I am trying to apply a Vignette effect on images with SVG filters. I am trying to implement this with the <fePointLight> primitive, but I find this a bit limited in that it is always has a circular shape. Is it possible to change the width such that the lighting effect takes on a wide elliptical shape? This is currently the filter I am using:
<filter id="vignette">
<feFlood id="flood-5" result="blackfield-6" x="0%" y="0%" width="100%" height="100%" flood-color="#000000" flood-opacity="1"/>
<feSpecularLighting id="specular-5" result="Spotlight-6" lighting-color="#FFFFFF" surfaceScale="1" specularConstant="1" specularExponent="100">
<fePointLight id="pointlight-5" x="720" y="450" z="1200"/>
</feSpecularLighting>
<feBlend id="svg-7" result="A-6" in="blackfield-6" in2="Spotlight-6" mode="lighten"/>
<feBlend id="blend-5" result="B-6" in="A-6" in2="SourceGraphic" mode="multiply"/>
</filter>
I am aware that it is possible to do this with a radial gradient effect on a separate shape, but I have a requirement that it must be done purely using SVG filters.
The values of the x=350 and y=240 attributes of the fePointLight filter are chosen so that the point is in the center of the image.
Different values for the z attribute of the fePointLight filter render the light source at different depths in relation to the drawing. The nearest position corresponds to the largest size.
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Hover over image
#img {
width:700px;
height:481px;
}
#img:hover {
filter:url(#spotlight);
}
<img id="img" src="https://i.stack.imgur.com/mBuDo.jpg" >
<svg width="700" height="481" viewBox="0 0 700 481" xmlns="http://www.w3.org/2000/svg"
xmlns:xlink="http://www.w3.org/1999/xlink">
<defs>
<filter id="spotlight">
<feSpecularLighting result="spotlight" specularConstant="3.5"
specularExponent="70" lighting-color="grey">
<fePointLight x="350" y="240" z="520"/>
</feSpecularLighting>
<feComposite in="SourceGraphic" in2="spotlight" operator="in"/>
</filter>
</defs>
</svg>
Other image
#img {
width:700px;
height:481px;
}
#img:hover {
filter:url(#spotlight);
}
<img id="img" src="https://i.stack.imgur.com/GlhkD.jpg" >
<svg width="700" height="481" viewBox="0 0 700 481" xmlns="http://www.w3.org/2000/svg"
xmlns:xlink="http://www.w3.org/1999/xlink">
<defs>
<filter id="spotlight">
<feSpecularLighting result="spotlight" specularConstant="3.5"
specularExponent="70" lighting-color="grey">
<fePointLight x="350" y="240" z="520"/>
</feSpecularLighting>
<feComposite in="SourceGraphic" in2="spotlight" operator="in"/>
</filter>
</defs>
If you want that sort of effect (elliptical light), you probably want to be using a spotlight rather than a point light.
If you offset the light position to one side and shine the cone down at a shallow-ish angle, you will get an elliptical spot.
<svg width="600" height="529">
<defs>
<filter id="spotlight">
<feSpecularLighting result="spotlight" specularConstant="1.5"
specularExponent="4" lighting-color="#FFF">
<feSpotLight x="-200" y="265" z="400" limitingConeAngle="10" pointsAtX="300" pointsAtY="265" />
</feSpecularLighting>
<feComposite in="SourceGraphic" in2="spotlight" operator="out" k1="0" k2="1" k3="1" k4="0"/>
</filter>
</defs>
<rect x="0" y="0" width="600" height="529" style="fill: skyblue; filter:url(#spotlight);"/>
</svg>
Note that the lighting filter components can be unreliable to use. Each browser has differences in interpretation of the standard. Not to mention some bugs.
A point in case is the above example, which looks different in Firefox and Chrome.
But good luck with your project.
I've created an SVG filter and applied it to some text. When I scale the text smaller by resizing the browser window, some of the edges of the text have a colored line down one side.
<svg
class="tstx" viewBox="0 0 160 160"
height="160" width="160"
style="width: 100%; height: 100%">
<defs>
<filter id="innershadow" x0="-50%" y0="-50%" width="200%" height="200%">
<feGaussianBlur in="SourceAlpha" stdDeviation="2" result="blur"/>
<feOffset dy="3" dx="3"/>
<feComposite in2="SourceAlpha" operator="arithmetic"
k2="-1" k3="1" result="shadowDiff"/>
<feFlood flood-color="grey" flood-opacity="1"/>
<feComposite in2="shadowDiff" operator="in"/>
<feComposite in2="SourceGraphic" operator="over"/>
</filter>
</defs>
<g
font-family="Verdana" font-size="80" font-weight="bold"
stroke="none" fill="#fff" filter="url(#innershadow)">
<text x="10" y="70">A</text>
<text x="80" y="70">B</text>
</g>
</svg>
How can I fix this?
Codepen Example
Move the middle margin right to scale text.
EDIT: It looks like I may have fixed the problem - I just don't know why it worked or if it will cause problems later on. I removed the following:
<feComposite in2="SourceGraphic" operator="over"/>
And the lines disappeared. Is anyone able to explain why?
I am trying to create some ornate page dividers using SVGs with a fill pattern using the same image as the containing element's background image but I am having difficulty getting the SVG pattern to match the repeated background image of the containing element. I found a few similar questions on StackOverflow which mentioned using preserveAspectRatio but none of the solutions I've found are creating the desired effect.
