how to add text in canvas with react and canvg library? - javascript

i'm trying to add text in canvas ( bottom right ) with react and canvg lib
This is what i try :
DownloadImage = (i) => {
var _this = this;
this.modeler.saveSVG(function (err, svg) {
if (err) console.log(err)
_this.setState({ datasvg: svg }, function () {
const canvas = _this.refs.canvasforimage;
console.log(canvas)
const options = {
log: false,
ignoreMouse: true
};
canvg(canvas, this.state.datasvg, options);
const image = canvas.toDataURL("image/png").replace("image/png", "image/octet-stream");
const element = document.createElement("a");
element.setAttribute('download', 'diagram.png');
element.setAttribute('href', image);
element.click();
})
})
}
render = () => {
return (
<canvas ref="canvasforimage" id="canvasforimage">
{/* <div style="position:absolute;right:0;bottom:0">Text</div> */} Not working
</canvas>
)
function above is working... i can download as image but code at render the one i commented not working

thanks for the comment #Chris G
so i already solve the problem by adding code after canvg
canvg(canvas, this.state.datasvg, options);
const ctx = canvas.getContext('2d');
ctx.fillText('Hello world',50, 50);

Related

face-api conflicting with tensorflow-js

I'm using face-api.js Javascript API to develop a web app that user uploads her/his picture and we want to detect faces in the picture.
this is my HTML codes:
<input type="file" id="user_pic" accept="image/x-png,image/gif,image/jpeg">
<img src="images/250x250.webp" id="preview" alt="">
<canvas id="canvas"></canvas>
<script src="scripts/tfjs.js"></script>
<script src="scripts/face-api.min.js"></script>
<script src="scripts/index.js"></script>
and following code are what I wrote to face detection:
const model = tf.loadLayersModel('./web_model/vgg_model.json')
const user_pic = document.getElementById('user_pic')
const preview = document.getElementById('preview')
const canvas = document.getElementById('canvas');
const ctx = canvas.getContext('2d');
window.onload = function() {
canvas.width = preview.width;
canvas.height = preview.height;
ctx.drawImage(preview, 0, 0);
};
preview.onclick = () => user_pic.click()
const MODEL_URL = '../faceapi_models'
Promise.all([
faceapi.nets.ssdMobilenetv1.loadFromUri(MODEL_URL),
faceapi.nets.faceRecognitionNet.loadFromUri(MODEL_URL),
faceapi.nets.faceLandmark68Net.loadFromUri(MODEL_URL),])
.then((val) => {
console.log('val')
})
.catch((err) => {
console.log('err')
})
user_pic.addEventListener('change', () => {
const reader = new FileReader()
reader.onload = (e) => {
const img = new Image();
img.onload = function() {
canvas.width = img.width;
canvas.height = img.height;
ctx.drawImage(img, 0, 0);
};
img.src = e.target.result;
}
reader.readAsDataURL(user_pic.files[0]);
detectFaces(user_pic.files[0])
})
async function detectFaces(input) {
let imgURL = URL.createObjectURL(input)
const imgElement = new Image()
imgElement.src = imgURL
const results = await faceapi.detectAllFaces(imgElement)
// .withFaceLandmarks()
// .withFaceExpressions()
.then(results => {
if (Array.isArray(results) && results.forEach) {
results.forEach(result => {
console.log(result)
const { x, y, width, height } = result.box;
ctx.lineWidth = 3;
ctx.strokeRect(x, y, width, height);
});
} else {
console.error('Results is not an array or does not have a forEach function.');
}
});
}
So far I have only used face-api.min.js file and all things work fine and after selecting image File , face is recognized. But as soon as I added tfjs.js file to use const model = tf.loadLayersModel('./web_model/vgg_model.json') method I got new following Errors:
Uncaught (in promise) Error: SsdMobilenetv1 - load model before inference
And after a few seonds this error shown in console :
Uncaught (in promise) TypeError: Og(...).platform.isTypedArray is not a function
What is problem ?

Unknown background green lines in React downloaded image?

