I have a euclidean vector `a` sitting at the coordinates `(0, 1)`.
I want to rotate `a` by 90 degrees (clockwise) around the origin: `(0, 0)`.

If I have a proper understanding of how this should work, the resultant (x, y) coordinates after the rotation should be `(1, 0)`.
If I were to rotate it by 45 degrees (still clockwise) instead, I would have expected the resultant coordinates to be `(0.707, 0.707)`.

	theta = deg2rad(angle);

	cs = cos(theta);
	sn = sin(theta);
	
	x = x * cs - y * sn;
	y = x * sn + y * cs;

Using the above code, with an `angle` value of 90.0 degrees, the resultant coordinates are: `(-1, 1)`.
And I am so damn confused.
The examples seen in the following links represent the same formula shown above surely?

What have I done wrong?
Or have I misunderstood how a vector is to be rotated?

2D Euclidean vector rotations

I have a mesh that I want to rotate by 90 degrees inside Three JS. 
Here is the image of the current situation:
![enter image description here][1]


  [1]: http://i.stack.imgur.com/v0tPX.png

I want the selected mesh to be rotated parallelly to the large mesh.
I have tried rotating the matrix like this:

    matrix =   new THREE.Matrix4().makeRotationX(1.57)

But the mesh goes into strange rotations. Is there any easier way to rotate it by 90 degrees ? 

How can I rotate a mesh by 90 degrees in ThreeJS?

I want to know how to work out the new co-ordinates for a point when rotated by an angle relative to another point.

I have a block arrow and want to rotate it by an angle theta relative to a point in the middle of the base of the arrow.

This is required to allow me to draw a polygon between 2 onscreen controls. I can&#39;t use and rotate an image.

From what I have considered so far what complicates the matter further is that the origin of a screen is in the top left hand corner.


Rotate a point by another point in 2D

I have this ImageView in my layout:

    &lt;ImageView android:layout_width=&quot;fill_parent&quot;
            android:layout_height=&quot;wrap_content&quot;
            android:contentDescription=&quot;@string/image_divider&quot;
            android:paddingBottom=&quot;8dp&quot;
            android:paddingTop=&quot;4dp&quot;
            android:scaleType=&quot;fitXY&quot;
            android:src=&quot;@android:drawable/divider_horizontal_textfield&quot; /&gt;
It&#39;s a horizontal divider. I want to rotate it 90 degrees so I have a vertical divider.
 &lt;br/&gt;Is there any possible way to do it right here from the layout and not the Activity class?

Rotate ImageView source from layout xml file

I want to wobble an image back and forth in my application similar to how the iPhone icons wobble when you press down on it.  What&#39;s the best way to do that?  

This is my first foray into animations that&#39;s not using an animated GIF.  I think the idea is to slightly rotate the image back and forth to create the wobbling effect.  I&#39;ve looked at using CABasicAnimation and CAKeyframeAnimation.  CABasicAnimation creates a jitter every time it repeats because it jumps to the from position and doesn&#39;t interpolate back.  CAKeyframeAnimation seems like the solution except that I can&#39;t get it to work.  I must be missing something.  Here&#39;s my code using the CAKeyframeAnimation (which doesn&#39;t work):

    	NSString *keypath = @&quot;wobbleImage&quot;;
	CAKeyframeAnimation *animation = [CAKeyframeAnimation animationWithKeyPath:keypath];
	animation.duration = 1.0f;
	animation.delegate = self;
	animation.repeatCount = 5;
	
	CGFloat wobbleAngle = 0.0872664626f;
	NSValue *initial = [NSValue valueWithCATransform3D:CATransform3DMakeRotation(0.0f, 0.0f, 0.0f, 1.0f)];
	NSValue *middle = [NSValue valueWithCATransform3D:CATransform3DMakeRotation(wobbleAngle, 0.0f, 0.0f, 1.0f)];
	NSValue *final = [NSValue valueWithCATransform3D:CATransform3DMakeRotation(-wobbleAngle, 0.0f, 0.0f, 1.0f)];
	animation.values = [NSArray arrayWithObjects:initial, middle, final, nil];
	
	[imageView.layer addAnimation:animation forKey:keypath];

&lt;br /&gt;
Or there could be a totally simpler solution that I&#39;m just missing.  Appreciate any pointers.  Thanks!


how to create iphone&#39;s wobbling icon effect?

In iOS 8, the methods for interface rotation are [deprecated][1]. This includes:

* `willRotateToInterfaceOrientation:duration:`
* `didRotateFromInterfaceOrientation:`
* `willAnimateRotationToInterfaceOrientation:duration:`

The replacement methods include:

* `willTransitionToTraitCollection:withTransitionCoordinator:`
* `viewWillTransitionToSize:withTransitionCoordinator:`

If the new rotation methods are not implemented, and a project is compiled with the iOS 8 SDK, the view controllers -will **not receive calls**- to the deprecated rotation methods.

My concern is this: **What happens to an app already in the AppStore built with the iOS 7 SDK? Will the deprecated rotation methods still be called on an iOS 8 device or not?**


**EDIT:**

The rotation methods are still called, but there exist some changes/issues/bugs in iOS 8.

Also [`UIScreen` is now interface oriented][2]


  [1]: https://developer.apple.com/library/prerelease/ios/documentation/UIKit/Reference/UIViewController_Class/
  [2]: https://stackoverflow.com/a/24153540/354018

iOS 8 Rotation Methods Deprecation - Backwards Compatibility

I have CSS style for a layer:

    .element {
        -webkit-transform: rotate(7.5deg);    
         -moz-transform: rotate(7.5deg);    
          -ms-transform: rotate(7.5deg);    
           -o-transform: rotate(7.5deg);   
              transform: rotate(7.5deg);
    }

Is there a way to get curent rotation value through jQuery?

I tried this

    $(&#39;.element&#39;).css(&quot;-moz-transform&quot;)

The result is `matrix(0.991445, 0.130526, -0.130526, 0.991445, 0px, 0px)` which doesn&#39;t tell me a lot. What I&#39;m looking to get is `7.5`.

Get element -moz-transform:rotate value in jQuery

I have an iPad-application. In landscape orientation the `UIViewController`&#39;s view actual width = `1024px` and height = 768 - 20 (statusBar) - 44 (navigationBar) = `704px`.

So I wanna get this `[1024 x 704]` size and I&#39;m using `self.view.bounds` for it. It returns `[748 x 1024]`, which is wrong! But when I rotate the screen twice (current -&gt; portrait -&gt; current), the view&#39;s bounds are correct - `[1024 x 704]`. 

The view was initialized like this:

    - (void)loadView {
    	self.view = [[UIView alloc] initWithFrame:[[UIScreen mainScreen] applicationFrame]];
    	self.view.backgroundColor = [UIColor lightGrayColor];
    }

And bounds were get like this:

    - (void)viewDidLoad {
        [super viewDidLoad];
    	NSLog(@&quot;bounds = %@&quot;, NSStringFromCGRect(self.view.bounds));
    }
    - (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation {
    	NSLog(@&quot;bounds = %@&quot;, NSStringFromCGRect(self.view.bounds));
    }

So the question is.. How can I get the correct view&#39;s bound in the very beginning?

