How can I set the offset on a straight line in svg - javascript

I want to make a linear gradient on a straight line.But the offset always remains constant does not change because it is a straight line.
For example, the first stop is color red and the second stop is color blue, but the offset is a single color.
<defs>
<linearGradient id="Gradientm5cf5" x1="11.111" x2="33.111" y1="44.111" y2="77.111" gradientUnits="userSpaceOnUse">
<stop offset="0%" stop-color="red"></stop>
<stop offset="50%" stop-color="blue"></stop>
</linearGradient>
</defs>
<path d="M 1518 1131 L 1681.63 1131" fill="none" stroke="url(#Gradientm5cf5)" stroke-miterlimit="10" pointer-events="stroke" stroke-width="6" style="--animation-time:1s;" class="flow">
</path>

Related

How to calculate the position of a circle depending on the current time on the curve

<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1158 696">
<defs>
<linearGradient id="grad1" x1="0%" y1="0%" x2="100%" y2="0%">
<stop offset="0%" style="stop-color:red;stop-opacity:1" />
<stop offset="50%" style="stop-color:blue;stop-opacity:1" />
<stop offset="100%" style="stop-color:red;stop-opacity:1" />
</linearGradient>
</defs>
<g><g><g><path fill="none" stroke="url(#grad1)" stroke-miterlimit="50" stroke-width="4" d="M0 212.4c241.4 0 274.174-213.852 579-210 304.826 1.853 345.472 211 581 210"/></g></g></g>
<g>
<g opacity=".76">
<path fill="#011134" d="M.25 214.001c239.653 0 274.65-213.852 580.005-210 305.355 3.853 340.062 210 580.005 210v486H.25v-486z"/>
</g>
</g>
<g transform="translate(0, 198)" >
<filter id="blurMe">
<feGaussianBlur in="SourceGraphic" stdDeviation="2" />
</filter>
<circle filter="url(#blurMe)" cx="16" cy="16" r="12" fill="red" />
</g>
</svg>
I've tried to use a formula of Normal distribution
I need to achive a result where the circle moves along the curve depends on the current time for that i need to find a formula which represents the graph described above, but the Gaussian distribution does not give me a desirable graph, the Gaussian distribution gives me next:

