• I want to discuss canvas 2D and webgl with you


    background This article is included inData visualization and graphicsspecial column As mentioned above, I wrote my first column and realized a simple program for the cognition of graphics and visualization. It was originally intended that the follow-up sequence has focused on the algorithm and rendering direction. However, based on the students’ feedback on obscure problems […]

  • Analysis of konvajs principle


    preface Those who have used canvas know that it has many APIs and is troublesome to use. For example, if I want to draw a circle, I have to adjust a bunch of APIs, which is not friendly to development. const canvas = document.querySelector(‘canvas’); const context = canvas.getContext(‘2d’); //Set font style context.font = ’24px SimSun, […]

  • Unseen problems after setting box shadow


    Introduction When fixing the problem, it was found that an element was setbox-shadowAttribute, other elements also have common, but the shadow of this element is invisible. Try to make the color value more obvious, but it is still invisible. problemExample, example QR code. Origin My GitHub Cause of problem First, think about whether the attribute […]

  • [interview skills] n common skills of using CSS to realize triangles


    In some aspects, you can often see that there is a topic about CSSHow to draw triangles using CSS, and the usual answers are usually drawn using border. With the development of CSS today, there are many interesting ways to draw triangles only using CSS. This article will list them in detail. Through this article, […]

  • Canvas online signature plug-in


    about Original address:Canvas online signature plug-inPlug in address GitHub:https://github.com/javascript-wei/canvas-sign Experience Preview:canvas-sign background Recently, a temporary request was received, which requires the client to sign online and save it to the server. The functions generally include revocation (that is, revocation is required for each stroke), changing the signature color, and support on the mobile terminal and […]

  • Small program canvas drawing business card


    Drawing business cards with cancas involves technical prototype avatar, text beyond line feed, font size, color and background mapWxml page content <view class=”pages”> <canvas canvas-id=”shareKapian” style=”width:{{width}}px;height:{{height}}px;”></canvas> </view> Wxjs contentOnline pictures need to convert the online path to a local path through the localimge function.Step: first turn on the camera permission canvaskapian — > then start […]

  • Canvas draw posters or price tags, download a single picture, and download multiple picture zip packages


    Requirement: Download price tags in batch, click batch download, if you select a piece of data, draw a canvas and download it directly. Else for multiple pieces of data, cycle to draw multiple canvass, and download the zip. The zip name is set to “label” + the current date (the zip name can be set […]

  • Visualization of drawing scatter pie chart on map with R language


    Original link:http://tecdat.cn/?p=22537 The pie we made in ggplot2 is actually a bar graph converted to polar coordinates. If we want to make a map like the screenshot above, it will be very difficult. But when drawing pie chart on map, it also has its own shortcomings. First, when we draw a large number of pie […]

  • A brief introduction to the turtle Library in Python


    This paper makes some changes and deletions on the basis of the original text [turn]https://www.cnblogs.com/chen0307/articles/9645138.html [introduction and learning of Python drawing library turtle] In English, turtle means: turtle; Turtles (of any kind); Tortoise; Water turtles; Soft shelled turtleThe turtle library is a very popular function library for drawing images in Python language. Therefore, we can […]

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


    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 = […]

  • Implementation of regular expression visualization


    Ask questions For a regular expression, if there are many contents, for example, the following example: /\w{1,5}[^a-e]5(\w{1,4}|d)d(?!0)|199[0-9\w]/ Although it is very simple, it is difficult to interpret it quickly and intuitively. If it is the following effect: Obviously, you can know at once,199yCan be matched. Realization idea So, how do we achieve it? Analyze words […]

  • Html2canvas: converting DOM to canvas


    The following is the poster effect generated by relying on html2canvas, which is effective through personal test Take the layout of a background image + QR code as an example HTML section: <div class=”container”> <div class=”share-img”> <img style=”width: 300px; height: 300px” :src=”imgUrl” /> </div> <div class=”creat-img” ref=”box”> <img /> <div id=”qrcode” class=”qrcode”></div> </div> </div> Roughly […]