	try(ImageInputStream in = ImageIO.createImageInputStream(resourceFile)){
		final Iterator&lt;ImageReader&gt; readers = ImageIO.getImageReaders(in);
		if (readers.hasNext()) {
			ImageReader reader = readers.next();
			try {
				reader.setInput(in);
				return new Dimension(reader.getWidth(0), reader.getHeight(0));
			} finally {
				reader.dispose();
			}
		}
	} 

Thanks to sfussenegger for the suggestion

Using [ImageReader.getHeight(int)][1] and [ImageReader.getWidth(int)][2] normally only reads the image header (I&#39;m looking at JDK6 sources). So [ImageReader][3] is most likely the best choice.


  [1]: http://java.sun.com/javase/6/docs/api/javax/imageio/ImageReader.html#getHeight(int)
  [2]: http://java.sun.com/javase/6/docs/api/javax/imageio/ImageReader.html#getWidth(int)
  [3]: http://java.sun.com/javase/6/docs/api/javax/imageio/ImageReader.html

You&#39;ll have to look into [`ImageReader.getImageMetadata()`][1]. Unfortunately, The Java Image API is not at all easy to use.

You can find descriptions of the metadata formats in the package documentation of [`javax.imageio.metadata`][2].

There are third party libraries that are easier to use, such as [MediaUtil][3] (last updated 3 years ago, but it worked well for me).


  [1]: http://java.sun.com/javase/6/docs/api/javax/imageio/ImageReader.html#getImageMetadata(int)
  [2]: http://java.sun.com/javase/6/docs/api/javax/imageio/metadata/package-summary.html
  [3]: http://mediachest.sourceforge.net/mediautil/

The solution with ImageInputStream and ImageReader is still not so efficient though because they create tmp files. It becomes much slower when image is larger or concurrency is higher, i recommend to use [metadata-extractor][1] instead.


  [1]: https://github.com/drewnoakes/metadata-extractor

Why must local variables, including primitives, always be initialized in Java?  Why is the same not applicable in the case of instance variables?

Why must local variables, including primitives, always be initialized in Java?

Can the SQL &quot;truncate table&quot; command be used within a transaction?  I am creating an app and my table has a ton of records.  I want to delete all the records, but if the app fails I was to rollback my transaction.  Deleting each record takes a very long time.  I&#39;m wondering if I use truncate table, can I still rollback the transaction and get my data back in the event of a failure.  I realize that truncate table doesn&#39;t write each delete to the transaction log, but I&#39;m wondering if it writes the page deallocation to the log so that rollback works.  

Truncate Table Within Transaction

Is there a way to get the dimensions of an image without reading the entire file?

				
    URL url=new URL(&lt;BIG_IMAGE_URL&gt;);
    BufferedImage img=ImageIO.read(url);
    System.out.println(img.getWidth()+&quot; &quot;+img.getHeight());
    img=null;

Java/ImageIO getting image dimensions without reading the entire file?

Is there a way to get the dimensions of an image without reading the entire file?
<pre><code class="hljs language-ini">URL url=new URL(&#x3C;BIG_IMAGE_URL>);
BufferedImage img=ImageIO.read(url);
System.out.println(img.getWidth()+" "+img.getHeight());
img=null;
</code></pre>

I need to validate my JAXB objects before marshalling to an XML file.  Prior to JAXB 2.0, one could use a javax.xml.bind.Validator.  But that has been deprecated so I&#39;m trying to figure out the proper way of doing this.  I&#39;m familiar with validating at marshall time but in my case I just want to know if its valid.  I suppose I could marshall to a temp file or memory and throw it away but wondering if there is a more elegant solution.

How to validate against schema in JAXB 2.0 without marshalling?

I got a `AsyncTask` that is supposed to check the network access to a host name. But the `doInBackground()` is never timed out. Anyone have a clue?

    public class HostAvailabilityTask extends AsyncTask&lt;String, Void, Boolean&gt; {

	    private Main main;
	
    	public HostAvailabilityTask(Main main) {
    		this.main = main;
    	}
    
    	protected Boolean doInBackground(String... params) {
            Main.Log(&quot;doInBackground() isHostAvailable():&quot;+params[0]);
        
	    	try {
	    		return InetAddress.getByName(params[0]).isReachable(30); 
	    	} catch (UnknownHostException e) {
	    		e.printStackTrace();
	    	} catch (IOException e) {
	    		e.printStackTrace();
	    	}
	    	return false;		
	    }

	    protected void onPostExecute(Boolean... result) {
            Main.Log(&quot;onPostExecute()&quot;);
        
            if(result[0] == false) {
			    main.setContentView(R.layout.splash);
			    return;
            }
        
            main.continueAfterHostCheck();
	    }	
    }


How to check internet access on Android? InetAddress never times out

Are there any practical uses of anonymous code blocks in Java?

    public static void main(String[] args) {
        // in
        {
            // out
        }
    }

Please note that this is not about _named_ blocks, i.e.

    name: { 
         if ( /* something */ ) 
             break name;
    }

.

