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I have a web app that renders svg elements from cartesian points (lines, paths, etc) that come from a database.
I have a requirement that an end user can upload an svg file (icons) and drag the icon to fit within specific bounds of the points already defined and rendered in the app.
For example (see snippet), a user can upload the 'x' icon and drag it near the green line defined by two points, which should result in the icon being snapped and resized to the line - the upper left corner snapped to the line start point, and the width of the icon extending to the line end point. Same is true for the file icon being snapped to the red line. This is done dynamically during drag with js. I have omitted the js from the snippet to keep things simple, as I am confident that the answer lies with svg attributes and or style that I can set with js, but the svg properties/values are what I cannot pin down.
What I have tried - everything, I think. Given that I am nesting svg elements, I took the BBox values as an offset to used the x and y attributes on the icon svg element, and that moved it, but not to the start point. I also tried translate without success. I am able to move and resize, but not to the coordinates I need. I do not want to change the icon svg at all if possible, so i'd prefer to leave its viewBox as-is.
<svg height="700" width="700" fill="#e6e6e6" xmlns="http://www.w3.org/2000/svg">
<svg viewBox="0 0 512 512">
<path d="M443.6,387.1L312.4,255.4l131.5-130c5.4-5.4,5.4-14.2,0-19.6l-37.4-37.6c-2.6-2.6-6.1-4-9.8-4c-3.7,0-7.2,1.5-9.8,4 L256,197.8L124.9,68.3c-2.6-2.6-6.1-4-9.8-4c-3.7,0-7.2,1.5-9.8,4L68,105.9c-5.4,5.4-5.4,14.2,0,19.6l131.5,130L68.4,387.1 c-2.6,2.6-4.1,6.1-4.1,9.8c0,3.7,1.4,7.2,4.1,9.8l37.4,37.6c2.7,2.7,6.2,4.1,9.8,4.1c3.5,0,7.1-1.3,9.8-4.1L256,313.1l130.7,131.1 c2.7,2.7,6.2,4.1,9.8,4.1c3.5,0,7.1-1.3,9.8-4.1l37.4-37.6c2.6-2.6,4.1-6.1,4.1-9.8C447.7,393.2,446.2,389.7,443.6,387.1z"/>
</svg>
<svg viewBox="0 0 380 511.7">
<path fill-rule="nonzero" d="M26.18 0h221.14c3.1 0 5.85 1.51 7.56 3.84l122.88 145.08a9.27 9.27 0 0 1 2.21 6.05l.03 330.55c0 7.13-2.98 13.68-7.72 18.42l-.03.04c-4.75 4.74-11.29 7.72-18.43 7.72H26.18c-7.13 0-13.69-2.96-18.45-7.71l-.03-.04C2.97 499.22 0 492.69 0 485.52V26.18C0 19 2.95 12.46 7.68 7.72l.04-.04C12.46 2.95 19 0 26.18 0zm335.06 164.7c-134.78-5.58-134.35-17.38-129.82-134.02l.45-11.92H26.18c-2.05 0-3.91.83-5.26 2.16a7.482 7.482 0 0 0-2.16 5.26v459.34c0 2.02.84 3.88 2.18 5.23 1.36 1.35 3.22 2.19 5.24 2.19h327.64c2.01 0 3.86-.85 5.22-2.2 1.35-1.36 2.2-3.21 2.2-5.22V164.7zM250.25 27.32l-.15 4.01c-3.73 96.04-4.22 109.01 100.23 114.16L250.25 27.32z"/>
</svg>
<line x1="100" y1="20" x2="200" y2="20" stroke="green" />
<line x1="300" y1="20" x2="350" y2="20" stroke="red" />
</svg>
strong text
Although there may be several ways to accomplish this, I figured out one way that I am going to move forward with. The confusion with this was primarily due to my lack of understanding of the svg viewBox and how the coordinate system works.
The key to this is defining a new viewBox value for each nested svg based on its BBox coordinates. The purpose of doing this is to frame the drawing without 'whitespace' to enable its placement at the desired coordinates. Once you have the BBox data, you can set the viewBox and do some simple math to properly set the desired height and width (both of which must be defined for the nested svg). After updating the viewBox, width, and height, you can then move the svg to the new location.
