Question

I am having some REAL big problems coding SVG XML and having it being reproduced in Illustrator as I am expecting. Major problem right now is the feColorMatrix effect. I understand the effect and how the matrix changes the pixels but problem I am having is that when I specify 0.5 as the final output result on any of the color channel rows, Illustrator is not interpreting 0.5 as RGB 127, in other words, 50% the color value. It is more like 0.215 equates to 127 RGB decimal. Here is some code:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<svg
    xmlns="http://www.w3.org/2000/svg"
    version="1.2"
    viewBox="0 0 576 432"
    width="576"
    height="432"
    baseProfile="tiny"
    id="NicoleLovesSVG">
    <g id="Canvas">
        <rect
            width="576"
            height="432"
            x="0"
            y="0"
            transform="scale(1,1)"
            id="Canvas-Rect1"
            style="fill:#9d8654;fill-rule:evenodd;" />
    </g>
    <defs>
        <filter id="ShadowFilter-Text1" filterUnits="objectBoundingBox" primitiveUnits="userSpaceOnUse" width="200%" height="200%" x="-50%" y="-50%">
            <feColorMatrix type="matrix"  in="SourceAlpha"
                values="0 0 0 0 .5
                    0 0 0 0 0
                    0 0 0 0 0
                    0 0 0 1 0"/>
            <feOffset dx="24.395183950936" dy="24.395183950936" result="shadow"/>
            <feBlend in="SourceGraphic" in2="shadow" mode="normal"/>
        </filter>
    </defs>
    <g
        id="Text1"
        transform="translate(1.1272727272727,297.27272727273) rotate(0) scale(3.5238813920454546,2.642911044034091)"
        style="fill:#003300;fill-opacity:1;fill-rule:evenodd;stroke:#ff0000;stroke-width:15px;stroke-linecap:round;stroke-linejoin:round;stroke-opacity:1;"
        filter="url(#ShadowFilter-Text1)">
            <g
                id="Text1-Line1"
                transform="translate(0,0)">
                <path
                    transform="translate(0,0)"
                    vector-effect="non-scaling-stroke"
                    id="Text1-Line1-Glyph1"
                    d="M 0,0 M 46.4,-98.24 L 46.4,-15.68 C 46.4,-8.96 47.466666666667,-3.7333333333333 49.6,-0 L 30.4,-0 C 32.533333333333,-3.7333333333333 33.6,-8.96 33.6,-15.68 L 33.6,-98.24 L 31.36,-98.24 C 21.653333333333,-98.24 12.106666666667,-96.373333333333 2.72,-92.64 L 8.32,-106.72 L 79.68,-106.72 L 74.56,-92.64 C 68.693333333333,-96.48 59.306666666667,-98.346666666667 46.4,-98.24 z" />
            </g>
    </g>
</svg>

As you can see, the first filter retrieves the SourceAlpha which is all black. Then the color matrix takes that and does this on the first row of the matrix:

(a x red) + (b x green) + (c x blue) + (d x alpha) + e = final red output

plugging in the numbers:

(0 x 0) + (0 x 0) + (0 x 0) + (0 x 0) + 0.5 = 0.5

Should be 50% red! Or 127 RGB!!! I did the math and in Illy it is more like 0.215 = 127 = 50% ??????

Answer 1

This is due to the color space used by filters, which per default is linearRGB.

You can get the behaviour you want by specifying color-interpolation-filters="sRGB" on the <filter> element, or on the <feColorMatrix> element directly. See color-interpolation-filters.