Develop Reference

Writing a GIF image over PNG image

I wonder if there is a way in java to put a gif image over png image at particular location (say at particular value of x,y). If so please help me through this.
This is the case :
I have a base Image which is of png type. and I have gif images of size 62*62. I wanted to put several such gif images on png image and I need to render the png image on front end at every 5 seconds..

To extract image from GIF file.. This save the first image into png file from GIF.
try {
ImageReader reader = ImageIO.getImageReadersByFormatName("gif").next();
ImageInputStream stream = ImageIO.createImageInputStream(new File("c:/aaa.gif");
reader.setInput(stream);
int count = reader.getNumImages(true);
if(count>0){
BufferedImage frame = reader.read(0);
ImageIO.write(frame, "png", new File(filePath+fileName+".png"));
System.out.println("Donesss");
}
} catch (IOException ex) {
}

How to save indexed color PNG in java

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. ;-)

PDFBox draw black image from BufferedImage

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);
}
}

How to read a Image file selected by user using JFileChooser

I want to read the image selected by user using JFileChooser and then be able to get the color Channels(R,G,B) and the width and height of the image.
Is this the right approach to read the selected image file.
File im1 = new File(chooser.getSelectedFile(), null);
BufferedImage buff =ImageIO.read(im1);
Or is there a better way to read the image file in order to get the values of its separate color channels and get its separate values.

Your code looks okay. Just keep going with width, height and RGB.
File im1 = chooser.getSelectedFile();
BufferedImage buff = ImageIO.read(im1);
if (buff != null) {
System.out.println(buff.getWidth() + " " + buff.getHeight());
System.out.println(buff.getRGB(0, 0));
}

I haven't found any 'better' way to load the image so I believe you're doing it right.
To answer your whole question, here's an example how to get specific color channels out of the image.
Color c = new Color(image.getRGB());
int red = c.getRed();
int green = c.getGreen();
int blue = c.getBlue();

Compress JPG make the image turn green

When I try to compress the a jpg image, most of the time it work perfectly, however some jpg image turn green after the compression. Here is my code
public void compressImage(String filename, String fileExtension) {
BufferedImage img = null;
try {
File file = new File(filename);
img = ImageIO.read(file);
if (fileExtension.toLowerCase().equals(".png") || fileExtension.toLowerCase().equals(".gif")) {
//Since there might be transparent pixel, if I dont do this,
//the image will be all black.
for (int x = 0; x < img.getWidth(); x++) {
for (int y = 0; y < img.getHeight(); y++) {
int rgb = img.getRGB(x, y);
int alpha = (rgb >> 24) & 0xff;
if (alpha != 255) {
img.setRGB(x, y, -1); //set white
}
}
}
}
Iterator iter = ImageIO.getImageWritersByFormatName("jpg");
//Then, choose the first image writer available
ImageWriter writer = (ImageWriter) iter.next();
//instantiate an ImageWriteParam object with default compression options
ImageWriteParam iwp = writer.getDefaultWriteParam();
//Set the compression quality
iwp.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);
iwp.setCompressionQuality(0.8f);
//delete the file. If I dont the file size will stay the same
file.delete();
ImageOutputStream output = ImageIO.createImageOutputStream(new File(filename));
writer.setOutput(output);
IIOImage image = new IIOImage(img, null, null);
writer.write(null, image, iwp);
writer.dispose();
} catch (IOException ioe) {
logger.log(Level.SEVERE, ioe.getMessage());
}
}

Converting the final image from YUV back to RGB, will restore the colors of the image.
This conversion worked for me: cv2.cvtColor(img_file, cv2.COLOR_YUV2RGB)

From experience, I know that green is the color of freshly formatted YUV memory (YV12, in particular). So my guess is some step is failing, and you get luma information but the chroma gets botched. Looks to me like it's failing before it gets to the Cr plane.
Anyway, good luck, that's a tough one. Your code looks strange though--what's with the weird png specific code at the top? AFAIK, if you're using .NET you can pretty much treat any registered image format just as though it's an image without any funny work.

I have the same problem. In my test server run java 7 oracle and work fine. In my production server run openJDK 1.7, and compress images turn green...It´s seems bug in some JAVA versions.