$( document ).ready(function() {
const svg = document.querySelectorAll('svg.a');
svg.forEach(x => {
setSvg(x);
});
});
function setSvg(svg){
const { xMin, xMax, yMin, yMax } = [...svg.children].reduce((acc, el) => {
const { x, y, width, height } = el.getBBox();
if (!acc.xMin || x < acc.xMin) acc.xMin = x;
if (!acc.xMax || x + width > acc.xMax) acc.xMax = x + width;
if (!acc.yMin || y < acc.yMin) acc.yMin = y;
if (!acc.yMax || y + height > acc.yMax) acc.yMax = y + height;
return acc;
}, {});
const viewbox = `${xMin} ${yMin} ${xMax - xMin} ${yMax - yMin}`;
let newWidth = $(svg).attr('data-new-width');
let newPosition = $(svg).attr('data-new-position');
let newHeight = newWidth*(yMax - yMin)/(xMax - xMin);
svg.setAttribute('width', newWidth);
svg.setAttribute('height', newHeight);
svg.setAttribute('x', newPosition.split(",")[0]);
svg.setAttribute('y', newPosition.split(",")[1]);
svg.setAttribute('viewBox', viewbox);
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<svg height="700" width="700" fill="#e6e6e6" xmlns="http://www.w3.org/2000/svg">
<svg class="a" data-new-width="100" data-new-position="100,20" viewBox="0 0 512 512">
<path d="M443.6,387.1L312.4,255.4l131.5-130c5.4-5.4,5.4-14.2,0-19.6l-37.4-37.6c-2.6-2.6-6.1-4-9.8-4c-3.7,0-7.2,1.5-9.8,4 L256,197.8L124.9,68.3c-2.6-2.6-6.1-4-9.8-4c-3.7,0-7.2,1.5-9.8,4L68,105.9c-5.4,5.4-5.4,14.2,0,19.6l131.5,130L68.4,387.1 c-2.6,2.6-4.1,6.1-4.1,9.8c0,3.7,1.4,7.2,4.1,9.8l37.4,37.6c2.7,2.7,6.2,4.1,9.8,4.1c3.5,0,7.1-1.3,9.8-4.1L256,313.1l130.7,131.1 c2.7,2.7,6.2,4.1,9.8,4.1c3.5,0,7.1-1.3,9.8-4.1l37.4-37.6c2.6-2.6,4.1-6.1,4.1-9.8C447.7,393.2,446.2,389.7,443.6,387.1z"/>
</svg>
<svg class="a" data-new-width="50" data-new-position="300,20" viewBox="0 0 380 511.7">
<path fill-rule="nonzero" d="M26.18 0h221.14c3.1 0 5.85 1.51 7.56 3.84l122.88 145.08a9.27 9.27 0 0 1 2.21 6.05l.03 330.55c0 7.13-2.98 13.68-7.72 18.42l-.03.04c-4.75 4.74-11.29 7.72-18.43 7.72H26.18c-7.13 0-13.69-2.96-18.45-7.71l-.03-.04C2.97 499.22 0 492.69 0 485.52V26.18C0 19 2.95 12.46 7.68 7.72l.04-.04C12.46 2.95 19 0 26.18 0zm335.06 164.7c-134.78-5.58-134.35-17.38-129.82-134.02l.45-11.92H26.18c-2.05 0-3.91.83-5.26 2.16a7.482 7.482 0 0 0-2.16 5.26v459.34c0 2.02.84 3.88 2.18 5.23 1.36 1.35 3.22 2.19 5.24 2.19h327.64c2.01 0 3.86-.85 5.22-2.2 1.35-1.36 2.2-3.21 2.2-5.22V164.7zM250.25 27.32l-.15 4.01c-3.73 96.04-4.22 109.01 100.23 114.16L250.25 27.32z"/>
</svg>
<line x1="100" y1="20" x2="200" y2="20" stroke="green" />
<line x1="300" y1="20" x2="350" y2="20" stroke="red" />
</svg>
I have a path which is a semi-circle. How do I make the corners rounded? I do not want to use stroke-linecap: round as I need it to be rounded only on these corners:
<svg>
<g>
<!--background -->
<path fill="none" stroke-dasharray="" stroke-width="16" stroke="#607985" d="M30 100 A 40 40 0 0 1 170 100"></path>
<!-- strokes -->
<path id="meter-back" fill="none" stroke-width="15" stroke="white" d="M30 100 A 40 40 0 0 1 170 100"></path>
<!--progress -->
<path id="meter-fill" fill="none" stroke-dashoffset="219.942" stroke-dasharray="109.971, 109.971" stroke="rgba(96,121,133,0.7)" stroke-width="15" d="M30 100 A 40 40 0 0 1 170 100" stroke="#607985"></path>
</g>
</svg>
Here is a fixed solution. dividerPos can be in range from 0 to 1:
const getPath = (outerRadius, innerRadius, cornerRadius, dividerPos) => {