Transitioning the gradient fill of a single node among many

Let's say I have an SVG with a structure similar to this:
<svg>
<defs>
<linearGradient id="gradient-red">...</linearGradient>
<linearGradient id="gradient-blue">...</linearGradient>
</defs>
<g class="node">
<circle r="50" style="fill: url('#gradient-red');"></circle>
</g>
<g class="node">
<circle r="100" style="fill: url('#gradient-red');"></circle>
</g>
<g class="node">
<circle r="150" style="fill: url('#gradient-red');"></circle>
</g>
<g class="node">
<circle r="200" style="fill: url('#gradient-red');"></circle>
</g>
<g class="node">
<circle r="250" style="fill: url('#gradient-red');"></circle>
</g>
</svg>
I now have five circles with reddish gradients. I understand how to change the color of a selected node -- I just target it (via d3.select) and alter its style to 'fill', 'url("#gradient-blue"). But how would I go about transitioning the gradient fill from red to blue for that one node?
Something like this results in no tween/transition and instead causes an instant color swap:
d3.transition().duration(1000)
.tween('start', () => {
let test = d3.select(currentTarget);
test.transition().duration(1000).style('fill', 'url("#gradient-blue")');
And if I were to transition the stop-color of the gradients themselves, it changes all of the nodes/circles (because you're altering the <defs>).
What am I doing wrong?
Transition's interpolation
In D3, a transition basically interpolates a start value to an end value. This can be easy to demonstrate if we interpolate numbers. For instance, let's transition from 50 to 2000:
const interpolator = d3.interpolate(50, 2000);
d3.range(0, 1.05, 0.05).forEach(function(d) {
console.log(interpolator(d))
})
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/5.7.0/d3.min.js"></script>
We can also interpolate strings:
const interpolator = d3.interpolate("March, 2000", "March, 2020");
d3.range(0, 1.05, 0.05).forEach(function(d) {
console.log(interpolator(d))
})
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/5.7.0/d3.min.js"></script>
The problem
Now, let's have a look at your case: you want to interpolate from this:
url("#gradient-red")
To this:
url("#gradient-blue")
What are the possible intermediates here? Can you see that this is impossible? Here is the proof:
const interpolator = d3.interpolate("url(#gradient-red)", "url(#gradient-blue)");
d3.range(0, 1.1, 0.1).forEach(function(d) {
console.log(interpolator(d))
})
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/5.7.0/d3.min.js"></script>
As you can see, the very first interpolation will instantly lead to the end value.
Possible solutions
The most obvious solution is interpolating the stop colour. However, as you just discovered, this will change the gradient of all circles.
So, the naive fix is creating several gradients, one for each circle, with unique IDs. While this may be an adequate solution for 3 or 4 circles, it's clearly not a clever solution if you have tens or hundreds of elements.
That being said, this is my suggestion:
Create a temporary gradient, let's give it the ID #gradient-temporary, just like the red one.
Then, when you select (or filter it somehow) a circle, change it's fill from "url(#gradient-red)" to "url(#gradient-temporary)". This change is immediate, no effect is obvious on the screen.
Do the transition on the stop colour of this temporary gradient.
When the transition finishes, change the circle's fill from "url(#gradient-temporary)" to "url(#gradient-blue)". Again, this is immediate. Also, change the stop colour of the temporary gradient back to red.
That way, you can have hundreds of circles, but you just need 3 gradients to transition them.
Here is a demo with that approach, click on each circle to transition it:
const circles = d3.selectAll("circle");
circles.on("click", function() {
const element = this;
d3.select(element).style("fill", "url(#gradient-temporary)");
d3.select("#gradient-temporary").select("stop:nth-child(2)")
.transition()
.duration(1000)
.style("stop-color", "rgb(0,0,255)")
.on("end", function() {
d3.select(element).style("fill", "url(#gradient-blue)");
d3.select("#gradient-temporary").select("stop:nth-child(2)")
.style("stop-color", "rgb(255,0,0)")
})
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/5.7.0/d3.min.js"></script>
<svg>
<defs>
<linearGradient id="gradient-red" x1="0%" y1="0%" x2="100%" y2="0%">
<stop offset="0%" style="stop-color:rgb(211,211,211);stop-opacity:1" />
<stop offset="100%" style="stop-color:rgb(255,0,0);stop-opacity:1" />
</linearGradient>
<linearGradient id="gradient-temporary" x1="0%" y1="0%" x2="100%" y2="0%">
<stop offset="0%" style="stop-color:rgb(211,211,211);stop-opacity:1" />
<stop offset="100%" style="stop-color:rgb(255,0,0);stop-opacity:1" />
</linearGradient>
<linearGradient id="gradient-blue" x1="0%" y1="0%" x2="100%" y2="0%">
<stop offset="0%" style="stop-color:rgb(211,211,211);stop-opacity:1" />
<stop offset="100%" style="stop-color:rgb(0,0,255);stop-opacity:1" />
</linearGradient>
</defs>
<g class="node">
<circle r="20" cx="20" cy="70" style="fill: url('#gradient-red');"></circle>
</g>
<g class="node">
<circle r="20" cx="80" cy="70" style="fill: url('#gradient-red');"></circle>
</g>
<g class="node">
<circle r="20" cx="140" cy="70" style="fill: url('#gradient-red');"></circle>
</g>
<g class="node">
<circle r="20" cx="200" cy="70" style="fill: url('#gradient-red');"></circle>
</g>
<g class="node">
<circle r="20" cx="260" cy="70" style="fill: url('#gradient-red');"></circle>
</g>
</svg>

Is it possible to start/stop SVG gradients at a certain absolute position?

