In server side image process, should I use AWT or SWT?
I think AWT maybe too abstract away from the actual image data bits, so I guess SWT maybe slightly faster.
Or do you suggest another open source image process library? (BSD or Apache licensed)
The server is running Ubuntu 11.04.
Requirements:
Read/write image from/to stream instead of files.
The image type is given as parameter rather then guess from extension.
(This is optional if it can determine the image type from the header bytes.)
Support of JPG, PNG, GIF.
(Bonus) Support of Animated GIF.
Use cases:
Generate thumbnails.
Add some banner texts.
Add cryptic image watermark and validation.
SWT has very little in terms of image processing. The standard JDK image stuff has the fancy ImageIO package, and Java2D which can do pretty much everything. I'd call this a no-brainer: use Java's built-in stuff, and don't try to use SWT for something it's not intended for.
I can second Ernest's notion about SWT for this task, forget it.
But while Swing is fine for image manipulation and output, Swing's ImageIO fails too often during input: many images which you'll meet in the wild, and which work fine in the browser, produce Exceptions.
The best Java option I know of is JAI, which unfortunately is a pain to use. So do yourself a favor, and use JAI for input, and Swing for the rest, like this:
RenderedImage renderedImage = JAI.create("fileload", imageFile.getAbsolutePath());
RenderedImageAdapter planarImage = new RenderedImageAdapter(renderedImage);
BufferedImage image planarImage.getAsBufferedImage();
JAI will also fail in rare cases (JPGs with custom color space, as written by Photoshop, are an example). If you want to do even better, use ImageMagick, which is an ultra-powerful command line tool. There are Java interfaces available, which either provide an API for the command line, or use JNI to call the native library, see here.
Related
I need a solution to create one big image with sprites from ~100 single images periodically without intervention because the number of images and the images itself are changing over time. To create the sprites with e.g. http://css-sprit.es/ or any other toolu with a GUI would not be feasible.
Each image has a different width and height. Images formats are png, gif, jpg. My approach would be write a custom java program to concatenate the images vertically into one big image and create a json file to provide the coordinates for later processing. A google search returned me this java awt based tutorial:
https://sites.google.com/site/javagamescorner/home/creating-sprites
Is there another way you would recommend to create sprites? There are a lot of (too?) complex tools and libraries and maybe there is an easier solution.
This Stackoverflow thread mentions a lot of java libraries: open source image processing lib in java
Since you didn't mention Swing or SWT, I'm going to give you a SWT approach.
Engineer an ImageBuilder. Follow the builder pattern, and design it so that it suits your needs. Extend it from CompositeImageDescriptor (if you look at the class' APIs, you'll instantly figure out how to draw the images) to work with ImageDescriptors, construct your sprite, then eventually cache the result so it can be used later on.
I need to write an application in Java which need to be able to manipulate the pixels of an image regardless of the format of the image (JPEG, BitMap, Gif, ...).
It means I need to access the pixels and also I need to calculate some attributes of the image such as size, resolution, contrast, brightness and the compression algorithm.
I also need to manipulate the bits of individual pixels.
Now what I need to know is that can I do these by means of pure Java SE classes or I need to use a third party library? If so, which is the best for me? JAI, ImageJ, ...?
Take a look at the Java Advanced Imagining API FAQ and you should be able to decide from it whether you want to use the native Java APIs or a 3rd-party library. (The concept of manipulating pixels can vary tremendously in complexity. The examples you mentioned are not difficult but other operations may be.) Getting the size, resolution and compression alg is somewhat trivial as they are all attributes of the objects you use in image manipulation. (Though resolution is relative.) Working with contrast and brightness is a little more involved but not much. See here for an interesting sample. Java2s has lots of Java image-manipulation snippets available .
Here's a link directly to the Supported File Formats section in the FAQ.
JAI Hello World:
PlanarImage source = JAI.create("fileload", file);
This function automatically determines
the file format and produces an image
object which can be displayed or
processed.
I'm brand new to Java Advanced Imaging, and the first stumbling block I've reached is the ability to read in a 12 bit, single band, greyscale JPEG file. I've seen references to it being possible with JAI, but no code or even suggestions about how it should be done. Could someone please help me out with either a helpful link or a short code snippet?
I've been using this tutorial so far, but it hasn't helped me on this issue.
Thanks.
JAI-ImageIO will register itself into Java's ImageIO api, so you should be able to use it just by having the jai-imageio jars in your classpath an calling the normal ImageIO methods, such as ImageIO.read(file).
The problem with jpeg might be that Java has a default jpeg reader in the IIORegistry, and you may have to select the right one manually using something like ImageIO.getImageReadersForFormatName().
