Animate SVG images - html

Can I animate an SVG circle?
<svg>
<circle id="orange-circle" r="30" cx="50" cy="50" fill="orange" />
<animate
xlink:href="#orange-circle"
attributeName="cx"
from="50"
to="450"
dur="1s"
fill="freeze"
repeatCount="indefinite" />
</svg>
Similarly, I am trying to animate an image:
<svg>
<image id="orange-circle" x="0" y="20" width="200" height="180" xlink:href="cat.png" />
<animate
xlink:href="#orange-circle"
attributeName="cx"
from="50"
to="450"
dur="1s"
fill="freeze"
repeatCount="indefinite" />
</svg>
How can I make the above code work?


Example code (easy) with image is beautiful:
<svg>
<circle fill="blue" cx="150" cy="100" r="50"></circle>
<image xlink:href="http://i.imgur.com/ANS7Rkc.png" x="-50" y="72" width="100" height="50">
<animate attributeName="x" from="-50" to="300" dur="5s" repeatCount="indefinite"></animate>
</image>
</svg>
Example (no image)
https://codepen.io/danjiro/post/how-to-make-svg-loop-animation
Tutorial:
https://developer.mozilla.org/en-US/docs/Web/SVG/Tutorial
enjoin us ;)

Related

Stroke animation, how to attach another path to the appearing stroke?

I have the following animation:
#keyframes dash {
to {
stroke-dashoffset: 0;
}
}
#currency-chart-path {
stroke-dasharray: 1000;
stroke-dashoffset: 1000;
animation: dash 30s linear forwards;
}
<svg id="city-total-v2" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px" viewBox="0 0 1000 1000" enable-background="new 0 0 1000 1000" xml:space="preserve">
<g id="Chartline">
<path id="currency-chart-path" stroke="#7C0A67" stroke-width="3px" fill="none" d="M443,439 L464,435 487,421 511,416 532,424 552,408 572,414 591,413 606,419" />
<path id="chart-arrow" fill="#7C0A67" d="M604.4,423.5l6.88-2.26l-2.44-3.3c-0.1-0.22-0.25-0.41-0.43-0.58l0.01,0.02l-0.02-0.02
c0,0,0,0.01,0.01,0.01l-2.48-3.36l-0.08,0.42l-0.27,1.66l-0.03-0.01l-0.68,3.8l0.09,0.04L604.4,423.5z"/>
</g>
</svg>
Run the code snippet to see the animation.
I want to attach the arrow to the stroke so it look like following the path.
How is that possible?

Yes, it's possible, however in this case you will need JavaScript. Please reed the comments in my code.
let chart = document.querySelector("#currency_chart_path");
// the length of the chart path
let length = currency_chart_path.getTotalLength();
// the request animation id
let rid = null;
// setting the stroke-dasharray and the stroke-dashoffset for the chart
chart.style.strokeDasharray = length;
chart.style.strokeDashoffset = length;
// the animation frames
let frames = length;
// two points on the path: the actual point and an other point very near used to calculate the angle of rotation for the arrow
let point1, point2;
// the animation:
function Frame() {
rid = requestAnimationFrame(Frame);
chart.style.strokeDashoffset = frames;
//two points on the path: the actual point and an other point very near
point1 = chart.getPointAtLength(length - frames);
point2 = chart.getPointAtLength((length - frames + 2) % length);
//the angle of rotation for the arrow
angle = Math.atan2(point2.y - point1.y, point2.x - point1.x);
// set the transformation for the arrow
arrow.setAttribute(
"transform",
"translate(" +
[point1.x, point1.y] +
")" +
"rotate(" +
angle * 180 / Math.PI +
")"
);
frames--;
// stop the animation
if (frames <= 2) {
cancelAnimationFrame(rid);
rid = null;
}
}
Frame();
svg{border:1px solid}
<svg id="city-total-v2" viewBox="400 370 250 100" >
<g id="Chartline">
<path id="currency_chart_path" stroke="#7C0A67" stroke-width="3px" fill="none" d="M443,439 L464,435 487,421 511,416 532,424 552,408 572,414 591,413 606,419" />
<path id="arrow" fill="#7C0A67" d="M0,0L0,-5L7,0L0,5"/>
</g>
</svg>
This is inspired by a demo in Using SVG with CSS3 and HTML5: Vector Graphics for Web Design

