your PPI as-is.
PS: For production code, you also want to dispose() of the reader and writer above, but I left it out to keep focus and avoid further discussion on try/finally. ;-)
I try to draw an image from a bufferedImage into a PDF using PDFBox but fails, and I get black images and Acrobat Reader warns whith errors like "Out of memory" (but PDF is display).
I use a bufferedImage because I need to draw a JavaFX Image object (with came from call to Funciones.crearImagenDesdeTexto(), is a function which converts a text into an Image) into PDF. Rest of images works well without using bufferedimage.
PDPixelMap img = null;
BufferedImage bi;
try {
//If item has id, I try to get image with that id (image it's shows OK on PDF)
img = new PDPixelMap(documento, read(getClass().getResourceAsStream("/com/img/" + item.getId() + ".png")));
}
catch (Exception e) {
//If item has not id or fails load image, I create image on the fly (which contains item name. This not work on PDF, shows black images)
bi = new BufferedImage(alto, ancho, BufferedImage.TYPE_INT_ARGB);
bi.createGraphics().drawImage(SwingFXUtils.fromFXImage(Funciones.crearImagenDesdeTexto(item.getNombre()), null), ancho, alto, null);
img = new PDPixelMap(documento, bi);
}
finally {
contenedor.drawXObject(img, x, y, alto, ancho);
}
NOTE: crearImagenDesdeTexto() returns a JavaFX Image Object that is create on the fly (I try this function in other parts of the program and works well, function is take from other stackOverflow response).
Your code is confusing, you have three "new PDJpeg" and one of them is in a catch (which should just handle the error). And what does "read()" do? Does it pass a stream or a BufferedImage? If it is a stream, then it is wrong, because PDJpeg is for JPEGs, not for PNG.
The second one
img = new PDJpeg(documento, (getClass().getResourceAsStream("/com/img/" + Byte.toString(item.getId()) + ".png")));
is definitively wrong for the same reason: PDJPeg is not for PNG files / streams.
If you want to create an image from a PNG file / stream, use PDPixelMap.
It is possible to create a PDJpeg object from a BufferedImage, but this is recommended only if the image wasn't encoded before. Because if you would read a BufferedImage from a JPEG, and then use PDJPeg for this, you'll have a slight loss of quality as the image is decoded and encoded again (JPEG is a "lossy" compression format).
If my advice doesn't help, please upload the JPEG file and the PDF somewhere.
Also make sure that you're using the latest version, which is 1.8.7.
Update after comments:
the parameters to createGraphics.drawImage() should be 0, 0 and not width, height. The two parameters are a location, not a size.
Finally, I find a solution (thanks also to Tilman Hausherr):
private void dibujarImagen(Item i, int x, int y, int alto, int ancho) throws IOException {
PDPixelMap img = null;
try {
img = new PDPixelMap(documento, read(getClass().getResourceAsStream("/com/img/" + i.getId() + ".png")));
}
catch (IllegalArgumentException e) {
img = new PDPixelMap(documento, SwingFXUtils.fromFXImage(Funciones.crearImagenDesdeTexto(i.getNombre()),null));
}
finally {
contenedor.drawXObject(img, x, y, alto, ancho);
}
}
i am doing work on images using java.
i read a gray scale image and convert the pixel values to 0 and 1 i got the output image correctly for only some images.
in others some image portions are lost
here is the code i am using to make the image array back into image
`BufferedImage I = ImageIO.read(new File("path"));
SampleModel sampleModel;
Raster pixelData;
pixelData = I.getData();
int[][] pixels=new int[wid][hgt];
sampleModel=pixelData.getSampleModel();
BufferedImage image=new BufferedImage(wid,hgt,BufferedImage.TYPE_BYTE_BINARY);
WritableRaster raster=Raster.createWritableRaster(sampleModel,new Point(0,0));
for(int i=0;i<wid;i++)
{
for(int j=0;j<hgt;j++)
{
raster.setSample(i,j,0,pixels[i][j]);
}
}
image.setData(raster);
File output=new File("path");
ImageIO.write(image,"png",output);
System.out.println("..End..");`
size of the image is same as original but the entire size contains only a portion of original image.can u help me
Your problem is probably related to the sample model you are using. The sample model is responsible to describe how the Raster is going to store the data, maybe you are using a model that puts more info per pixel and then the image gets only a part of the original buffer.