Getting the correct bounds of UIViewController&#39;s view

Auto Layout is making my life difficult. In theory, it was going to be really useful when I switched, but I seem to fight it all of the time.

I&#39;ve made a demo project to try to find help. Does anyone know how to make the spaces between views increase or decrease evenly whenever the view is resized?

Here are three labels (manually spaced vertically even):

![image1][2]

What I want is for them to resize their spacing (not the view size) evenly when I rotate. By default, the top and bottom views squish towards the center:

![image2][3]

  [2]: http://i.stack.imgur.com/rc7LK.png
  [3]: http://i.stack.imgur.com/APdX9.png

Evenly space multiple views within a container view

anyway to make a rotation work on the pseudo 

    content:&quot;\24B6&quot;? 

I&#39;m trying to rotate a unicode symbol.

css rotate a pseudo :after or :before content:&quot;&quot;

I am using the following code to rotate a image in ImageView by an angle. Is there any simpler and less complex method available.

    ImageView iv = (ImageView)findViewById(imageviewid);
    TextView tv = (TextView)findViewById(txtViewsid);
    Matrix mat = new Matrix();
    Bitmap bMap = BitmapFactory.decodeResource(getResources(),imageid);
    mat.postRotate(Integer.parseInt(degree));===&gt;angle to be rotated
    Bitmap bMapRotate = Bitmap.createBitmap(bMap, 0, 0,bMap.getWidth(),bMap.getHeight(), mat, true);
    iv.setImageBitmap(bMapRotate);

Android: Rotate image in imageview by an angle

Digital camera photos are often saved as JPEG with an EXIF &quot;orientation&quot; tag. To display correctly, images need to be rotated/mirrored depending on which orientation is set, but browsers ignore this information rendering the image. Even in large commercial web apps, support for EXIF orientation can be spotty [1]. The same source also provides a nice summary of the __8 different orientations__  a JPEG can have:

![Summary of EXIF Orientations](https://i.stack.imgur.com/6cJTP.gif)

Sample images are available at [4]. 

__The question is how to rotate/mirror the image on the client side so that it displays correctly and can be further processed if necessary?__

There are JS libraries available to parse EXIF data, including the orientation attribute [2]. Flickr noted possible performance problem when parsing large images, requiring use of webworkers [3].

Console tools can correctly re-orient the images [5]. A PHP script solving the problem is available at [6]

[1]: http://www.daveperrett.com/articles/2012/07/28/exif-orientation-handling-is-a-ghetto/
[2]: https://github.com/jseidelin/exif-js
[3]: http://code.flickr.net/2012/06/01/parsing-exif-client-side-using-javascript-2/
[4]: http://www.galloway.me.uk/2012/01/uiimageorientation-exif-orientation-sample-images/
[5]: https://superuser.com/questions/36645/how-to-rotate-images-automatically-based-on-exif-data
[6]: http://www.neilyoungcv.com/blog/code-share/image-resizing-with-php-exif-orientation-fix/

JS Client-Side Exif Orientation: Rotate and Mirror JPEG Images

I am using -webkit-transform (and -moz-transform / -o-transform) to rotate a div. Also have position fixed added so the div scrols down with the user.

In Firefox it works fine, but in webkit based browsers it&#39;s broken. After using the -webkit-transform, the position fixed doesn&#39;t work anymore! How is that possible?

Positions fixed doesn&#39;t work when using -webkit-transform

When I load an image from the media gallery into a Bitmap, everything is working fine, except that pictures that were shot with the camera while holding the phone vertically, are rotated so that I always get a horizontal picture even though it appears vertical in the gallery.
Why is that and how can I load it correctly?

Android: Bitmaps loaded from gallery are rotated in ImageView

Left and right shift operators (&lt;&lt; and &gt;&gt;) are already available in C++.
However, I couldn&#39;t find out how I could perform circular shift or rotate operations.

How can operations like &quot;Rotate Left&quot; and &quot;Rotate Right&quot; be performed? 


Rotating right twice here 

    Initial --&gt; 1000 0011 0100 0010

should result in:

    Final   --&gt; 1010 0000 1101 0000


An example would be helpful.

(editor&#39;s note: Many common ways of expressing rotates in C suffer from undefined behaviour if the rotate count is zero, or compile to more than just a single rotate machine instruction.  This question&#39;s answer should document best practices.)

Best practices for circular shift (rotate) operations in C++

What *exactly* happens when you call `setRetainInstance(true)` on a `Fragment`? The documentation is virtually non-existent and this seems like a very important function. Specifically I want to know how much of this sequence (that I made up) is true:

&gt; 1. The user rotates the device.
&gt; 2. The fragment is detached from the `Activity` and `Fragment.onDetach()` is called.
&gt; 3. The activity is destroyed; `Activity.onDestroy()` is called.
&gt; 4. The `Activity` java object is deleted (when possible, by the GC).
&gt; 5. A new `Activity` java object is created; its constructor, and `onCreate()` are called.
&gt; 6. In `Activity.onCreate()` we either have `setContentView(...)` which sets a layout containing a fragment, or we use `FragmentTransaction`
&gt; to add a fragment.
&gt; 7. I&#39;m really not sure about this, but I assume that android is smart enough to find the old fragment, and call `Fragment.onAttach()` to
&gt; reattach it to the new `Activity`
&gt; 8. Next (or before? who knows?) `Activity.onResume()` is called.

So is that correct? Is Android smart enough to find the old fragment, even if I explicitly use `FragmentTransaction.add(new MyFragment(), ...)` the first time? And if so, how do I avoid adding *another* fragment in `onCreate()`? Do I need to do something like this?:


		if (getSupportFragmentManager().findFragmentByTag(&quot;foo&quot;) == null)
		{
			FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
			ft.add(new FooFragment(), &quot;foo&quot;).commit();
		}


Further understanding setRetainInstance(true)

I was wondering what was the most efficient way to rotate a JavaScript array.

I came up with this solution, where a positive `n` rotates the array to the right, and a negative `n` to the left (`-length &lt; n &lt; length`) :

    Array.prototype.rotateRight = function( n ) {
      this.unshift( this.splice( n, this.length ) );
    }

Which can then be used this way:

    var months = [&quot;Jan&quot;, &quot;Feb&quot;, &quot;Mar&quot;, &quot;Apr&quot;, &quot;May&quot;, &quot;Jun&quot;, &quot;Jul&quot;, &quot;Aug&quot;, &quot;Sep&quot;, &quot;Oct&quot;, &quot;Nov&quot;, &quot;Dec&quot;];
    months.rotate( new Date().getMonth() );

My original version above has a flaw, as pointed out by [Christoph][1] in the comments bellow, a correct version is (the additional return allows chaining):

    Array.prototype.rotateRight = function( n ) {
      this.unshift.apply( this, this.splice( n, this.length ) );
      return this;
    }


Is there a more compact and/or faster solution, possibly in the context of a JavaScript framework? (none of the proposed versions bellow is either more compact or faster)

Is there any JavaScript framework out there with an array rotate built-in? (Still not answered by anyone)

  [1]: https://stackoverflow.com/users/48015/christoph

Rotate the elements in an array in JavaScript

&gt; **Possible Duplicate:**  
&gt; [Efficient way to shift a list in python](https://stackoverflow.com/questions/2150108/efficient-way-to-shift-a-list-in-python)  

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

I&#39;d like to rotate a Python list by an arbitrary number of items to the right or left (the latter using a negative argument).

