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Currently building a browser-based SVG application. Within this app, various shapes can be styled and positioned by the user, including rectangles.
When I apply a stroke-width to an SVG rect element of say 1px, the stroke is applied to the rect’s offset and inset in different ways by different browsers. This is proving to be troublesome, especially when I try to calculate the outer width and visual position of a rectangle and position it next to other elements.
For example:
Firefox adds 1px inset (bottom and left), and 1px offset (top and right)
Chrome adds 1px inset (top and left), and 1px offset (bottom and right)
My only solution so far would be to draw the actual borders myself (probably with the path tool) and position the borders behind the stroked element. But this solution is an unpleasant workaround, and I’d prefer not to go down this road if possible.
So my question is, can you control how an SVG’s stroke-width is drawn on elements?
No, you cannot specify whether the stroke is drawn inside or outside an element. I made a proposal to the SVG working group for this functionality in 2003, but it received no support (or discussion).
As I noted in the proposal,
you can achieve the same visual result as "inside" by doubling your stroke width and then using a clipping path to clip the object to itself, and
you can achieve the same visual result as 'outside' by doubling the stroke width and then overlaying a no-stroke copy of the object on top of itself.
Edit: This answer may be wrong in the future. It should be possible to achieve these results using SVG Vector Effects, by combining veStrokePath with veIntersect (for 'inside') or with veExclude (for 'outside). However, Vector Effects are still a working draft module with no implementations that I can yet find.
Edit 2: The SVG 2 draft specification includes a stroke-alignment property (with center|inside|outside possible values). This property may make it into UAs eventually.
Edit 3: Amusingly and dissapointingly, the SVG working group has removed stroke-alignment from SVG 2. You can see some of the concerns described after the prose here.
UPDATE: The stroke-alignment attribute was on April 1st, 2015 moved to a completely new spec called SVG Strokes.
As of the SVG 2.0 Editor’s Draft of February 26th, 2015 (and possibly since February 13th), the stroke-alignment property is present with the values inner, center (default) and outer.
It seems to work the same way as the stroke-location property proposed by #Phrogz and the later stroke-position suggestion. This property has been planned since at least 2011, but apart from an annotation that said
SVG 2 shall include a way to specify stroke position
, it has never been detailed in the spec as it was deferred - until now, it seems.
No browser support this property, or, as far as I know, any of the new SVG 2 features, yet, but hopefully they will soon as the spec matures. This has been a property I personally have been urging to have, and I'm really happy that it's finally there in the spec.
There seems to be some issues as to how to the property should behave on open paths as well as loops. These issues will, most probably, prolong implementations across browsers. However, I will update this answer with new information as browsers begin to support this property.
I found an easy way, which has a few restrictions, but worked for me:
define the shape in defs
define a clip path referencing the shape
use it and double the stroke with as the outside is clipped
Here a working example:
<svg width="240" height="240" viewBox="0 0 1024 1024">
<defs>
<path id="ld" d="M256,0 L0,512 L384,512 L128,1024 L1024,384 L640,384 L896,0 L256,0 Z"/>
<clipPath id="clip">
<use xlink:href="#ld"/>
</clipPath>
</defs>
<g>
<use xlink:href="#ld" stroke="#0081C6" stroke-width="160" fill="#00D2B8" clip-path="url(#clip)"/>
</g>
</svg>
You can use CSS to style the order of stroke and fills. That is, stroke first and then fill second, and get the desired effect.
MDN on paint-order: https://developer.mozilla.org/en-US/docs/Web/SVG/Attribute/paint-order
CSS code:
paint-order: stroke;
Here's a function that will calculate how many pixels you need to add - using the given stroke - to the top, right, bottom and left, all based on the browser:
var getStrokeOffsets = function(stroke){
var strokeFloor = Math.floor(stroke / 2), // max offset
strokeCeil = Math.ceil(stroke / 2); // min offset
if($.browser.mozilla){ // Mozilla offsets
return {
bottom: strokeFloor,
left: strokeFloor,
top: strokeCeil,
right: strokeCeil
};
}else if($.browser.webkit){ // WebKit offsets
return {
bottom: strokeCeil,
left: strokeFloor,
top: strokeFloor,
right: strokeCeil
};
}else{ // default offsets
return {
bottom: strokeCeil,
left: strokeCeil,
top: strokeCeil,
right: strokeCeil
};
}
};
As people above have noted you'll either have to recalculate an offset to the stroke's path coordinates or double its width and then mask one side or the other, because not only does SVG not natively support Illustrator's stroke alignment, but PostScript doesn't either.
The specification for strokes in Adobe's PostScript Manual 2nd edition states:
"4.5.1 Stroking:
The stroke operator draws a line of some thickness along the current path. For each straight or curved segment in the path, stroke draws a line that is centered on the segment with sides parallel to the segment." (emphasis theirs)
The rest of the specification has no attributes for offsetting the line's position. When Illustrator lets you align inside or outside, it's recalculating the actual path's offset (because it's still computationally cheaper than overprinting then masking). The path coordinates in the .ai document are reference, not what gets rastered or exported to a final format.
