rotation

问题 I am wondering if it is possible to rotate an image using a reference point. For example, rotating this image by 30 degrees: instead of having: I would like to have: which means rotating the image on the bottom-left point. I would do this overlapping the rectangle to the original image if needed, and rotating it as needed only after. 回答1: The ImageMagick extension can do this, using the DISTORTION_SCALEROTATETRANSLATE option. You might need to tweak the coordinates and angle a bit to fit your

问题 As I know, the most of android devices allows to detect rotation by accelerometer, but I've noticed, that it doesn't detect rotation parallel to the ground. For example, if I put the device on a table and turn it around, no one of accelerometer indicators doesn't change. At the picture, it's called "alfa" rotation. So how can I detect this kind of turning? 回答1: For sensing rotation around z-axis you need to implement a compass function. A good tutorial is this one. To make the resulting

问题 How do I rotate the z-axis of a matplotlib figure so that it appears as the horizontal axis? I have created the following 3d figure : I tried adjusting the values in ax.view_init() but no matter what values I used, I can't flip the z-axis so that the orientation of the three axes appear as like the ones in the following figure: I thought of changing the three components of all the data so that I use the x-axis to plot the z-component of the data, but then it will be very inconvenient to many

问题 Hi to whole stackoverflow group, I am having a series of problems when defining the axes range in my graphic and format in general, and I would like to share it with you to see if among all we can find the error I have found on this website a user who has made it similar. My idea is to have something similar like the graphic of the link below. But for some reason, it's probably silly, it does not appear correctly. My code is as following: set term post eps enhanced color "Times-Roman" 14 set

问题 I am using PhotoView (https://pub.dev/packages/photo_view) to showcase a map saved in gif format. I need the ability to zoom and rotate. My code: class MapView extends StatelessWidget { @override Widget build(BuildContext context) { return PhotoView( imageProvider: AssetImage("assets/maps/my_map.gif"), enableRotation: true, backgroundDecoration: BoxDecoration( color: Colors.white, ), ); } } The problem is that the picture is rotated relative to the center of the picture, which is inconvenient

问题 I am working on a simple game. I created a pygame sprite which and tested it by making it move forward and rotating at a consistent speed. However, it seams to be moving left and up (where sin and cos are negative) quicker than right and down (where sin and cos are positive). I tested it without moving and just rotating and it works. Here is the code: import pygame import sys from math import cos, sin, pi from time import sleep SCREEN_WIDTH = 800 SCREEN_HEIGHT = 800 FPS = 60 pygame.init()

问题 I am working on a simple game. I created a pygame sprite which and tested it by making it move forward and rotating at a consistent speed. However, it seams to be moving left and up (where sin and cos are negative) quicker than right and down (where sin and cos are positive). I tested it without moving and just rotating and it works. Here is the code: import pygame import sys from math import cos, sin, pi from time import sleep SCREEN_WIDTH = 800 SCREEN_HEIGHT = 800 FPS = 60 pygame.init()

问题 TL;DR : Applying visual effects to the contents of a ScrollView causes thousands of requests for the same (unchanging) image for each drag gesture. Can I reduce this? (In my real app, I have 50-odd images in the view, and the scrolling is correspondingly sluggish.) Gist To give a little life to a scrolling HStack of images, I applied a few transforms for a circular "carousel" effect. (Tips of the hat to sample code from John M. and Paul Hudson) The code is copy-paste-runnable as given. (You

问题 TL;DR : Applying visual effects to the contents of a ScrollView causes thousands of requests for the same (unchanging) image for each drag gesture. Can I reduce this? (In my real app, I have 50-odd images in the view, and the scrolling is correspondingly sluggish.) Gist To give a little life to a scrolling HStack of images, I applied a few transforms for a circular "carousel" effect. (Tips of the hat to sample code from John M. and Paul Hudson) The code is copy-paste-runnable as given. (You

问题 I'm learning about more quaternion conversions and I have a question regarding quaternion to spherical rotation conversion code at the following section of this website: http://web.archive.org/web/20041029003853/http://www.j3d.org/matrix_faq/matrfaq_latest.html#Q59 What are angle and sin_angle in this code supposed to be? Angle is never used so I was guessing it's the rotation angle. Is sin_angle supposed to be sin_a? If this was a function returning an array of float with the spherical