How do I add gradient color to strokeStyle canvas in javascript. Please help me my code works perfect but problem is only that I've been trying to add gradient color to a stroke style but it just breaks my code.
Any one who can help on this Gradient color to strokeStyle
HTML
<div class="countItem minutes">
<canvas id="minutes-canvas" width="200" height="200"></canvas>
<svg width="100%" height="100%">
<circle id="outer" cx="50%" cy="50%" r="45%" fill="transparent" stroke-width="1%" stroke="#fff" />
</svg>
<h3>
<span id="minutes-value"></span><br>
<small>minutes</small>
</h3>
</div>
JAVASCRIPT
// Set Launch Date (ms)
const launchDate = new Date("May 7, 2020 00:00").getTime();
// Context object
const c = {
context: {},
values: {},
times: {}
};
// Convert radians to degrees
function deg(d) {
return (Math.PI / 180) * d - (Math.PI / 180) * 90;
}
function render() {
c.context.minutes.clearRect(0, 0, 200, 200);
c.context.minutes.beginPath();
c.context.minutes.strokeStyle = "#bbee2b";
c.context.minutes.arc(100, 100, 90, deg(0), deg(6 * (c.times.minutes - 60)));
c.context.minutes.lineWidth = 12;
c.context.minutes.lineCap = "round";
c.context.minutes.stroke();
}
function init() {
// Get 2D contexts
c.context.minutes = document.getElementById('minutes-canvas').getContext('2d');
// Get displayed values
c.values.minutes = document.getElementById('minutes-value');
setInterval(function () {
// Get todays date and time (ms)
const now = new Date().getTime();
// Get distance from now to launchDate
const distance = launchDate - now;
// Time calculations
c.times.minutes = Math.floor((distance % (1000 * 60 * 60)) / (1000 * 60));
c.values.minutes.innerText = c.times.minutes;
render(); // Draw!
}, 1000);
}
init();
You can create a gradient and assign that to stroke
var gradient = document.getElementById('minutes-canvas').getContext('2d').createLinearGradient(0, 0, 0, 170); gradient.addColorStop(0, '#05a'); gradient.addColorStop(1, '#0a5');
// Set Launch Date (ms) const launchDate = new Date("May 7, 2020 00:00").getTime(); // Context object const c = { context: {}, values: {}, times: {} }; // Convert radians to degrees function deg(d) { return (Math.PI / 180) * d - (Math.PI / 180) * 90; } function render() { var gradient = document.getElementById('minutes-canvas').getContext('2d').createLinearGradient(0, 0, 0, 170); gradient.addColorStop(0, '#05a'); gradient.addColorStop(1, '#0a5'); c.context.minutes.clearRect(0, 0, 200, 200); c.context.minutes.beginPath(); c.context.minutes.strokeStyle = gradient; c.context.minutes.arc(100, 100, 90, deg(0), deg(6 * (c.times.minutes - 60))); c.context.minutes.lineWidth = 12; c.context.minutes.lineCap = "round"; c.context.minutes.stroke(); } function init() { // Get 2D contexts c.context.minutes = document.getElementById('minutes-canvas').getContext('2d'); // Get displayed values c.values.minutes = document.getElementById('minutes-value'); setInterval(function() { // Get todays date and time (ms) const now = new Date().getTime(); // Get distance from now to launchDate const distance = launchDate - now; // Time calculations c.times.minutes = Math.floor((distance % (1000 * 60 * 60)) / (1000 * 60)); c.values.minutes.innerText = c.times.minutes; render(); // Draw, }; 1000); } init();
<div class="countItem minutes"> <canvas id="minutes-canvas" width="200" height="200"></canvas> <svg width="100%" height="100%"> <circle id="outer" cx="50%" cy="50%" r="45%" fill="transparent" stroke-width="1%" stroke="#fff" /> </svg> <h3> <span id="minutes-value"></span><br> <small>minutes</small> </h3> </div>
You can create a CanvasGradient
by calling the methods createLinearGradient
or createRadialGradient
of your CanvasRenderingContext2D
. After creating a gradient you add color stops to it by calling the method addColorStop(offset, color)
.
In your code you are storing the CanvasRenderingContext2D
in c.context.minutes
, so you can do something along these lines:
function render() {
c.context.minutes.clearRect(0, 0, 200, 200);
c.context.minutes.beginPath();
const gradient = c.context.minutes.createLinearGradient(0,0, 200,200);
gradient.addColorStop(0, 'red');
gradient.addColorStop(.5, 'blue');
gradient.addColorStop(1, 'green');
c.context.minutes.strokeStyle = gradient;
c.context.minutes.arc(100, 100, 90, deg(0), deg(6 * (c.times.minutes - 60)));
c.context.minutes.lineWidth = 12;
c.context.minutes.lineCap = "round";
c.context.minutes.stroke();
}
References:https://developer.mozilla.org/en-US/docs/Web/API/CanvasGradient
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