Because Inkscape's native format is spec SVG, it can't offer a feature the spec lacks.
Here is a work around for inner bordered rect using symbol and use.
Example: https://jsbin.com/yopemiwame/edit?html,output
SVG:
<svg>
<symbol id="inner-border-rect">
<rect class="inner-border" width="100%" height="100%" style="fill:rgb(0,255,255);stroke-width:10;stroke:rgb(0,0,0)">
</symbol>
...
<use xlink:href="#inner-border-rect" x="?" y="?" width="?" height="?">
</svg>
Note: Make sure to replace the ? in use with real values.
Background: The reason why this works is because symbol establishes a new viewport by replacing symbol with svg and creating an element in the shadow DOM. This svg of the shadow DOM is then linked into your current SVG element. Note that svgs can be nested and every svg creates a new viewport, which clips everything that overlaps, including the overlapping border. For a much more detailed overview of whats going on read this fantastic article by Sara Soueidan.
I don’t know how helpful will that be but in my case I just created another circle with border only and placed it “inside” the other shape.
This worked for me:
.btn {
border: 1px solid black;
box-shadow: inset 0 0 0 1px black;
}
A (dirty) possible solution is by using patterns,
here is an example with an inside stroked triangle :
https://jsfiddle.net/qr3p7php/5/
<style>
#triangle1{
fill: #0F0;
fill-opacity: 0.3;
stroke: #000;
stroke-opacity: 0.5;
stroke-width: 20;
}
#triangle2{
stroke: #f00;
stroke-opacity: 1;
stroke-width: 1;
}
</style>
<svg height="210" width="400" >
<pattern id="fagl" patternUnits="objectBoundingBox" width="2" height="1" x="-50%">
<path id="triangle1" d="M150 0 L75 200 L225 200 Z">
</pattern>
<path id="triangle2" d="M150 0 L75 200 L225 200 Z" fill="url(#fagl)"/>
</svg>
The solution from Xavier Ho of doubling the width of the stroke and changing the paint-order is brilliant, although only works if the fill is a solid color, with no transparency.
I have developed other approach, more complicated but works for any fill. It also works in ellipses or paths (with the later there are some corner cases with strange behaviour, for example open paths that crosses theirselves, but not much).
The trick is to display the shape in two layers. One without stroke (only fill), and another one only with stroke at double width (transparent fill) and passed through a mask that shows the whole shape, but hides the original shape without stroke.
<svg width="240" height="240" viewBox="0 0 1024 1024">
<defs>
<path id="ld" d="M256,0 L0,512 L384,512 L128,1024 L1024,384 L640,384 L896,0 L256,0 Z"/>
<mask id="mask">
<use xlink:href="#ld" stroke="#FFFFFF" stroke-width="160" fill="#FFFFFF"/>
<use xlink:href="#ld" fill="#000000"/>
</mask>
</defs>
<g>
<use xlink:href="#ld" fill="#00D2B8"/>
<use xlink:href="#ld" stroke="#0081C6" stroke-width="160" fill="red" mask="url(#mask)"/>
</g>
</svg>
The easiest way I found is to add clip-path into circle
Add clip-path="circle()"
<circle id="circle" clip-path="circle()" cx="100" cy="100" r="100" fill="none" stroke="currentColor" stroke-width="5" />
Then the stroke-width="5" will magically become inner 5px stroke with absolute 100px radius.
Update 2023: The current draft renamed the attribute to stroke-align
Browser Support 2023:
See caniuse
This CSS property is not supported in any modern browser, nor are
there any known plans to support it.
Polyfill-like helper function
Based on the previous approaches to combine paint-order, mask and clip-path.
(As suggested by #Xavier Ho
#Jorg Janke)
//emulateStrokeAlign();
function emulateStrokeAlign() {
let supportsSvgStrokeAlign = CSS.supports("stroke-align", "outer") ?
true :
CSS.supports("stroke-alignment", "outer") ?
true :
false;
console.log("supportsSvgStrokeAlign", supportsSvgStrokeAlign);
if (!supportsSvgStrokeAlign) {
let ns = "http://www.w3.org/2000/svg";
let strokeAlignmentEls = document.querySelectorAll(
"*[stroke-alignment], *[stroke-align]"
);
strokeAlignmentEls.forEach((el, s) => {
let svg = el.closest("svg");
// set auto ids to prevent non-unique mask ids
let svgID = svg.id ? svg.id : "svg_" + s;
svg.id = svgID;
//create <defs> if not previously appended
let defs = svg.querySelector("defs");
if (!defs) {
defs = document.createElementNS(ns, "defs");
svg.insertBefore(defs, svg.children[0]);
}
let style = window.getComputedStyle(el);
let strokeWidth = parseFloat(style.strokeWidth);
let strokeAlignment = el.getAttribute("stroke-alignment") ?
