在Svg中获取String的像素长度 [英] Get pixel length of String in Svg
问题描述
我目前正在使用SVG。我需要知道字符串长度(以像素为单位)才能进行一些对齐。如何以像素为单位获取字符串的长度?
I'm currently working with SVG. I need to know the string length in pixels in order to do some alignment. How can I do to get the length of a string in pixel ?
更新:感谢nrabinowitz。基于他的帮助,我现在可以获得动态添加文本的长度。这是一个例子:
Update: Thanks to nrabinowitz. Based on his help, I can now get the length of dynamic-added text. Here is an example:
<svg id="main"
xmlns="http://www.w3.org/2000/svg"
xmlns:xlink="http://www.w3.org/1999/xlink"
version="1.1"
width="1020"
height="620"
viewBox="0 0 1020 620"
onload="startup(evt)">
<script>
<![CDATA[
var startup = function (evt) {
var width;
var svgNS = "http://www.w3.org/2000/svg";
var txtNode = document.createTextNode("Hello");
text = document.createElementNS(svgNS,"text");
text.setAttributeNS(null,"x",100);
text.setAttributeNS(null,"y",100);
text.setAttributeNS(null,"fill","black");
text.appendChild(txtNode);
width = text.getComputedTextLength();
alert(" Width before appendChild: "+ width);
document.getElementById("main").appendChild(text);
width = text.getComputedTextLength();
alert(" Width after appendChild: "+ width)
document.getElementById("main").removeChild(text);
}
//]]>
</script>
</svg>
推荐答案
我一直在想这个,我当时令人惊喜地发现,根据SVG规范,有一个特定的功能可以返回此信息: getComputedTextLength( )
I've been wondering this too, and I was pleasantly surprised to find that, according to the SVG spec, there is a specific function to return this info: getComputedTextLength()
// access the text element you want to measure
var el = document.getElementsByTagName('text')[3];
el.getComputedTextLength(); // returns a pixel integer
工作小提琴(仅在Chrome中测试): http://jsfiddle.net/jyams/
Working fiddle (only tested in Chrome): http://jsfiddle.net/jyams/
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