const angle = Math.PI * (1 - dividerPos);
const outerPointX = outerRadius * Math.cos(angle);
const outerPointY = outerRadius * -Math.sin(angle);
const innerPointX = innerRadius * Math.cos(angle);
const innerPointY = innerRadius * -Math.sin(angle);
const left = `M ${-outerRadius},0
A ${outerRadius},${outerRadius} 0 0 1
${outerPointX},${outerPointY}
L ${innerPointX},${innerPointY}
A ${innerRadius},${innerRadius} 0 0 0 ${-innerRadius},0
Q ${-innerRadius},${cornerRadius}
${-innerRadius-cornerRadius},${cornerRadius}
H ${-outerRadius+cornerRadius}
Q ${-outerRadius},${cornerRadius}
${-outerRadius},0
Z`;
const right = `M ${outerPointX},${outerPointY}
A ${outerRadius},${outerRadius} 0 0 1
${outerRadius},0
Q ${outerRadius},${cornerRadius}
${outerRadius-cornerRadius},${cornerRadius}
H ${innerRadius+cornerRadius}
Q ${innerRadius},${cornerRadius}
${innerRadius},0
A ${innerRadius},${innerRadius} 0 0 0
${innerPointX},${innerPointY}
Z`;
return {left, right};
};
const {left, right} = getPath(120, 90, 15, 0.5);
d3.select('.left').attr('d', left);
d3.select('.right').attr('d', right);
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/5.7.0/d3.min.js"></script>
<svg width='300' height='200'>
<g transform='translate(150,150)'>
<path stroke='grey' fill='grey' class='left'/>
<path stroke='grey' fill='none' class='right'/>
</g>
</svg>
Use getPath routine to compute the desired path
(The 0,0 point in the center of the semi-circle):
const getPath = (outerRadius, innerRadius, cornerRadius) => {
return `M ${-outerRadius},0
A ${outerRadius},${outerRadius} 1 1 1 ${outerRadius},0
Q ${outerRadius},${cornerRadius}
${outerRadius-cornerRadius},${cornerRadius}
H ${innerRadius+cornerRadius}
Q ${innerRadius},${cornerRadius}
${innerRadius},0
A ${innerRadius},${innerRadius} 0 0 0
${-innerRadius},0
Q ${-innerRadius},${cornerRadius}
${-innerRadius-cornerRadius},${cornerRadius}
H ${-outerRadius+cornerRadius}
Q ${-outerRadius},${cornerRadius}
${-outerRadius},0
Z`;
};
d3.select('path').attr('d', getPath(120, 90, 12));
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/5.7.0/d3.min.js"></script>
<svg width='300' height='200'>
<g transform='translate(150,150)'>
<path stroke='red' fill='none'/>
<circle fill='red' r='5' cx='0' cy='0'/>
</g>
</svg>
I'm trying to create a curved arrow with svg. I'm using d3.line() to generate the path.
let points = [
[400,100],
[450,200],
[350,200],
[385,275]
]
let path = d3.line().curve(d3.curveCardinal)(points)
console.log(path)
// -> M400,100C400,100,458.3333333333333,183.33333333333334,450,200C441.6666666666667,216.66666666666666,360.8333333333333,187.5,350,200C339.1666666666667,212.5,385,275,385,275
But when I try to use this result in a svg:
<svg width="1200" height="1200" viewBox="0 0 1200 1200" xmlns="http://www.w3.org/2000/svg" version="1.1">
<defs>
<marker id="Triangle" viewBox="0 0 10 10" refX="1" refY="5" markerWidth="6" markerHeight="6" orient="auto">
<path d="M 0 0 L 10 5 L 0 10 z" />
</marker>
</defs>
<path d="M400,100C400,100,458.3333333333333,183.33333333333334,450,200C441.6666666666667,216.66666666666666,360.8333333333333,187.5,350,200C339.1666666666667,212.5,385,275,385,275"
stroke-width="2" stroke="lightblue" fill="none" style="marker-end: url(#Triangle);"></path>
</svg>
And here is the SVG result
.