el.getAttribute("stroke-alignment") :
el.getAttribute("stroke-align");
el.removeAttribute("stroke-align");
el.removeAttribute("stroke-alignment");
el.setAttribute("data-stroke-align", strokeAlignment);
let maskClipId = `mask-${svgID}-${s}`;
if (strokeAlignment === "outer") {
// create mask
let mask = document.createElementNS(ns, "mask");
mask.id = maskClipId;
let maskEl = el.cloneNode();
mask.appendChild(maskEl);
defs.appendChild(mask);
maskEl.setAttribute("fill", "#000");
mask.setAttribute("maskUnits", "userSpaceOnUse");
maskEl.setAttribute("stroke", "#fff");
maskEl.removeAttribute("stroke-opacity");
maskEl.removeAttribute("id");
maskEl.setAttribute("paint-order", "stroke");
maskEl.style.strokeWidth = strokeWidth * 2;
// clone stroke
let cloneStroke = el.cloneNode();
cloneStroke.style.fill = "none";
cloneStroke.style.strokeWidth = strokeWidth * 2;
cloneStroke.removeAttribute("id");
cloneStroke.removeAttribute("stroke-alignment");
cloneStroke.classList.add("cloneStrokeOuter");
cloneStroke.setAttribute("mask", `url(#${maskClipId})`);
el.parentNode.insertBefore(cloneStroke, el.nextElementSibling);
//remove stroke from original element
el.style.stroke = "none";
}
if (strokeAlignment === "inner") {
//create clipPath
let clipPathEl = el.cloneNode();
let clipPath = document.createElementNS(ns, "clipPath");
clipPath.id = maskClipId;
defs.appendChild(clipPath);
clipPathEl.removeAttribute("id");
clipPath.appendChild(clipPathEl);
el.setAttribute("clip-path", `url(#${maskClipId})`);
el.style.strokeWidth = strokeWidth * 2;
}
});
}
}
body {
margin: 2em;
}
svg {
width: 100%;
height: auto;
overflow: visible;
border: 1px solid #ccc;
}
body {
margin: 2em;
}
svg {
height: 20em;
overflow: visible;
border: 1px solid #ccc;
}
<p><button onclick="emulateStrokeAlign()">Emulate stroke align</button></p>
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 380 120">
<g id="myGroup" style="fill:rgb(45, 130, 255); stroke:#000; stroke-width:10; stroke-opacity:1;">
<rect id="el1" stroke-alignment="outer" x="10" y="10" width="100" height="100" />
<rect id="el2" x="140" y="10" width="100" height="100" />
<rect id="el3" stroke-alignment="inner" x="270" y="10" width="100" height="100" />
</g>
</svg>
<svg viewBox="0 0 12 6" xmlns="http://www.w3.org/2000/svg" stroke-width="0.5">
<path d="M1,5 a2,2 0,0,0 2,-3 a3,3 0 0 1 2,3.5z" fill="blue" stroke-align="outer" stroke="red" stroke-opacity="0.5" stroke-linecap="butt" />
<path d="M7,5 a2,2 0,0,0 2,-3 a3,3 0 0 1 2,3.5z" fill="blue" stroke-align="inner" stroke="red" stroke-opacity="0.5" />
</svg>
Hardcoded offset via paper.js offset glenzli's plugin
This approach will actually grow/shrink your <path> elements to get the desired stroke position (using the default middle stroke-alignment).
const canvas = document.createElement("canvas");
canvas.style.display='none';
document.body.appendChild(canvas);
//const canvas = document.querySelector("canvas");
paper.setup(canvas);
let strokeEls = document.querySelectorAll("*[stroke-alignment]");
strokeEls.forEach((el,i) => {
let type = el.nodeName;
let style = window.getComputedStyle(el);
let strokeWidth = parseFloat(style.strokeWidth);
let strokeAlignment = el.getAttribute('stroke-alignment');
let offset = strokeAlignment==='outer' ? strokeWidth/2 : (strokeAlignment==='inner' ? strokeWidth / -2 : 0);
// convert primitive
if(type!=='path'){
el = convertPrimitiveToPath(el);
}
let d = el.getAttribute("d");
let polyPath = new paper.Path(el.getAttribute("d"));
let dOffset = offset ? PaperOffset.offset(polyPath, offset)
.exportSVG()
.getAttribute("d") : d;
el.setAttribute("d", dOffset);
});
body{
margin:2em;
}
svg{
width:100%;
overflow:visible;
border:1px solid #ccc;
}
<svg viewBox="0 0 12 6" xmlns="http://www.w3.org/2000/svg" stroke-width="0.5">
<path d="M1,5 a2,2 0,0,0 2,-3 a3,3 0 0 1 2,3.5" stroke="black" fill="none" stroke-linejoin="miter"/>
<path d="M1,5 a2,2 0,0,0 2,-3 a3,3 0 0 1 2,3.5" fill="none" stroke-linejoin="miter" stroke-alignment="outer" stroke="red" stroke-opacity="0.5" />
<path d="M7,5 a2,2 0,0,0 2,-3 a3,3 0 0 1 2,3.5" stroke="black" fill="none" stroke-linejoin="round" />
<path d="M7,5 a2,2 0,0,0 2,-3 a3,3 0 0 1 2,3.5" fill="none" stroke-linejoin="round" stroke-alignment="inner" stroke="red" stroke-opacity="0.5" />
</svg>
<script src="https://unpkg.com/paper#0.12.15/dist/paper-full.min.js"></script>
<script src="https://unpkg.com/paperjs-offset#1.0.8/dist/paperjs-offset.js"></script>
However, the library struggles with complex shapes.