Something like this:

    &gt;&gt;&gt; l = [1,2,3,4]
    &gt;&gt;&gt; l.rotate(0)
    [1,2,3,4]
    &gt;&gt;&gt; l.rotate(1)
    [4,1,2,3]
    &gt;&gt;&gt; l.rotate(-1)
    [2,3,4,1]
    &gt;&gt;&gt; l.rotate(4)
    [1,2,3,4]

How might this be done?

Python list rotation

I have been trying to figure out how to rotate videos with FFmpeg. I am working with iPhone videos taken in portrait mode. I know how to determine the current degrees of rotation using [MediaInfo][1] (excellent library, btw) but I&#39;m stuck on FFmpeg now.

From what I&#39;ve read, what you need to use is a **vfilter** option. According to what I see, it should look like this:

    ffmpeg -vfilters &quot;rotate=90&quot; -i input.mp4 output.mp4

However, I can&#39;t get this to work. First, **-vfilters** doesn&#39;t exist anymore, it&#39;s now just **-vf**. Second, I get this error:

    No such filter: &#39;rotate&#39;
    Error opening filters!

As far as I know, I have an all-options-on build of FFmpeg. Running ***ffmpeg -filters*** shows this:

    Filters:
    anull            Pass the source unchanged to the output.
    aspect           Set the frame aspect ratio.
    crop             Crop the input video to x:y:width:height.
    fifo             Buffer input images and send them when they are requested.
    format           Convert the input video to one of the specified pixel formats.
    hflip            Horizontally flip the input video.
    noformat         Force libavfilter not to use any of the specified pixel formats
     for the input to the next filter.
    null             Pass the source unchanged to the output.
    pad              Pad input image to width:height[:x:y[:color]] (default x and y:
     0, default color: black).
    pixdesctest      Test pixel format definitions.
    pixelaspect      Set the pixel aspect ratio.
    scale            Scale the input video to width:height size and/or convert the i
    mage format.
    slicify          Pass the images of input video on to next video filter as multi
    ple slices.
    unsharp          Sharpen or blur the input video.
    vflip            Flip the input video vertically.
    buffer           Buffer video frames, and make them accessible to the filterchai
    n.
    color            Provide an uniformly colored input, syntax is: [color[:size[:ra
    te]]]
    nullsrc          Null video source, never return images.
    nullsink         Do absolutely nothing with the input video.

Having the options for **vflip** and **hflip** are great and all, but they just won&#39;t get me where I need to go. I need to the ability to rotate videos 90 degrees at the very least. 270 degrees would be an excellent option to have as well. Where have the rotate options gone?


  [1]: http://mediainfo.sourceforge.net/en

Rotating videos with FFmpeg

I&#39;d like to statically rotate my font-awesome icons by 45 degrees. It says on the site that:

&gt; To arbitrarily rotate and flip icons, use the fa-rotate-* and fa-flip-* classes.

However, doing

    &lt;i class=&quot;fa fa-link fa-rotate-45&quot; style=&quot;font-size:1.5em&quot;&gt;&lt;/i&gt;

does not work, whereas replacing `fa-rotate-45` with `fa-rotate-90` does. Does this mean that they in fact cannot rotate arbitrarily?






Statically rotate font-awesome icons

I&#39;m looking for a way to rotate videos shot with my Nexus 4 on my Debian Wheezy sytem. The videos are shot in portrait mode and I would like to rotate them to landscape mode. Preferably the rotation is command-line driven.

I have found several previous questions which are hinting at a good solution but I can&#39;t seem to manage to get it working.

To begin with there was this question:
https://stackoverflow.com/questions/3937387/rotating-videos-with-ffmpeg

But it indicates that ffmpeg is outdated and that I should use avconv. I found this question detailing the way to go forward.
https://askubuntu.com/questions/269429/how-can-i-rotate-video-by-180-degrees-with-avconv

This made me using following command:

    avconv -i original.mp4 -vf &quot;transpose=1&quot; -codec:v libx264 -preset slow -crf 25 -codec:a copy flipped.mp4

However, this is painstakingly slow (last test took me more than 6 hours for less than 3 minutes of footage) and does not result in a playable movie. I also get an error in logging output which states Mb Rate &gt; level limit.

Is there an issue here with the re-encoding? Should I first re-encode the videos from my phone to another, more &quot;workable&quot; encoding before applying the rotations? Or am I missing another important point?

Rotate mp4 videos without re-encoding

I&#39;m capturing an image and setting it to image view.

    public void captureImage() {

        Intent intentCamera = new Intent(&quot;android.media.action.IMAGE_CAPTURE&quot;);
        File filePhoto = new File(Environment.getExternalStorageDirectory(), &quot;Pic.jpg&quot;);
        imageUri = Uri.fromFile(filePhoto);
        MyApplicationGlobal.imageUri = imageUri.getPath();
        intentCamera.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
        startActivityForResult(intentCamera, TAKE_PICTURE);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent intentFromCamera) {
        super.onActivityResult(requestCode, resultCode, intentFromCamera);

        if (resultCode == RESULT_OK &amp;&amp; requestCode == TAKE_PICTURE) {

            if (intentFromCamera != null) {
                Bundle extras = intentFromCamera.getExtras();
                if (extras.containsKey(&quot;data&quot;)) {
                    bitmap = (Bitmap) extras.get(&quot;data&quot;);
                }
                else {
                    bitmap = getBitmapFromUri();
                }
            }
            else {
                bitmap = getBitmapFromUri();
            }
            // imageView.setImageBitmap(bitmap);
            imageView.setImageURI(imageUri);
        }
        else {
        }
    }

    public Bitmap getBitmapFromUri() {

        getContentResolver().notifyChange(imageUri, null);
        ContentResolver cr = getContentResolver();
        Bitmap bitmap;

        try {
            bitmap = android.provider.MediaStore.Images.Media.getBitmap(cr, imageUri);
            return bitmap;
        }
        catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

But the problem is, the image on some devices every time it gets rotated. For example, on a Samsung device it works good, but on a [Sony Xperia][1] the image gets rotated by 90 degrees and on [Toshiba Thrive][2] (tablet) by 180 degrees.

  [1]: https://en.wikipedia.org/wiki/Sony_Xperia
  [2]: https://en.wikipedia.org/wiki/Toshiba_Thrive


Why does an image captured using camera intent gets rotated on some devices on Android?

    jQuery(&#39;#carregar&#39;).click(function() {
	  var canvas	= document.getElementById(&#39;canvas&#39;);
	  var image   = document.getElementById(&#39;image&#39;);
	  var element = canvas.getContext(&quot;2d&quot;);
	  element.clearRect(0, 0, canvas.width, canvas.height);
	  element.drawImage(image, 0, 0, 300, 300);
    });

[jsfiddle.net/braziel/nWyDE/](http://jsfiddle.net/braziel/nWyDE/)



I have a problem to rotate an image 90 &#176; to the right or to the left.

I use an image on the canvas, the same screen will have several canvas equal to that of the example, but I left it as close as possible to the project.

