If you rotate point `(px, py)` around point `(ox, oy)` by angle `theta` you&#39;ll get:

&lt;pre&gt;
p&#39;x = cos(theta) * (px-ox) - sin(theta) * (py-oy) + ox
p&#39;y = sin(theta) * (px-ox) + cos(theta) * (py-oy) + oy
&lt;/pre&gt;

If you are using GDI+ to do that, you can use `Transform` methods of the `Graphics` object:

    graphics.TranslateTransform(point of origin);
    graphics.RotateTransform(rotation angle);

Then draw the actual stuff.

If you have the `System.Windows.Media` namespace available, then you can use the built in transformations:

        using System.Windows.Media;
        
        var transform = new RotateTransform() {Angle = angleInDegrees, CenterX = center.X, CenterY = center.Y};
        var transformedPoint = transform.Transform(point);

Using C#, is there a better way to handle multiple types of exceptions rather than a bunch of ugly catch blocks?

What is considered best practice for this type of situation?

For example:

    try
    {
        // Many types of exceptions can be thrown
    }
    catch (CustomException ce)
    {
        ...
    }
    catch (AnotherCustomException ace)
    {
        ...
    }
    catch (Exception ex)
    {
        ...
    }



More Elegant Exception Handling Than Multiple Catch Blocks?

Is it possible to add messages to  the built-in error console of Firefox from JavaScript code running in web pages?

I know that I there&#39;s Firebug, which provides a `console` object and its own error console, but I was looking for a quick fix earlier on and couldn&#39;t find anything.

I guess it might not be possible at all, to prevent malicious web pages from spamming the log?

Log to Firefox Error Console from JavaScript

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 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'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.

I am using Microsoft&#39;s Unity for dependency injection and I want to do something like this:  

    IDataContext context = _unityContainer.Resolve&lt;IDataContext&gt;();
    var repositoryA = _unityContainer.Resolve&lt;IRepositoryA&gt;(context); //Same instance of context
    var repositoryB = _unityContainer.Resolve&lt;IRepositoryB&gt;(context); //Same instance of context
    
    IDataContext context2 = _unityContainer.Resolve&lt;IDataContext&gt;(); //New instance
    var repositoryA2 = _unityContainer.Resolve&lt;IRepositoryA&gt;(context2);

`RepositoryA` and `RepositoryB` both have a constructor that takes an `IDataContext` parameter, and I want Unity to initialize the repository with the context that I pass it. Also note that `IDataContext` is not registered with Unity (I don&#39;t want 3 instances of `IDataContext`).

Can I pass constructor parameters to Unity&#39;s Resolve() method?

We started using C# (.NET 3.0) and I wonder how you guys are using extension methods? When do you use them? 

Also, I would appreciate if you also list all dark prerequisites for using them. 



When do you use extension methods, ext. methods vs. inheritance?

How do I use C# regular expression to replace/remove all HTML tags, including the angle brackets?
Can someone please help me with the code?


Using C# regular expressions to remove HTML tags

Why does ReSharper complain when a method can become static, but is not?

Is it because only one instance of a static method is created (on the type) and thus save on performance?  

ReSharper complains when method can be static, but isn&#39;t

Is there any relatively easy way to insert a modern browser into a .NET application? 

As far as I understand, the `WebBrowser` control is a wrapper for **IE**, which wouldn&#39;t be a problem except that it looks like it is a very old version of **IE**, with all that entails in terms of CSS screw-ups, potential security risks (if the rendering engine wasn&#39;t patched, can I really expect the zillion buffer overflow problems to be fixed?), and other issues. 

I am using *Visual Studio C#* (express edition - does it make any difference here?)

I would like to integrate a good web browser in my applications. In some, I just use it to handle the user registration process, interface with some of my website&#39;s features and other things of that order, but I have another application in mind that will require more err... control. 

I need:

 - A browser that can integrate inside a window of my application (not a separate window)
 - A good support for CSS, js and other web technologies, on par with any modern browser
 - Basic browser functions like &quot;navigate&quot;, &quot;back&quot;, &quot;reload&quot;...
 - Liberal access to the page code and output. 

I was thinking about Chrome, since it comes under the BSD license, but I would be just as happy with a recent version of IE. 

As much as possible, I would like to keep things simple. The best would be if one could patch the existing `WebBrowser` control, which does already about 70% of what I need, but I don&#39;t think that&#39;s possible.

I have found an activeX control for Mozilla (http://www.iol.ie/~locka/mozilla/control.htm) but it looks like it&#39;s an old version, so it&#39;s not necessarily an improvement.

I am open to suggestions

Replacing .NET WebBrowser control with a better browser, like Chrome?

I cannot understand the calculation &quot;66 &amp;oplus; fa = 9c&quot;. 
The sum is clearly over &quot;ff&quot;, so I am confused. 
The topic is simple encryption algorithm.

**What does a circled plus mean?**

What does a circled plus mean?

How can the following function be implemented in various languages?