In short i want that no matter where the circle move, a text will be with him.
I have a code similiar to this:
<svg width="100%" height="100%">
<g>
<circle cx="50%" cy="6%" r="7%" [ngStyle]="{'fill': circlerColor, 'transform': 'rotate(' + circleDegrees + 'deg)', 'transform-origin': 'center center', 'transition': 'transform 0.5s'}"></circle>
<text cx="50%" cy="6%" r="7%" style="z-index: 100; font-size: 10px; font-weight: bold;" [ngStyle]="{'fill': circlerColor, 'transform': 'rotate(' + circleDegrees + 'deg)', 'transform-origin': 'center center', 'transition': 'transform 0.5s'}"></text>
</g>
</svg>
From the code you see that the circle move like a clock, 360 degrees.
Now, this code realy "cling" the text to the circle, but rotated! For example when its on 180 degrees, the text is "up side down".
I want some how, from the text to stay horizonal, "cling" but horizontally.
Thanks in ahead!
Ok, the solution i ended with is like my code in my question.
Must be a 'g' tag, which wrap the text and the circle.
Now, you dont move the circle alone with transform: rotate, translate etc, all this operation must be on the whole group, i mean on the 'g' tag.
I had a specific problem, that even if the rotation will be inside the 'g' tag, the text wont be horizontally.
The solution is simple, the 'g' is the "parent", the text inside is the "child". So rotate the parent for ex' 180 degrees, and rotate the child - 180 degrees.
Read more about "move element in a circular path" :
https://usefulangle.com/post/32/moving-an-element-in-circular-path-with-css
Currently building a browser-based SVG application. Within this app, various shapes can be styled and positioned by the user, including rectangles.
When I apply a stroke-width to an SVG rect element of say 1px, the stroke is applied to the rect’s offset and inset in different ways by different browsers. This is proving to be troublesome, especially when I try to calculate the outer width and visual position of a rectangle and position it next to other elements.
For example:
Firefox adds 1px inset (bottom and left), and 1px offset (top and right)
Chrome adds 1px inset (top and left), and 1px offset (bottom and right)
My only solution so far would be to draw the actual borders myself (probably with the path tool) and position the borders behind the stroked element. But this solution is an unpleasant workaround, and I’d prefer not to go down this road if possible.
So my question is, can you control how an SVG’s stroke-width is drawn on elements?
No, you cannot specify whether the stroke is drawn inside or outside an element. I made a proposal to the SVG working group for this functionality in 2003, but it received no support (or discussion).
As I noted in the proposal,
you can achieve the same visual result as "inside" by doubling your stroke width and then using a clipping path to clip the object to itself, and
you can achieve the same visual result as 'outside' by doubling the stroke width and then overlaying a no-stroke copy of the object on top of itself.
Edit: This answer may be wrong in the future. It should be possible to achieve these results using SVG Vector Effects, by combining veStrokePath with veIntersect (for 'inside') or with veExclude (for 'outside). However, Vector Effects are still a working draft module with no implementations that I can yet find.
Edit 2: The SVG 2 draft specification includes a stroke-alignment property (with center|inside|outside possible values). This property may make it into UAs eventually.
Edit 3: Amusingly and dissapointingly, the SVG working group has removed stroke-alignment from SVG 2. You can see some of the concerns described after the prose here.
UPDATE: The stroke-alignment attribute was on April 1st, 2015 moved to a completely new spec called SVG Strokes.
As of the SVG 2.0 Editor’s Draft of February 26th, 2015 (and possibly since February 13th), the stroke-alignment property is present with the values inner, center (default) and outer.
It seems to work the same way as the stroke-location property proposed by #Phrogz and the later stroke-position suggestion. This property has been planned since at least 2011, but apart from an annotation that said
SVG 2 shall include a way to specify stroke position
, it has never been detailed in the spec as it was deferred - until now, it seems.
No browser support this property, or, as far as I know, any of the new SVG 2 features, yet, but hopefully they will soon as the spec matures. This has been a property I personally have been urging to have, and I'm really happy that it's finally there in the spec.
There seems to be some issues as to how to the property should behave on open paths as well as loops. These issues will, most probably, prolong implementations across browsers. However, I will update this answer with new information as browsers begin to support this property.
I found an easy way, which has a few restrictions, but worked for me:
define the shape in defs
define a clip path referencing the shape
use it and double the stroke with as the outside is clipped
Here a working example:
<svg width="240" height="240" viewBox="0 0 1024 1024">
<defs>
<path id="ld" d="M256,0 L0,512 L384,512 L128,1024 L1024,384 L640,384 L896,0 L256,0 Z"/>
<clipPath id="clip">
<use xlink:href="#ld"/>
</clipPath>
</defs>
<g>
<use xlink:href="#ld" stroke="#0081C6" stroke-width="160" fill="#00D2B8" clip-path="url(#clip)"/>
</g>
</svg>
You can use CSS to style the order of stroke and fills. That is, stroke first and then fill second, and get the desired effect.
