从另一个包含元素的SVG图像创建一个嵌入Base64字符串的SVG图像

5

我有一个包含多个元素(如路径、圆、矩形等)的SVG文件。

我想将该SVG文件转换为带有嵌入式base64数据的SVG,而不是多个元素。使用Batik能实现吗?

我正在开发的项目要求只能使用Java库。

1个回答

10

我用过一种方法来在Blogger文章中嵌入SVG图像,这个方法可能对你有用。基本上,它是一个两步骤的过程:

  1. 序列化你想嵌入的SVG图像,并将其URL编码。
  2. 然后将URL编码的字符串作为SVG use元素的xlink:href属性的数据URI使用。

下面是我用Batik测试过的一个工作示例。假设你要嵌入以下SVG文档circle.svg:

<?xml version="1.0" standalone="no"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" 
  "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
<svg width="4in" height="4in" id="the_svg"
     viewBox="0 0 4 4" version="1.1"
     xmlns="http://www.w3.org/2000/svg">
    <circle cx="1" cy="1" r="1" fill="blue" stroke="none" id="the_circle"/>
</svg>

你可以通过将其路径传递给以下小的Rhino脚本来对其进行URL编码:

#!/usr/bin/env rhino
print(escape(readFile(arguments[0])))

当然,如果你想在Java中以编程方式完成此操作,则需要使用Java专用的序列化SVG文档并对字符串进行URL编码的方法。

这将以URL编码的字符串形式给出文档:

%3C%3Fxml%20version%3D%221.0%22%20standalone%3D%22no%22%3F%3E%0A%3C%21DOCTYPE%20svg%20PUBLIC%20%22-//W3C//DTD%20SVG%201.1//EN%22%20%0A%20%20%22http%3A//www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd%22%3E%0A%3Csvg%20width%3D%224in%22%20height%3D%224in%22%20id%3D%22the_svg%22%0A%20%20%20%20%20viewBox%3D%220%200%204%204%22%20version%3D%221.1%22%0A%20%20%20%20%20xmlns%3D%22http%3A//www.w3.org/2000/svg%22%3E%0A%09%3Ccircle%20cx%3D%221%22%20cy%3D%221%22%20r%3D%221%22%20fill%3D%22blue%22%20stroke%3D%22none%22%20id%3D%22the_circle%22/%3E%0A%3C/svg%3E%0A%0A

你可以使用数据URI来嵌入此文档,数据URI的格式如下:

data:image/svg+xml,%3C%3Fxml%20version%3D%221.0%22%20standalone%3D%22no%22%3F%3E%0A%3C%21DOCTYPE%20svg%20PUBLIC%20%22-//W3C//DTD%20SVG%201.1//EN%22%20%0A%20%20%22http%3A//www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd%22%3E%0A%3Csvg%20width%3D%224in%22%20height%3D%224in%22%20id%3D%22the_svg%22%0A%20%20%20%20%20viewBox%3D%220%200%204%204%22%20version%3D%221.1%22%0A%20%20%20%20%20xmlns%3D%22http%3A//www.w3.org/2000/svg%22%3E%0A%09%3Ccircle%20cx%3D%221%22%20cy%3D%221%22%20r%3D%221%22%20fill%3D%22blue%22%20stroke%3D%22none%22%20id%3D%22the_circle%22/%3E%0A%3C/svg%3E%0A%0A
例如,下面的HTML文档使用了object标签和data URI嵌入SVG文档:
<html>
    <head>
    </head>
    <body>
        <object data="data:image/svg+xml,%3C%3Fxml%20version%3D%221.0%22%20standalone%3D%22no%22%3F%3E%0A%3C%21DOCTYPE%20svg%20PUBLIC%20%22-//W3C//DTD%20SVG%201.1//EN%22%20%0A%20%20%22http%3A//www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd%22%3E%0A%3Csvg%20width%3D%224in%22%20height%3D%224in%22%20id%3D%22the_svg%22%0A%20%20%20%20%20viewBox%3D%220%200%204%204%22%20version%3D%221.1%22%0A%20%20%20%20%20xmlns%3D%22http%3A//www.w3.org/2000/svg%22%3E%0A%09%3Ccircle%20cx%3D%221%22%20cy%3D%221%22%20r%3D%221%22%20fill%3D%22blue%22%20stroke%3D%22none%22%20id%3D%22the_circle%22/%3E%0A%3C/svg%3E%0A%0A" width="400" height="400"></object>
    </body>
</html>

您可以使用SVG 'use'元素的xlink:href属性执行相同操作,但有一个限制:引用完整文档是不合法的。相反,您需要通过其id引用文档中的元素,并将该元素深度克隆到SVG主机文档中。在此示例中,SVG文档根元素通过其id“the_svg”进行引用(请注意URI末尾的散列标签)。

<?xml version="1.0" standalone="no"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" 
  "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
<svg width="4in" height="4in" id="the_svg"
     viewBox="0 0 4 4" version="1.1"
     xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
    <use x="0" y="0" width="4" height="4" xlink:href="data:image/svg+xml,%3C%3Fxml%20version%3D%221.0%22%20standalone%3D%22no%22%3F%3E%0A%3C%21DOCTYPE%20svg%20PUBLIC%20%22-//W3C//DTD%20SVG%201.1//EN%22%20%0A%20%20%22http%3A//www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd%22%3E%0A%3Csvg%20width%3D%224in%22%20height%3D%224in%22%20id%3D%22the_svg%22%0A%20%20%20%20%20viewBox%3D%220%200%204%204%22%20version%3D%221.1%22%0A%20%20%20%20%20xmlns%3D%22http%3A//www.w3.org/2000/svg%22%3E%0A%09%3Ccircle%20cx%3D%221%22%20cy%3D%221%22%20r%3D%221%22%20fill%3D%22blue%22%20stroke%3D%22none%22%20id%3D%22the_circle%22/%3E%0A%3C/svg%3E%0A%0A#the_svg"/>
</svg>

顺便提一下,这在Batik 1.7中运行良好(在Squiggle浏览器中测试过),但在Chromium或Firefox中不行。


一个SVG的“image”标签也可以代替“use”。在这种情况下,您不需要在URL中引用根元素的ID。 - jbeard4
太好了!你应该将这个答案标记为正确的。 - jbeard4

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