An idea is to run the animation in the opposite direction while doing a translation
#keyframes dash {
to {
stroke-dasharray: 190;
}
}
#keyframes move {
to {
transform: translateX(0);
}
}
#currency-chart-path {
stroke-dasharray: 279;
stroke-dashoffset: 381;
animation: dash 10s linear forwards;
}
#Chartline {
animation: move 10s linear forwards;
transform: translateX(-200px);
}
<svg id="city-total-v2" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px" viewBox="300 300 400 400">
<g id="Chartline">
<path id="currency-chart-path" stroke="#7C0A67" stroke-width="3px" fill="none" d="M443,439 L464,435 487,421 511,416 532,424 552,408 572,414 591,413 606,419" />
<path id="chart-arrow" fill="#7C0A67" d="M604.4,423.5l6.88-2.26l-2.44-3.3c-0.1-0.22-0.25-0.41-0.43-0.58l0.01,0.02l-0.02-0.02
c0,0,0,0.01,0.01,0.01l-2.48-3.36l-0.08,0.42l-0.27,1.66l-0.03-0.01l-0.68,3.8l0.09,0.04L604.4,423.5z"/>
</g>
</svg>

Pure SVG Smil solution
You can use stroke-dashoffset to animate line growth.
A marker is used as an arrow at the end of the line, but it cannot be made to move with the line, since the line does not actually grow.
The line is drawn in advance and its growth is simply animated by decreasing the stroke-dashoffset from 177px to zero.
You can use another technique: add an animation of the movement of an arrow along this line to the animation of the growth of the line. It is necessary to set the same time for both animations and therefore the desired effect will be created:
<svg id="city-total-v2" viewBox="400 370 250 100" style="border:1px solid;" >
<g id="Chartline">
<path id="currency_chart_path" stroke-dasharray="177" stroke="#7C0A67" stroke-width="3px" fill="none" d="M443,439 L464,435 487,421 511,416 532,424 552,408 572,414 591,413 606,419" >
<!-- Line growth animation -->
<animate
attributeName="stroke-dashoffset"
begin="0s"
dur="4s"
values="177;0"
repeatCount="indefinite" />
</path>
<path id="arrow" transform="rotate(180)" fill="#7C0A67" d="M0,0L0,-5L7,0L0,5">
<!-- Animate an arrow along a line -->
<animateMotion
id="an"
dur="4s"
repeatCount="indefinite"
rotate="auto-reverse"
begin="0s"
restart="whenNotActive">
<mpath xlink:href="#currency_chart_path"/>
</animateMotion>
</path>
</g>
</svg>
Option with additional chart elements
The animation will start after clicking
<svg id="city_total_v2" viewBox="400 370 250 100" style="border:1px solid;" >
<defs>
<marker id="mark" markerWidth="6.5" markerHeight="8" refX="5.5" refY="1"
orient="45">
<polygon points="0,3.25 3.25,6.5 6.5,0" fill="black" stroke-width="0.25" stroke="black" />
</marker>
<marker id="mark2" markerWidth="7" markerHeight="7" refX="3.5" refY="3"
orient="-45">
<polygon points="0,3.25 3.25,6.5 6.5,0" fill="black" stroke-width="0.25" stroke="black" />
</marker>
</defs>
<g transform="translate(440 465)">
<polyline points="0,0 190,0" marker-end ="url(#mark)" fill="none" stroke="black" />
<polyline points="0,0 0,-85" marker-end ="url(#mark2)" fill="none" stroke="black" />
<rect x="3" y="-24" width="19" height="23" fill="red" />
<rect x="28" y="-30" width="19" height="29" fill="crimson" />
<rect x="53" y="-43" width="19" height="42" fill="gold" />
<rect x="78" y="-38" width="19" height="37" fill="orange" />
<rect x="103" y="-52" width="19" height="51" fill="skyblue" />
<rect x="128" y="-48" width="19" height="47" fill="yellowgreen" />
<rect x="153" y="-41" width="19" height="40" fill="orange" />
</g>
<g id="Chartline">
<path id="currency_chart_path" stroke-dasharray="177" stroke-dashoffset="177" stroke="#7C0A67" stroke-width="3px" fill="none" d="M443,439 L464,435 487,421 511,416 532,424 552,408 572,414 591,413 606,419" >
<!--Line growth animation -->
<animate
attributeName="stroke-dashoffset"
begin="city_total_v2.click"
dur="7s"
values="177;0"
fill="freeze"
restart="whenNotActive" />
</path>
<path id="arrow" transform="rotate(180)" fill="#7C0A67" d="M0,0L0,-5L7,0L0,5">
<!--Arrow movement animation -->
<animateMotion
id="an"
dur="7s"
repeatCount="1"
rotate="auto-reverse"
begin="city_total_v2.click"
fill="freeze"
restart="whenNotActive">
<mpath xlink:href="#currency_chart_path"/>
</animateMotion>
</path>
</g>
</svg>
Added rectangle animations to arrow animation
<svg id="city_total_v2" viewBox="400 370 250 100" style="border:1px solid;" >
<defs>
<marker id="mark" markerWidth="6.5" markerHeight="8" refX="5.5" refY="1" orient="45">
<polygon points="0,3.25 3.25,6.5 6.5,0" fill="black" stroke-width="0.25" stroke="black" />
</marker>
<marker id="mark2" markerWidth="7" markerHeight="7" refX="3.5" refY="3" orient="-45">
<polygon points="0,3.25 3.25,6.5 6.5,0" fill="black" stroke-width="0.25" stroke="black" />
</marker>
</defs>
<g transform="translate(440 465)">
<rect x="3" y="0" width="19" height="23" fill="red" >
<!-- Animating the first rectangle -->
<animate id="an1" attributeName="y" begin="city_total_v2.click" dur="1s" values="-1;-24" fill="freeze" restart="whenNotActive" />
</rect>
