Background
I have a set of SVG icons that all have drop shadows. To make this work in Chrome, I can't just use filter:drop-shadow. I have to use filter:url(#drop-shadow), and define the drop shadow in my <defs> section.
I also have multiple instances of these icons on the page (they are filetype icons in a list of files), so I am using <use> to keep my page DRY.
Code
Exernal SVG File
<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1">
<defs>
<filter id="drop-shadow">
<feGaussianBlur xmlns="http://www.w3.org/2000/svg" in="SourceAlpha" stdDeviation="4"/>
..... more filter lines, shortened for brevity
</filter>
</defs>
<symbol id="download-pdf">
<path filter="url(#drop-shadow)" d="" fill="">...</path>
</symbol>
<symbol id="download-zip">
..... another icon
</symbol>
... more icons
</svg>
Inline SVG on the Page
<svg>
<use xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="URL_OF_EXTERNAL_SVG"></use>
</svg>
See minimal working example here: http://h.andymercer.net/chrome-svg-bug/
Problem
The problem is that Chrome isn't finding the #drop-shadow link, and so is breaking the icons. Firefox, conversely, displays the icons perfectly.
Firefox:
Chrome:
If you notice, the Chrome screenshot DOES show some portion of the icon. It is displaying the portions that don't use the drop shadow filter.
I can't figure out why this is, because the drop shadow is in the <defs> that is on the same page as the <symbol>.
Question
Is there something I am missing, or is this a Chrome bug?
Edit
Per comments, I was asked for a MCVE. I hadn't done that because the problem inherently requires external URLs, which is typically frowned upon here. However, to demonstrate the problem, take a look at this:
http://h.andymercer.net/chrome-svg-bug/
In Firefox, you can see the icon. In Chrome, it is blank.
In Chrome, <defs> must be located inside the same <svg>.
In your case:
<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1">
<defs>
<filter id="drop-shadow">
<feGaussianBlur xmlns="http://www.w3.org/2000/svg" in="SourceAlpha" stdDeviation="4"/>
</filter>
</defs>
<symbol id="download-pdf">
<path filter="url(#drop-shadow)" d="" fill="">...</path>
</symbol>
<use xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#download-pdf"></use>
</svg>
Conforming to modern browsers capabilities, it's easier and cleaner to create different external svg files, one for each icon, then embed them using <object> or <img> tags.
<object> lets javascript access and modify SVG code via DOM, while <img> embed SVGs denying DOM access to them. So, in your case using <img> should be a better choice.
I'm playing around with SVG and wanted to see if I could store the SVG in an external file and call on it with url(link), since FireFox doesn't support clip-path when declaring the shape in CSS.
However, the clipping doesn't work at all when linking to an external file.
Here's a fiddle with the SVG included and referenced to in the same document.
<img src="http://sarasoueidan.com/demos/css-svg-clipping/html-img-clipped-with-css-svg-clippath/flowers.jpg" style="clip-path: url(#svgPath); -webkit-clip-path: url(#svgPath)" />
<svg height="0" width="0">
<defs>
<clipPath id="svgPath">
<path stroke-width="1.5794" stroke-miterlimit="10" d="M215,100.3c97.8-32.6,90.5-71.9,336-77.6
c92.4-2.1,98.1,81.6,121.8,116.4c101.7,149.9,53.5,155.9,14.7,178c-96.4,54.9,5.4,269-257,115.1c-57-33.5-203,46.3-263.7,20.1
c-33.5-14.5-132.5-45.5-95-111.1C125.9,246.6,98.6,139.1,215,100.3z"/>
</clipPath>
</defs>
</svg>
But when I include it while it's hosted on my server, it doesn't work. See this fiddle.
<img src="http://sarasoueidan.com/demos/css-svg-clipping/html-img-clipped-with-css-svg-clippath/flowers.jpg" style="clip-path: url(rvervuurt.com/svg.html#svgPath); -webkit-clip-path: url(rvervuurt.com/svg.html/#svgPath)" />
I don't see what the difference is between url(#svgPath) and url(external.com/#svgPath) in this case. Should it be included in a different way?
Update: I have tried adding it as an .svg file, but it doesn't seem to work. Fiddle. Can someone check the .svg? The shape looks like it should in Illustrator.