I can't figure out why the marker doesn't orientate. Is there a better library to generate path to resolve this?
That's the expected behaviour. The issue is that in a cardinal spline...
Two additional points are required on either end of the curve.
And those points seem to interfere with the marker orientation (which is indeed the case, see LeBeau's answer).
You can easily see this if you change the curve. For instance, using curveBasis:
let points = [
[400,100],
[450,200],
[350,200],
[385,275]
]
let path = d3.line().curve(d3.curveBasis)(points)
d3.select("#myPath").attr("d", path);
<script src="https://d3js.org/d3.v5.min.js"></script>
<svg width="1200" height="1200" viewBox="0 0 1200 1200" xmlns="http://www.w3.org/2000/svg" version="1.1">
<defs>
<marker id="Triangle" viewBox="0 0 10 10" refX="1" refY="5" markerWidth="6" markerHeight="6" orient="auto">
<path d="M 0 0 L 10 5 L 0 10 z" />
</marker>
</defs>
<path id="myPath" stroke-width="2" stroke="lightblue" fill="none" style="marker-end: url(#Triangle);"></path>
</svg>
In your case, a solution (arguably a hack) may be adding a final line to the path, just 1px away from the final point:
path = path + "L387,277";
Here is the demo:
let points = [
[400,100],
[450,200],
[350,200],
[385,275]
]
let path = d3.line().curve(d3.curveCardinal)(points)
path = path + "L387,277";
d3.select("#myPath").attr("d", path);
<script src="https://d3js.org/d3.v5.min.js"></script>
<svg width="1200" height="1200" viewBox="0 0 1200 1200" xmlns="http://www.w3.org/2000/svg" version="1.1">
<defs>
<marker id="Triangle" viewBox="0 0 10 10" refX="1" refY="5" markerWidth="6" markerHeight="6" orient="auto">
<path d="M 0 0 L 10 5 L 0 10 z" />
</marker>
</defs>
<path id="myPath" stroke-width="2" stroke="lightblue" fill="none" style="marker-end: url(#Triangle);"></path>
</svg>
This is because the last control point and the end-point of your path have the same coordinates: (385,275).
SVG uses the control point vector to work out what the curve direction is at that point. If your control point vector is from (385,275) to (385,275), then it can't determine the angle. So it defaults to an angle of 0 degrees.
First, the ref attributes are sort of correct but can be better I think, make the refX 0 since you using the full viewBox.
I think the marker's orientation is correct and updated. But based on the ending of the path, the interpolation of the orientation might look incorrect. So you can verify this behavior by cutting your pathstring from the last C... curve and will see that the orientation is correct.
I further tested it to see if it is correct, at least for line segments, here is a fiddle and i didn't even use d3:
https://jsfiddle.net/ibowankenobi/L8x19rco/2/
var path = document.querySelector("path[stroke]");
var arr = Array.apply(null,Array(path.getTotalLength()/4 << 0)).map(function(d,i){
var p = this.getPointAtLength(i*4);
return [p.x,p.y];
},path);
var length = arr.length;
animate();
function animate(index){
if(index >= length){
return;
}
var index = index || 0;
path.setAttribute("d","M"+arr.slice(1,Math.min(++index+1,length)).join("L"));
window.requestAnimationFrame(function(){animate(index);});
}
From this link, I would like to put a math equation (generated from Latex with tex2svg tool) into a canvas.
You can see here [this SVG formula][2] (fill color is black).
Now, I include this SVG into canvas like this :
<body>
<canvas id="textbox"></canvas>
<script>
// Draw SVG formula of absolute differential
var textCanvas = document.getElementById('textbox');
var contextTextBox = textCanvas.getContext('2d');
var img = new Image;
img.onload = function(){ contextTextBox.drawImage(img,0,0); };
img.src = "./formula.svg";
</script>
</body>
You can see the result on [this link][3] (fill color of SVG is white).
The issue is that rendering is not pretty, formula is tight and blurred.
Anyone could give me clues to improve the quality of equation rendering (I don't know if it is possible to have the same quality as MathJax equation).
Thanks for your help
Math latex on canvas with subpixel rendering.
The image you provided is not of the SVG image you have linked to, so i do not know why you have the image split into 3 and squashed?