I ask, how do I rotate the image 90 &#176; to the left or right when I click &quot;Rotate Left&quot; and &quot;Rotate Right&quot;?

I tried several codes on the internet but none worked.


  [1]: http://jsfiddle.net/braziel/nWyDE/1/

HTML5 Canvas Rotate Image

I&#39;m working on creating a cross-browser compatible rotation (ie9+) and I have the following code in a [jsfiddle][1]

    $(document).ready(function () { 
        DoRotate(30);
        AnimateRotate(30);
    });
    
    function DoRotate(d) {
    
        $(&quot;#MyDiv1&quot;).css({
              &#39;-moz-transform&#39;:&#39;rotate(&#39;+d+&#39;deg)&#39;,
              &#39;-webkit-transform&#39;:&#39;rotate(&#39;+d+&#39;deg)&#39;,
              &#39;-o-transform&#39;:&#39;rotate(&#39;+d+&#39;deg)&#39;,
              &#39;-ms-transform&#39;:&#39;rotate(&#39;+d+&#39;deg)&#39;,
              &#39;transform&#39;: &#39;rotate(&#39;+d+&#39;deg)&#39;
         });  
    }
    
    function AnimateRotate(d) {
    
            $(&quot;#MyDiv2&quot;).animate({
              &#39;-moz-transform&#39;:&#39;rotate(&#39;+d+&#39;deg)&#39;,
              &#39;-webkit-transform&#39;:&#39;rotate(&#39;+d+&#39;deg)&#39;,
              &#39;-o-transform&#39;:&#39;rotate(&#39;+d+&#39;deg)&#39;,
              &#39;-ms-transform&#39;:&#39;rotate(&#39;+d+&#39;deg)&#39;,
              &#39;transform&#39;:&#39;rotate(&#39;+d+&#39;deg)&#39;
         }, 1000); 
    }

The CSS and HTML are really simple and just for demo:

    .SomeDiv{
        width:50px;
        height:50px;       
        margin:50px 50px;
        background-color: red;}
    
    &lt;div id=&quot;MyDiv1&quot; class=&quot;SomeDiv&quot;&gt;test&lt;/div&gt;
    &lt;div id=&quot;MyDiv2&quot; class=&quot;SomeDiv&quot;&gt;test&lt;/div&gt;

The rotation works when using `.css()` but not when using `.animate()`; why is that and is there a way to fix it?

Thanks.


  [1]: http://jsfiddle.net/UB2XR/21/

CSS rotation cross browser with jquery.animate()

Is there a way I could add in the source of my image codes that could rotate my image?

Something like this:

    &lt;img id=&quot;image_canv&quot; src=&quot;/image.png&quot; rotate=&quot;90&quot;&gt;

I&#39;m making my images dynamic, so I was wondering if I could append some extra code to rotate it if I want it to.

Rotate an image in image source in html

I have two vectors as Python lists and an angle. E.g.:

    v = [3,5,0]
    axis = [4,4,1]
    theta = 1.2 #radian

What is the best/easiest way to get the resulting vector when rotating the v vector around the axis?

The rotation should appear to be counter clockwise for an observer to whom the axis vector is pointing. This is called the [right hand rule][1]


  [1]: http://en.wikipedia.org/wiki/Right_hand_rule

Rotation of 3D vector?

I have the coordinates of the top left point of a rectangle as well as its width, height and rotation from 0 to 180 and -0 to -180.

I am trying to get the bounding coordinates of the actual box around the rectangle.

What is a simple way of calculating the coordinates of the bounding box 

- Min y, max y, min x, max x?

The A point is not always on the min y bound, it can be anywhere.

I can use matrix the transform toolkit in as3 if needed.

Calculate Bounding box coordinates from a rotated rectangle

I&#39;m having a hard time finding examples for rotating an image around a specific point by a specific (often very small) angle in Python using OpenCV.

This is what I have so far, but it produces a very strange resulting image, but it is rotated somewhat:

    def rotateImage( image, angle ):
        if image != None:
            dst_image = cv.CloneImage( image )

            rotate_around = (0,0)
            transl = cv.CreateMat(2, 3, cv.CV_32FC1 )

            matrix = cv.GetRotationMatrix2D( rotate_around, angle, 1.0, transl )
            cv.GetQuadrangleSubPix( image, dst_image, transl )
            cv.GetRectSubPix( dst_image, image, rotate_around )

        return dst_image


OpenCV Python rotate image by X degrees around specific point

I have one UIView which is not using Auto-Layout and some components are displayed based on their percent of X and Y co-ordinates from the main view.

Previously I would have run a function to update their positions in didRotateFromInterfaceOrientation however I see this is now deprecated in iOS8.

I&#39;ve taken a look at viewWillTransitionToSize but it&#39;s giving weird results, and there doesn&#39;t appear to be a viewDidtransitionToSize function.

Is there an easy way (in Swift) to run a function after a device rotation?

iOS: How to run a function after Device has Rotated (Swift)

I have an element that needs to be vertical in a design I have done. I have got the css for this to work in all browsers except IE9. I used the filter for IE7 &amp; IE8:

    progid:DXImageTransform.Microsoft.BasicImage(rotation=3);

This however seems to render my element transparent in IE9 and the CSS3 &#39;tranform&#39; porperty doesn&#39;t seem to do anything!

Does anyone know anyway of rotating elements in IE9?

Really appreciate the help!

W.

CSS3 transform: rotate; in IE9

I have a button that I want to put on a 45 degree angle. For some reason I can&#39;t get this to work. 

Can someone please provide the code to accomplish this?

Rotating a view in Android

I want to rotate the DIV to a certain degree. In FF it functions but in IE I am facing a problem.

For example in the following style I can set rotation=1 to 4

     filter: progid:DXImageTransform.Microsoft.BasicImage(rotation=1);

This means that the DIV will be rotated to 90 or 180 or 270 or 360 degree. But if I need to rotate the DIV only 20 degrees, then it doesn&#39;t work anymore.

How may I solve this problem in IE?

CSS rotate property in IE

How can you rotate text for `UIButton` and `UILabel`? 90 degrees, 180 degrees.

**Note:** Before you mark this as a duplicate, I am intentionally modelling my question as a Swift version of this one: https://stackoverflow.com/questions/6326720/objective-c-how-can-you-rotate-text-for-uibutton-and-uilabel



How can you rotate text for UIButton and UILabel in Swift?

I am creating an Android app in which I&#39;m drawing a view on a canvas. When the device&#39;s orientation changes, the activity restarts. I don&#39;t want it to.

How can I avoid restarting the activity when the orientation changes?

How to avoid restarting activity when orientation changes on Android

Rotation is a style transform and in RN, you can rotate things like this

      render() {
        return (
          &lt;View style={{transform:[{rotate: &#39;10 deg&#39;}]}}&gt;
            &lt;Image source={require(&#39;./logo.png&#39;)} /&gt;
          &lt;/View&gt;
        );
      }

However, to animate things in RN, you have to use numbers, not strings.  Can you still animate transforms in RN or do I have to come up with some kind of sprite sheet and change the Image src at some fps?

React Native: How do you animate the rotation of an Image?

How can you rotate text for `UIButton` and `UILabel`? 90 degrees, 180 degrees.


How can you rotate text for UIButton and UILabel in Objective-C?