I'm using the below code to download screenshots of my application:
download = filename => {
const a = document.createElement('a');
a.download = filename;
getDownloadURL().then(url => {
a.href = url;
document.body.appendChild(a);
a.click();
a.remove();
});
};
getDownloadURL = async () => {
const svg = document.querySelector('#widget svg'),
canvas = new OffscreenCanvas(svg.clientWidth * 3, svg.clientHeight * 3),
svgString = new XMLSerializer().serializeToString(svg),
ctx = canvas.getContext('2d'),
v = await Canvg.fromString(ctx, svgString, presets.offscreen());
await v.render();
const blob = await canvas.convertToBlob(),
pngUrl = URL.createObjectURL(blob);
return pngUrl;
},
The downloaded image has few unknown green lines at the background, what are these?
And how can these be removed?
This element appears fine in the application without these unknown lines.

Download canvas as image not working in firefox and microsoft edge

I want to download canvas as image but not working in firefox and microsoft edge but working with chrome
This is my code :
DownloadImage = (i) => {
var _this = this;
this.modeler.saveSVG(function (err, svg) {
if (err) console.log(err)
_this.setState({ datasvg: svg }, function () {
const canvas = _this.refs.canvasforimage;
const options = {
log: false,
ignoreMouse: true,
};
canvg(canvas, this.state.datasvg, options);
const image = canvas.toDataURL("image/png").replace("image/png", "image/octet-stream");
const element = document.createElement("a");
element.setAttribute('download', 'diagram.png');
element.setAttribute('href', image);
element.click();
are there any solution ?
This is the code I use to save canvas contents as PNG image file:
canvas.toBlob(blob => {
var a = document.createElement("a"),
url = URL.createObjectURL(blob);
a.href = url;
a.download = "image.png";
document.body.appendChild(a);
a.click();
setTimeout(function() {
document.body.removeChild(a);
window.URL.revokeObjectURL(url);
}, 0);
});

Fabricjs: Update SVG on the canvas

I am using fabricjs 1.6.4 and I want to update the existing svg with the new one. I am using this code to add the new SVG:
fabric.loadSVGFromURL(url, function (objects, options) {
var image = fabric.util.groupSVGElements(objects, options);
image.name = 'sticker';
canvas.add(image);
image.scaleToHeight(100);
image.center();
image['selectable'] = false;
image['evented'] = false;
image.setCoords();
canvas.renderAll();
});
}
How can I replace the existing SVG with the new one. I have done something related to this in the image but I can not replicate in SVG. Here is the code for image:
$scope.fillImage = function(src) {
fabric.Image.fromURL(src, function(img) {
var object = canvas.getActiveObject();
object._element.src = src;
canvas.renderAll();
});
}
I need something like this. Please help.
You already have the variable image just make it global an you can remove before you add... here is an example:
var image;
var canvas = new fabric.Canvas('canvas');
var url = "http://swagger-net-test.azurewebsites.net/api/SvgImage?"
function callback(objects, options) {
if (image) canvas.remove(image);
image = fabric.util.groupSVGElements(objects, options);
image.name = 'sticker';
canvas.add(image);
image.scaleToHeight(60);
image.center();
image.setCoords();
canvas.renderAll();
}
fabric.loadSVGFromURL(url + "color=red", callback)
setTimeout(
function() {
fabric.loadSVGFromURL(url + "color=blue", callback)
},
3000
);
<canvas id="canvas" width="180" height="180"></canvas>
<script src="https://cdnjs.cloudflare.com/ajax/libs/fabric.js/2.3.4/fabric.min.js"></script>