MDN on paint-order: https://developer.mozilla.org/en-US/docs/Web/SVG/Attribute/paint-order
CSS code:
paint-order: stroke;
Here's a function that will calculate how many pixels you need to add - using the given stroke - to the top, right, bottom and left, all based on the browser:
var getStrokeOffsets = function(stroke){
var strokeFloor = Math.floor(stroke / 2), // max offset
strokeCeil = Math.ceil(stroke / 2); // min offset
if($.browser.mozilla){ // Mozilla offsets
return {
bottom: strokeFloor,
left: strokeFloor,
top: strokeCeil,
right: strokeCeil
};
}else if($.browser.webkit){ // WebKit offsets
return {
bottom: strokeCeil,
left: strokeFloor,
top: strokeFloor,
right: strokeCeil
};
}else{ // default offsets
return {
bottom: strokeCeil,
left: strokeCeil,
top: strokeCeil,
right: strokeCeil
};
}
};
As people above have noted you'll either have to recalculate an offset to the stroke's path coordinates or double its width and then mask one side or the other, because not only does SVG not natively support Illustrator's stroke alignment, but PostScript doesn't either.
The specification for strokes in Adobe's PostScript Manual 2nd edition states:
"4.5.1 Stroking:
The stroke operator draws a line of some thickness along the current path. For each straight or curved segment in the path, stroke draws a line that is centered on the segment with sides parallel to the segment." (emphasis theirs)
The rest of the specification has no attributes for offsetting the line's position. When Illustrator lets you align inside or outside, it's recalculating the actual path's offset (because it's still computationally cheaper than overprinting then masking). The path coordinates in the .ai document are reference, not what gets rastered or exported to a final format.
Because Inkscape's native format is spec SVG, it can't offer a feature the spec lacks.
Here is a work around for inner bordered rect using symbol and use.
Example: https://jsbin.com/yopemiwame/edit?html,output
SVG:
<svg>
<symbol id="inner-border-rect">
<rect class="inner-border" width="100%" height="100%" style="fill:rgb(0,255,255);stroke-width:10;stroke:rgb(0,0,0)">
</symbol>
...
<use xlink:href="#inner-border-rect" x="?" y="?" width="?" height="?">
</svg>
Note: Make sure to replace the ? in use with real values.
Background: The reason why this works is because symbol establishes a new viewport by replacing symbol with svg and creating an element in the shadow DOM. This svg of the shadow DOM is then linked into your current SVG element. Note that svgs can be nested and every svg creates a new viewport, which clips everything that overlaps, including the overlapping border. For a much more detailed overview of whats going on read this fantastic article by Sara Soueidan.
I don’t know how helpful will that be but in my case I just created another circle with border only and placed it “inside” the other shape.
This worked for me:
.btn {
border: 1px solid black;
box-shadow: inset 0 0 0 1px black;
}
A (dirty) possible solution is by using patterns,
here is an example with an inside stroked triangle :
https://jsfiddle.net/qr3p7php/5/
<style>
#triangle1{
fill: #0F0;
fill-opacity: 0.3;
stroke: #000;
stroke-opacity: 0.5;
stroke-width: 20;
}
#triangle2{
stroke: #f00;
stroke-opacity: 1;
stroke-width: 1;
}
</style>
<svg height="210" width="400" >
<pattern id="fagl" patternUnits="objectBoundingBox" width="2" height="1" x="-50%">
<path id="triangle1" d="M150 0 L75 200 L225 200 Z">
</pattern>
<path id="triangle2" d="M150 0 L75 200 L225 200 Z" fill="url(#fagl)"/>
</svg>
The solution from Xavier Ho of doubling the width of the stroke and changing the paint-order is brilliant, although only works if the fill is a solid color, with no transparency.
I have developed other approach, more complicated but works for any fill. It also works in ellipses or paths (with the later there are some corner cases with strange behaviour, for example open paths that crosses theirselves, but not much).
The trick is to display the shape in two layers. One without stroke (only fill), and another one only with stroke at double width (transparent fill) and passed through a mask that shows the whole shape, but hides the original shape without stroke.
<svg width="240" height="240" viewBox="0 0 1024 1024">
<defs>
<path id="ld" d="M256,0 L0,512 L384,512 L128,1024 L1024,384 L640,384 L896,0 L256,0 Z"/>
<mask id="mask">
<use xlink:href="#ld" stroke="#FFFFFF" stroke-width="160" fill="#FFFFFF"/>
<use xlink:href="#ld" fill="#000000"/>
</mask>
</defs>
<g>
<use xlink:href="#ld" fill="#00D2B8"/>
<use xlink:href="#ld" stroke="#0081C6" stroke-width="160" fill="red" mask="url(#mask)"/>
</g>
</svg>
The easiest way I found is to add clip-path into circle
Add clip-path="circle()"
<circle id="circle" clip-path="circle()" cx="100" cy="100" r="100" fill="none" stroke="currentColor" stroke-width="5" />
Then the stroke-width="5" will magically become inner 5px stroke with absolute 100px radius.