Anyways see this answer for a way to improve text rendering (like Latex equations) by re-rendering the image at the (physical) sub pixel level.
Note that the image must have a non opaque background colour.
The following snippet uses the core function from that answer to do the same to the SVG image.
I am using the SVG image you provided which is black on white but this method will work for all colours except for transparent pixels. If you use transparent pixels you will have to access the quality for yourself as it will depend on the background the image is drawn onto.
Note may not work on outdated browsers.
// the SVG image
var svg = `<svg xmlns:xlink="http://www.w3.org/1999/xlink" width="21.371ex" height="3.676ex" style="vertical-align: -1.338ex;" viewBox="0 -1006.6 9201.2 1582.7" role="img" focusable="false" xmlns="http://www.w3.org/2000/svg">
<defs>
<path stroke-width="1" id="E1-MJMAIN-44" d="M130 622Q123 629 119 631T103 634T60 637H27V683H228Q399 682 419 682T461 676Q504 667 546 641T626 573T685 470T708 336Q708 210 634 116T442 3Q429 1 228 0H27V46H60Q102 47 111 49T130 61V622ZM593 338Q593 439 571 501T493 602Q439 637 355 637H322H294Q238 637 234 628Q231 624 231 344Q231 62 232 59Q233 49 248 48T339 46H350Q456 46 515 95Q561 133 577 191T593 338Z"></path>
<path stroke-width="1" id="E1-MJMATHI-76" d="M173 380Q173 405 154 405Q130 405 104 376T61 287Q60 286 59 284T58 281T56 279T53 278T49 278T41 278H27Q21 284 21 287Q21 294 29 316T53 368T97 419T160 441Q202 441 225 417T249 361Q249 344 246 335Q246 329 231 291T200 202T182 113Q182 86 187 69Q200 26 250 26Q287 26 319 60T369 139T398 222T409 277Q409 300 401 317T383 343T365 361T357 383Q357 405 376 424T417 443Q436 443 451 425T467 367Q467 340 455 284T418 159T347 40T241 -11Q177 -11 139 22Q102 54 102 117Q102 148 110 181T151 298Q173 362 173 380Z"></path>
<path stroke-width="1" id="E1-MJMATHI-69" d="M184 600Q184 624 203 642T247 661Q265 661 277 649T290 619Q290 596 270 577T226 557Q211 557 198 567T184 600ZM21 287Q21 295 30 318T54 369T98 420T158 442Q197 442 223 419T250 357Q250 340 236 301T196 196T154 83Q149 61 149 51Q149 26 166 26Q175 26 185 29T208 43T235 78T260 137Q263 149 265 151T282 153Q302 153 302 143Q302 135 293 112T268 61T223 11T161 -11Q129 -11 102 10T74 74Q74 91 79 106T122 220Q160 321 166 341T173 380Q173 404 156 404H154Q124 404 99 371T61 287Q60 286 59 284T58 281T56 279T53 278T49 278T41 278H27Q21 284 21 287Z"></path>
<path stroke-width="1" id="E1-MJMAIN-3D" d="M56 347Q56 360 70 367H707Q722 359 722 347Q722 336 708 328L390 327H72Q56 332 56 347ZM56 153Q56 168 72 173H708Q722 163 722 153Q722 140 707 133H70Q56 140 56 153Z"></path>
<path stroke-width="1" id="E1-MJMAIN-64" d="M376 495Q376 511 376 535T377 568Q377 613 367 624T316 637H298V660Q298 683 300 683L310 684Q320 685 339 686T376 688Q393 689 413 690T443 693T454 694H457V390Q457 84 458 81Q461 61 472 55T517 46H535V0Q533 0 459 -5T380 -11H373V44L365 37Q307 -11 235 -11Q158 -11 96 50T34 215Q34 315 97 378T244 442Q319 442 376 393V495ZM373 342Q328 405 260 405Q211 405 173 369Q146 341 139 305T131 211Q131 155 138 120T173 59Q203 26 251 26Q322 26 373 103V342Z"></path>