I am creating in Javascript different L- shaped paths. They differ in length and in position. I would like to have a linearGradient as a stroke for them, where the first stop offset is at the position of x=10 pixels, i.e. the change in color always starts after x pixels.
Using gradient the standard way just offers relative positioning (e.g. wrt the object bounding box). This results in different stop offsets due to the different object bounding boxes.
Here is one example how it looks like:
path.p1 {
fill: none;
stroke-width: 20px;
}
<svg height="600" width="1000">
<path class="p1" d="M10 10 V 100 H 100 " stroke="url(#cl1)"/>
<path class="p1" d="M150 10 V 100 H 200 " stroke="url(#cl1)"/>
<path class="p1" d="M250 10 V 100 H 400 " stroke="url(#cl1)"/>
<defs>
<linearGradient id="cl1" gradientUnits="objectBoundingBox" x1="0%" y1="0%" x2="100%" y2="0%">
<stop offset="0" style="stop-color:grey;stop-opacity:1" />
<stop offset="0.02" style="stop-color:grey;stop-opacity:1" />
<stop offset="0.15" style="stop-color:orange;stop-opacity:1" />
<stop offset="0.2" style="stop-color:orange;stop-opacity:1" />
</linearGradient>
</defs>
</svg>
Is there a way to use one gradient but a clever way to reference it through SVG nesting or javascript?
Use gradientUnits="userSpaceOnUse". This way, the gradient is positioned in absolute units, but always in the local coordinate system of the element it is defined on.
In your case, having all paths in the same coordinate system would mean you defined an overall gradient spanning all paths. To avoid that, you have to change that, for example by defining a transform attribute. Each consecutive path is moved more to the right, while its starting point, measured in the local coordinate system, remains in the same place.
path.p1 {
fill: none;
stroke-width: 20px;
}
<svg height="600" width="1000">
<path class="p1" d="M10 10 V 100 H 100 " stroke="url(#cl1)"/>
<path class="p1" d="M10 10 V 100 H 60 " stroke="url(#cl1)" transform="translate(140)"/>
<path class="p1" d="M10 10 V 100 H 160 " stroke="url(#cl1)" transform="translate(240)"/>
<defs>
<linearGradient id="cl1" gradientUnits="userSpaceOnUse" x1="10" y1="0" x2="110" y2="0">
<stop offset="0" style="stop-color:grey;stop-opacity:1" />
<stop offset="0.02" style="stop-color:grey;stop-opacity:1" />
<stop offset="0.15" style="stop-color:orange;stop-opacity:1" />
<stop offset="0.2" style="stop-color:orange;stop-opacity:1" />
</linearGradient>
</defs>
</svg>