Update 2023: The current draft renamed the attribute to stroke-align
Browser Support 2023:
See caniuse
This CSS property is not supported in any modern browser, nor are
there any known plans to support it.
Polyfill-like helper function
Based on the previous approaches to combine paint-order, mask and clip-path.
(As suggested by #Xavier Ho
#Jorg Janke)
//emulateStrokeAlign();
function emulateStrokeAlign() {
let supportsSvgStrokeAlign = CSS.supports("stroke-align", "outer") ?
true :
CSS.supports("stroke-alignment", "outer") ?
true :
false;
console.log("supportsSvgStrokeAlign", supportsSvgStrokeAlign);
if (!supportsSvgStrokeAlign) {
let ns = "http://www.w3.org/2000/svg";
let strokeAlignmentEls = document.querySelectorAll(
"*[stroke-alignment], *[stroke-align]"
);
strokeAlignmentEls.forEach((el, s) => {
let svg = el.closest("svg");
// set auto ids to prevent non-unique mask ids
let svgID = svg.id ? svg.id : "svg_" + s;
svg.id = svgID;
//create <defs> if not previously appended
let defs = svg.querySelector("defs");
if (!defs) {
defs = document.createElementNS(ns, "defs");
svg.insertBefore(defs, svg.children[0]);
}
let style = window.getComputedStyle(el);
let strokeWidth = parseFloat(style.strokeWidth);
let strokeAlignment = el.getAttribute("stroke-alignment") ?
el.getAttribute("stroke-alignment") :
el.getAttribute("stroke-align");
el.removeAttribute("stroke-align");
el.removeAttribute("stroke-alignment");
el.setAttribute("data-stroke-align", strokeAlignment);
let maskClipId = `mask-${svgID}-${s}`;
if (strokeAlignment === "outer") {
// create mask
let mask = document.createElementNS(ns, "mask");
mask.id = maskClipId;
let maskEl = el.cloneNode();
mask.appendChild(maskEl);
defs.appendChild(mask);
maskEl.setAttribute("fill", "#000");
mask.setAttribute("maskUnits", "userSpaceOnUse");
maskEl.setAttribute("stroke", "#fff");
maskEl.removeAttribute("stroke-opacity");
maskEl.removeAttribute("id");
maskEl.setAttribute("paint-order", "stroke");
maskEl.style.strokeWidth = strokeWidth * 2;
// clone stroke
let cloneStroke = el.cloneNode();
cloneStroke.style.fill = "none";
cloneStroke.style.strokeWidth = strokeWidth * 2;
cloneStroke.removeAttribute("id");
cloneStroke.removeAttribute("stroke-alignment");
cloneStroke.classList.add("cloneStrokeOuter");
cloneStroke.setAttribute("mask", `url(#${maskClipId})`);
el.parentNode.insertBefore(cloneStroke, el.nextElementSibling);
//remove stroke from original element
el.style.stroke = "none";
}
if (strokeAlignment === "inner") {
//create clipPath
let clipPathEl = el.cloneNode();
let clipPath = document.createElementNS(ns, "clipPath");
clipPath.id = maskClipId;
defs.appendChild(clipPath);
clipPathEl.removeAttribute("id");
clipPath.appendChild(clipPathEl);
el.setAttribute("clip-path", `url(#${maskClipId})`);
el.style.strokeWidth = strokeWidth * 2;
}
});
}
}
body {
margin: 2em;
}
svg {
width: 100%;
height: auto;
overflow: visible;
border: 1px solid #ccc;
}
body {
margin: 2em;
}
svg {
height: 20em;
overflow: visible;
border: 1px solid #ccc;
}
<p><button onclick="emulateStrokeAlign()">Emulate stroke align</button></p>
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 380 120">
<g id="myGroup" style="fill:rgb(45, 130, 255); stroke:#000; stroke-width:10; stroke-opacity:1;">
<rect id="el1" stroke-alignment="outer" x="10" y="10" width="100" height="100" />
<rect id="el2" x="140" y="10" width="100" height="100" />
<rect id="el3" stroke-alignment="inner" x="270" y="10" width="100" height="100" />
</g>
</svg>
<svg viewBox="0 0 12 6" xmlns="http://www.w3.org/2000/svg" stroke-width="0.5">
<path d="M1,5 a2,2 0,0,0 2,-3 a3,3 0 0 1 2,3.5z" fill="blue" stroke-align="outer" stroke="red" stroke-opacity="0.5" stroke-linecap="butt" />
<path d="M7,5 a2,2 0,0,0 2,-3 a3,3 0 0 1 2,3.5z" fill="blue" stroke-align="inner" stroke="red" stroke-opacity="0.5" />
</svg>
Hardcoded offset via paper.js offset glenzli's plugin
This approach will actually grow/shrink your <path> elements to get the desired stroke position (using the default middle stroke-alignment).