I am making an android project in opengl es that uses accelerometer to calculate change in specific axes and my aim is to rotate my spacecraft-like object&#39;s movement vector. The problem is that i can&#39;t understand the math behind rotation matrices. Default movement vector is 0,1,0 , means +y, so the object looks upward in the beginning. and i am trying to rotate its movement vector so i can move the object where it points. I can gather rotation changes in phone. x-axis : rotate[0], y-axis : rotate[1], z-axis : rotate[2]. How can i rotate my movement vector using rotation matrix ?

Rotating a Vector in 3D Space

Why doesn&#39;t the textView become invisible?

Here is my layout xml:

    &lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
    &lt;LinearLayout xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
        android:layout_width=&quot;match_parent&quot;
        android:layout_height=&quot;match_parent&quot;
        android:orientation=&quot;vertical&quot; &gt;
	
        &lt;TextView
	    android:id=&quot;@+id/tvRotate&quot;
	    android:layout_width=&quot;wrap_content&quot;
	    android:layout_height=&quot;wrap_content&quot;
	    android:text=&quot;Rotate Me&quot;
	/&gt;
    &lt;/LinearLayout&gt;

..and here is my activity:

	public class RotateMeActivity extends Activity
	{
		@Override
		public void onCreate(Bundle savedInstanceState) 
		{
			super.onCreate(savedInstanceState);
			setContentView(R.layout.main);
			TextView tvRotate = (TextView) findViewById(R.id.tvRotate);
			
			RotateAnimation r = new RotateAnimation(0, 180, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);
			r.setDuration(0);
			r.setFillAfter(true);
			tvRotate.startAnimation(r);
			tvRotate.setVisibility(View.INVISIBLE);
		}
	}
	
My goal is to rotate a view and then be able to hide and show it in code by setting setVisibility. The following works, but setRotation is available only in API Level 11. I need a way to do it in API Level 10.

    tvRotate.setRotation(180);//instead of the RotateAnimation, only works in API Level 11
    tvRotate.setVisibility(View.INVISIBLE);
        




Why doesn&#39;t setVisibility work after a view is animated?

What is the best way (in c/c++) to rotate an IplImage/cv::Mat by 90 degrees? I would assume that there must be something better than transforming it using a matrix, but I can&#39;t seem to find anything other than that in the API and online.

Easiest way to rotate by 90 degrees an image using OpenCV?

I am working on a swift app for iPhone. There is a modal view in my application that I want only to be in portrait view.

My question is, how do I programmatically force the phone to not allow rotation? In other words, I am looking for code that will not allow a modal view to be displayed in landscape mode (turning on portrait rotation lock).

This is just for 1 modal view, so I can&#39;t turn off rotation for the entire app, otherwise I would just disable rotation altogether.

I found code in my research [here][1]
But it is in objective C, in case that helps. Thanks!

  [1]: https://stackoverflow.com/questions/4330979/how-to-set-device-ui-orientation-programmatically

Setting device orientation in Swift iOS

I&#39;m trying to rotate an ``UIView`` a few radians but after applying the transformation it doesn&#39;t look to be keeping its size. What&#39;s the proper way to achieve this?

Here&#39;s what I&#39;m doing and what I get (Blue box with the arrow is the View I&#39;m trying to rotate -- it should keep same aspect as red box behind):

    #define DEGREES_TO_RADIANS(angle) ((angle) / 180.0 * M_PI)

    double rads = DEGREES_TO_RADIANS(240);
    CGAffineTransform transform = CGAffineTransformRotate(CGAffineTransformIdentity, rads);
    self.arrowView.transform = transform;

![enter image description here][1]

Thanks!


  [1]: http://i.stack.imgur.com/GGDxk.png

Rotate UIView around its center keeping its size

![enter image description here][1]


  [1]: http://i.stack.imgur.com/mHexZ.gif


two objects in the scene.
the cube rotate axis should be the cube&#39;s center,that&#39;s my expect.

but the shoe model&#39;s rotate axis is the world&#39;s y axis.

my original code is.

    cube.rotation.y += 0.01;
    shoe.rotation.y += 0.01;

I found a solution in stackoverflow,like this:

    cube.rotation.y += 0.01;
    var pivot = new THREE.Object3D();
    pivot.add(shoe);
    pivot.rotation.y += 0.01;

But it doesn&#39;t work.
And then, I change the shoe&#39;s position. 

    cube.rotation.y += 0.01;
    var pivot = new THREE.Object3D();
    shoe.position.set(-5,0,0);
    pivot.add(shoe);
    pivot.rotation.y += 0.01;

The result is better now, but it still not perfect. And since there are a lot of shoe&#39;s model, I can&#39;t determine different position for every shoe model.

threejs how to rotate around object&#39;s own center,instead of world center

I have one of my activities which I would like to prevent from rotating because I&#39;m starting an AsyncTask, and screen rotation makes it restart.

Is there a way to tell this activity &quot;DO NOT ROTATE the screen even if the user is shaking his phone like mad&quot;?


Prevent screen rotation on Android

How can I get log4j to delete old rotating log files?  I know I can set up automated jobs (cron for UNIX and scheduled task for Windows), but I want it cross platform, and I want it in our application&#39;s log configuration as a part of our application, rather than in separate code outside in OS specific scripting languages.  Our application is not written in OS scripting languages, and I don&#39;t want to do this part of it in them.

How can I get log4j to delete old rotating log files?

**( edit: I added the best working approach in my [augmented reality framework][1] and now also take the gyroscope into account which makes it much more stable again: [DroidAR framework][1] )**

I have written a TestSuite to find out how to calculate the rotation angles from the data you get in `SensorEventListener.onSensorChanged()`.
I really hope you can complete my solution to help people who will have the same problems like me. Here is the code, I think you will understand it after reading it.

Feel free to change it, the main idea was to implement several methods to send the orientation angles to the opengl view or any other target which would need it.

method 1 to 4 are working, they are directly sending the rotationMatrix to the OpenGl view.

method 6 works now too, but I have no explanation why the rotation has to be done y x z..

all other methods are not working or buggy and I hope someone knows to get them working.I think the best method would be method 5 if it would work, because it would be the easiest to understand but i&#39;m not sure how efficient it is. the complete code isn&#39;t optimized so I recommend to not use it as it is in your project.

here it is:
    
    
    /**
     * This class provides a basic demonstration of how to use the
     * {@link android.hardware.SensorManager SensorManager} API to draw a 3D
     * compass.
     */
    public class SensorToOpenGlTests extends Activity implements Renderer,
      SensorEventListener {
    
     private static final boolean TRY_TRANSPOSED_VERSION = false;
    