directed gradient in svg's path element

I'm writing a simple webpage that displays a graph and shows dependencies. I found an unexpected behavior in how path elements are rendered within svg.
Here's the full HTML of the example:
<html>
<body>
<svg id="svgConnections" xmlns="http://www.w3.org/2000/svg" style="width: 300px; height: 120px">
<defs>
<linearGradient id="grad1" >
<stop offset="0%" style="stop-color:yellow;stop-opacity:1" />
<stop offset="100%" style="stop-color:red;stop-opacity:1" />
</linearGradient>
</defs>
<path d="M40,40 L100,100 Z" stroke="url(#grad1)" strokeWidth="1px" />
<path d="M200,100 L140,40 Z" stroke="url(#grad1)" strokeWidth="1px" />
</svg>
</body>
</html>
The same example is on https://jsfiddle.net/4fLjm0e2/
What bugs me is that the first line, which goes from top left to bottom right corner, looks exactly like the second line, which goes "in reverse": from bottom right corner to the top left.
How do I make the path always start with yellow and end with red?
This is not a bug. This is problem in understanding.
The default behavior of a linear gradient is to transition along a horizontal line from the left side of an object to its right side. It doesn't matter if you draw a path from left to right or from right to left. In both cases gradient will appear as from left to right as per default settings.
Consider the demo below:
<svg width="120" height="120" xmlns="http://www.w3.org/2000/svg">
<defs>
<linearGradient id="grad1" gradientUnits="userSpaceOnUse">
<stop offset="0%" style="stop-color:yellow;stop-opacity:1" />
<stop offset="100%" style="stop-color:red;stop-opacity:1" />
</linearGradient>
</defs>
<g stroke-width="2">
<path d="M10,40 L110,40 Z" stroke="url(#grad1)" />
<path d="M110,70 L10,70 Z" stroke="url(#grad1)" />
</g>
</svg>
If you wants the transition of colors to occur across a vertical line or a line at an angle, you must specify the line's starting point with the x1 and
y1 attributes and its ending points with the x2 and y2 attributes.
Rather than duplicate the stops into each <linearGradient> element, we'll use the xlink:href attribute to refer to the original gradient. The stops will be inherited, but the x- and y-coordinates will be overridden by each individual gradient.
<linearGradient id="grad1" x1="0" y1="0" x2="1" y2="1">
<stop offset="0%" style="stop-color:rgb(255,255,0);stop-opacity:1" />
<stop offset="100%" style="stop-color:rgb(255,0,0);stop-opacity:1" />
</linearGradient>
<linearGradient id="grad2" xlink:href="#grad1" x1="1" y1="1" x2="0" y2="0"></linearGradient>
Extending the above example:
<svg width="120" height="120" xmlns="http://www.w3.org/2000/svg">
<defs>
<linearGradient id="grad1" gradientUnits="userSpaceOnUse">
<stop offset="0%" style="stop-color:rgb(255,255,0);stop-opacity:1" />
<stop offset="100%" style="stop-color:rgb(255,0,0);stop-opacity:1" />
</linearGradient>
<linearGradient id="grad2" xlink:href="#grad1" x1="120" y1="0" x2="0" y2="0"></linearGradient>
</defs>
<g stroke-width="2">
<path d="M10,40 L110,40" stroke="url(#grad1)" />
<path d="M110,70 L10,70 Z" stroke="url(#grad2)" />
</g>
</svg>
As in your example, you are using diagonal paths so we need to override x1, y1, x2 and y2 attribute of both <linearGradient> elements.
These values on the first <linearGradient> element will override the default left to right settings to produce a diagonal gradient from top left to the right bottom.
While on the <linearGradient> element these values will change the direction of gradient i.e from bottom to top.
Now we can apply these gradients to the respective paths.
<svg width="300" height="120" xmlns="http://www.w3.org/2000/svg">
<defs>
<linearGradient id="grad1" x1="0" y1="0" x2="1" y2="1">
<stop offset="0%" style="stop-color:rgb(255,255,0);stop-opacity:1" />
<stop offset="100%" style="stop-color:rgb(255,0,0);stop-opacity:1" />
</linearGradient>
<linearGradient id="grad2" xlink:href="#grad1" x1="1" y1="1" x2="0" y2="0"></linearGradient>
</defs>
<g stroke-width="2">
<path d="M40,40 L100,100 Z" stroke="url(#grad1)" />
<path d="M200,100 L140,40 Z" stroke="url(#grad2)" />
</g>
</svg>
Note: This Question can be useful in context with the current problem.

Lower and Upper case issues in SVG

I have drawn line and a circle using two paths in SVG. I have used gradient units property for linear gradient in SVG and I have applied the gradient color to the circle and line. While applying into DOM the "gradientUnits" property is applied as "gradientunits"; because of this Upper and Lower case issue I was not able to get my required output.
Image 1:
Having issue
mentioned in green colored rectangle.
Image 2: Required output
mentioned in green colored rectangle.
Here is my SVG code:
<svg id="legend_container_svg" class="e-designerhide" style="height: 40px; width: 71px;">
<g id="container_svg_Legend">
<defs>
<linearGradient id="container_svg_legend0Gradient" x1="0%" y1="0%" x2="0%" y2="558%" gradientUnits="userSpaceOnUse">
<stop offset="0%" stop-color="#F34649" stop-opacity="1"></stop>
<stop offset="100%" stop-color="#B74143" stop-opacity="1"></stop></linearGradient>
</defs>
<g id="container_svg_Legend0" cursor="pointer">
<path id="container_svg_LegendItemShape0" fill="url(#container_svg_legend0Gradient)" stroke-width="2" stroke="url(#container_svg_legend0Gradient)" opacity="1" d="M 7.5 21.5 L 12.5 21.5 M 22.5 21.5 L 27.5 21.5" lgndctx="true"></path>
<path id="container_svg_LegendItemShape0" fill="transparent" stroke-width="2" stroke="url(#container_svg_legend0Gradient)" opacity="1" d="M 12.5 21.5 a 5 5 0 1 0 10 0 a5 5 0 1 0 -10 0" lgndctx="true"></path>
</g>
</g>
</svg>
Is there any method in JavaScript to apply the attribute property in DOM as if what I have given in my source code?
Anyone help me on resolving the issue.
Thanks, Dharani.

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