SUMMARY: An SVG sprite contains five icon <symbol> blocks, one of which references its own gradient definition by ID. It is no longer able to find this gradient and render properly.
JSFIDDLE: http://jsfiddle.net/Qtq24/1/
I am switching some graphics to SVG, and being that they are icons (in this case for social networking profiles) I'd like to keep them in a sprite (as I had with PNG before).
I've followed this guide to SVG sprites on CSS-tricks.com (along with this follow-up which advises using <symbol> instead of <g>).
I now have an SVG sprite file, social-sprite.svg, which you can view in full here.
This is one complete <svg> block containing five different <symbol> blocks, each with an id and with a viewBox attribute. In each case I got the SVG code for each symbol by preparing official icons in Adobe Illustrator and retaining the relevant parts of the processed code.
The .svg file is included via PHP as soon as the <body> tag opens (and this is why the main <svg> container inside it is marked with style="display: none;") so that the references to each symbol work from the HTML.
Four icons work perfectly, and the only one I am having trouble with is the YouTube icon, because it uses an internally-defined gradient. Here is the YouTube part of the SVG code:
<symbol id="youtube" viewBox="0 0 400 281.641">
<path id="Triangle" fill="#FFFFFF" d="M159.845,191.73l106.152-54.999L159.845,81.348V191.73z"/>
<path id="The_Sharpness" opacity="0.12" fill-rule="evenodd" clip-rule="evenodd" fill="#420000" d="M159.845,81.348l93.091,62.162
l13.061-6.778L159.845,81.348z"/>
<g id="Lozenge">
<g>
<linearGradient id="SVGID_1_" gradientUnits="userSpaceOnUse" x1="200.4204" y1="2.6162" x2="200.4204" y2="278.9292">
<stop offset="0" style="stop-color:#E52D27"/>
<stop offset="1" style="stop-color:#BF171D"/>
</linearGradient>
<path fill="url(#SVGID_1_)" d="M392.928,62.226c0,0-3.839-27.073-15.617-38.995C362.371,7.583,345.626,7.506,337.947,6.59
c-54.975-3.974-137.441-3.974-137.441-3.974h-0.171c0,0-82.464,0-137.44,3.974c-7.68,0.916-24.419,0.993-39.364,16.641
C11.753,35.153,7.92,62.226,7.92,62.226s-3.929,31.792-3.929,63.583v29.805c0,31.791,3.929,63.582,3.929,63.582
s3.833,27.073,15.611,38.995c14.945,15.646,34.575,15.152,43.318,16.792c31.43,3.015,133.571,3.946,133.571,3.946
s82.552-0.124,137.526-4.099c7.679-0.915,24.424-0.993,39.363-16.64c11.778-11.922,15.617-38.995,15.617-38.995
s3.923-31.791,3.923-63.582v-29.805C396.851,94.017,392.928,62.226,392.928,62.226z M159.863,191.73l-0.018-110.383
l106.152,55.384L159.863,191.73z"/>
</g>
</g>
</symbol>
And this is called in the HTML with:
<svg width="30" height="21">
<use xlink:href="#youtube" src="fallback.png" width="30" height="21" />
</svg>
The opening two paths work fine, the problem is that in this new combined sprite SVG file, with each icon separated as a <symbol>, the "Lozenge" <path> is unable to find the #SVGID_1_ reference to the <linearGradient>.
In Firefox this causes the lozenge to display as white (I assume, perhaps it is not displaying at all - not really looked into it):
whilst Chrome renders it in black:
Obviously neither is acceptable. The only thing I can do at the moment is remove fill="url(#SVGID_1_)" on the path and just fill with a flat colour red appropriate to the YouTube logo. This is not a proper solution though, even discounting the fact that bastardising the YouTube logo in this way would not be accepted under their brand guidelines.
Things I've tried (and had no luck with):
removing the two <g> wrappers that surround the gradient and the path, so the whole of the symbol is just <path>-<path>-<linearGradient>-<path>
wrapping the gradient definition inside a <defs> container
wrapping it in a <defs> and also moving it to the top of the SVG file, i.e. outside the bounds of the YouTube-specific <symbol>
changing ID name (you never know!)
redefining the gradient with percentages rather than pixel values
So how do I get an already-internal <symbol> to reference an also-internal <linearGradient> definition?
