gistfile1.xml

<svg xmlns="http://www.w3.org/2000/svg"
xmlns:xlink="http://www.w3.org/1999/xlink"
width="256" height="256">
    <defs>
        <filter id="filter_ok">
            <feColorMatrix type="matrix" values="0 0 0 0 1
                                                        0 0 0 0 0
                                                        0 0 0 0 0
                                                        -1 0 0 1 0"></feColorMatrix>
        </filter>
        <filter id="filter_wrong">
            <feColorMatrix type="matrix" values=" 0 0 0 0 1
                                                        0 0 0 0 0
                                                        0 0 0 0 0
                                                        -1 0 0 1 0"></feColorMatrix>
        </filter>
    </defs>
    <text filter="url(#filter_ok)" x="10" y="20">This is filtered to be red</text>
    <text filter="url(#filter_wrong)" x="10" y="50">This is not visible on iOS safari</text>
</svg>