• [easeljs] vector shape class


    Class introduction Inherited from displayobject A shape allows you to display a vector graph in the display list. It contains a Graphics instance with all the methods for drawing vector graphics. Graphics instances can be shared among multiple shape instances, so that the same vector graphics can be copied in multiple different positions and different […]

  • [share] IOS development – limit the sliding of Scrollview (including tableview) after sliding to the top or bottom


    1. Use of agents <UIScrollViewDelegate> 2. Set the proxy target to self (this is not required for uitableview, because uitableview itself inherits from uiscrollview) self.scrollView.delegate = self; 3. #pragma mark – #pragma mark – UIScrollView Delegate -(void)scrollViewDidScroll:(UIScrollView *)scrollView { CGPoint offset = scrollView.contentOffset;// Scrollview the offset of the current display area point from the frame […]

  • Multiple time series rolling prediction based on extended data tecdat: R language: Arima, regression and arimax model analysis


    Link to the original text:http://tecdat.cn/?p=22849 When it is necessary to choose the most suitable prediction model or method for data, forecasters usually divide the available samples into two parts: inner samples (also known as “training set”) and reserved samples (or outer samples, or “test set”). Then, the model is estimated in the sample, and some […]

  • Push to origin / Master was rejected


    This problem is quite common. It usually occurs when the project is uploaded to GitHub or gitee for the first time. This problem occurred when uploading projects to GitHub in the past. Find an easy-to-use solution by all means. Enter the following command in turn: git pull git pull origin master git pull origin master […]

  • Grasp the soul of computer programming, matrix application and graphic conversion


    The author of this article: Le byte – Keng Wang Lao Xue Matrix transformation of two dimensional graphics (1) — basic concepts The basic two-dimensional transformation includes rotation, scaling, twisting, and translation, These geometric operations can be transformed into some basic matrix operations These transformations are linear, but the translation operation is not linear and […]

  • Canvas graphics transformation


    translation Translate (x, y) notice that the coordinate origin is translated, not the line itself canvas <span style=”background-color: #f5f5f5; color: #800000;”> .canvas</span><span style=”background-color: #f5f5f5; color: #000000;”>{</span><span style=”background-color: #f5f5f5; color: #ff0000;”>border</span><span style=”background-color: #f5f5f5; color: #000000;”>:</span><span style=”background-color: #f5f5f5; color: #0000ff;”>1px solid pink</span><span style=”background-color: #f5f5f5; color: #000000;”>;</span><span style=”background-color: #f5f5f5; color: #000000;”>}</span> Your browser does not support canvas <span […]

  • IOS transform coordinates change


    When using cgcontext, because the coordinates of quartz 2D and UIKit are inconsistent, it is necessary to change the context again to achieve the desired effect. 1. Introduction to origin of different coordinates In quartz 2D, the coordinate origin is in the lower left corner of the canvas, while in UIKit, it is consistent with […]

  • What you didn’t notice in the introduction to canvas


    preface This article was written at the end of July. I sorted it out without working overtime. Some very basic knowledge is worth reading for those who have just started canvas. Let’s start with a rainbow Compared with reading a variety of articles, I prefer the logic in mathematics; compared with learning a variety of […]

  • Leetcode 657. Can the robot return to the origin | Python


    657. Can the robot return to the origin Source: leetcode https://leetcode-cn.com/problems/robot-return-to-origin subject In the two-dimensional plane, there is a robot starting from the origin (0, 0). Give its moving order and judge whether the robot ends at (0, 0) after completing the movement. The order of movement is represented by a string. The character move […]

  • Understanding data and caching from a front end Perspective


    Understanding of data systems Data system design is about data storage, sharing, update (and propagation update), cache (and cache failure) technology. Most software systems can be understood from the perspective of data systems. Data systems are so pervasive that developers actually design data systems every day, but they often don’t realize their universality and treat […]

  • Why does export default let arr = [] report errors? Explore the details


    Why?export default let arr = []Will you report an error?and let arr = [] export default arr Is it right? Can named functions be set to default export?export default function fun(){} In many articles, you can’t follow the default statement,For example: But I think it’s a bit of a forced explanation. There are essential causes […]

  • CSS3’s transform attribute and matrix


    About transform Transform is a new attribute of control element transformation added in CSS3 (in fact, it has become W3C standard as early as svg1.1 standard in 2003, and can be used as an attribute of an element). It can be used to realize the displacement, scale, rotate and skew of an element. andtransitionProperties can […]