     /*
      * MODUS overview:
      * 
      * 1 - unbufferd data directly transfaired from the rotation matrix to the
      * modelview matrix
      * 
      * 2 - buffered version of 1 where both acceleration and magnetometer are
      * buffered
      * 
      * 3 - buffered version of 1 where only magnetometer is buffered
      * 
      * 4 - buffered version of 1 where only acceleration is buffered
      * 
      * 5 - uses the orientation sensor and sets the angles how to rotate the
      * camera with glrotate()
      * 
      * 6 - uses the rotation matrix to calculate the angles
      * 
      * 7 to 12 - every possibility how the rotationMatrix could be constructed
      * in SensorManager.getRotationMatrix (see
      * http://www.songho.ca/opengl/gl_anglestoaxes.html#anglestoaxes for all
      * possibilities)
      */
    
     private static int MODUS = 2;
    
     private GLSurfaceView openglView;
     private FloatBuffer vertexBuffer;
     private ByteBuffer indexBuffer;
     private FloatBuffer colorBuffer;
    
     private SensorManager mSensorManager;
     private float[] rotationMatrix = new float[16];
     private float[] accelGData = new float[3];
     private float[] bufferedAccelGData = new float[3];
     private float[] magnetData = new float[3];
     private float[] bufferedMagnetData = new float[3];
     private float[] orientationData = new float[3];
    
     // private float[] mI = new float[16];
    
     private float[] resultingAngles = new float[3];
    
     private int mCount;
    
     final static float rad2deg = (float) (180.0f / Math.PI);
    
     private boolean landscape;
    
     public SensorToOpenGlTests() {
     }
    
     /** Called with the activity is first created. */
     @Override
     public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
    
      mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
      openglView = new GLSurfaceView(this);
      openglView.setRenderer(this);
      setContentView(openglView);
     }
    
     @Override
     protected void onResume() {
      // Ideally a game should implement onResume() and onPause()
      // to take appropriate action when the activity looses focus
      super.onResume();
      openglView.onResume();
    
      if (((WindowManager) getSystemService(WINDOW_SERVICE))
        .getDefaultDisplay().getOrientation() == 1) {
       landscape = true;
      } else {
       landscape = false;
      }
    
      mSensorManager.registerListener(this, mSensorManager
        .getDefaultSensor(Sensor.TYPE_ACCELEROMETER),
        SensorManager.SENSOR_DELAY_GAME);
      mSensorManager.registerListener(this, mSensorManager
        .getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD),
        SensorManager.SENSOR_DELAY_GAME);
      mSensorManager.registerListener(this, mSensorManager
        .getDefaultSensor(Sensor.TYPE_ORIENTATION),
        SensorManager.SENSOR_DELAY_GAME);
     }
    
     @Override
     protected void onPause() {
      // Ideally a game should implement onResume() and onPause()
      // to take appropriate action when the activity looses focus
      super.onPause();
      openglView.onPause();
      mSensorManager.unregisterListener(this);
     }
    
     public int[] getConfigSpec() {
      // We want a depth buffer, don&#39;t care about the
      // details of the color buffer.
      int[] configSpec = { EGL10.EGL_DEPTH_SIZE, 16, EGL10.EGL_NONE };
      return configSpec;
     }
    
     public void onDrawFrame(GL10 gl) {
    
      // clear screen and color buffer:
      gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
      // set target matrix to modelview matrix:
      gl.glMatrixMode(GL10.GL_MODELVIEW);
      // init modelview matrix:
      gl.glLoadIdentity();
      // move camera away a little bit:
    
      if ((MODUS == 1) || (MODUS == 2) || (MODUS == 3) || (MODUS == 4)) {
    
       if (landscape) {
        // in landscape mode first remap the rotationMatrix before using
        // it with glMultMatrixf:
        float[] result = new float[16];
        SensorManager.remapCoordinateSystem(rotationMatrix,
          SensorManager.AXIS_Y, SensorManager.AXIS_MINUS_X,
          result);
        gl.glMultMatrixf(result, 0);
       } else {
        gl.glMultMatrixf(rotationMatrix, 0);
       }
      } else {
       //in all other modes do the rotation by hand
       //the order y x z is important!
       gl.glRotatef(resultingAngles[2], 0, 1, 0);
       gl.glRotatef(resultingAngles[1], 1, 0, 0);
       gl.glRotatef(resultingAngles[0], 0, 0, 1);
      }
      
      //move the axis to simulate augmented behaviour:
      gl.glTranslatef(0, 2, 0);
      
      // draw the 3 axis on the screen:
      gl.glVertexPointer(3, GL_FLOAT, 0, vertexBuffer);
      gl.glColorPointer(4, GL_FLOAT, 0, colorBuffer);
      gl.glDrawElements(GL_LINES, 6, GL_UNSIGNED_BYTE, indexBuffer);
     }
    
     public void onSurfaceChanged(GL10 gl, int width, int height) {
      gl.glViewport(0, 0, width, height);
      float r = (float) width / height;
      gl.glMatrixMode(GL10.GL_PROJECTION);
      gl.glLoadIdentity();
      gl.glFrustumf(-r, r, -1, 1, 1, 10);
     }
    
     public void onSurfaceCreated(GL10 gl, EGLConfig config) {
      gl.glDisable(GL10.GL_DITHER);
      gl.glClearColor(1, 1, 1, 1);
      gl.glEnable(GL10.GL_CULL_FACE);
      gl.glShadeModel(GL10.GL_SMOOTH);
      gl.glEnable(GL10.GL_DEPTH_TEST);
    
      gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
      gl.glEnableClientState(GL10.GL_COLOR_ARRAY);
    
      // load the 3 axis and there colors:
      float vertices[] = { 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1 };
      float colors[] = { 0, 0, 0, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 0, 1, 1 };
      byte indices[] = { 0, 1, 0, 2, 0, 3 };
    
      ByteBuffer vbb;
      vbb = ByteBuffer.allocateDirect(vertices.length * 4);
      vbb.order(ByteOrder.nativeOrder());
      vertexBuffer = vbb.asFloatBuffer();
      vertexBuffer.put(vertices);
      vertexBuffer.position(0);
    
      vbb = ByteBuffer.allocateDirect(colors.length * 4);
      vbb.order(ByteOrder.nativeOrder());
      colorBuffer = vbb.asFloatBuffer();
      colorBuffer.put(colors);
      colorBuffer.position(0);
    
      indexBuffer = ByteBuffer.allocateDirect(indices.length);
      indexBuffer.put(indices);
      indexBuffer.position(0);
     }
    
     public void onAccuracyChanged(Sensor sensor, int accuracy) {
     }
    
     public void onSensorChanged(SensorEvent event) {
    
      // load the new values:
      loadNewSensorData(event);
    
      if (MODUS == 1) {
       SensorManager.getRotationMatrix(rotationMatrix, null, accelGData,
         magnetData);
      }
    
      if (MODUS == 2) {
       rootMeanSquareBuffer(bufferedAccelGData, accelGData);
       rootMeanSquareBuffer(bufferedMagnetData, magnetData);
       SensorManager.getRotationMatrix(rotationMatrix, null,
         bufferedAccelGData, bufferedMagnetData);
      }
    
      if (MODUS == 3) {
       rootMeanSquareBuffer(bufferedMagnetData, magnetData);
       SensorManager.getRotationMatrix(rotationMatrix, null, accelGData,
         bufferedMagnetData);
      }
    
      if (MODUS == 4) {
       rootMeanSquareBuffer(bufferedAccelGData, accelGData);
       SensorManager.getRotationMatrix(rotationMatrix, null,
         bufferedAccelGData, magnetData);
      }
    
