如何将“字母间距”值从SVG的文本节点映射到FabricJS中fabric.TextBox的“ charSpacing”属性？

Question

我对如何用SVG文档中的“ letter-spacing”重新将SVG中的节点表示为fabric.TextBox遇到问题。
在文件SVG中，文本节点为：

<text transform="matrix(1 0 0 1 51.5211 22.2889)" style="fill:#3C2415; font-size:11px; letter-spacing:3;">MINH TUẤN</text>

我的fabric.TextBox是：

var textbox_0_1 = new fabric.Textbox("MINH TUẤN", {
width: 200, 
fontSize: 11, 
fill: "#3C2415",
editable: true, 
textAlign: "center",
charSpacing: 3, 
});

此处显示在SVG和FabricJS上：

如何在SVG的“文本”节点中找到分别具有 letter-spacing 属性的正确 charSpacing ？

注释：
在fabric.TextBox文档中写：
charSpacing：Number 以数千个em单位表示的字符之间的额外空格
And in document for SVG写：
（如果未提供单位标识符）用户空间中的值，例如“ 15”

这是我的代码：

var canvasObject = document.getElementById("editorCanvas");
// set canvas equal size with div
$(canvasObject).width($("#canvasContainer").width());
$(canvasObject).height($("#canvasContainer").height());

var canvas = new fabric.Canvas('editorCanvas', {
  backgroundColor: 'white',
  selectionLineWidth: 2,
  width: $("#canvasContainer").width(),
  height: $("#canvasContainer").height()
});

var textbox_0_1 = new fabric.Textbox("MINH TUẤN", {
  top: 20,
  left: 20,
  width: 200, 
  fontSize: 11, 
  fill: "#000000",
  editable: true, 
  textAlign: "center",
  charSpacing: 3, 
});

canvas.add(textbox_0_1); 

setObjectCoords();
canvas.renderAll();

function setObjectCoords() {
  canvas.forEachObject(function(object) {
    object.setCoords();
  });
}

#canvasContainer {
  width: 100%;
  height: 100vh;
  background-color: gray;
}

<script src="https://code.jquery.com/jquery-3.3.1.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/fabric.js/2.4.3/fabric.js"></script>
  
<div id="canvasContainer">
  <canvas id="editorCanvas"></canvas>
</div>

谢谢你，

Answer 1

您需要从像素解析到em。

演示

var canvas = new fabric.Canvas('editorCanvas', {
  backgroundColor: 'white',
  width: 300,
  height: 100
});
var letterSpacing = 5, fontSize = 30;
var textbox = new fabric.Text("MINH TUẤN", {
  top: 20,
  fontSize: fontSize, 
  fill: "#000000",
  fontFamily : "Verdana"
});

canvas.add(textbox);

var parsedSpacing = fabric.util.parseUnit(letterSpacing, fontSize) / fontSize * 1000;

textbox.set({charSpacing : parsedSpacing});
canvas.requestRenderAll();

console.log(parsedSpacing)

canvas{
  border:1px solid;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/fabric.js/2.4.3/fabric.js"></script>
<svg width="300" height="100" viewBox="0 0 300 100">
  <text font-size="30" letter-spacing="5" font-family="Verdana" y="40">MINH TUẤN</text>
</svg>

<canvas id="editorCanvas"></canvas>