EDIT: It turns out the gradient fails when the whole <svg> block is marked with style="display: none;". If this style is removed, the gradient renders properly. But as a reminder, this styling is added so that when you import the SVG sprite it is not rendered instantly on the page, and just allows you to make references to the id-defined symbols as required.
visibility: hidden or opacity: 0 both allow the gradient to render properly, obviously they don't offer proper solutions though as they still demarcate the space that the SVG would have taken up if visible.
After discovering all this, I was pretty sure it would be no problem to have the fully visible <svg> with no stylings added INSIDE a container <div> which is hidden. However, even this causes the gradient not to render. I'm no closer to solving the issue.
Firstly please note the edit to my question - whereupon I discover that the use of display: none to hide the SVG symbols until we need them was the problem.
I kept fiddling and settled upon this "answer", which is far from perfect, but should still be reliable for any such situation.
All you need to do is wrap the entire <svg> code in a <div> container which must be displayed but will never affect layout, so I've just done this via mega overkill CSS such as:
height: 0; width: 0; position: absolute; visibility: hidden;
And this works great. See the final fiddle: http://jsfiddle.net/Qtq24/5/
If anyone has a better solution, I'd love to hear it as this feels like a bit of a hacky way of doing it but I guess no more hacky than having to use display: none; anyway.
Don't use style="display: none;" in SVG. You have it on the root <svg> element. Either visibility:hidden, height/width="0" or <defs> are better alternatives.
There used to be a bug in Firefox with gradient elements in symbols. That bug was fixed many versions ago now. The original code works as expected.
<svg width="30" height="21">
<symbol id="youtube" viewBox="0 0 400 281.641">
<linearGradient id="SVGID_1_" gradientUnits="userSpaceOnUse" x1="200.4204" y1="2.6162" x2="200.4204" y2="278.9292">
<stop offset="0" style="stop-color:#E52D27"/>
<stop offset="1" style="stop-color:#BF171D"/>
</linearGradient>
<path id="Triangle" fill="#FFFFFF" d="M159.845,191.73l106.152-54.999L159.845,81.348V191.73z"/>
<path id="The_Sharpness" opacity="0.12" fill-rule="evenodd" clip-rule="evenodd" fill="#420000" d="M159.845,81.348l93.091,62.162
l13.061-6.778L159.845,81.348z"/>
<g id="Lozenge">
<g>
<path fill="url(#SVGID_1_)" d="M392.928,62.226c0,0-3.839-27.073-15.617-38.995C362.371,7.583,345.626,7.506,337.947,6.59
c-54.975-3.974-137.441-3.974-137.441-3.974h-0.171c0,0-82.464,0-137.44,3.974c-7.68,0.916-24.419,0.993-39.364,16.641
C11.753,35.153,7.92,62.226,7.92,62.226s-3.929,31.792-3.929,63.583v29.805c0,31.791,3.929,63.582,3.929,63.582
s3.833,27.073,15.611,38.995c14.945,15.646,34.575,15.152,43.318,16.792c31.43,3.015,133.571,3.946,133.571,3.946
s82.552-0.124,137.526-4.099c7.679-0.915,24.424-0.993,39.363-16.64c11.778-11.922,15.617-38.995,15.617-38.995
s3.923-31.791,3.923-63.582v-29.805C396.851,94.017,392.928,62.226,392.928,62.226z M159.863,191.73l-0.018-110.383
l106.152,55.384L159.863,191.73z"/>
</g>
</g>
</symbol>
<use xlink:href="#youtube" width="30" height="21" />
</svg>
I have easily made a mask with a PNG (black circle, transparent background) and using -webkit-mask-image:url(images/mask.png) for browsers like chrome. But i am having serious issues getting the mask to show in Firefox using SVG
<svg>
<defs>
<mask id="mask" maskUnits="userSpaceOnUse" maskContentUnits="userSpaceOnUse">
<image width="78px" height="78px" xlink:href="images/mask.png"/>
</mask>
</defs>
<foreignObject width="78px" height="78px" style="mask: url(#mask);">
<img src="images/avatar-sample.jpg" />
</foreignObject>
</svg>
I really cannot see why this isn't working!