Cheers
[Update]
#Joop Egen is correct you need to use the sample model from the image in which you defined that you are using a grayscale byte per pixel "configuration"
got a gud answer for my problem it worked well for all images(including 24 bit and 8 bit images)
BufferedImage I = ImageIO.read(new File("path"));
Raster pixelData;
pixelData = I.getData();
int pixels[][]=new int[wid][hgt];
for ( x=0;x<wid;x++)
{
for( y=0;y<hgt;y++)
{
pixels[x][y]=pixelData.getSample(x,y,0);
}
}
BufferedImage image=new BufferedImage(wid,hgt,BufferedImage.TYPE_BYTE_BINARY);
ColorSpace cs = ColorSpace.getInstance(ColorSpace.CS_GRAY);
int[] nBits = { 8 };
ColorModel cm = new ComponentColorModel(cs, nBits, false, true,Transparency.OPAQUE, DataBuffer.TYPE_BYTE);
SampleModel sm = cm.createCompatibleSampleModel(wid, hgt);
WritableRaster raster=Raster.createWritableRaster(sm,new Point(0,0));
for(int i=0;i<wid;i++)
{
for(int j1=0;j1<hgt;j1++)
{
raster.setSample(i,j1,0,pixels[i][j1]);
}
}
image.setData(raster);
File output=new File("path");
ImageIO.write(image,"png",output);`
I am using an Applet to save image from clipboard. The image is saved but something happened with its format. It is darken and lost colors.
here's how I am doing it:
AccessController.doPrivileged(new PrivilegedAction() {
public Object run() {
try {
//create clipboard object
Clipboard clipboard = Toolkit.getDefaultToolkit().getSystemClipboard();
//Get data from clipboard and assign it to an image.
//clipboard.getData() returns an object, so we need to cast it to a BufferdImage.
BufferedImage image = (BufferedImage) clipboard.getData(DataFlavor.imageFlavor);
//file that we'll save to disk.
File file = new File("/tmp/clipboard.jpg");
//class to write image to disk. You specify the image to be saved, its type,
// and then the file in which to write the image data.
ImageIO.write(image, "jpg", file);
//getData throws this.
} catch (UnsupportedFlavorException ufe) {
ufe.printStackTrace();
return "Não tem imagem na área de transferência";
} catch (Exception ioe){
ioe.printStackTrace();
}
return null;
}
}
);
I read that Mac uses a different image format but I did not find how to convert it to a format I could save. I imagined that java should have taken care of that.
So, how can I convert the image from clipboard to jpg?
PS. I tried using png instead of jpg, got a worse result: black image
To solve the issue on Mac, I used the solution proposed on The nightmares of getting images from the Mac OS X clipboard using Java.
I pass the retrieved BufferedImage to method that redraws it to new BufferedImage, returning a valid image. Here follows the code from that page:
public static BufferedImage getBufferedImage(Image img) {
if (img == null) return null;
int w = img.getWidth(null);
int h = img.getHeight(null);
// draw original image to thumbnail image object and
// scale it to the new size on-the-fly
BufferedImage bufimg = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
Graphics2D g2 = bufimg.createGraphics();
g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
g2.drawImage(img, 0, 0, w, h, null);
g2.dispose();
return bufimg;
}
And how I use it:
Clipboard clipboard = Toolkit.getDefaultToolkit().getSystemClipboard();
//Get data from clipboard and assign it to an image.
//clipboard.getData() returns an object, so we need to cast it to a BufferdImage.
BufferedImage image = (BufferedImage) clipboard.getData(DataFlavor.imageFlavor);
if (isMac()) {
image = getBufferedImage(image);
}
PNG is the preferred image format for Macs. You might want to try saving as that and then converting to a JPG if needed afterwards.
I am trying to write out a png file from a java.awt.image.BufferedImage. Everything works fine but the resulting png is a 32-bit file.
Is there a way to make the png file be 8-bit? The image is grayscale, but I do need transparency as this is an overlay image. I am using java 6, and I would prefer to return an OutputStream so that I can have the calling class deal with writing out the file to disk/db.
Here is the relevant portion of the code:
public static ByteArrayOutputStream createImage(InputStream originalStream)
throws IOException {
ByteArrayOutputStream oStream = null;
java.awt.Image newImg = javax.imageio.ImageIO.read(originalStream);
int imgWidth = newImg.getWidth(null);
int imgHeight = newImg.getHeight(null);
java.awt.image.BufferedImage bim = new java.awt.image.BufferedImage(imgWidth,
imgHeight, java.awt.image.BufferedImage.TYPE_INT_ARGB);
Color bckgrndColor = new Color(0x80, 0x80, 0x80);
Graphics2D gf = (Graphics2D)bim.getGraphics();
// set transparency for fill image
gf.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.3f));
gf.setColor(bckgrndColor);
gf.fillRect(0, 0, imgWidth, imgHeight);
oStream = new ByteArrayOutputStream();
javax.imageio.ImageIO.write(bim, "png", oStream);
oStream.close();
return oStream;
}
The build in imageio png writer will write 32bit png files on all the platforms I have used it on, no matter what the source image is. You should also be aware that many people have complained that the resulting compression is much lower than what is possible with the png format. There are several independent png libraries available that allow you to specify the exact format, but I don't actually have any experience with any of them.