Anonymous code blocks in Java

I just got bit by using `.clone()` on my 2d `boolean` array, thinking that this was a deep copy.

How can I perform a deep copy of my `boolean[][]` array?

Should I loop through it and do a series of `System.arraycopy`&#39;s?

How do I do a deep copy of a 2d array in Java?

With HTML, how do I limit what kind of filetypes can be uploaded? 

To easy the user experience, I want to limit file uploads to be only images (jpeg, gif, png).

    &lt;form method=&quot;post&quot; action=&quot;...&quot; enctype=&quot;multipart/form-data&quot;&gt;
    &lt;label for=&quot;image&quot;&gt;Photo&lt;/label&gt;
    &lt;input name=&quot;image&quot; type=&quot;file&quot; /&gt;
    &lt;/form&gt;



HTML: How to limit file upload to be only images?

How much faster is it to use a base64/line to display images than opposed to simply linking to the hard file on the server?

    url(data:image/png;base64,.......)

I haven&#39;t been able to find any type of performance metrics on this.

I have a few concerns:


 - You no longer gain the benefit of caching
 - Isn&#39;t a base64 A LOT larger in size than what a PNG/JPEG file size?

**Let&#39;s define &quot;faster&quot; as in: the time it takes for a user to see a full rendered HTML web page**

			

How much faster is it to use inline/base64 images for a web site than just linking to the hard file?

I am given a byte[] array in Java which contains the bytes for an image, and I need to output it into an image. How would I go about doing this?

Much thanks

Byte Array to Image object

Often I need to download a webpage and then edit it offline.
I have tried a few tools and the main feature they lack is downloading images referenced in the CSS files.

Is there a tool (for Linux) that will download everything so that the webpage will render the same offline (excluding AJAX)?

download webpage and dependencies, including css images

Is there a way to adjust the position of list-style-image?

When I use padding for list items the image will stay at its position and won&#39;t move with padding...


Adjust list style image position?

I&#39;m currently trying to learn Numpy and Python. Given the following array:

    import numpy as np
    a = np.array([[1,2],[1,2]])

Is there a function that returns the dimensions of `a` (e.g.a is a 2 by 2 array)?

`size()` returns 4 and that doesn&#39;t help very much. 

Numpy array dimensions

I have an url to the image, like `$var = http://example.com/image.png`

**How do I get its dimensions to an array**, **like** `array([h]=&gt; 200, [w]=&gt;100)` `(height=200, width=100)`**?**

Get image dimensions

I&#39;m new to the CUDA paradigm. My question is in determining the number of threads per block, and blocks per grid. Does a bit of art and trial play into this? What I&#39;ve found is that many examples have seemingly arbitrary number chosen for these things.

I&#39;m considering a problem where I would be able to pass matrices - of any size - to a method for multiplication. So that, each element of C (as in C = A * B) would be calculated by a single thread. How would you determine the threads/block, blocks/grid in this case?

CUDA determining threads per block, blocks per grid

I have a file called `FPN = &quot;c:\ggs\ggs Access\images\members\1.jpg &quot;`

I&#39;m trying to get the dimension of image `1.jpg`, and I&#39;d like to check whether image dimension is valid or not before loading.

How to get the the dimensions of an image file?

&gt; **Possible Duplicate:**  
&gt; [Difference of px, dp, dip and sp in android](https://stackoverflow.com/questions/2025282/difference-of-px-dp-dip-and-sp-in-android)  

&lt;!-- End of automatically inserted text --&gt;

I&#39;ve found several topics on this. But none really answers my question.

Dp and dip in android. What is the difference? Is it the same thing?

Is dp the same as dip?


I have a BufferedImage I&#39;m trying to write to a jpeg file, but my Java program throws an exception. I&#39;m able to successfully save the same buffer to a gif and png. I&#39;ve tried looking around on Google for solutions, but to no avail.

Code:

	   File outputfile = new File(&quot;tiles/&quot; + row + &quot;:&quot; + col + &quot;.jpg&quot;);
	   try {
		   ImageIO.write(mapBufferTiles[row][col], &quot;jpg&quot;, outputfile);
	   } catch (IOException e) {
		   	outputfile.delete();
	   		throw new RuntimeException(e);
	   }


Exception:


	 Exception in thread &quot;main&quot; java.lang.RuntimeException: javax.imageio.IIOException: Invalid argument to native writeImage
	 at MapServer.initMapBuffer(MapServer.java:90)
	 at MapServer.&lt;init&gt;(MapServer.java:24)
	 at MapServer.main(MapServer.java:118)
	 Caused by: javax.imageio.IIOException: Invalid argument to native writeImage
	 at com.sun.imageio.plugins.jpeg.JPEGImageWriter.writeImage(Native Method)
	 at com.sun.imageio.plugins.jpeg.JPEGImageWriter.writeOnThread(JPEGImageWriter.java:1055)
	 at com.sun.imageio.plugins.jpeg.JPEGImageWriter.write(JPEGImageWriter.java:357)
	 at javax.imageio.ImageWriter.write(ImageWriter.java:615)
	 at javax.imageio.ImageIO.doWrite(ImageIO.java:1602)
	 at javax.imageio.ImageIO.write(ImageIO.java:1526)
	 at MapServer.initMapBuffer(MapServer.java:87)
	 ... 2 more


ImageIO not able to write a JPEG file

I&#39;m using the new ImageIO framework in iOS 4.1. I successfully retrieve the exif metadata using the following:

    CFDictionaryRef metadataDict = CMGetAttachment(sampleBuffer, kCGImagePropertyExifDictionary , NULL);

Reading it out, it appears valid. Saving an image out works, but there is never any exif data in the image.

        CGImageDestinationRef myImageDest = CGImageDestinationCreateWithURL((CFURLRef) docurl, kUTTypeJPEG, 1, NULL);
        
        // Add the image to the destination using previously saved options. 
        CGImageDestinationAddImage(myImageDest, iref, NULL);
        
        //add back exif
        NSDictionary *props = [NSDictionary dictionaryWithObjectsAndKeys:
                                [NSNumber numberWithFloat:.1], kCGImageDestinationLossyCompressionQuality,
                               metadataDict, kCGImagePropertyExifDictionary, //the exif metadata
                                                            nil];
                               
                              //kCGImagePropertyExifAuxDictionary
        
        CGImageDestinationSetProperties(myImageDest, (CFDictionaryRef) props);
        
        // Finalize the image destination. 
        bool status = CGImageDestinationFinalize(myImageDest);



Problem setting exif data for an image

I&#39;m looking for the fastest way to get pixel data (int the form `int[][]`) from a [`BufferedImage`][1]. My goal is to be able to address pixel `(x, y)` from the image using `int[x][y]`. All the methods I have found do not do this (most of them return `int[]`s).


  [1]: http://download.oracle.com/javase/6/docs/api/java/awt/image/BufferedImage.html

Java - get pixel array from image

I have a web server running with Jersey REST resources up and I wonder how to get an image/png reference for the browsers img tag; after submitting a Form or getting an Ajax response. The image processing code for adding graphics is working, just need to return it somehow.

Code:

    @POST
    @Path(&quot;{fullsize}&quot;)
    @Consumes(MediaType.MULTIPART_FORM_DATA)
    @Produces(&quot;image/png&quot;)
    // Would need to replace void
    public void getFullImage(@FormDataParam(&quot;photo&quot;) InputStream imageIS,
                             @FormDataParam(&quot;submit&quot;) String extra) {

          BufferedImage image = ImageIO.read(imageIS);

          // .... image processing
          //.... image processing

          return ImageIO.  ..  ?

    }


Cheers

How to return a PNG image from Jersey REST service method to the browser

I&#39;m using [`javax.imageio.ImageIO`][2] to save a `BufferedImage` as a jpeg file. 
In particular, I created the following Java function:

    public static void getScreenShot(BufferedImage capture, Path folder, String filename) {
            try {
                ImageIO.write(capture, &quot;jpeg&quot;, new File(folder.toString()+&quot;/&quot;+filename+&quot;.jpg&quot;));
            } catch (AWTException | IOException ex) {
                Logger.getLogger(ScreenShotMaker.class.getName()).log(Level.SEVERE, null, ex);
            }
    }

Likewise any image manipulation software, I wish to change the compression level of the jpeg file. However, I&#39;m searching for this option that seems to be missing in `ImageIO`. 

Can I set the compression level and how?


  [1]: http://docs.oracle.com/javase/6/docs/api/java/awt/Robot.html
  [2]: http://docs.oracle.com/javase/6/docs/api/javax/imageio/ImageIO.html

Content Type	Original Author	Original Content on Stackoverflow
Question	Pierre	View Question on Stackoverflow
Solution 1 - Java	Sam Barnum	View Answer on Stackoverflow
Solution 2 - Java	sfussenegger	View Answer on Stackoverflow
Solution 3 - Java	Michael Borgwardt	View Answer on Stackoverflow
Solution 4 - Java	kensou97	View Answer on Stackoverflow

Java/ImageIO getting image dimensions without reading the entire file?

Java Problem Overview

Java Solutions

Solution 1 - Java

Solution 2 - Java

Solution 3 - Java

Solution 4 - Java

Truncate Table Within Transaction

Why must local variables, including primitives, always be initialized in Java?

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