      if (MODUS == 5) {
       // this mode uses the sensor data recieved from the orientation
       // sensor
       resultingAngles = orientationData.clone();
       if ((-90 &gt; resultingAngles[1]) || (resultingAngles[1] &gt; 90)) {
        resultingAngles[1] = orientationData[0];
        resultingAngles[2] = orientationData[1];
        resultingAngles[0] = orientationData[2];
       }
      }
    
      if (MODUS == 6) {
       SensorManager.getRotationMatrix(rotationMatrix, null, accelGData,
         magnetData);
       final float[] anglesInRadians = new float[3];
       SensorManager.getOrientation(rotationMatrix, anglesInRadians);
       //TODO check for landscape mode
       resultingAngles[0] = anglesInRadians[0] * rad2deg;
       resultingAngles[1] = anglesInRadians[1] * rad2deg;
       resultingAngles[2] = anglesInRadians[2] * -rad2deg;
      }
    
      if (MODUS == 7) {
       SensorManager.getRotationMatrix(rotationMatrix, null, accelGData,
         magnetData);
    
       rotationMatrix = transpose(rotationMatrix);
       /*
        * this assumes that the rotation matrices are multiplied in x y z
        * order Rx*Ry*Rz
        */
    
       resultingAngles[2] = (float) (Math.asin(rotationMatrix[2]));
       final float cosB = (float) Math.cos(resultingAngles[2]);
       resultingAngles[2] = resultingAngles[2] * rad2deg;
       resultingAngles[0] = -(float) (Math.acos(rotationMatrix[0] / cosB))
         * rad2deg;
       resultingAngles[1] = (float) (Math.acos(rotationMatrix[10] / cosB))
         * rad2deg;
      }
    
      if (MODUS == 8) {
       SensorManager.getRotationMatrix(rotationMatrix, null, accelGData,
         magnetData);
       rotationMatrix = transpose(rotationMatrix);
       /*
        * this assumes that the rotation matrices are multiplied in z y x
        */
    
       resultingAngles[2] = (float) (Math.asin(-rotationMatrix[8]));
       final float cosB = (float) Math.cos(resultingAngles[2]);
       resultingAngles[2] = resultingAngles[2] * rad2deg;
       resultingAngles[1] = (float) (Math.acos(rotationMatrix[9] / cosB))
         * rad2deg;
       resultingAngles[0] = (float) (Math.asin(rotationMatrix[4] / cosB))
         * rad2deg;
      }
    
      if (MODUS == 9) {
       SensorManager.getRotationMatrix(rotationMatrix, null, accelGData,
         magnetData);
       rotationMatrix = transpose(rotationMatrix);
       /*
        * this assumes that the rotation matrices are multiplied in z x y
        * 
        * note z axis looks good at this one
        */
    
       resultingAngles[1] = (float) (Math.asin(rotationMatrix[9]));
       final float minusCosA = -(float) Math.cos(resultingAngles[1]);
       resultingAngles[1] = resultingAngles[1] * rad2deg;
       resultingAngles[2] = (float) (Math.asin(rotationMatrix[8]
         / minusCosA))
         * rad2deg;
       resultingAngles[0] = (float) (Math.asin(rotationMatrix[1]
         / minusCosA))
         * rad2deg;
      }
    
      if (MODUS == 10) {
       SensorManager.getRotationMatrix(rotationMatrix, null, accelGData,
         magnetData);
       rotationMatrix = transpose(rotationMatrix);
       /*
        * this assumes that the rotation matrices are multiplied in y x z
        */
    
       resultingAngles[1] = (float) (Math.asin(-rotationMatrix[6]));
       final float cosA = (float) Math.cos(resultingAngles[1]);
       resultingAngles[1] = resultingAngles[1] * rad2deg;
       resultingAngles[2] = (float) (Math.asin(rotationMatrix[2] / cosA))
         * rad2deg;
       resultingAngles[0] = (float) (Math.acos(rotationMatrix[5] / cosA))
         * rad2deg;
      }
    
      if (MODUS == 11) {
       SensorManager.getRotationMatrix(rotationMatrix, null, accelGData,
         magnetData);
       rotationMatrix = transpose(rotationMatrix);
       /*
        * this assumes that the rotation matrices are multiplied in y z x
        */
    
       resultingAngles[0] = (float) (Math.asin(rotationMatrix[4]));
       final float cosC = (float) Math.cos(resultingAngles[0]);
       resultingAngles[0] = resultingAngles[0] * rad2deg;
       resultingAngles[2] = (float) (Math.acos(rotationMatrix[0] / cosC))
         * rad2deg;
       resultingAngles[1] = (float) (Math.acos(rotationMatrix[5] / cosC))
         * rad2deg;
      }
    
      if (MODUS == 12) {
       SensorManager.getRotationMatrix(rotationMatrix, null, accelGData,
         magnetData);
       rotationMatrix = transpose(rotationMatrix);
       /*
        * this assumes that the rotation matrices are multiplied in x z y
        */
    
       resultingAngles[0] = (float) (Math.asin(-rotationMatrix[1]));
       final float cosC = (float) Math.cos(resultingAngles[0]);
       resultingAngles[0] = resultingAngles[0] * rad2deg;
       resultingAngles[2] = (float) (Math.acos(rotationMatrix[0] / cosC))
         * rad2deg;
       resultingAngles[1] = (float) (Math.acos(rotationMatrix[5] / cosC))
         * rad2deg;
      }
      logOutput();
     }
    
     /**
      * transposes the matrix because it was transposted (inverted, but here its
      * the same, because its a rotation matrix) to be used for opengl
      * 
      * @param source
      * @return
      */
     private float[] transpose(float[] source) {
      final float[] result = source.clone();
      if (TRY_TRANSPOSED_VERSION) {
       result[1] = source[4];
       result[2] = source[8];
       result[4] = source[1];
       result[6] = source[9];
       result[8] = source[2];
       result[9] = source[6];
      }
      // the other values in the matrix are not relevant for rotations
      return result;
     }
    
     private void rootMeanSquareBuffer(float[] target, float[] values) {
    
      final float amplification = 200.0f;
      float buffer = 20.0f;
    
      target[0] += amplification;
      target[1] += amplification;
      target[2] += amplification;
      values[0] += amplification;
      values[1] += amplification;
      values[2] += amplification;
    
      target[0] = (float) (Math
        .sqrt((target[0] * target[0] * buffer + values[0] * values[0])
          / (1 + buffer)));
      target[1] = (float) (Math
        .sqrt((target[1] * target[1] * buffer + values[1] * values[1])
          / (1 + buffer)));
      target[2] = (float) (Math
        .sqrt((target[2] * target[2] * buffer + values[2] * values[2])
          / (1 + buffer)));
    
      target[0] -= amplification;
      target[1] -= amplification;
      target[2] -= amplification;
      values[0] -= amplification;
      values[1] -= amplification;
      values[2] -= amplification;
     }
    
     private void loadNewSensorData(SensorEvent event) {
      final int type = event.sensor.getType();
      if (type == Sensor.TYPE_ACCELEROMETER) {
       accelGData = event.values.clone();
      }
      if (type == Sensor.TYPE_MAGNETIC_FIELD) {
       magnetData = event.values.clone();
      }
      if (type == Sensor.TYPE_ORIENTATION) {
       orientationData = event.values.clone();
      }
     }
    
     private void logOutput() {
      if (mCount++ &gt; 30) {
       mCount = 0;
       Log.d(&quot;Compass&quot;, &quot;yaw0: &quot; + (int) (resultingAngles[0])
         + &quot;  pitch1: &quot; + (int) (resultingAngles[1]) + &quot;  roll2: &quot;
         + (int) (resultingAngles[2]));
      }
     }
    }


  [1]: https://github.com/bitstars/droidar

How to use onSensorChanged sensor data in combination with OpenGL

In my Android application, when I rotate the device (slide out the keyboard) then my `Activity` is restarted (`onCreate` is called). Now, this is probably how it&#39;s supposed to be, but I do a lot of initial setting up in the `onCreate` method, so I need either:

1. Put all the initial setting up in another function so it&#39;s not all lost on device rotation or
2. Make it so `onCreate` is not called again and the layout just adjusts or
3. Limit the app to just portrait so that `onCreate` is not called.