According to http://www.w3.org/TR/SVG/propidx.html you can apply a mask to container elements and graphics elements. Unfortunately <foreignObject> is in neither of these lists so the correct rendering for that element is to ignore the mask property. IE and Firefox are therefore correct in their rendering of this example.
Because IE does not understand the "foreign" object, you have to work around it with javascript and check if you can support it, if so inject it in, and if not avoid it. then you have to use IE's built in color filters to create your own chromakey effect specifically for IE. this site below shows you how to do it with examples.
http://thenittygritty.co/css-masking
You could rewrite your svg like this to make it work in all svg-supporting browsers:
<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
<defs>
<mask id="mask" maskUnits="userSpaceOnUse" maskContentUnits="userSpaceOnUse">
<image width="78" height="78" xlink:href="images/mask.png"/>
</mask>
</defs>
<image xlink:href="images/avatar-sample.jpg" width="78" height="78"/>
</svg>
What are the cons to using SVG in terms of validation, accessibility, and maintainability for CMS-based websites?
In a project I need to make the Navigation fluid scalable without losing the quality of text and gradient. and it's not possible with HTML, CSS only.
A button like this:
So I found this example (although it's not exactly like what I want).
but it's not valid:
This button was made by SVG code-- no HTML and CSS here.
SVG Code:
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<svg width="100%" height="100%" viewBox="0 0 480 360"
xmlns:svg="http://www.w3.org/2000/svg" xmlns="http://www.w3.org/2000/svg"
xmlns:xlink="http://www.w3.org/1999/xlink">
<defs>
<linearGradient id="button_surface" gradientUnits="objectBoundingBox"
x1="1" x2="1" y1="0" y2="1">
<stop stop-color="#434343" offset="0"/>
<stop stop-color="#000000" offset="0.67"/>
</linearGradient>
<linearGradient id="virtual_light" gradientUnits="objectBoundingBox"
x1="0" x2="0" y1="0" y2="1">
<stop stop-color="#EEEEEE" offset="0" stop-opacity="1"/>
<stop stop-color="#EEEEEE" offset="0.4" stop-opacity="0"/>
</linearGradient>
</defs>
<!-- button content -->
<rect x="10" y="10" rx="15" ry="15" width="150" height="80"
fill="url(#button_surface)" stroke="#363636"/>
<text x="30" y="55" fill="white"
font-family="Tahoma" font-size="20" font-weight="500">
SVG Button
</text>
<!-- vitual lighting effect -->
<rect x="12" y="12" rx="15" ry="15" width="146" height="76"
fill="url(#virtual_light)" stroke="#FFFFFF" stroke-opacity="0.4"/>
</svg>
My question arose because this website will be made using WordPress. What are the disadvantages to using SVG code over HTML, CSS, and JavaScript?
Edit: I found this article on Microsoft's Website, which says SVG is better than Canvas to make UI Elements because of less UI code.
The biggest problem you'll have is browser compatibility. If you need to support older versions of IE (and most public web sites will need to) then you can't use SVG without resorting to Javascript hacks because the browser doesn't support it.
In addition, SVG isn't supported in the Android browser prior to version 3.0, which currently accounts for virtually all Android mobiles out there apart from a few tablets. If you need to support these, then again SVG isn't the solution.
If you're okay with not supporting those browsers (or if you can work out a fall-back solution) then go for it.
In terms of maintainability, I recommend creating your button using a vector graphic editor that can export to SVG. It will be a lot easier to maintain if you have a source file which you can edit in a graphical environment than if you are trying to edit the SVG markup directly.
In terms of validation, the reason you're getting errors is because of the way you're embedding the SVG into your HTML. You shouldn't be defining an XML header for the SVG when it's embedded like this, be cause an XML header should only ever appear as the first line of an XML document.
If the whole document is XML (ie xhtml) then you need to put the namespace definitions for both xhtml and SVG at the top of the document. If the document is non-XML (ie plain HTML), then you don't need the XML declaration at all.
The following will work in all browsers that support embedded SVG:
<html>
<head>...</head>
<body>
<svg xmlns="http://www.w3.org/2000/svg" version="1.1">
....svg content here....
</svg>
</body>
</html>
This should solve your validation issues.
If the SVG is to be loaded from an an external file, then it should include the XML declaraion.