<rect x="28" y="0" width="19" height="29" fill="crimson" >
<!-- Animating the second rectangle -->
<animate id="an2" attributeName="y" begin="an1.end" dur="1s" values="-1;-30" fill="freeze" restart="whenNotActive" />
</rect>
<rect x="53" y="0" width="19" height="42" fill="gold" >
<animate id="an3" attributeName="y" begin="an2.end" dur="1s" values="-1;-43" fill="freeze" restart="whenNotActive" />
</rect>
<rect x="78" y="0" width="19" height="37" fill="orange" >
<animate id="an4" attributeName="y" begin="an3.end" dur="1s" values="-1;-37" fill="freeze" restart="whenNotActive" />
</rect>
<rect x="103" y="0" width="19" height="51" fill="skyblue" >
<animate id="an5" attributeName="y" begin="an4.end" dur="1s" values="-1;-52" fill="freeze" restart="whenNotActive" />
</rect>
<rect x="128" y="0" width="19" height="47" fill="yellowgreen" >
<animate id="an6" attributeName="y" begin="an5.end" dur="1s" values="-1;-48" fill="freeze" restart="whenNotActive" />
</rect>
<rect x="153" y="0" width="19" height="40" fill="orange" >
<animate id="an7" attributeName="y" begin="an6.end" dur="1s" values="-1;-41" fill="freeze" restart="whenNotActive" />
</rect>
<!-- masking strip -->
<rect x="1" y="0" width="100%" height="100%" fill="white" />
<polyline marker-end ="url(#mark)" points="0,0 200,0" fill="none" stroke="black" />
<polyline marker-end ="url(#mark2)" points="0,0 0,-85" fill="none" stroke="black" />
</g>
<g id="Chartline">
<path id="currency_chart_path" stroke-dasharray="177" stroke-dashoffset="177" stroke="#7C0A67" stroke-width="3px" fill="none" d="M443,439 L464,435 487,421 511,416 532,424 552,408 572,414 591,413 606,419" >
<!-- Line animation -->
<animate attributeName="stroke-dashoffset" begin="city_total_v2.click" dur="7s" values="177;0" fill="freeze" restart="whenNotActive" />
</path>
<path id="arrow" transform="rotate(180)" fill="#7C0A67" d="M0,0L0,-5L7,0L0,5">
<!-- Arrow animation -->
<animateMotion
id="an"
dur="7s"
repeatCount="1"
rotate="auto-reverse"
begin="city_total_v2.click"
fill="freeze"
restart="whenNotActive">
<mpath xlink:href="#currency_chart_path"/>
</animateMotion>
</path>
</g>
</svg>
Chart animation loop
<svg id="city_total_v2" viewBox="400 370 250 100" style="border:1px solid;" >
<defs>
<marker id="mark" markerWidth="6.5" markerHeight="8" refX="5.5" refY="1" orient="45">
<polygon points="0,3.25 3.25,6.5 6.5,0" fill="black" stroke-width="0.25" stroke="black" />
</marker>
<marker id="mark2" markerWidth="7" markerHeight="7" refX="3.5" refY="3" orient="-45">
<polygon points="0,3.25 3.25,6.5 6.5,0" fill="black" stroke-width="0.25" stroke="black" />
</marker>
</defs>
<g transform="translate(440 465)">
<rect x="3" y="0" width="19" height="23" fill="red" >
<animate id="an1" attributeName="y" begin="city_total_v2.click;an7.end" dur="1s" values="-1;-24" fill="freeze" restart="whenNotActive" />
</rect>
<rect x="28" y="0" width="19" height="29" fill="crimson" >
<animate id="an2" attributeName="y" begin="an1.end" dur="1s" values="-1;-30" fill="freeze" restart="whenNotActive" />
</rect>
<rect x="53" y="0" width="19" height="42" fill="gold" >
<animate id="an3" attributeName="y" begin="an2.end" dur="1s" values="-1;-43" fill="freeze" restart="whenNotActive" />
</rect>
<rect x="78" y="0" width="19" height="37" fill="orange" >
<animate id="an4" attributeName="y" begin="an3.end" dur="1s" values="-1;-37" fill="freeze" restart="whenNotActive" />
</rect>
<rect x="103" y="0" width="19" height="51" fill="skyblue" >
<animate id="an5" attributeName="y" begin="an4.end" dur="1s" values="-1;-52" fill="freeze" restart="whenNotActive" />
</rect>
<rect x="128" y="0" width="19" height="47" fill="yellowgreen" >
<animate id="an6" attributeName="y" begin="an5.end" dur="1s" values="-1;-48" fill="freeze" restart="whenNotActive" />
</rect>
<rect x="153" y="0" width="19" height="40" fill="orange" >
<animate id="an7" attributeName="y" begin="an6.end" dur="1s" values="-1;-41" fill="freeze" restart="whenNotActive" />
</rect>
<!-- masking strip -->
<rect x="1" y="0" width="100%" height="100%" fill="white" />
<polyline marker-end ="url(#mark)" points="0,0 200,0" fill="none" stroke="black" />
<polyline marker-end ="url(#mark2)" points="0,0 0,-85" fill="none" stroke="black" />
</g>
<g id="Chartline">
<path id="currency_chart_path" stroke-dasharray="177" stroke-dashoffset="177" stroke="#7C0A67" stroke-width="3px" fill="none" d="M443,439 L464,435 487,421 511,416 532,424 552,408 572,414 591,413 606,419" >
<!-- Line animation -->
<animate attributeName="stroke-dashoffset" begin="city_total_v2.click;an7.end" dur="7s" values="177;0" fill="freeze" restart="whenNotActive" />
</path>
<path id="arrow" transform="rotate(180)" fill="#7C0A67" d="M0,0L0,-5L7,0L0,5">
<!-- Arrow animation -->
<animateMotion
id="an"
dur="7s"
repeatCount="1"
rotate="auto-reverse"
begin="city_total_v2.click;an7.end"
fill="freeze"
restart="whenNotActive">
<mpath xlink:href="#currency_chart_path"/>
</animateMotion>
</path>
</g>
</svg>