const canvas = document.createElement("canvas");
canvas.style.display='none';
document.body.appendChild(canvas);
//const canvas = document.querySelector("canvas");
paper.setup(canvas);
let strokeEls = document.querySelectorAll("*[stroke-alignment]");
strokeEls.forEach((el,i) => {
let type = el.nodeName;
let style = window.getComputedStyle(el);
let strokeWidth = parseFloat(style.strokeWidth);
let strokeAlignment = el.getAttribute('stroke-alignment');
let offset = strokeAlignment==='outer' ? strokeWidth/2 : (strokeAlignment==='inner' ? strokeWidth / -2 : 0);
// convert primitive
if(type!=='path'){
el = convertPrimitiveToPath(el);
}
let d = el.getAttribute("d");
let polyPath = new paper.Path(el.getAttribute("d"));
let dOffset = offset ? PaperOffset.offset(polyPath, offset)
.exportSVG()
.getAttribute("d") : d;
el.setAttribute("d", dOffset);
});
body{
margin:2em;
}
svg{
width:100%;
overflow:visible;
border:1px solid #ccc;
}
<svg viewBox="0 0 12 6" xmlns="http://www.w3.org/2000/svg" stroke-width="0.5">
<path d="M1,5 a2,2 0,0,0 2,-3 a3,3 0 0 1 2,3.5" stroke="black" fill="none" stroke-linejoin="miter"/>
<path d="M1,5 a2,2 0,0,0 2,-3 a3,3 0 0 1 2,3.5" fill="none" stroke-linejoin="miter" stroke-alignment="outer" stroke="red" stroke-opacity="0.5" />
<path d="M7,5 a2,2 0,0,0 2,-3 a3,3 0 0 1 2,3.5" stroke="black" fill="none" stroke-linejoin="round" />
<path d="M7,5 a2,2 0,0,0 2,-3 a3,3 0 0 1 2,3.5" fill="none" stroke-linejoin="round" stroke-alignment="inner" stroke="red" stroke-opacity="0.5" />
</svg>
<script src="https://unpkg.com/paper#0.12.15/dist/paper-full.min.js"></script>
<script src="https://unpkg.com/paperjs-offset#1.0.8/dist/paperjs-offset.js"></script>
However, the library struggles with complex shapes.
I am trying to animate few Svg elements( Windmill , Door Open) using Tweenmax.js
The Windmill rotation works fine but the door opening animation doesn't work at all in Internet Explorer 9.
Here's my code :
var dooropen = $('#door-open');
var windmill = $('#windmill');
function DoorOpen() {
TweenMax.to(dooropen, 3, {
rotationY: 180,
transformOrigin: "0% 0%"
});
}
function rotateFan() {
TweenMax.to(windmill, 40, {
rotation: 360,
transformOrigin: "51% 64%"
});
}
$('.run').click(function() {
DoorOpen();
rotateFan();
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<script src="http://cdnjs.cloudflare.com/ajax/libs/gsap/1.18.0/TweenMax.min.js"></script>
<svg xmlns="http://www.w3.org/2000/svg" id="Layer_1" width="887.996" height="567.947">
<path fill="#231F20" d="M89.917 99.025h31.58v468.42h-31.58z" />
<g id="windmill" fill="#FFF" stroke="#231F20" stroke-miterlimit="10">
<path d="M105.706 116.57s-50.877-56.142 0-115.79c0 0 47.368 57.894 0 115.79zM105.707 116.57s73.15-19.732 103.088 52.726c0 0-73.114 15.808-103.088-52.727z" />
<path d="M105.707 116.57S76.25 186.372.71 165.385c0 0 32.528-67.36 104.997-48.817z" />
</g>
<path fill="#FFF" stroke="#231F20" stroke-miterlimit="10" d="M485.496 162.376h402v402h-402z" />
<path fill="#231F20" d="M567.496 266.376h246v298h-246z" />
<g id="door-open">
<path fill="#B51543" d="M567.496 266.376h246v298h-246z" />
<path fill="#841C3F" d="M791.496 419.376c0 2.762-2.238 5-5 5h-26c-2.762 0-5-2.238-5-5v-26c0-2.762 2.238-5 5-5h26c2.762 0 5 2.238 5 5v26z" />
</g>
</svg>
Run
It looks like your issue is that your mixing string values with a numerical ones. The default transform-origin are percentages 50% 50% 0. So also it is best to stick with percentage based or numerical values for transform-origin in GSAP.
A two-value syntax is preferred like #Tahir Ahmed commented above. Even though the third parameter is accepted. The third value will automatically default to zero anyway, since that is the default value from the spec 0. And is only necessary when using 3D transforms, since it aligns itself to the z-axis. Which you cant use in SVG, since SVG does not support CSS 3D Transforms.