Convert SVG to image (JPEG, PNG, etc.) in the browser

I want to convert SVG into bitmap images (like JPEG, PNG, etc.) through JavaScript.
Here is how you can do it through JavaScript:
Use the canvg JavaScript library to render the SVG image using Canvas: https://github.com/gabelerner/canvg
Capture a data URI encoded as a JPG (or PNG) from the Canvas, according to these instructions: Capture HTML Canvas as gif/jpg/png/pdf?
jbeard4 solution worked beautifully.
I'm using Raphael SketchPad to create an SVG. Link to the files in step 1.
For a Save button (id of svg is "editor", id of canvas is "canvas"):
$("#editor_save").click(function() {
// the canvg call that takes the svg xml and converts it to a canvas
canvg('canvas', $("#editor").html());
// the canvas calls to output a png
var canvas = document.getElementById("canvas");
var img = canvas.toDataURL("image/png");
// do what you want with the base64, write to screen, post to server, etc...
});
This seems to work in most browsers:
function copyStylesInline(destinationNode, sourceNode) {
var containerElements = ["svg","g"];
for (var cd = 0; cd < destinationNode.childNodes.length; cd++) {
var child = destinationNode.childNodes[cd];
if (containerElements.indexOf(child.tagName) != -1) {
copyStylesInline(child, sourceNode.childNodes[cd]);
continue;
}
var style = sourceNode.childNodes[cd].currentStyle || window.getComputedStyle(sourceNode.childNodes[cd]);
if (style == "undefined" || style == null) continue;
for (var st = 0; st < style.length; st++){
child.style.setProperty(style[st], style.getPropertyValue(style[st]));
}
}
}
function triggerDownload (imgURI, fileName) {
var evt = new MouseEvent("click", {
view: window,
bubbles: false,
cancelable: true
});
var a = document.createElement("a");
a.setAttribute("download", fileName);
a.setAttribute("href", imgURI);
a.setAttribute("target", '_blank');
a.dispatchEvent(evt);
}
function downloadSvg(svg, fileName) {
var copy = svg.cloneNode(true);
copyStylesInline(copy, svg);
var canvas = document.createElement("canvas");
var bbox = svg.getBBox();
canvas.width = bbox.width;
canvas.height = bbox.height;
var ctx = canvas.getContext("2d");
ctx.clearRect(0, 0, bbox.width, bbox.height);
var data = (new XMLSerializer()).serializeToString(copy);
var DOMURL = window.URL || window.webkitURL || window;
var img = new Image();
var svgBlob = new Blob([data], {type: "image/svg+xml;charset=utf-8"});
var url = DOMURL.createObjectURL(svgBlob);
img.onload = function () {
ctx.drawImage(img, 0, 0);
DOMURL.revokeObjectURL(url);
if (typeof navigator !== "undefined" && navigator.msSaveOrOpenBlob)
{
var blob = canvas.msToBlob();
navigator.msSaveOrOpenBlob(blob, fileName);
}
else {
var imgURI = canvas
.toDataURL("image/png")
.replace("image/png", "image/octet-stream");
triggerDownload(imgURI, fileName);
}
document.removeChild(canvas);
};
img.src = url;
}
The solution to convert SVG to blob URL and blob URL to png image
const svg=`<svg version="1.1" baseProfile="full" width="300" height="200"
xmlns="http://www.w3.org/2000/svg">
<rect width="100%" height="100%" fill="red" />
<circle cx="150" cy="100" r="80" fill="green" />
<text x="150" y="125" font-size="60" text-anchor="middle" fill="white">SVG</text></svg>`
svgToPng(svg,(imgData)=>{
const pngImage = document.createElement('img');
document.body.appendChild(pngImage);
pngImage.src=imgData;
});
function svgToPng(svg, callback) {
const url = getSvgUrl(svg);
svgUrlToPng(url, (imgData) => {
callback(imgData);
URL.revokeObjectURL(url);
});
}
function getSvgUrl(svg) {
return URL.createObjectURL(new Blob([svg], { type: 'image/svg+xml' }));
}
function svgUrlToPng(svgUrl, callback) {
const svgImage = document.createElement('img');
// imgPreview.style.position = 'absolute';
// imgPreview.style.top = '-9999px';
document.body.appendChild(svgImage);