Data visualisation: selectively animate shape but not the text in group of svg

I am working over the following layout (Use Chrome to see correctly) to represent some data. I want an svg-sphere will be "breathing" but every svg-text connected to mentioned sphere will be not animated.
For now both: spheres and text are "breathing":
<svg height="100px" width="100px">
<defs>
<radialGradient id="grad1" cx="50%" cy="50%"
r="50%" fx="50%" fy="50%">
<stop offset="0%" style="stop-
color:rgb(0,0,0);stop-opacity:1"/>
<stop offset="100%" style="stop-
color:rgb(255,255,255);stop-opacity:1"/>
</radialGradient>
</defs>
<g>
<ellipse stroke="rgb(0,{% include
indexmod.html %},0)" stroke-opacity="{%
include indexmod.html %}" stroke-width="{%
include stroke.html %}" cx="50" cy="50"
rx="10" ry="10" fill="url(#grad1)"/>
<text x="50%" y="70%" fill="green" text-
anchor="middle">{% include age.html %}</text>
<text x="50%" y="80%" fill="black" text-
anchor="middle">{{page.shortname}}</text>
</g>
<animateTransform attributeName="transform"
type="scale" additive="sum" from="1 1" to="2
2" begin="0s" dur="5s" rotate="auto-reverse"
repeatCount="indefinite"></animateTransform>
<animateTransform attributeName="transform"
type="scale" additive="sum" from="2 2" to="1
1" begin="5s" dur="5s"
repeatCount="indefinite"></animateTransform>
</svg>

How to transform SVG circle animation into text?