<path stroke-width="1" id="E1-MJMAIN-2212" d="M84 237T84 250T98 270H679Q694 262 694 250T679 230H98Q84 237 84 250Z"></path>
<path stroke-width="1" id="E1-MJMATHI-6B" d="M121 647Q121 657 125 670T137 683Q138 683 209 688T282 694Q294 694 294 686Q294 679 244 477Q194 279 194 272Q213 282 223 291Q247 309 292 354T362 415Q402 442 438 442Q468 442 485 423T503 369Q503 344 496 327T477 302T456 291T438 288Q418 288 406 299T394 328Q394 353 410 369T442 390L458 393Q446 405 434 405H430Q398 402 367 380T294 316T228 255Q230 254 243 252T267 246T293 238T320 224T342 206T359 180T365 147Q365 130 360 106T354 66Q354 26 381 26Q429 26 459 145Q461 153 479 153H483Q499 153 499 144Q499 139 496 130Q455 -11 378 -11Q333 -11 305 15T277 90Q277 108 280 121T283 145Q283 167 269 183T234 206T200 217T182 220H180Q168 178 159 139T145 81T136 44T129 20T122 7T111 -2Q98 -11 83 -11Q66 -11 57 -1T48 16Q48 26 85 176T158 471L195 616Q196 629 188 632T149 637H144Q134 637 131 637T124 640T121 647Z"></path>
<path stroke-width="1" id="E1-MJMAIN-393" d="M128 619Q121 626 117 628T101 631T58 634H25V680H554V676Q556 670 568 560T582 444V440H542V444Q542 445 538 478T523 545T492 598Q454 634 349 634H334Q264 634 249 633T233 621Q232 618 232 339L233 61Q240 54 245 52T270 48T333 46H360V0H348Q324 3 182 3Q51 3 36 0H25V46H58Q100 47 109 49T128 61V619Z"></path>
<path stroke-width="1" id="E1-MJMATHI-6A" d="M297 596Q297 627 318 644T361 661Q378 661 389 651T403 623Q403 595 384 576T340 557Q322 557 310 567T297 596ZM288 376Q288 405 262 405Q240 405 220 393T185 362T161 325T144 293L137 279Q135 278 121 278H107Q101 284 101 286T105 299Q126 348 164 391T252 441Q253 441 260 441T272 442Q296 441 316 432Q341 418 354 401T367 348V332L318 133Q267 -67 264 -75Q246 -125 194 -164T75 -204Q25 -204 7 -183T-12 -137Q-12 -110 7 -91T53 -71Q70 -71 82 -81T95 -112Q95 -148 63 -167Q69 -168 77 -168Q111 -168 139 -140T182 -74L193 -32Q204 11 219 72T251 197T278 308T289 365Q289 372 288 376Z"></path>
<path stroke-width="1" id="E1-MJMATHI-79" d="M21 287Q21 301 36 335T84 406T158 442Q199 442 224 419T250 355Q248 336 247 334Q247 331 231 288T198 191T182 105Q182 62 196 45T238 27Q261 27 281 38T312 61T339 94Q339 95 344 114T358 173T377 247Q415 397 419 404Q432 431 462 431Q475 431 483 424T494 412T496 403Q496 390 447 193T391 -23Q363 -106 294 -155T156 -205Q111 -205 77 -183T43 -117Q43 -95 50 -80T69 -58T89 -48T106 -45Q150 -45 150 -87Q150 -107 138 -122T115 -142T102 -147L99 -148Q101 -153 118 -160T152 -167H160Q177 -167 186 -165Q219 -156 247 -127T290 -65T313 -9T321 21L315 17Q309 13 296 6T270 -6Q250 -11 231 -11Q185 -11 150 11T104 82Q103 89 103 113Q103 170 138 262T173 379Q173 380 173 381Q173 390 173 393T169 400T158 404H154Q131 404 112 385T82 344T65 302T57 280Q55 278 41 278H27Q21 284 21 287Z"></path>
</defs>
<g stroke="currentColor" fill="black" stroke-width="0" transform="matrix(1 0 0 -1 0 0)">
<use xlink:href="#E1-MJMAIN-44" x="0" y="0"></use>
<g transform="translate(764,0)">
<use xlink:href="#E1-MJMATHI-76" x="0" y="0"></use>
<use transform="scale(0.707)" xlink:href="#E1-MJMATHI-69" x="686" y="-213"></use>
</g>
<use xlink:href="#E1-MJMAIN-3D" x="1872" y="0"></use>
<use xlink:href="#E1-MJMAIN-64" x="2928" y="0"></use>
