when I use toDataUrl () to convert canvas to png, sometimes I get an all-black picture, but the amazing thing is that sometimes the picture is normal, does anyone know what s going on? "stage" canvas const canvas = document.querySelec...
it is known that a polygon consists of n squares of the same size (this polygon is not necessarily a rectangle, but it must be a figure made up of squares). To cut this figure, you can only cut from the edge of each square. When you click submit, you can...
original image size: 750x1334 canvas size: 750X1334 I m going to lay a 750x1334 picture as the background on the canvas of 750x1334. the code is as follows: var image = new Image() image.src = img background.png image.onload = drawImg ...
var img = document.getElementById( testimg ) console.log( img , img) console.log( typeimg , typeof (img)) context.drawImage(img, 0, 0, 750, 1334) so how exactly do you need to pass it on? ...
due to project requirements, the name field of the echarts relational node needs to be displayed directly, not when the mouse is moved into the node. As shown in the figure is there a configuration that supports the direct display of node name attr...
encountered a problem in learning canvas, in the process of making a tablet demo , yiy, the code is as follows <template> <div> <canvas id="canvas" @touchstart="drawStart" @touchend...
Mini Program draws the text with canvas, and sets the text to be bold but does not respond. The code is as follows ctx.font=`50px bold` ctx.fillText("",0,0) ...
problem description after putting some animations made by canvas into vue, stutters obviously appear the environmental background of the problems and what methods you have tried The animation code comes from https: github.com Whitevinyl., which ...
found a section of code for drawing k-diagram from the Internet and changed it, and found that the effect is a little different from what you expected. Please take a look at . according to reason, as long as the mouse is moved into the drawing path,...
has obtained a canvas, and then downloaded and saved it, but the result part cannot be downloaded. the size of the picture is 4m, while it is said online that the href length of an is limited. how to download function aa(src,imgname){ var alink=d...
how do I make the scale rotate separately? Instead of rotating the whole canvas? Canvas novice asks the boss to answer ...
problem description const jsdom = require ( "jsdom "); const echarts = require ( echarts ) var d3 = require ( d3 ); const {JSDOM} = jsdom; const html2canvas = require ( html2canvas ) const {createCanvas} = require ( canvas ) require ( ...
there is a problem with WeChat Mini Programs web-wiew nesting h5, and the mobile browser displays normally. Open the mobile browser web-view this is written in canvas ...
as shown in the figure, the angle of the pointer changes dynamically. Due to the need to be compatible with the old version of the browser (ie7 ie8), css3 rotation does not support, canvas does not support, there is any way to make a pointer to rotat...
need to do a picture graffiti function, and then need to undo the function, save () method seems to be useless, checked the data and said that it only saves the state, can not restore the canvas content. no, no, no. how can I save the operation steps to...
the following picture shows that when the mouse draws a circle from the upper left corner, the mouse position is not captured correctly, and the more the mouse goes to the right or down, it will move a great distance, as shown in figures 1 to 4 below. ...
github link: https: github.com hpstream n. <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title< title> <style type="text css"> html, ...
resolved the tiles on the right are obtained through the interface, but the map on the left becomes distorted after rendering here is my code. Has anyone ever encountered a similar problem? <!DOCTYPE html> <html> <head> ...
problem description accidentally found the following picture of such an effect of a page, the effect is very good, but the source code is compressed can not see, would like to ask the experienced boss, the idea to achieve this effect. Page address ...
use canvas to draw the image first locate several div, on the image to trigger events when an event is triggered, the box and connection of the message description are displayed div, is not affected by the frame of information description conne...
problem description attempts to calculate the least square solution of the nonlinear equation, but it is suggested that the matrix is a nonsingular matrix and cannot be calculated, but the demo given in the official document is also a nonsingular matr...
if the figure shows a section of the log, you need to count the execution time of this API and the corresponding parameters. That is, all the content between the beginning of the api dialog line until the end of the [info] execution time: 1.036043...
content=etree(tr_list[i]).xpath( td[@class="pl20"] span )[0].xpath( string(.) ) ? ...
Radial gradient radial-gradient setting the gradient radius seems to be just these four values: closest-side,closest-corner,farthest-side,farthest-corner. Can you directly use px to set the radius distance? ...
problem description render () { return ( <div onClick={()=>{alert(1)}}> <div onClick={()=>{alert(2)}}>Hello< div> <NavLinkBar onClick={()=>{alert(3)}} data={navList}> < NavLinkBar> < di...