<svg width="1000" height="100">
<circle id="orange-circle" r="30" cx="50" cy="50" fill="orange" />
<animate
xlink:href="#orange-circle"
attributeName="cx"
from="50"
to="900"
dur="2s"
begin="0s"
values="50; 990; 760; 900"
keyTimes="0; 0.7; 0.8; 1"
fill="freeze"
id="circ-anim"/>
</svg>
I tried writing this instead of the line with the circle:
<text id="textAnimation" x="25" y="25" font-size:24">Learn Now!</text>
but the text doesn't have the animation (yes, I've changed the id #orange-circle to #textAnimation)

Changing the cx to x, fixing the href and correcting the style syntax error on the text element makes it animate for me.
<svg width="1000" height="100">
<text id="textAnimation" x="25" y="25" style="font-size:24px">Learn Now!</text>
<animate
xlink:href="#textAnimation"
attributeName="x"
from="50"
to="900"
dur="2s"
begin="0s"
values="50; 990; 760; 900"
keyTimes="0; 0.7; 0.8; 1"
fill="freeze"
id="circ-anim"/>
</svg>

Svg fill animation for the given path

I am trying to animate an arrow from left to right.The code of my arrow's path is given below:
<svg id="svg_circle" width="100%" height="100%" viewBox = '0 0 450 400'>
<g transform = "translate(0,0)">
<path class="path" stroke="#F0F0F0" fill="#fff" stroke-width="1" opacity="1" d="m34.97813,21.70979l-33.55223,0.47088l-0.0394,-13.57138l34.2665,-0.47295l-0.0208,-7.14282l14.50618,14.42226l-14.95643,15.04345l-0.20382,-8.74944z" id="svg_1">
<animate id="project_anim1" attributeName="fill" from="#fff" to="#4DAF4C" begin="1s" dur="1s" fill="freeze" repeatCount="1"></animate>
</path>
</g>
</svg>
The above is the svg path content of my arrow.
Kindly anyone help me how to fill the path from left to right. Waiting for quick response

You can do this by just animating the <stop>s in a <linear gradient>.
<svg id="svg_circle" width="100%" height="100%" viewBox = '0 0 450 400'>
<defs>
<linearGradient id="left-to-right">
<stop offset="0" stop-color="#4DAF4C">
<animate dur="2s" attributeName="offset" fill="freeze" from="0" to="1" />
</stop>
<stop offset="0" stop-color="#fff">
<animate dur="2s" attributeName="offset" fill="freeze" from="0" to="1" />
</stop>
</linearGradient>
</defs>
<path class="path" stroke="#F0F0F0" fill="url(#left-to-right)" stroke-width="1" opacity="1" d="m34.97813,21.70979l-33.55223,0.47088l-0.0394,-13.57138l34.2665,-0.47295l-0.0208,-7.14282l14.50618,14.42226l-14.95643,15.04345l-0.20382,-8.74944z" id="svg_1" />
</svg>
How this works is that we have a linear gradient representing an abrupt change from green to white. The <animation> elements move the position, of that abrupt change, from the left of the arrow (offset=0) to the right (offset="1").
Note that SVG <animate> elements will not work in IE. If you need to support IE, you will need to use the FakeSmile library or use a different method (such as a JS animation library).

Building upon andreas' answer. You can cover your arrow with a shape that is animated to uncover it.
<svg id="svg_circle" width="450" height="400" viewBox='0 0 450 400'>
<path class="path" stroke="#F0F0F0" fill="#fff"
stroke-width="1" opacity="1" id="svg_1"
d="m34.97813,21.70979l-33.55223,0.47088l-0.0394,
-13.57138l34.2665,-0.47295l-0.0208,-7.14282
l14.50618,14.42226l-14.95643,15.04345l-0.20382,
-8.74944z">
<animate id="project_anim1" attributeName="fill"
from="#fff" to="#4DAF4C" begin="0s" dur="3s"
fill="freeze" repeatCount="indefinite" />
</path>
<rect x="0" y="0" width="53" height="34" fill="#fff">
<animate attributeType="XML" attributeName="x"
from="0" to="53" begin="0s" dur="3s"
repeatCount="indefinite" />
<animate attributeType="XML" attributeName="width"
from="53" to="0" begin="0s" dur="3s"
repeatCount="indefinite" />
</rect>
</svg>

