create an SVG image with embedded base64 string from another svg image with elements

别说谁变了你拦得住时间么 提交于 2019-11-30 21:44:08

There's a technique which I've used to embed SVG images in Blogger posts which might work for this. Basically, it's a two-step process:

  1. You serialize the SVG you want to embed, and URL-encode it.
  2. You then use the URL-encoded string as a data URI in the xlink:href attribute of an SVG use element.

Here's a working example that I've tested with Batik. Say that you want to embed the following SVG document, 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>

You can URL-encode it by passing its path to the following small Rhino script:

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

Of-course, if you want to do this programmatically in Java, then you'll need a Java-specific method of serializing the SVG document and URL-encoding the string.

This gives you the document as a URL-encoded string:

%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

You can then embed this document by using it in a data URI, which looks like this:

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

For example, the following HTML document uses an object tag and the data URI to embed the SVG document:

<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>

You can do the same thing with the xlink:href attribute of an SVG 'use' element, with one caveat: it's illegal to reference a full document. Instead, you need to reference an element in the document by its id, and that element will be deep-cloned into the SVG host document. In this example, the SVG document root element is reference by its id "the_svg" (note the hash tag at the end of URI).

<?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>

FYI, this works well in Batik 1.7 (tested in the Squiggle browser), but not Chromium or Firefox.

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