Have a look at the transform-origin spec:
https://developer.mozilla.org/en-US/docs/Web/CSS/transform-origin
Try this:
var dooropen = $('#door-open');
var windmill = $('#windmill');
function DoorOpen() {
TweenMax.to(dooropen, 3, {
rotationY: 180,
transformOrigin: "0% 0%" /* top and left, omit 0 since is the default */
});
}
function rotateFan() {
TweenMax.to(windmill, 40, {
rotation: 360,
transformOrigin: "51% 64%"
});
}
$('.run').click(function() {
DoorOpen();
rotateFan();
});
tranform-origin keyword equivalents:
left = 0%
center = 50%
right = 100%
top = 0%
bottom = 100%
Also check out the CSSPlugin Docs and the use of SVG transformOrigin
http://greensock.com/docs/#/HTML5/GSAP/Plugins/CSSPlugin/
GSAP svgOrigin property, taken from CSSPlugin Docs:
[Only for SVG elements] Works exactly like transformOrigin but it uses the SVG's global coordinate space instead of the element's local coordinate space. This can be very useful if, for example, you want to make a bunch of SVG elements rotate around a common point. You can either define an svgOrigin or a transformOrigin, not both (for obvious reasons).
See codepen example here of svgOrigin.
So you can do TweenLite.to(svgElement, 1, {rotation:270, svgOrigin:"250 100"}) if you'd like to rotate svgElement as though its origin is at x:250, y:100 in the SVG canvas's global coordinates. Units are not required. It also records the value in a data-svg-origin attribute so that it can be parsed back in. svgOrigin doesn't accommodate percentage-based values.
If you're trying to animate the rotationY of an SVG element, that's the problem - the SVG spec does NOT allow 3D at all. That's not a GSAP problem or limitation - it's literally the SVG spec. Some webkit browsers do technically recognize 3D CSS transforms, but that's non-standard and it definitely isn't supported in IE because IE ignores all CSS transforms on SVG elements. Transforms are supposed to be applied via the "transform" attribute which, again, does not support 3D.
My advice: don't do 3D in SVG. I wish I had better news for you.
I have the following SVG graphic:
<svg version="1.1" id="diagram" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px" width="375px" height="150px">
<path d="M45,11.5H33.333c0.735-1.159,1.167-2.528,1.167-4C34.5,3.364,31.136,0,27,0s-7.5,3.364-7.5,7.5c0,1.472,0.432,2.841,1.167,4H9l-9,32h54L45,11.5z M22.5,7.5C22.5,5.019,24.519,3,27,3s4.5,2.019,4.5,4.5c0,1.752-1.017,3.257-2.481,4h-4.037 C23.517,10.757,22.5,9.252,22.5,7.5z" id="control"/>
</svg>
I want to programmatically change the scale of this object, but I want it to scale from the center point.
I've tried wrapping it around a <g> tag, like so
<g transform="translate(0,0)">
<path x="0" y="0" id="control" transform="scale(2)">...</path>
</g>
But this doesn't seem to work. It seems that scaling a path requires manipulation of the path's matrix, which seems horrifically difficult. Annoyingly, it's easy to scale using additive="sum" property but in this instance, I am not using a transform animation.
Can anyone help me out?
Edit: Managed to get this working nicely, for anyone who is stuck on the same thing, here is a nice way of doing it programmatically:
var elem = document.getElementById("control");
var bBox = elem.getBBox();
var scaleX = 2;
var scaleY = 2;
$(elem).attr("transform", `scale(${scaleX}, ${scaleY}) translate(${-bBox.width/2},${-bBox.height/2})`);
If you know the coordinates of the center point, then you can combine a translate and scale in one transformation. The translation is calculated as: (1 - scale) * currentPosition.
If the center is (10, 20) and you are scaling by 3 then translate by (1 - 3)*10, (1 - 3)*20 = (-20, -40):
<g transform="translate(-20, -40) scale(3)">
<path d="M45,11.5H33.333c0.735-1.159,1.167-2.528,1.167-4C34.5,3.364,31.136,0,27,0s-7.5,3.364-7.5,7.5c0,1.472,0.432,2.841,1.167,4H9l-9,32h54L45,11.5z M22.5,7.5C22.5,5.019,24.519,3,27,3s4.5,2.019,4.5,4.5c0,1.752-1.017,3.257-2.481,4h-4.037 C23.517,10.757,22.5,9.252,22.5,7.5z" id="control"/>
</g>
The transformations are applied in reverse order from the one they are declared, so in the example, above, the scale is performed first and then the translate. Scaling affects the coordinates so the translation here is in scaled coordinates.
You can calculate the center point programmatically using element.getBBox().
You can alter the origin to center:
.scaled-path-svg {
svg {
path {
transform-origin: center;
transform: scale(1.1);
}
}
}
The answer provided by aetheria earlier is great. There is another thing to take care of as well -- stroke-width, so that the outline stays of the same width while the object scales. Usage:
stroke-width: (1/scaling-factor)
So, if your scaling is by say 2, then:
stroke-width: (0.5)
NOTE: You shouldn't missout the transform: translate(...) scale(2) as mentioned by aetheria.