<g transform="translate(3484,0)">
<use xlink:href="#E1-MJMATHI-76" x="0" y="0"></use>
<use transform="scale(0.707)" xlink:href="#E1-MJMATHI-69" x="686" y="-213"></use>
</g>
<use xlink:href="#E1-MJMAIN-2212" x="4536" y="0"></use>
<g transform="translate(5537,0)">
<use xlink:href="#E1-MJMATHI-76" x="0" y="0"></use>
<use transform="scale(0.707)" xlink:href="#E1-MJMATHI-6B" x="686" y="-213"></use>
</g>
<g transform="translate(6491,0)">
<use xlink:href="#E1-MJMAIN-393" x="0" y="0"></use>
<use transform="scale(0.707)" xlink:href="#E1-MJMATHI-6B" x="884" y="499"></use>
<g transform="translate(625,-304)">
<use transform="scale(0.707)" xlink:href="#E1-MJMATHI-69" x="0" y="0"></use>
<use transform="scale(0.707)" xlink:href="#E1-MJMATHI-6A" x="345" y="0"></use>
</g>
</g>
<use xlink:href="#E1-MJMAIN-64" x="7753" y="0"></use>
<g transform="translate(8309,0)">
<use xlink:href="#E1-MJMATHI-79" x="0" y="0"></use>
<use transform="scale(0.707)" xlink:href="#E1-MJMATHI-6A" x="706" y="583"></use>
</g>
</g>
</svg>`;
const backgroundColour = "White";
// creates a blank image with 2d context
var createImage=function(w,h){var i=document.createElement("canvas");i.width=w;i.height=h;i.ctx=i.getContext("2d");return i;}
// helper function
function createInfoDiv(text){ var div = document.createElement("div"); div.textContent = text; return div;}
// create a canvas and add to the dom
var canvas = createImage(350,100);
canvas.style.border = "1px red solid";
var ctx = canvas.ctx;
document.body.appendChild(canvas);
// double canvas resolution if pixels are 2 times CSS pixel size. (might be hires or retina display)
if(devicePixelRatio === 2){
var w = canvas.width;
var h = canvas.height;
canvas.style.width = w + "px;"
canvas.style.height = h + "px;"
canvas.width = w * 2;
canvas.height = h * 2;
}
// This function uses subpixels to render hi quality image.
// Note that the image must have a non opaque background colour
// returns the same imgData with 1st 1/3rd containing new image.
var subPixelBitmap = function(imgData){
var spR,spG,spB; // sub pixels
var id,id1; // pixel indexes
var w = imgData.width;
var h = imgData.height;
var d = imgData.data;
var x,y;
var ww = w*4;
var ww4 = ww+4;
for(y = 0; y < h; y+=1){
for(x = 0; x < w; x+=3){
var id = y*ww+x*4;
var id1 = Math.floor(y)*ww+Math.floor(x/3)*4;
spR = Math.sqrt(d[id + 0] * d[id + 0] * 0.2126 + d[id + 1] * d[id + 1] * 0.7152 + d[id + 2] * d[id + 2] * 0.0722);
id += 4;
spG = Math.sqrt(d[id + 0] * d[id + 0] * 0.2126 + d[id + 1] * d[id + 1] * 0.7152 + d[id + 2] * d[id + 2] * 0.0722);
id += 4;
spB = Math.sqrt(d[id + 0] * d[id + 0] * 0.2126 + d[id + 1] * d[id + 1] * 0.7152 + d[id + 2] * d[id + 2] * 0.0722);
d[id1++] = spR;
d[id1++] = spG;
d[id1++] = spB;
d[id1++] = 255; // alpha always 255
}
}
return imgData;
}
// clear the canvas
ctx.clearRect(0,0,canvas.width,canvas.height);
// Create the SVG image
var SVGImage = new Image(155*3,27*3);
SVGImage.src = "data:image/svg+xml;base64," + btoa(('<?xml version="1.0"?>'+svg))
// When the image has been parsed create the hiquality subpixel rendered image.
