How to operate svg with JS to draw pictures

This article mainly introduces how to operate svg with JS to draw pictures. It has a certain reference value. Now I share it with everyone. Friends in need can refer to it

Background:

Total There are 3 files: svg file, html file, js file.

There is an svg image, using the embed tag, introduced into the html file

svg file:

HTML file:

Then use js file to manipulate svg and insert graphics.

The first obstacle: getting svg dom,

If your svg is written directly in the html file, then svg and HTML share a document, you can directly use document.getElementById(svg id) can be obtained.

However, under normal circumstances, it is not recommended to mix them together. For example, the column image here is a separate svg file, and then inserted into HTML using embed.

Note: The svg file inserted using embed and object has its own document:

At this time, again If you want to get svg, you need to use:getSVGDocument();

Usage method: Get the embed node first, then the svg document, and then the svg node:

function drawColumn(data) { var nameSpace = 'http://www.w3.org/2000/svg'; var max = Math.max.apply(null, data); var proportion = 350/max; var interval = 35; //column间隔 var columnStyle = 'stroke: blue; fill: orange'; var embedSVG = document.getElementById('embed').getSVGDocument().getElementById('svgColumn');//关键代码：embedSVG的赋值。最后的getElementById('svgColumn')，是svg文件中，svg标签的id for (let singleColumn of data) { var rect = document.createElementNS(nameSpace,'rect');//creat新的svg节点，rect。 rect.style = columnStyle; //给rect节点设置style height = singleColumn*proportion; rect.setAttribute('width', '30'); //使用setAttribute来设置rect节点属性 rect.setAttribute('height', height); rect.setAttribute('x', interval); rect.setAttribute('y', 380-height); embedSVG.appendChild(rect); //将这个新的rect节点 添加到svg节点里 interval += 45 } }

Note:

In addition, unlike HTML element objects that can directly assign values to some attributes, SVG element objects need to set attribute values by calling thesetAttribute()method.

Using rect.width = 30 does not work.

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