I found the answer as to how to convert RGBA to Indexed here: http://www.eichberger.de/2007/07/transparent-gifs-in-java.html
However, the resulting 8-bit png file only has 100% or 0% transparency. You could probably tweak the IndexColorModel arrays, but we have decided to make the generated file (what was an overlay mask) into an underlay jpg and use what was the static base as the transparent overlay.
It is an interesting question... It is late, I will experiment tomorrow. I will first try and use a BufferedImage.TYPE_BYTE_INDEXED (perhaps after drawing) to see if Java is smart enough to generate an 8bit PNG.
Or perhaps some image library can allow that.
[EDIT] Some years later... Actually, I made the code at the time, but forgot to update this thread... I used the code pointed at by Kat, with a little refinement on the handling of transparency, and saving in PNG format instead of Gif format. It works in making a 8-bit PNG file with all-or-nothing transparency.
You can find a working test file at http://bazaar.launchpad.net/~philho/+junk/Java/view/head:/Tests/src/org/philhosoft/tests/image/AddTransparency.java
using my ImageUtil class.
Since the code isn't that big, for posterity sake, I post it here, without the JavaDoc to save some lines.
public class ImageUtil
{
public static int ALPHA_BIT_MASK = 0xFF000000;
public static BufferedImage imageToBufferedImage(Image image, int width, int height)
{
return imageToBufferedImage(image, width, height, BufferedImage.TYPE_INT_ARGB);
}
public static BufferedImage imageToBufferedImage(Image image, int width, int height, int type)
{
BufferedImage dest = new BufferedImage(width, height, type);
Graphics2D g2 = dest.createGraphics();
g2.drawImage(image, 0, 0, null);
g2.dispose();
return dest;
}
public static BufferedImage convertRGBAToIndexed(BufferedImage srcImage)
{
// Create a non-transparent palletized image
Image flattenedImage = transformTransparencyToMagenta(srcImage);
BufferedImage flatImage = imageToBufferedImage(flattenedImage,
srcImage.getWidth(), srcImage.getHeight(), BufferedImage.TYPE_BYTE_INDEXED);
BufferedImage destImage = makeColorTransparent(flatImage, 0, 0);
return destImage;
}
private static Image transformTransparencyToMagenta(BufferedImage image)
{
ImageFilter filter = new RGBImageFilter()
{
#Override
public final int filterRGB(int x, int y, int rgb)
{
int pixelValue = 0;
int opacity = (rgb & ALPHA_BIT_MASK) >>> 24;
if (opacity < 128)
{
// Quite transparent: replace color with transparent magenta
// (traditional color for binary transparency)
pixelValue = 0x00FF00FF;
}
else
{
// Quite opaque: get pure color
pixelValue = (rgb & 0xFFFFFF) | ALPHA_BIT_MASK;
}
return pixelValue;
}
};
ImageProducer ip = new FilteredImageSource(image.getSource(), filter);
return Toolkit.getDefaultToolkit().createImage(ip);
}
public static BufferedImage makeColorTransparent(BufferedImage image, int x, int y)
{
ColorModel cm = image.getColorModel();
if (!(cm instanceof IndexColorModel))
return image; // No transparency added as we don't have an indexed image
IndexColorModel originalICM = (IndexColorModel) cm;
WritableRaster raster = image.getRaster();
int colorIndex = raster.getSample(x, y, 0); // colorIndex is an offset in the palette of the ICM'
// Number of indexed colors
int size = originalICM.getMapSize();
byte[] reds = new byte[size];
byte[] greens = new byte[size];
byte[] blues = new byte[size];
originalICM.getReds(reds);
originalICM.getGreens(greens);
originalICM.getBlues(blues);
IndexColorModel newICM = new IndexColorModel(8, size, reds, greens, blues, colorIndex);
return new BufferedImage(newICM, raster, image.isAlphaPremultiplied(), null);
}
}
Thanks for responding, I was going to try an TYPE_BYTE_INDEXED with an IndexColorModel and may still but if ImageIO writes out 32-bit regardless it appears that I may be wasting my time there.
The image I am trying to write out can be very large (up to 8000x4000) but is just a simple mask for the image underneath, so will only have a ~30% transparent gray and a 100% transparent cutout. I would use a GIF but IE6 seems to have trouble with displaying one that large.
It only gets generated once and in an internal set-up type screen, so performance isn't an issue either, but it does have to be done within the java code and not by an offline utility.
The libraries that you specified might be used to transform it while writing... I am going to go check that out.
If anyone has a better way, please let me know!!
Thanks!