svgImage.onload = function () {
const canvas = document.createElement('canvas');
canvas.width = svgImage.clientWidth;
canvas.height = svgImage.clientHeight;
const canvasCtx = canvas.getContext('2d');
canvasCtx.drawImage(svgImage, 0, 0);
const imgData = canvas.toDataURL('image/png');
callback(imgData);
// document.body.removeChild(imgPreview);
};
svgImage.src = svgUrl;
}
change svg to match your element
function svg2img(){
var svg = document.querySelector('svg');
var xml = new XMLSerializer().serializeToString(svg);
var svg64 = btoa(xml); //for utf8: btoa(unescape(encodeURIComponent(xml)))
var b64start = 'data:image/svg+xml;base64,';
var image64 = b64start + svg64;
return image64;
};svg2img()
My use case was to have the svg data loaded from a network and this ES6 Class did the Job.
class SvgToPngConverter {
constructor() {
this._init = this._init.bind(this);
this._cleanUp = this._cleanUp.bind(this);
this.convertFromInput = this.convertFromInput.bind(this);
}
_init() {
this.canvas = document.createElement("canvas");
this.imgPreview = document.createElement("img");
this.imgPreview.style = "position: absolute; top: -9999px";
document.body.appendChild(this.imgPreview);
this.canvasCtx = this.canvas.getContext("2d");
}
_cleanUp() {
document.body.removeChild(this.imgPreview);
}
convertFromInput(input, callback) {
this._init();
let _this = this;
this.imgPreview.onload = function() {
const img = new Image();
_this.canvas.width = _this.imgPreview.clientWidth;
_this.canvas.height = _this.imgPreview.clientHeight;
img.crossOrigin = "anonymous";
img.src = _this.imgPreview.src;
img.onload = function() {
_this.canvasCtx.drawImage(img, 0, 0);
let imgData = _this.canvas.toDataURL("image/png");
if(typeof callback == "function"){
callback(imgData)
}
_this._cleanUp();
};
};
this.imgPreview.src = input;
}
}
Here is how you use it
let input = "https://restcountries.eu/data/afg.svg"
new SvgToPngConverter().convertFromInput(input, function(imgData){
// You now have your png data in base64 (imgData).
// Do what ever you wish with it here.
});
If you want a vanilla JavaScript version, you could head over to Babel website and transpile the code there.
Here a function that works without libraries and returns a Promise:
/**
* converts a base64 encoded data url SVG image to a PNG image
* #param originalBase64 data url of svg image
* #param width target width in pixel of PNG image
* #return {Promise<String>} resolves to png data url of the image
*/
function base64SvgToBase64Png (originalBase64, width) {
return new Promise(resolve => {
let img = document.createElement('img');
img.onload = function () {
document.body.appendChild(img);
let canvas = document.createElement("canvas");
let ratio = (img.clientWidth / img.clientHeight) || 1;
document.body.removeChild(img);
canvas.width = width;
canvas.height = width / ratio;
let ctx = canvas.getContext("2d");
ctx.drawImage(img, 0, 0, canvas.width, canvas.height);
try {
let data = canvas.toDataURL('image/png');
resolve(data);
} catch (e) {
resolve(null);
}
};
img.onerror = function() {
resolve(null);
};
img.src = originalBase64;
});
}
On Firefox there is an issue for SVGs without set width / height.
See this working example including a fix for the Firefox issue.
This is an old question, in 2022 we have ES6 and we don't need 3rd party libraries.
Here is a very basic way to convert svg images into other formats.
The trick is to load the svg element as an img element, then use a canvas element to convert the image into the desired format. So, four steps are needed:
Extract svg as xml data string.
Load the xml data string into a img element
Convert the img element to a dataURL using a canvas element
Load the converted dataURL into a new img element
Step 1
Extracting a svg as xml data string is simple, we don't need to convert it as a base64 string. We just serialize it as XML then we encode the string as a URI:
