• ## Teach you how to draw a new Xiaomi logo with CSS painting API, but border radius can’t

Time：2021-11-27

This is Xiaomi’s new logoYou can’t draw it with border radiusBecause the circle of this graph is [hyperellipse]Can border radius write hyperellipses? What is hyperellipse Hyperellipse, also known as Lam é curve, is a closed curve similar to ellipse, which retains the characteristics of long axis, short axis and symmetry of ellipse. How useCSS Painting […]

• ## R language principal component analysis (PCA) wine visualization: dispersion point diagram and load diagram of principal components

Time：2021-10-19

Original link:http://tecdat.cn/?p=22492  === We will use the wine data set for principal component analysis. data Data frame with 177 samples and 13 variables; Vintages contains class labels. These data are the results of chemical analysis of wines grown in the same region of Italy but from three different cultivated varieties: Nebiolo, Barbera and Grignard grapes. […]

• ## [openxml] convert openxml’s elliptical arc arcto to SVG’s elliptical arc

Time：2021-10-6

This article describes how to convert ACTTO of openxml to the arc of SVG (a) Artto for openxml First, the following is an arcto arc of openxml Assuming that our current point is (0,0), the information we know is as follows: Current point coordinates: (x1, Y1) = (0,0) Radius of ellipse: semimajor axis RX = […]

• ## Code implementation of ECC algorithm

Time：2021-9-27

Code implementation of ECC algorithm What is ECC algorithm Elliptic curve cryptography, or ECC. Is a public key encryption algorithm based on elliptic curve mathematics. The use of elliptic curve in cryptography was independently proposed by Neal Koblitz and Victor Miller in 1985. Details link https://www.cnblogs.com/Kalafinaian/p/7392505.html 。 If you can insist on reading the above […]

• ## Foundation of Android custom controls (1) — geometry drawing

Time：2021-7-3

Although I have a few years of development experience, but the custom control together, little research, shame… When used is Baidu search, copy and paste. Working hours are tight. I always want to finish it as soon as possible（ It’s all excuses. If you want to learn, there will always be time As an Android […]

• ## Weekly canvas animation — circular motion

Time：2021-5-1

Next to “weekly canvas animation” — wave motion Circular motion can be divided into two basic formsCircular motionandElliptical motion。Before explaining circular motion, the essential mathematical formula is about to come. So, ladies and gentlemen, please protect your knees. It doesn’t matter if you don’t understand, just understand the principle. Of course, can understand is the […]

• ## CSS3 draw basic graphics, such as circle, ellipse, triangle, etc

Time：2021-3-12

CSS3 circle#css3-circle{ width: 150px; height: 150px; border-radius: 50%; background-color: #232323;}CSS3 oval#css3-elipse{ width: 200px; height: 100px; border-radius: 50%; background-color: #232323;}CSS3 triangle#css3-triangle{ width: 0; height: 0; border-left: 100px solid transparent; border-right: 100px solid transparent; border-bottom: 150px solid #232323;}CSS3 parallelogram#css3-parallelogram{ width: 200px; height: 100px; background: #232323; -webkit-transform: skew(-45deg); -moz-transform: skew(-45deg); -o-transform: skew(-45deg); transform: skew(-45deg);}CSS3 trapezoid#css3-trapezoid{ width: 100px; height: 0; border-bottom: 100px solid #232323; border-left: 50px solid transparent; border-right: 50px solid transparent;}CSS3 hexagonal star#css3-six-star{ width: 0; height: 0; position: relative; border-bottom: 100px solid #232323; border-left: 50px solid transparent; border-right: 50px […]

• ## [notes] secrets of CSS

Time：2020-12-20

Chapter 1 Introduction DRY (don’t repeat yourself) Code is easy to maintain and a small amount of code can not have both border-width: 10px 10px 10px 0; /** better **/ border-width:10px; border-left-width: 0; currentColor /**Make the horizontal split line automatically match the color of the text**/ hr { height: 1px; background: currentColor; } inherit Inherit […]

• ## 01_ Private key, public key and address

Time：2020-11-25

The private key, public key and address are a string of (almost) impossible to collide.It can be illustrated by four equations = random() (0 < k < n; n = 1.158 * 10^77) =K * g (G is a constant of elliptic curve cryptography) = Hash.ripemd160(Hash.sha256(K)) = base58(0 + a + checksum) The process from […]

• ## Canvas draws a cone

Time：2020-10-16

I can’t find it online, so I can only draw and study; <html> <head> < title > my first HTML page < / Title > </head> <body> <canvas id=’cvs’ width=’1000′ height=”800″> </canvas> <script> const cvs =document.getElementById(‘cvs’); //Calculate the width of the canvas const width = cvs.offsetWidth; //Calculate the height of the canvas const height = […]

• ## WPF inkcanvas draws rectangles and ellipses

Time：2020-3-1

I mentioned the basic operation of inkcanvas before. Here is an example to illustrate the specific application: drawing rectangle and ellipse. Design sketch Xaml code <Window x:Class=”WPF_InkCanvas.ROI_InkCanvas” xmlns=”http://schemas.microsoft.com/winfx/2006/xaml/presentation” xmlns:x=”http://schemas.microsoft.com/winfx/2006/xaml” xmlns:d=”http://schemas.microsoft.com/expression/blend/2008″ xmlns:mc=”http://schemas.openxmlformats.org/markup-compatibility/2006″ xmlns:local=”clr-namespace:WPF_InkCanvas” mc:Ignorable=”d” Title=”ROI_InkCanvas” Height=”450″ Width=”800″> <Grid> <Grid.RowDefinitions> <RowDefinition/> <RowDefinition Height=”auto”/> </Grid.RowDefinitions> <Image Name=”imgMeasure” HorizontalAlignment=”Center” Stretch=”Uniform”/> <InkCanvas Name=”inkCanvasMeasure” EditingMode=”None” Background=”Transparent” Strokes=”{Binding InkStrokes, Mode=TwoWay}” HorizontalAlignment=”Center” Width=”{Binding […]

• ## Teigha.net entity attribute comment

Time：2020-1-29

Polyline3d: The type of 3D polyline is stored by the polytype attribute, It is an integer value defined by the poly3dtype enumeration. Polytype property is an approximate method of drawing 3D polyline Polyline3d polyline = new Polyline3d(Poly3dType.SimplePoly, p3dc, false); Closed or not: polyline.Closed = false;   The polytype property can be used to set and […]