Another thing with the more esoteric formats is that JAI ImageIO usually has two implementations - one pure Java and the other using native binary libraries, so make sure that you include the *lib-wrapper.dll (or whatever suits your particular OS) in the LD_LiBRARY_PATH or have the in the working directory of your program. The native implementation usually supports mode format variants than the pure-java one.
we usually read JPEG 12bit grayscale images using JAI + JAI Image I/O.
Additionally to previous answers, you need the native binary libraries to read JPEG 12bit, so mediaLib library is required.
You only need the "ImageRead" operation from Image I/O:
byte[] imageBytes = ...
RenderedOp readImage = JAI.create("ImageRead", new MemoryImageInputStream(imageBytes));
Whe usually read the image files from FTP, so get the byte[] and need the custom MemoryImageInputStream that wraps a byte[] into a ImageInputStream by subclassing ImageInputStreamImpl.
I wanted to find out how can one capture screencast using java. I know that using Robot class one can get a screenshot but how do I go about capturing it as a video and then uploading it to the server? How exactly would that work?
ideas?
With a pure Java solution, I doubt that it will work, but it depends of course on what your interpretation of "video".
On my desktop with a 1920x1200 resolution, I am able to get about 20 frames per second when using the Java Robot to capture the entire screen. Since each image contains >6 MByte of uncompressed data, I would need more than 1 Gbps bandwidth to transmit the raw data of these images to a server. Most probably, requiring so much bandwidth is not acceptable, so you either have to decrease the number of frames per second or apply some kind of compression to the images.
One possibility is to compress each image using one of the image formats supported by ImageIO. The size of the compressed images will of course depend heavily on what is actually shown on the screen, but the performance of the compressors is not particularly good. Compressing to PNG ought to give the best lossless compression ratio for most desktop content, but at least my computer is only able to process just about 2 frames per second. Using the JPEG compressor with default quality settings reaches about 5 frames per second.
Using common video codecs through an abstraction layer like jffmpeg will probably achieve both better performance and better compression ratio, but I doubt that mainstream video codecs like WMV or H.264 are suitable for common desktop content.
If you really require a pure Java solution (and are not able to use any of the available standalone software, which do what you're asking for), I would make an attempt to implement my own, simple compression algorithm. With common desktop activity, there ought to be very little difference between most consecutive screen shots, so what might work quite well is to transmit the first frame completely and after that implement an algorithm to roughly detect rectangles, in which changes have been made and then transmit only these combined with JPG or preferrably (quality) PNG compression.
Or use Xuggler, a better wrapper for FFmpeg in Java. In fact, the code for capturing the screen and encoding the video is one of the standard tutorials.
I'm also curious about this. https://www.screencast.com/ is currently doing just this with a pure java (or at least straight out of the browser) experience.
You can just use something like Java to a native FFMPEG build, and execute the command line at runtime. Here is an applet that I made that does just that: http://have2chat.net/screencast/
I have downloaded the main capture *.JAR file for the Screencast-O-Matic.com. To download the file:
Go to http://screencast-o-matic.com/jars/ScreencastOMaticRun-1.0.5.jar
Save the file
Extract the contents (I DO NOT intend to use this commercially!)
Canon/Nikon/other cameras save raw output of their sensor in some of their proprietary formats (.CR2, whatever). Is there any Java library designed to read them and convert into manageable BufferedImages?
I don't reqlly care here about fully customizable conversion similar to ufraw or imagemagick, rather something simple that "just works" for rendering simple previews of such images.
I've been where you are, and I feel for you. Your best bet is to use an Adobe or dcraw-based program to create thumbnails automatically. Temporary DNG files using Adobe's converter may be easier to use.
IF you insist on doing it in Java, you're about to run into a mountain of pain. RAW formats change often, have all sorts of crazy nuances and are intentionally hard to work with. Camera makers want you to use THEIR RAW conversion software, to show the camera's abilities at its best and screw Adobe. The guy behind dcraw found that some are camera manufacturers even use encryption now!
The existing Java libraries are poor -- JRawIO has improved since I last looked at it, but it supports only a fraction of the formats that dcraw does. In addition to the listed libraries, the imagero library may provide the ability to display a thumbnail for your image.
From personal experience, don't even think about writing your own RAW file reader.
I tried to do this with a very simple RAW format once (just a solid array of sensor data, 12 bits per pixel). The dcraw source translates badly to Java. You haven't seen such a nightmare of bit-fiddling ever. Took me days to debug problems with byte alignment and endian-ness.
jrawio is a plugin for Java Image I/O. With it you can read the raster data, the thumbnails and the metadata from the raw image file.
nef and cr2 already contains preview images in jpeg. just find the right offset and the right length to extract it...
Laurent Clevy # lclevy.free.fr/raw
Laurent
Unless you want to write you own file parser/loader (sounds fun imho ;) ), perhaps JMagick will help you. I haven't tried it and it might not work given your target platform since JMagick uses JNI.
UPDATE: dcraw looks like a good resource/reference