Make Blend Modes in SVG actually work? - svg

Question

I've many times done the following:
<defs>
<filter id="screen">
<feBlend mode="screen" in2="BackgroundImage"/>
</filter>
</defs>
But when I, inside a shape, write "filter="url(#screen)", my shape disappears.
I've tried it in every browser (Safari, Chrome, Firefox, FfxNightly). What am I doing wrong?
It would help if someone could give me an example that they know works
Thanks

Answer 1

You should try Opera and see the difference. It seems, Opera is the only browser that currently implements this more or less correctly. The specs for <feBlend> give an example:
<?xml version="1.0"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN"
"http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
<svg width="5cm" height="5cm" viewBox="0 0 500 500"
xmlns="http://www.w3.org/2000/svg" version="1.1">
<title>Example feBlend - Examples of feBlend modes</title>
<desc>Five text strings blended into a gradient,
with one text string for each of the five feBlend modes.</desc>
<defs>
<linearGradient id="MyGradient" gradientUnits="userSpaceOnUse"
x1="100" y1="0" x2="300" y2="0">
<stop offset="0" stop-color="#000000" />
<stop offset=".33" stop-color="#ffffff" />
<stop offset=".67" stop-color="#ff0000" />
<stop offset="1" stop-color="#808080" />
</linearGradient>
<filter id="Normal">
<feBlend mode="normal" in2="BackgroundImage" in="SourceGraphic"/>
</filter>
<filter id="Multiply">
<feBlend mode="multiply" in2="BackgroundImage" in="SourceGraphic"/>
</filter>
<filter id="Screen">
<feBlend mode="screen" in2="BackgroundImage" in="SourceGraphic"/>
</filter>
<filter id="Darken">
<feBlend mode="darken" in2="BackgroundImage" in="SourceGraphic"/>
</filter>
<filter id="Lighten">
<feBlend mode="lighten" in2="BackgroundImage" in="SourceGraphic"/>
</filter>
</defs>
<rect fill="none" stroke="blue"
x="1" y="1" width="498" height="498"/>
<g enable-background="new" >
<rect x="100" y="20" width="300" height="460" fill="url(#MyGradient)" />
<g font-family="Verdana" font-size="75" fill="#888888" fill-opacity=".6" >
<text x="50" y="90" filter="url(#Normal)" >Normal</text>
<text x="50" y="180" filter="url(#Multiply)" >Multiply</text>
<text x="50" y="270" filter="url(#Screen)" >Screen</text>
<text x="50" y="360" filter="url(#Darken)" >Darken</text>
<text x="50" y="450" filter="url(#Lighten)" >Lighten</text>
</g>
</g>
</svg>
This example should look like this if rendered correctly:
It actually looks like this in your browser:
In my Opera it looks like this:
I.e., not entirely perfect, there are problems with mode="lighten".