// Select the element:
const $svg = document.getElementById('svg-container').querySelector('svg')
// Serialize it as xml string:
const svgAsXML = (new XMLSerializer()).serializeToString($svg)
// Encode it as a data string:
const svgData = `data:image/svg+xml,${encodeURIComponent(svgAsXML)}`
Step 2
Loading the xml data string into a img element:
// This function returns a Promise whenever the $img is loaded
const loadImage = async url => {
const $img = document.createElement('img')
$img.src = url
return new Promise((resolve, reject) => {
$img.onload = () => resolve($img)
$img.onerror = reject
$img.src = url
})
}
Step 3
Converting the img element to a dataURL using a canvas element:
const $canvas = document.createElement('canvas')
$canvas.width = $svg.clientWidth
$canvas.height = $svg.clientHeight
$canvas.getContext('2d').drawImage(img, 0, 0, $svg.clientWidth, $svg.clientHeight)
return $canvas.toDataURL(`image/${format}`, 1.0)
Step 4
Loading the converted dataURL into a new img element:
const $img = document.createElement('img')
$img.src = dataURL
$holder.appendChild($img)
Here you have a working snippet:
const $svg = document.getElementById('svg-container').querySelector('svg')
const $holder = document.getElementById('img-container')
const $label = document.getElementById('img-format')
const destroyChildren = $element => {
while ($element.firstChild) {
const $lastChild = $element.lastChild ?? false
if ($lastChild) $element.removeChild($lastChild)
}
}
const loadImage = async url => {
const $img = document.createElement('img')
$img.src = url
return new Promise((resolve, reject) => {
$img.onload = () => resolve($img)
$img.onerror = reject
})
}
const convertSVGtoImg = async e => {
const $btn = e.target
const format = $btn.dataset.format ?? 'png'
$label.textContent = format
destroyChildren($holder)
const svgAsXML = (new XMLSerializer()).serializeToString($svg)
const svgData = `data:image/svg+xml,${encodeURIComponent(svgAsXML)}`
const img = await loadImage(svgData)
const $canvas = document.createElement('canvas')
$canvas.width = $svg.clientWidth
$canvas.height = $svg.clientHeight
$canvas.getContext('2d').drawImage(img, 0, 0, $svg.clientWidth, $svg.clientHeight)
const dataURL = await $canvas.toDataURL(`image/${format}`, 1.0)
console.log(dataURL)
const $img = document.createElement('img')
$img.src = dataURL
$holder.appendChild($img)
}
const buttons = [...document.querySelectorAll('[data-format]')]
for (const $btn of buttons) {
$btn.onclick = convertSVGtoImg
}
.wrapper {
display: flex;
flex-flow: row nowrap;
width: 100vw;
}
.images {
display: flex;
flex-flow: row nowrap;
width: 70%;
}
.image {
width: 50%;
display: flex;
flex-flow: row wrap;
justify-content: center;
}
.label {
width: 100%;
text-align: center;
}
<div class="wrapper">
<div class="item images">
<div class="image left">
<div class="label">svg</div>
<div id="svg-container">
<svg xmlns="http://www.w3.org/2000/svg" xml:space="preserve" width="200" height="200" viewBox="0 0 248 204">
<path fill="#1d9bf0" d="M221.95 51.29c.15 2.17.15 4.34.15 6.53 0 66.73-50.8 143.69-143.69 143.69v-.04c-27.44.04-54.31-7.82-77.41-22.64 3.99.48 8 .72 12.02.73 22.74.02 44.83-7.61 62.72-21.66-21.61-.41-40.56-14.5-47.18-35.07 7.57 1.46 15.37 1.16 22.8-.87-23.56-4.76-40.51-25.46-40.51-49.5v-.64c7.02 3.91 14.88 6.08 22.92 6.32C11.58 63.31 4.74 33.79 18.14 10.71c25.64 31.55 63.47 50.73 104.08 52.76-4.07-17.54 1.49-35.92 14.61-48.25 20.34-19.12 52.33-18.14 71.45 2.19 11.31-2.23 22.15-6.38 32.07-12.26-3.77 11.69-11.66 21.62-22.2 27.93 10.01-1.18 19.79-3.86 29-7.95-6.78 10.16-15.32 19.01-25.2 26.16z"/>
</svg>
</div>
</div>
<div class="image right">
<div id="img-format" class="label"></div>
<div id="img-container"></div>
</div>
</div>