Calculate the `(x,y)` point on the circumference of a circle, given input values of:

- Radius
- Angle
- Origin (optional parameter, if supported by the language)

How do I calculate a point on a circle’s circumference?

How do I raise a number to a power?

    2^1
    
    2^2
    
    2^3

etc...

What is the C++ function to raise a number to a power?

I have a 2d array that looks like this:

    XX
    xx

What&#39;s the most efficient way to add an extra row and column:

    xxy
    xxy
    yyy

For bonus points, I&#39;d like to also be able to knock out single rows and columns, so for example in the matrix below I&#39;d like to be able to knock out all of the a&#39;s leaving only the x&#39;s - specifically I&#39;m trying to delete the nth row and the nth column at the same time - and I want to be able to do this as quickly as possible:

    xxaxx
    xxaxx
    aaaaa
    xxaxx
    xxaxx


What&#39;s the simplest way to extend a numpy array in 2 dimensions?

I&#39;m using Python and Numpy to calculate a best fit polynomial of arbitrary degree.  I pass a list of x values, y values, and the degree of the polynomial I want to fit (linear, quadratic, etc.).

This much works, but I also want to calculate r (coefficient of correlation) and r-squared(coefficient of determination).  I am comparing my results with Excel&#39;s best-fit trendline capability, and the r-squared value it calculates.  Using this, I know I am calculating r-squared correctly for linear best-fit (degree equals 1).  However, my function does not work for polynomials with degree greater than 1.

Excel is able to do this.  How do I calculate r-squared for higher-order polynomials using Numpy?

Here&#39;s my function:

    import numpy
        
    # Polynomial Regression
    def polyfit(x, y, degree):
    	results = {}
    
    	coeffs = numpy.polyfit(x, y, degree)
         # Polynomial Coefficients
    	results[&#39;polynomial&#39;] = coeffs.tolist()
    	
    	correlation = numpy.corrcoef(x, y)[0,1]

         # r
    	results[&#39;correlation&#39;] = correlation
         # r-squared
    	results[&#39;determination&#39;] = correlation**2
    
    	return results


How do I calculate r-squared using Python and Numpy?

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?

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?

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 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

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?

Given 2 angles in the range -PI -&gt; PI around a coordinate, what is the value of the smallest of the 2 angles between them?

Taking into account that the difference between PI and -PI is not 2 PI but zero.

**Example:**

Imagine a circle, with 2 lines coming out from the center, there are 2 angles between those lines, the angle they make on the inside aka **the smaller angle**, and the angle they make on the outside, aka the bigger angle. Both angles when added up make a full circle. Given that each angle can fit within a certain range, **what is the smaller angles value, taking into account the rollover**

How can I find the difference between two angles?

The OpenGL designers were never afraid of mathematics, and knowledge of linear algebra is essential for all but the simplest OpenGL applications. I think it can safely be assumed that OpenGL programmers are familiar with angles in radians.

Mathematically, radians are more elegant than degrees in every respect. They also have practical advantages:

* The C standard library uses radians.
* Pretty much any other library out there uses radians as well.
* Radians are more convenient in some computations, e.g. the length of a circular arc.

Why, then, did the OpenGL designers decide to specify functions like `glRotatef` and `gluPerspective` to use degrees?

(I know it&#39;s of no practical importance, and it&#39;s not going to change anyway. I&#39;m just curious, and I couldn&#39;t find the answer on OpenGL.org.)

Why does OpenGL use degrees instead of radians?

I need to determine the angle(s) between two n-dimensional vectors in Python. For example, the input can be two lists like the following: `[1,2,3,4]` and `[6,7,8,9]`.

Angles between two n-dimensional vectors in Python

I want to get a simple solution to calculate the angle of a line (like a pointer of a clock).

I have 2 points:

    cX, cY - the center of the line.
    eX, eY - the end of the line.
    
    The result is angle (0 &lt;= a &lt; 360).

Which function is able to provide this value?
 


How to calculate an angle from points?

I need to calculate the angle in degrees between two points for my own Point class, Point a shall be the center point.

Method:

    public float getAngle(Point target) {
		return (float) Math.toDegrees(Math.atan2(target.x - x, target.y - y));
	}

Test 1: // returns 45

    Point a = new Point(0, 0);
		System.out.println(a.getAngle(new Point(1, 1)));

Test 2: // returns -90, expected: 270

    Point a = new Point(0, 0);
		System.out.println(a.getAngle(new Point(-1, 0)));

How can i convert the returned result into a number between 0 and 359?

Content Type	Original Author	Original Content on Stackoverflow
Question	James	View Question on Stackoverflow
Solution 1 - C#	Sophie Alpert	View Answer on Stackoverflow
Solution 2 - C#	mmx	View Answer on Stackoverflow
Solution 3 - C#	thumbmunkeys	View Answer on Stackoverflow

Rotate a point by another point in 2D

C# Problem Overview

C# Solutions

Solution 1 - C#

Solution 2 - C#

Solution 3 - C#

Log to Firefox Error Console from JavaScript

More Elegant Exception Handling Than Multiple Catch Blocks?

Attributions