What is the best approach for overlapping SVG elements area fill? - javascript

I am studying some basic image manipulations with SVG and trying to find optimal approach for the following challenge:
We have one SVG file which has various SVG elements (circles, rectangle, triangle). They all are overlapping each other creating new "areas" of different forms (see pic).
So filling actual Elements - no problem there. But what if I want to fill with color only specific intersect area?
My current thinking was:
Consider drawing all elements as Paths, then see if I can treat overall composition as One large path and then play with fill-rule.
Consider calculating the area shape and drawing a new shape on top of it, then fill it.
Consider something else?

Michael's filter method is cool and tricky, but perhaps a little hard to understand.
You can also do it with masks.
<svg width="391" height="400">
<defs>
<!-- define the shapes in the image, which we will use for the outlines
and for creating intersection masks -->
<rect id="square" x="92" y="48" width="218" height="218"/>
<polygon id="triangle" points="54,366 277,366 165,142"/>
<circle id="circle" cx="256" cy="264" r="85"/>
<!-- the masks -->
<!-- white parts are visible, black parts are invisible -->
<mask id="square-minus-triangle">
<!-- square with triangle cut out of it -->
<use xlink:href="#square" fill="white"/>
<use xlink:href="#triangle" fill="black"/>
</mask>
<mask id="triangle-minus-square">
<!-- triangle with square cut out of it -->
<use xlink:href="#triangle" fill="white"/>
<use xlink:href="#square" fill="black"/>
</mask>
</defs>
<!-- background -->
<rect width="100%" height="100%" fill="#e5e4da"/>
<!-- the intersection shapes (yellow) -->
<!-- first draw the circle, but use the square-minus-triangle mask.-->
<use xlink:href="#circle" fill="#e4e400" mask="url(#square-minus-triangle)"/>
<!-- draw the circle again, but use the triangle-minus-square mask.-->
<use xlink:href="#circle" fill="#e4e400" mask="url(#triangle-minus-square)"/>
<!-- draw the outlined shapes -->
<g fill="none" stroke="black" stroke-width="6">
<use xlink:href="#square"/>
<use xlink:href="#triangle"/>
<use xlink:href="#circle"/>
</g>
</svg>

You can do this with filters. An easy way to do is to use near transparent fill and then use a filter to dial the non-overlapping areas to fully transparent and the overlapping areas to fully opaque. It makes the stroke a little crispy though.
<svg height="600px" width="800px">
<defs>
<filter id="opacitychange">
<feComponentTransfer>
<feFuncA type="linear" intercept="-.05"/>
</feComponentTransfer>
<feComponentTransfer>
<feFuncA type="gamma" amplitude="4" exponent=".4"/>
</feComponentTransfer>
</filter>
</defs>
<g filter="url(#opacitychange)">
<circle stroke="black" fill="blue" fill-opacity="0.05" cx="150" cy="150" r="100"/>
<rect stroke="black" x="200" y="100" width="100" height="300" fill="blue" fill-opacity="0.05"/>
<polygon stroke="black" points="50,50 50,400 300,400" fill="blue" fill-opacity="0.05"/>
</g>
</svg>

Related

Expanding A Mask in Javascript

I have a circular, image mask set up in HTML to cover an image.
Here is that code for reference:
<div id="group-focus">
<svg height="800" viewbox="0 0 1000 800">
<defs>
<mask id="text-mask" maskUnits="userSpaceOnUse"
maskContentUnits="userSpaceOnUse">
<circle cx="600" cy="400" r="400" fill="white">
</mask>
</defs>
<!-- this is the image that I masked -->
<g mask="url(#text-mask)">
<image id="text-focus" width="2560" height="1440"
y="0" x="0" xlink:href="img/Asset13x.png" />
</g>
</svg>
</div>
Because I have the mask size set in HTML to the size I want, I am unsure of how to go about expanding the mask to a different size. Can you animate a mask in Javascript? This is for a motion graphic project I am working on currently.
Thanks!