I don't think this is possible with the fill attribute. But instead, you can invert your SVG path to a rectangle with a triangle like hole. Now you just need a second element behind that path, where you can simply animate the scale in x-direction, to fill the hole from left to right.
Here is an image showing the technique:
An here is a working example:
<svg width="100%" height="100%" viewBox='0 0 450 400'>
<rect x="0" y="0" width="1" height="22" style="fill: black;" >
<animateTransform attributeName="transform" type="scale" from="1 1" to="50 1" begin="0s" dur="2s" repeatCount="indefinite" />
</rect>
<path fill="#ffffff" d="M0,0v29.8h86V0H0z M6.5,25V5.5L48.8,25H6.5z"/>
</svg>
Note: The answer was updated from triangle to arrow, I won't update my answer as the technique is the same for every shape.

<svg id="svg_circle" width="100%" height="100%" viewBox = '0 0 450 400'>
<defs>
<linearGradient id="left-to-right">
<stop offset="0" stop-color="#4DAF4C">
<animate dur="2s" attributeName="offset" fill="freeze" from="0" to="1" />
</stop>
<stop offset="0" stop-color="#fff">
<animate dur="2s" attributeName="offset" fill="freeze" from="0" to="1" />
</stop>
</linearGradient>
</defs>
<path class="path" stroke="#F0F0F0" fill="url(#left-to-right)" stroke-width="1" opacity="1" d="m34.97813,21.70979l-33.55223,0.47088l-0.0394,-13.57138l34.2665,-0.47295l-0.0208,-7.14282l14.50618,14.42226l-14.95643,15.04345l-0.20382,-8.74944z" id="svg_1" />
</svg>

SVG animation pattern - Traffic light

I want to animate a repeating traffic light just like in real life. I am changing the opacity from dark to brighter to display which light is on. Which works but it doesn't repeat.
Pattern I want
Redlight for 6 seconds...turn off
then begin Yellowlight for 3 seconds...turn off
then begin Greenlight for 6 seconds...turn off
Then back to Yellowlight for 3 seconds...turn off
Then back to Redlight for 6 seconds ...turn off
and the pattern keeps repeating.
Pattern I have
Redlight begin at 0s for 2 seconds ...then turn off
Yellowlight begin at 2s for 2 seconds...then turn off
Greenlight begin at 4s for 2 seconds...then turn off
They all stay off (no repeat)
The SVG code (for the pattern I have):
<svg>
<line x1="100" y1="100" x2="400" y2="100" style="stroke: green; stroke-width:50" />
<line x1="400" y1="0" x2="400" y2="600" style="stroke: green; stroke-width:50" />
<rect x="300" y="600" height="100" width="200" fill="green"></rect>
<rect id="stoplight" x="30" y="0" height="308" width="100"></rect>
<rect id="redlight" x="55" y="25" height="60" width="50"></rect>
<animate xlink:href="#redlight" id="redlight" attributeName="opacity" from=".3" to="1" dur="2s" begin="0s"/>
<rect id="yellowlight" x="55" y="125" height="60" width="50"></rect>
<animate xlink:href="#yellowlight" id="yellowlight" attributeName="opacity" from=".3" to="1" dur="2s" begin="2s"/>
<rect id="greenlight" x="55" y="225" height="60" width="50"></rect>
<animate xlink:href="#greenlight" id="greenlight" attributeName="opacity" from=".3" to="1" dur="2s" begin= "4s" />
</svg>
We just started learning SVG so I'm just a beginner.
JSFiddle
Update Edited the code with repeating lights working. Issues with the pattern, the yellow light transitions back to red light.
Updated: JSFiddle

You've multiple elements with the same id which is invalid. After fixing that you can target the animation end correctly e.g.
<rect id="stoplight" x="30" y="0" height="308" width="100"></rect>
<rect id="redlight" x="55" y="25" height="60" width="50"></rect>
<animate xlink:href="#redlight" id="redlight2" attributeName="opacity" from=".3" to="1" dur="2s" begin="0s;greenlight2.end"/>
<rect id="yellowlight" x="55" y="125" height="60" width="50"></rect>
<animate xlink:href="#yellowlight" id="yellowlight2" attributeName="opacity" from=".3" to="1" dur="2s" begin="2s"/>
<rect id="greenlight" x="55" y="225" height="60" width="50"></rect>
<animate xlink:href="#greenlight" id="greenlight2" attributeName="opacity" from=".3" to="1" dur="2s" begin="4s" />