Here's what my SVG code looks like:
<svg id="Layer_1" class="divider" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1400 150" >
<defs>
<pattern id="imgpattern" patternUnits="userSpaceOnUse" width="576" height="576" preserveAspectRatio="xMinYMin slice">
<image width="576" height="576" xlink:href="http://s12.postimg.org/730a258rx/pattern2.jpg"/>
</pattern>
<filter id="dropshadow" height="130%">
<feGaussianBlur in="SourceAlpha" stdDeviation="3"/>
<feOffset dx="0" dy="2" result="offsetblur"/>
<feMerge>
<feMergeNode/>
<feMergeNode in="SourceGraphic"/>
</feMerge>
</filter>
</defs>
<path d="M-394.09,367.9V295.34l1400,0v70s-3.39.9-4.92,1.38c-56.68,17.79-114.85,25.72-174.22,26.17-36.9.27-73.6-2.7-110.25-6.28q-67.4-6.59-134.7-14.08c-49.65-5.51-99.28-8.74-149-1.64-35.12,5-68.54,15.05-99.24,33.08-6,3.53-12.09,7-18.13,10.48-8.94,5.18-17.93,5.51-27,.36-3.47-2-7.14-3.6-10.51-5.71-48.22-30.22-101-43.79-157.83-41.84-29.13,1-58.27,2.45-87.3,4.94-40.49,3.48-80.88,8.18-121.32,12.27-24.37,2.46-48.71,5.26-73.14,7a714.52,714.52,0,0,1-96.42.34,605.73,605.73,0,0,1-96.81-13.9C-368.07,374.88-394.09,367.9-394.09,367.9Z" transform="translate(394.09 -295.32)" stroke="none" fill="url(#imgpattern)" filter="url(#dropshadow)" />
</svg>
And here's a JSFiddle which recreates my issue. Notice how the background pattern of the SVG appears more stretched and because of that does not completely match the repeated background image of the container.
One option is just to move the pattern fill into the filter like so - although there is a small problem that your texture has a one pixel black border, so the tiling isn't perfect.
<filter id="dropshadowandfill" height="130%" >
<feImage x="0" y="0" width="575" height="575" xlink:href="http://s12.postimg.org/730a258rx/pattern2.jpg"></feImage>
<feTile/>
<feComposite operator="in" in2="SourceGraphic" result="filledOriginal"/>
<feGaussianBlur in="SourceAlpha" stdDeviation="3"/>
<feOffset dx="0" dy="2" result="offsetblur"/>
<feMerge>
<feMergeNode/>
<feMergeNode in="filledOriginal"/>
</feMerge>
</filter>
</defs>
<path d="M-394.09,367.9V295.34l1400,0v70s-3.39.9-4.92,1.38c-56.68,17.79-114.85,25.72-174.22,26.17-36.9.27-73.6-2.7-110.25-6.28q-67.4-6.59-134.7-14.08c-49.65-5.51-99.28-8.74-149-1.64-35.12,5-68.54,15.05-99.24,33.08-6,3.53-12.09,7-18.13,10.48-8.94,5.18-17.93,5.51-27,.36-3.47-2-7.14-3.6-10.51-5.71-48.22-30.22-101-43.79-157.83-41.84-29.13,1-58.27,2.45-87.3,4.94-40.49,3.48-80.88,8.18-121.32,12.27-24.37,2.46-48.71,5.26-73.14,7a714.52,714.52,0,0,1-96.42.34,605.73,605.73,0,0,1-96.81-13.9C-368.07,374.88-394.09,367.9-394.09,367.9Z" transform="translate(394.09 -295.32)" stroke="none" filter="url(#dropshadowandfill)" />
Svg shapes other than text are affected by the shape-rendering attribute which can be set to the crispEdges value (https://developer.mozilla.org/en-US/docs/Web/SVG/Attribute/shape-rendering). This value seems to turn anti-aliasing off.
But text is only affected by text-rendering. However, this does not provide the crispEdges value (https://developer.mozilla.org/en-US/docs/Web/SVG/Attribute/text-rendering). Why? Is there another way to get non-anti-alias?
For really crisp edges, you can use a filter to posterize your text.
<svg width="400px" height="400px">
<defs>
<filter id="crispify">
<feComponentTransfer>
<feFuncA type="discrete" tableValues="0 1"/>
</feComponentTransfer>
</filter>
</defs>
<text filter="url(#crispify)" font-size="60" y="60" >Some crispy text</text>
</svg>
I'm using the "offset everything by half a pixel" trick discussed in the second answer to this question to get a crisp 1px stroke on a shape.
(There are rounded edges involved, so the shape-rendering: crispEdges solution isn't viable here -- it makes the curved parts of strokes look terrible.)
How come adding a filter (I'm using a gaussian blur + offset filter to implement a drop shadow) breaks the half-pixel offset hack?
You can play with the jsfiddle.
<svg xmlns="http://www.w3.org/2000/svg" version="1.1">
<defs>
<filter id="f1" x="-20%" y="-20%" width="160%" height="160%">
<feOffset result="offOut" in="SourceAlpha" dx="10" dy="10" />
<feGaussianBlur result="blurOut" in="offOut" stdDeviation="2" />
<feBlend in="SourceGraphic" in2="blurOut" mode="normal" />
</filter>
</defs>
<g transform="translate(5.5,5.5)">
<!-- This one has a blurry stroke -->
<rect width="50" height="50" rx="5" ry="5" stroke="black" stroke-width="1" fill="steelblue" filter="url(#f1)" />
<!-- This one has a crisp stroke -->
<rect x="150" width="50" height="50" rx="5" ry="5" stroke="black" stroke-width="1" fill="steelblue" />
</g>
</svg>
Apparently I can't post inline images as a new user, but you can this is an image of how the svg looks for me.
If you don't like the blurry edges, you can always experiment with adding an feComponentTransfer with feFuncA to manually manipulate the edge blur. Aka:
<filter id="fee" x="-20%" y="-20%" width="160%" height="160%">
<feComponentTransfer>
<feFuncA type="table" tableValues="0 0 1" />
</feComponentTransfer>
</filter>