<div class="item buttons">
<button id="btn-png" data-format="png">PNG</button>
<button id="btn-jpg" data-format="jpeg">JPG</button>
<button id="btn-webp" data-format="webp">WEBP</button>
</div>
</div>
Svg to png can be converted depending on conditions:
If svg is in format SVG (string) paths:
create canvas
create new Path2D() and set svg as parameter
draw path on canvas
create image and use canvas.toDataURL() as src.
example:
const canvas = document.createElement('canvas');
const ctx = canvas.getContext('2d');
let svgText = 'M10 10 h 80 v 80 h -80 Z';
let p = new Path2D('M10 10 h 80 v 80 h -80 Z');
ctx.stroke(p);
let url = canvas.toDataURL();
const img = new Image();
img.src = url;
Note that Path2D not supported in ie and partially supported in edge. Polyfill solves that:
https://github.com/nilzona/path2d-polyfill
Create svg blob and draw on canvas using .drawImage():
make canvas element
make a svgBlob object from the svg xml
make a url object from domUrl.createObjectURL(svgBlob);
create an Image object and assign url to image src
draw image into canvas
get png data string from canvas: canvas.toDataURL();
Nice description:
https://web.archive.org/web/20200125162931/http://ramblings.mcpher.com:80/Home/excelquirks/gassnips/svgtopng
Note that in ie you will get exception on stage of canvas.toDataURL(); It is because IE has too high security restriction and treats canvas as readonly after drawing image there. All other browsers restrict only if image is cross origin.
Use canvg JavaScript library. It is separate library but has useful functions.
Like:
ctx.drawSvg(rawSvg);
var dataURL = canvas.toDataURL();
I recently discovered a couple of image tracing libraries for JavaScript that indeed are able to build an acceptable approximation to the bitmap, both size and quality. I'm developing this JavaScript library and CLI :
https://www.npmjs.com/package/svg-png-converter
Which provides unified API for all of them, supporting browser and node, non depending on DOM, and a Command line tool.
For converting logos/cartoon/like images it does excellent job. For photos / realism some tweaking is needed since the output size can grow a lot.
It has a playground although right now I'm working on a better one, easier to use, since more features has been added:
https://cancerberosgx.github.io/demos/svg-png-converter/playground/#
There are several ways to convert SVG to PNG using the Canvg library.
In my case, I needed to get the PNG blob from inline SVG.
The library documentation provides an example (see OffscreenCanvas example).
But this method does not work at the moment in Firefox. Yes, you can enable the gfx.offscreencanvas.enabled option in the settings. But will every user on the site do this? :)
However, there is another way that will work in Firefox too.
const el = document.getElementById("some-svg"); //this is our inline SVG
var canvas = document.createElement('canvas'); //create a canvas for the SVG render
canvas.width = el.clientWidth; //set canvas sizes
canvas.height = el.clientHeight;
const svg = new XMLSerializer().serializeToString(el); //convert SVG to string
//render SVG inside canvas
const ctx = canvas.getContext('2d');
const v = await Canvg.fromString(ctx, svg);
await v.render();
let canvasBlob = await new Promise(resolve => canvas.toBlob(resolve));
For the last line thanks to this answer
get data URIs from SVG:
data:image/svg+xml;base64,${btoa(new XMLSerializer().serializeToString(svgElem))}
prepare an Image
create a canvas and use toDataURL to export.
Example
<!-- test data-->