Activity restart on rotation Android

I&#39;ve created a UICollectionView, so that I can arrange views into neat columns. I&#39;d like there to be a single column on devices &gt; 500 pixels wide.

In order to achieve this, I created this function:

    func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -&gt; CGSize {
        let size = collectionView.frame.width
        if (size &gt; 500) {
            return CGSize(width: (size/2) - 8, height: (size/2) - 8)
        }
        return CGSize(width: size, height: size)
    }

This works as expected on first load, however when I rotate the device, the calculation doesn&#39;t always happen again, and the views don&#39;t always redraw as expected. Here&#39;s my code for when the device is rotated:

    override func willRotateToInterfaceOrientation(toInterfaceOrientation: UIInterfaceOrientation, duration: NSTimeInterval) {
        collectionView.collectionViewLayout.invalidateLayout()
        self.view.setNeedsDisplay()
    }

I&#39;m assuming I&#39;ve forgotten to redraw something, but I&#39;m not sure what. Any ideas are very gratefully recieved!

UICollectionView - resizing cells on device rotate - Swift

I have following code for my vector:

    &lt;vector xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
        android:width=&quot;24dp&quot;
        android:height=&quot;24dp&quot;
    
        android:viewportWidth=&quot;314.015&quot;
        android:viewportHeight=&quot;314.015&quot;&gt;
        &lt;path
            android:fillColor=&quot;#FCD83500&quot;
            android:pathData=&quot;M157.007,0C70.291,0 0,70.289 0,157.007c0,86.712 70.29,157.007 157.007,157.007c86.709,0 157.007,-70.295 157.007,-157.007C314.014,70.289 243.716,0 157.007,0zM31.403,157.015c0,-69.373 56.228,-125.613 125.604,-125.613V282.62C87.631,282.62 31.403,226.38 31.403,157.015z&quot; /&gt;
    &lt;/vector&gt;

and Output is:

[![enter image description here][1]][1]


But I want this image in all direction as below:

[![enter image description here][2]][2] [![enter image description here][3]][3] [![enter image description here][4]][4]


  [1]: https://i.stack.imgur.com/6nLwws.png
  [2]: https://i.stack.imgur.com/WYiSrs.png
  [3]: https://i.stack.imgur.com/XQaars.png
  [4]: https://i.stack.imgur.com/t9ii0s.png

## What I have tried:

Added `&lt;vector&gt;` tag in between `&lt;rotate&gt;` but its giving me warning like **`Element vector is not allowed here`**

    &lt;rotate xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
        android:fromDegrees=&quot;90&quot;
        android:pivotX=&quot;50%&quot;
        android:pivotY=&quot;50%&quot;
        android:toDegrees=&quot;90&quot;&gt;
    
        &lt;vector 
            android:width=&quot;24dp&quot;
            android:height=&quot;24dp&quot;
    
            android:viewportWidth=&quot;314.015&quot;
            android:viewportHeight=&quot;314.015&quot;&gt;
            &lt;path
                android:fillColor=&quot;#FCD83500&quot;
                android:pathData=&quot;M157.007,0C70.291,0 0,70.289 0,157.007c0,86.712 70.29,157.007 157.007,157.007c86.709,0 157.007,-70.295 157.007,-157.007C314.014,70.289 243.716,0 157.007,0zM31.403,157.015c0,-69.373 56.228,-125.613 125.604,-125.613V282.62C87.631,282.62 31.403,226.38 31.403,157.015z&quot; /&gt;
        &lt;/vector&gt;
    &lt;/rotate&gt;

I have also tried to put `&lt;bitmap&gt;` tag in between `&lt;rotate&gt;` as below:

    &lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
    &lt;rotate xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
        xmlns:app=&quot;http://schemas.android.com/apk/res-auto&quot;
        android:fromDegrees=&quot;90&quot;
        android:pivotX=&quot;50%&quot;
        android:pivotY=&quot;50%&quot;
        android:toDegrees=&quot;90&quot;&gt;
    
        &lt;bitmap app:srcCompat=&quot;@drawable/ic_round&quot; /&gt;
    
    &lt;/rotate&gt;

but its giving me **&#39;src&#39; attribute should be defined** and I can&#39;t use `src` with vector images. 

Any solution to use this (one image) with all angle?

&gt; NOTE: I want to use this image in `&lt;TextView&gt;` drawable.



Android : Rotate Vector Image to 90 degree

    &lt;img class=&quot;image&quot; src=&quot;&quot; alt=&quot;&quot; width=&quot;120&quot; height=&quot;120&quot;&gt;


Cannot get this animated image to work, it is supposed to do a 360 degrees rotation.

I guess something&#39;s wrong with the CSS below, as it just stays still.

    .image {
        float: left;
    	margin: 0 auto;
    	position: absolute;
    	top: 50%;
    	left: 50%;
    	width: 120px;
    	height: 120px;
    	margin-top: -60px;
    	margin-left: -60px;

        -webkit-animation-name: spin;
        -webkit-animation-duration: 4000ms;
        -webkit-animation-iteration-count: infinite;
        -webkit-animation-timing-function: linear;

        -moz-animation-name: spin;
        -moz-animation-duration: 4000ms;
        -moz-animation-iteration-count: infinite;
        -moz-animation-timing-function: linear;

        -ms-animation-name: spin;
        -ms-animation-duration: 4000ms;
        -ms-animation-iteration-count: infinite;
        -ms-animation-timing-function: linear;

        animation-name: spin;
        animation-duration: 4000ms;
        animation-iteration-count: infinite;
        animation-timing-function: linear;

        @-ms-keyframes spin { 
            from { 
                -ms-transform: rotate(0deg); 
            } to { 
                -ms-transform: rotate(360deg); 
            }
        }
        @-moz-keyframes spin { 
            from { 
                -moz-transform: rotate(0deg); 
            } to { 
                -moz-transform: rotate(360deg); 
            }
        }
        @-webkit-keyframes spin { 
            from { 
                -webkit-transform: rotate(0deg); 
            } to { 
                -webkit-transform: rotate(360deg); 
            }
        }
        @keyframes spin { 
            from { 
                transform: rotate(0deg); 
            } to { 
                transform: rotate(360deg); 
            }
        }
    }

CSS3 Rotate Animation

How do you get the current angle/rotation/radian a UIView has?

All Rotation Solutions on Gang of Coders

Total of 50 Rotation Solutions