Create rect with blurred stroke in svg using d3.js

How could I create a rect with blurred stroke in svg using d3.js?
Or at least an ordinary svg markup.
I was not able to find such an example or a solution to the problem. If you will tell me that it is a duplicate and provide a similar question I will gladly delete this one. But I am pretty sure that it is not a duplicate.
You might want to look at this article "Adding a subtle touch of glow to your d3.js visualizations"
If you want to do it manually, you can use the feGaussianBlur filter, more infos here : feGaussianBlur
From Mozilla Developer :
<svg width="230" height="120"
xmlns="http://www.w3.org/2000/svg"
xmlns:xlink="http://www.w3.org/1999/xlink">
<filter id="blurMe">
<feGaussianBlur in="SourceGraphic" stdDeviation="5" />
</filter>
<circle cx="60" cy="60" r="50" fill="green" />
<circle cx="170" cy="60" r="50" fill="green"
filter="url(#blurMe)" />
</svg>

Apply shadow on hidden svg path

Here is pen
I want to apply drop shadow effect on rect, when rect is hidden using one of the following technique:
opacity:0 // or
fill:rgba(1,1,1,0) // or
fill-opacity:0 // or
display:none
when I trying to apply filter on such elements, shadow not appearing at all...
Is it possible to apply drop shadow on hidden Svg paths? How?
The simplest way is by using a mask.
In the demo below we have added a drop shadow to a circle. Then we construct the mask so that it hides the circle itself, but keeps the area outside the circle (ie the shadow). Revealing the red rectangle behind it.
<svg width="200" height="200" xmlns="http://www.w3.org/2000/svg">
<defs>
<filter id="shadow">
<feDropShadow dx="4" dy="8" stdDeviation="4"/>
</filter>
<mask id="invisible">
<rect width="100%" height="100%" fill="white"/>
<circle cx="50%" cy="50%" r="80" fill="black"/>
</mask>
</defs>
<rect x="40" y="60" width="150" height="80" fill="red"/>
<circle cx="50%" cy="50%" r="80"
style="fill:blue; filter:url(#shadow); mask: url(#invisible);"/>
</svg>
If you're just looking for a drop shadow with no rect, setting the fill to the background color will work:
.square{
fill:#fff;
width:100px;
height:100px;
filter:url('#drop-shadow');
}
If you've got multiple elements under the rect, you could try hiding just the filled in area with a clip-path or mask.

Animated SVG Mask Wipe

Here's a storyboard of the CSS/JS/SVG animation I'm trying to accomplish. Two triangle masks enter from either side, then intersect resulting in a negative mask:
The point where the triangles intersect is where it gets tricky. When I export the mask for panel 4 to SVG, it looks like this:
<svg width="416px" height="289px" viewBox="0 0 416 289" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
<defs>
<path d="M211.503681,65.6626347 L507.009604,-138.787586 L507.009604,425.787586 L211.507182,221.339788 L-84,425.792431 L-84,-138.787586 L211.503681,65.6626347 Z M211.503681,65.6626347 L99,143.5 L211.507182,221.339788 L324.01001,143.502422 L211.503681,65.6626347 Z" id="path-1"></path>
</defs>
<g id="Page-1" stroke="none" stroke-width="1" fill="none" fill-rule="evenodd">
<rect id="Rectangle-1-Copy-3" fill="#F6A623" x="0" y="0" width="416" height="289"></rect>
<mask id="mask-2" fill="white">
<use xlink:href="#path-1"></use>
</mask>
<use id="Combined-Shape" fill="#000000" xlink:href="#path-1"></use>
<rect id="Rectangle-1-Copy-2" fill="#4990E2" mask="url(#mask-2)" x="0" y="0" width="416" height="289"></rect>
</g>
</svg>
It looks like it's basically drawing two shapes, the negative-space diamond mask in the center and the remainder of the outer triangles.
So the static mask itself appears to be possible with SVG, but I don't know how to animate it. Is there a library that can simplify this kind of SVG transition/tweening, or a fancy math equation that can calculate the paths dynamically?
Or am I looking at this the wrong way entirely and there's a much easier way to do it altogether?
So the solution was to make it both more simple AND more complicated.
Instead of two layers on top of each other with one mask, I needed three layers. One on the bottom to show behind the first mask, the second to be masked by the incoming triangles, and a third layer above that, duplicate to the first, where a diamond-shaped mask is applied.
<svg width="500" height="300" viewbox="0 0 500 300">
<defs>
<clipPath id="triangles">
<path id="left" d="M-250,-150 L250,150 L-250,450 Z" fill="black" />
<path id="right" d="M250,150 L750,-150 L750,450 Z" fill="black" />
</clipPath>
<clipPath id="diamond">
<path id="diamond-path" d="M250,0 L500,150 L250,300 L0,150 Z" fill="black" />
</clipPath>
</defs>
<!-- bottom -->
<g id="bottom">
<rect fill="darkorange" x="0" y="0" width="500" height="300" />
<text x="50%" y="65%" text-anchor="middle" class="text">Text</text>
</g>
<!-- middle/triangles -->
<g id="middle" clip-path="url(#triangles)">
<rect fill="dodgerblue" x="0" y="0" width="500" height="300" />
<text x="50%" y="65%" text-anchor="middle" class="text">Text</text>
</g>
<!-- top/diamond -->
<g id="top" clip-path="url(#diamond)">
<rect fill="darkorange" x="0" y="0" width="500" height="300" />
<text x="50%" y="65%" text-anchor="middle" class="text">Text</text>
</g>
</svg>
The top layer with the diamond path starts out scaled to 0, making it invisible. The two triangle clip paths are animated in towards each other, showing the bottom layer underneath. When the two triangle points meet, the diamond clip path on the top layer is scaled up, revealing the top layer which is a duplicate of the bottom.
I also switched to clip paths instead of masks because they're a) better supported and b) allow for multiple paths.
Here's a Codepen using CSS for the animations (only works in WebKit for the moment).
UPDATE: Here's a Codepen using GSAP that works in all browsers: http://s.codepen.io/kgrote/debug/mPxzZY