SVGImage.onload = function(){
try{
var image3;
var scale = 1;
if(devicePixelRatio === 2){ // only for 2 as this is guessing that a Hires display is being used
scale = 2;
}
image3 = createImage(this.width * scale, this.height * scale);
var h = Math.ceil(image3.height/ 3);
image3.ctx.fillStyle = backgroundColour;
image3.ctx.fillRect(0,0,image3.width,image3.height);
image3.ctx.drawImage(this,0,0,image3.width,image3.height);
image3.ctx.drawImage(this,0,0,image3.width,image3.height+1);
image3.ctx.drawImage(this,0,0,image3.width+0.5,image3.height);
image3.ctx.drawImage(this,0,0,image3.width+0.5,image3.height+1);
image3.ctx.drawImage(image3,0,0,image3.width,h)
var dat = subPixelBitmap(image3.ctx.getImageData(0,0,image3.width,h));
image3.width /= 3;
image3.height = h;
this.width /= 3;
this.height = h;
//================================================================
// image3 now has the hi quality image
image3.ctx.putImageData(dat,0,0);
ctx.fillStyle = backgroundColour;
ctx.fillRect(0,0,canvas.width,canvas.height);
ctx.fillStyle = "black";
// draw high qual image
ctx.font = (16 * scale) + "px arial";
ctx.drawImage(image3,0,20 * scale);
ctx.fillText("SVG plus (Sub pixel) render.", 5,16 * scale)
// draw normal SVG on canvas
ctx.drawImage(this,0,image3.height + 40 * scale, this.width * scale, this.height * scale);
ctx.fillText("SVG as is rendered on canvas",5,image3.height + (20 + 16) * scale)
document.body.appendChild(createInfoDiv("Original SVG as HTML <svg> object"));
document.body.appendChild(this); // show original SVG
}catch(e){
document.body.innerHTML = "<h1>So sorry but you need to upgrade to Firefox, Edge, or Chrome!</h1>"
}
}
I am trying to add an extra path to each SVG on a webpage. I set up my for loop and it is working, but once it loops through it tells me appendChild() is not a function. If I take everything out of the loop appendChild() works. What am I doing incorrectly here?
var svg = document.getElementsByClassName('curve-position-bottom'); //Get svg element
for (var i = 0; i < svg.length; i++) {
console.log(svg.length);
function addPath() {
console.log('working');
var newElement = document.createElementNS("http://www.w3.org/2000/svg", 'path'); //Create a path in SVG's namespace
newElement.setAttribute("d", "M0 0 C50 100 50 100 100 0 "); //Set path's data
newElement.style.stroke = "#005780"; //stroke colour
newElement.style.strokeWidth = "13px"; //Set stroke width
newElement.style.fill = "none"; //Set stroke width
svg.appendChild(newElement);
}
addPath();
}
<svg xmlns="http://www.w3.org/2000/svg" width="100%" viewBox="0 0 100 100" version="1.1" preserveAspectRatio="none" height="45px" class="engle-curve curve-position-bottom" style="fill:#e6e2af">
<path stroke-width="0" d="M0 0 C50 100 50 100 100 0 L100 100 0 100"></path>
</svg>
<svg xmlns="http://www.w3.org/2000/svg" width="100%" viewBox="0 0 100 100" version="1.1" preserveAspectRatio="none" height="45px" class="engle-curve curve-position-bottom" style="fill:#e6e2af">
<path stroke-width="0" d="M0 0 C50 100 50 100 100 0 L100 100 0 100"></path>
</svg>
<svg xmlns="http://www.w3.org/2000/svg" width="100%" viewBox="0 0 100 100" version="1.1" preserveAspectRatio="none" height="45px" class="engle-curve curve-position-bottom" style="fill:#e6e2af">
<path stroke-width="0" d="M0 0 C50 100 50 100 100 0 L100 100 0 100"></path>
</svg>
The return value of document.getElementsByClassName is a NodeList, not an individual element. To use your defined SVG, you'll need to use svg[i].
Also, unrelated to your question, but it would be a good idea to move that function definition out of the loop (for performance and scoping reasons) and to call it with an SVG element as a parameter. It would look more like this:
var svg = document.getElementsByClassName('curve-position-bottom'); //Get svg elements
function addPath(svg) {
console.log('working');
var newElement = document.createElementNS("http://www.w3.org/2000/svg", 'path'); //Create a path in SVG's namespace
newElement.setAttribute("d", "M0 0 C50 100 50 100 100 0 "); //Set path's data
newElement.style.stroke = "#005780"; //stroke colour
newElement.style.strokeWidth = "13px"; //Set stroke width
newElement.style.fill = "none"; //Set stroke width
svg.appendChild(newElement);
}
for (var i = 0, length = svg.length; i < length; i++) {
addPath(svg[i]);
}
Instead
svg.appendChild(newElement);
try:
svg[i].appendChild(newElement);