<svg width="400" height="400"><g transform="translate(23.915343915343925,-80.03971756398937)" class="glyph" stroke="#000000" fill="#a0a0a0"><path d="M74.97 108.70L74.97 108.70L100.08 110.77Q93.89 147.91 87.35 179.89L87.35 179.89L148.23 179.89L148.23 194.34Q143.76 277.91 113.84 339.81L113.84 339.81Q144.44 363.54 163.70 382.46L163.70 382.46L146.51 402.75Q128.62 384.18 101.80 361.83L101.80 361.83Q75.32 405.85 34.39 436.80L34.39 436.80L17.20 415.82Q57.43 386.93 82.20 345.66L82.20 345.66Q57.78 326.40 27.86 304.39L27.86 304.39Q44.37 257.96 56.75 203.97L56.75 203.97L19.26 203.97L19.26 179.89L61.90 179.89Q69.47 145.16 74.97 108.70ZM93.20 323.99L93.20 323.99Q118.65 272.06 123.12 203.97L123.12 203.97L82.20 203.97Q69.47 260.03 55.71 297.17L55.71 297.17Q76.01 311.61 93.20 323.99ZM160.26 285.13L160.26 260.37L239.71 260.37L239.71 216.01Q268.25 191.24 294.05 155.48L294.05 155.48L170.58 155.48L170.58 130.71L322.94 130.71L322.94 155.48Q297.49 191.93 265.50 223.92L265.50 223.92L265.50 260.37L337.38 260.37L337.38 285.13L265.50 285.13L265.50 397.59Q265.50 431.64 237.65 431.64L237.65 431.64L187.09 431.64L180.21 407.57Q202.22 407.91 227.67 407.91L227.67 407.91Q239.71 407.91 239.71 390.03L239.71 390.03L239.71 285.13L160.26 285.13Z"></path></g></svg>
<button title="download">svg2png</button>
<script>
const output = {"name": "result.png", "width": 64, "height": 64}
document.querySelector("button").onclick = () => {
const svgElem = document.querySelector("svg")
// const uriData = `data:image/svg+xml;base64,${btoa(svgElem.outerHTML)}` // it may fail.
const uriData = `data:image/svg+xml;base64,${btoa(new XMLSerializer().serializeToString(svgElem))}`
const img = new Image()
img.src = uriData
img.onload = () => {
const canvas = document.createElement("canvas");
[canvas.width, canvas.height] = [output.width, output.height]
const ctx = canvas.getContext("2d")
ctx.drawImage(img, 0, 0, output.width, output.height)
// 👇 download
const a = document.createElement("a")
const quality = 1.0 // https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/imageSmoothingQuality
a.href = canvas.toDataURL("image/png", quality)
a.download = output.name
a.append(canvas)
a.click()
a.remove()
}
}
</script>
Here are my 2 cents. Somehow Download anchor tag is not working as expected in code snippet, however it was working fine in Chrome.
Here is working jsFiddle
const waitForImage = imgElem => new Promise(resolve => imgElem.complete ? resolve() : imgElem.onload = imgElem.onerror = resolve);
const svgToImgDownload = ext => {
if (!['png', 'jpg', 'webp'].includes(ext))
return;
const _svg = document.querySelector("#svg_container").querySelector('svg');
const xmlSerializer = new XMLSerializer();
let _svgStr = xmlSerializer.serializeToString(_svg);
const img = document.createElement('img');
img.src = 'data:image/svg+xml;base64,' + window.btoa(_svgStr);
waitForImage(img)
.then(_ => {
const canvas = document.createElement('canvas');
canvas.width = _svg.clientWidth;
canvas.height = _svg.clientHeight;
canvas.getContext('2d').drawImage(img, 0, 0, _svg.clientWidth, _svg.clientHeight);
return canvas.toDataURL('image/' + (ext == 'jpg' ? 'jpeg' : ext), 1.0);
})
.then(dataURL => {
console.log(dataURL);
document.querySelector("#img_download_btn").innerHTML = `Download`;
})
.catch(console.error);
};
document.querySelector('#map2Png').addEventListener('click', _ => svgToImgDownload('png'));
document.querySelector('#map2Jpg').addEventListener('click', _ => svgToImgDownload('jpg'));
document.querySelector('#map2Webp').addEventListener('click', _ => svgToImgDownload('webp'));
<div id="svg_container" style="float: left; width: 50%">
<svg width="200" height="200" viewBox="-100 -100 200 200">
<circle cx="0" cy="20" r="70" fill="#D1495B" />
<circle cx="0" cy="-75" r="12" fill="none" stroke="#F79257" stroke-width="2" />
<rect x="-17.5" y="-65" width="35" height="20" fill="#F79257" />
</svg>
</div>
<div>
<button id="map2Png">PNG</button>
<button id="map2Jpg">JPG</button>
<button id="map2Webp">WEBP</button>
</div>
<div id="img_download_btn"></div>

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