SVG - how to define transformation on two distinct elements

I have the following svg:
<svg
width="1750"
height="1125"
xmlns="http://www.w3.org/2000/svg"
xmlns:xlink="http://www.w3.org/1999/xlink">
<g>
<g id="svg_4">
<g id="imgG_4">
<image
transform="rotate(35.3608 608.333 503.301)"
xlink:href="https://www.google.com/images/srpr/logo4w.png"
id="img_4"
height="188.79927"
width="188.79927"
y="408.90001"
x="706.21582"/>
</g>
<rect
transform="rotate(35.3608 783.333 667.587)"
id="border_4"
height="264.31644"
width="360.92146"
y="535.42838"
x="602.87256"
fill-opacity="0"
stroke-width="5"
stroke="#000000"
fill="#000000"/>
</g>
</g>
</svg>
I'd like to change the angle of the both the rect and image. I cannot however, figure out how to adjust the image such that its spacing within the rect is consistent as i rotate the rect.
E.g. After rotating both the rect and the image the image has the same amount of whitespace above and to the left as it did prior to rotation of both elements.
I cannot put the rotation on the container groups due to other technical restraints.
I'd like to end up with something like:
<svg
width="1750"
height="1125"
xmlns="http://www.w3.org/2000/svg"
xmlns:xlink="http://www.w3.org/1999/xlink">
<g>
<g
id="svg_4">
<g
id="imgG_4">
<image
transform="rotate(70.3608 608.333 503.301)"
xlink:href="https://www.google.com/images/srpr/logo4w.png"
id="img_4"
height="188.79927"
width="188.79927"
y="408.90001"
x="706.21582"
/>
</g>
<rect
transform="rotate(70.3608 783.333 667.587)"
id="border_4"
height="264.31644"
width="360.92146"
y="535.42838"
x="602.87256"
fill-opacity="0"
stroke-width="5"
stroke="#000000"
fill="#000000"
/>
</g>
</g>
</svg>
The caveat is that the x,y values have to change on the image in order to get the layout correct and I have know idea how to calculate them.
Any idea on how I would go about this? I will be using javascript to do the math involved...
Plnkr is here
Assuming you wanted to rotate both elements around the same rotation point as the rectangle (ie. 783.333,667.587), then all you need to is apply the additional rotation to the front of both element transforms. So:
<image transform="rotate(90 783.333 667.587) rotate(70.3608 608.333 503.301)"
<rect transform="rotate(90 783.333 667.587) rotate(70.3608 783.333 667.587)"
would rotate both elements an additional 90deg round the above centre of rotation.
However you said you want to do the maths yourself in Javascript. So to get you started, it might help to know that the transform:
rotate(r x y)
is equivalent to:
translate(x y) rotate(r) translate(-x -y)

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