rotation

问题 I'm trying to have a circle follow an elliptical path that is rotated, using Snap.svg, but I've ran into a problem. Using the getPointAtLength only returns the point of the path that is not rotated, so when I rotate the path, the circle will still follow the original path, before rotation. var firstOrbit = s.path("M250,400a150,75 0 1,0 300,0a150,75 0 1,0 -300,0") .attr({stroke: "#000", strokeWidth:"5", fill: "transparent"}); var len = firstOrbit.getTotalLength(); firstOrbit = firstOrbit

问题 I have an iOS application with storyboard. I want my last viewcontroller to stay always in portrait mode. I've been reading and I found that since -(BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation is deprecated I should use other methods like -(BOOL)shouldAutorotate -(NSInteger)supportedInterfaceOrientations -(UIInterfaceOrientation)preferredInterfaceOrientationForPresentation but i have tried so many combinations of this methods and I have not been

问题 I have a question of RotationAnimation. First. Is there a Listener to during animation? start, start animation repeat, repeat animation stop, stop animation. but there are no animation listener to check the on going. second, is any other get a current rotate angle of image? I think, ImageView is rotate by rotationAnimation function. so I made a timer thread and run 1second ''' timer = new Timer(); timerTask = new TimerTask() { public void run(){ Log.e("LOG", " [angle]: " + String.format("%3

问题 js fiddle for what I want to achieve : http://jsfiddle.net/g3qgS/1/ The image of sun rises from bottom and then using jquery rotate, its being rotated till 360 degrees. These 2 animations run fine in chrome, FF, IE9 but not in IE8. In IE8, the sun will rise from bottom till the point where it is supposed to , then before the rotation, it comes back to its original position and rotates. I am using jquery rotate plugin (http://code.google.com/p/jqueryrotate/) for this, I know this can also be

问题 I am quite new to using OpenGL ES 2.0. Also im using an iPhone and the GLM maths library. As I reference I have been using this tutorial a lot: http://tomdalling.com/blog/modern-opengl/03-matrices-depth-buffering-animation/ But I have found it difficult to find a 2D OpenGL tutorial. I am trying to rotate a 2D sprite but the image is being distorted. For example at a rotation angle of 0 degrees: http://i.imgur.com/yBTN2ST.png and at a rotation angle of 45 degrees: http://i.imgur.com/cY5IJcg

问题 For a while now I've been using the following function to rotate a series of Points around a pivot point in various programs of mine. private Point RotatePoint(Point point, Point pivot, double radians) { var cosTheta = Math.Cos(radians); var sinTheta = Math.Sin(radians); var x = (cosTheta * (point.X - pivot.X) - sinTheta * (point.Y - pivot.Y) + pivot.X); var y = (sinTheta * (point.X - pivot.X) + cosTheta * (point.Y - pivot.Y) + pivot.Y); return new Point((int)x, (int)y); } This has always

问题 Is it a requirement for iPad apps to be able to rotate? I am looking at a few apps, one example is http://squareup.com they only have one rotation, while others have rotation. What is the exact spec? 回答1: It's not required but I've seen apps butchered for it in reviews. I believe I saw that for the app Facepad. 回答2: You do not have to support rotation; however almost all apps do. 回答3: At least support 180° rotation. Preferably 360°, but this depends on the content your app shows . Fir example

问题 I want to rotate an image at several angles sequentially. I do that using cv2.getRotationMatrix2D and cv2.warpAffine . Having a pair of pixels coordinates [x,y], where x=cols, y=rows (in this case) I want to find their new coordinates in the rotated images. I used the following slightly changed code courtesy of http://www.pyimagesearch.com/2017/01/02/rotate-images-correctly-with-opencv-and-python/ and the explanation from Affine Transformation to try to map the points in the rotated image :

问题 I want to rotate an image at several angles sequentially. I do that using cv2.getRotationMatrix2D and cv2.warpAffine . Having a pair of pixels coordinates [x,y], where x=cols, y=rows (in this case) I want to find their new coordinates in the rotated images. I used the following slightly changed code courtesy of http://www.pyimagesearch.com/2017/01/02/rotate-images-correctly-with-opencv-and-python/ and the explanation from Affine Transformation to try to map the points in the rotated image :

问题 Background: I want to make sure my viewControllers rotate properly when it appears. My viewControllers have excellent codes managing the rotation and orientation when it is visible. Problem: Given two viewControllers in a NavigationController, viewC1 and viewC2 . I did the following: 1.) Set rootViewController to viewC1 2.) Push viewC2 into the NavigationController 3.) Rotate 4.) Pop viewC2 5.) viewC1 is still stucked in the old orientation look (as in the transformation code in