I want to draw a figure like this.
I have used the Canvas to draw the line but failed to draw custom lines.
<!DOCTYPE html>
<html>
<head>
<meta charset=utf-8 />
<title>Line Joining</title>
</head>
<body>
<canvas id="DemoCanvas" width="400" height="400"></canvas>
<script>
var canvas = document.getElementById('DemoCanvas');
if (canvas.getContext)
{
var ctx = canvas.getContext("2d");
var lStart = 50;
var lEnd = 200;
var yStart = 20;
ctx.beginPath();
ctx.lineWidth = 25;
// Use a round corner.
ctx.beginPath();
ctx.lineJoin = "round";
ctx.moveTo(50, 140);
ctx.lineTo(150, 140);
ctx.lineTo(150, 260);
ctx.stroke();
}
</script>
</body>
</html>
I have also tried jQuery draggable and achieved results as figure below.
Kindly suggest me how these type of figures can be drawn using HTML and jQuery/JavaScript
Related
This question already has answers here:
clearRect not working
(2 answers)
Closed 6 months ago.
I don't see why this code isn't working. It should just draw a white rectangle covering the screen. Then a randomly placed blue dot and wait for the loop to complete. And then repeat the cycle by drawing the white rectangle again and turning off the dot and then redrawing it.
<!DOCTYPE html>
<html lang="en-US">
<head>
<meta charset="UTF-8"/>
<title>Peripheral vision checker</title>
<script type="application/javascript">
function draw() {
// draw crosshairs
var onFor = 1000;
const intervalID = setInterval(mytimer, onFor);
function mytimer()
{
// draw white rects
function getRandomInt(max) {
return Math.floor(Math.random() * max);
}
var x = 1280;//will be equal to window height
var y = 720;//will be equal to window width
const canvas = document.getElementById('canvas');
const ctx = canvas.getContext('2d');
ctx.fillStyle = 'white';
var xcoor =getRandomInt(x);
var ycoor =getRandomInt(y);
ctx.fillRect(0, 0, x, y);
ctx.fillStyle = 'blue';
var radius = 10;
moveTo(xcoor,ycoor);
ctx.arc(xcoor, ycoor, radius, 0, 2 * Math.PI);
//console.log(xcoor + ' ' + ycoor);//just temporary, to see they work
ctx.fill();
}
}
</script>
</head>
<h1>Peripheral vision checker</h1>
<body onload="draw();">
<canvas id="canvas" width="1280" height="720"></canvas>
</body>
</html>
You need to beginPath then closePath
<!DOCTYPE html>
<html lang="en-US">
<head>
<meta charset="UTF-8" />
<title>Peripheral vision checker</title>
<script type="application/javascript">
function draw() {
// draw crosshairs
var onFor = 1000;
const intervalID = setInterval(mytimer, onFor);
function mytimer() {
// draw white rects
function getRandomInt(max) {
return Math.floor(Math.random() * max);
}
var x = 500; //will be equal to window height
var y = 250; //will be equal to window width
const canvas = document.getElementById('canvas');
const ctx = canvas.getContext('2d');
ctx.fillStyle = 'white';
var xcoor = getRandomInt(x);
var ycoor = getRandomInt(y);
ctx.fillRect(0, 0, x, y);
ctx.fillStyle = 'blue';
var radius = 10;
ctx.beginPath();
moveTo(xcoor, ycoor);
ctx.arc(xcoor, ycoor, radius, 0, 2 * Math.PI);
//console.log(xcoor + ' ' + ycoor);//just temporary, to see they work
ctx.fill();
// no need to:
// ctx.closePath();
}
}
</script>
</head>
<h1>Peripheral vision checker</h1>
<body onload="draw();">
<canvas id="canvas" width="500" height="250"></canvas>
</body>
</html>
I have a web app that receives some array of points and I need to draw them on a canvas. Unfortunately, I get the dataset not the way I want. I need to rotate the shapes 180 degrees. I have no idea how to do this...
Please see the example in the snippet.
// Main template shape
let shape = [{x: 10, y:10}, {x: 120, y:10}, {x: 110, y:110}, {x: 50, y:175}];
let canvas = {}; // Canvas to draw on
let ctx = {}; // Context of the Canvas
// Init elements
$( document ).ready(function() {
canvas = document.getElementById("myCanvas");
ctx = canvas.getContext("2d");
drawShape();
});
// Draw the template
function drawShape() {
ctx.save();
ctx.beginPath();
ctx.strokeStyle = 'yellow';
ctx.fillStyle = 'red';
for(let point of shape) {
ctx.lineTo(point.x, point.y);
}
ctx.closePath();
ctx.fill();
ctx.stroke();
ctx.restore();
}
<!DOCTYPE html>
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
<title>Hahaha!</title>
</head>
<body>
<canvas id="myCanvas" width="200" height="200" style="border:1px solid #000000;"></canvas>
</body>
</html>
If I understand your question correctly, you want to turn the shape around by 180 degrees ?
As in vertically invert it ? If this is it, here's a solution, you need an axis relative to which to turn it. Problem is if you just invert for every point (x,y), you put (x,-y), canvas being defined for only positive values it won't show on your screen, imagine it outstide the screen, you need to "push" it back down onto the canvas, you do this by adding the height of the canvas after having inverted the shape.
// Main template shape
let shape = [ {x:10, y:10}, {x:120, y:10}, {x:110, y:110}, {x:50, y:175} ];
let canvas = {}; // Canvas to draw on
let ctx = {}; // Context of the Canvas
// Init elements
$( document ).ready(function() {
canvas = document.getElementById("myCanvas");
ctx = canvas.getContext("2d");
drawShape();
});
// Draw the template
function drawShape() {
ctx.save();
ctx.beginPath();
ctx.strokeStyle = 'yellow';
ctx.fillStyle = 'red';
for(let i = 0; i < shape.length; i++) {
ctx.lineTo(shape[i][0], -shape[i][1] + 200);
}
for(let point of shape) {
ctx.lineTo(point.x, -point.y + 200);
}
ctx.closePath();
ctx.fill();
ctx.stroke();
ctx.restore();
}
<!DOCTYPE html>
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
<title>Hahaha!</title>
</head>
<body>
<canvas id="myCanvas" width="200" height="200" style="border:1px solid #000000;"></canvas>
</body>
</html>
I am trying to make to objects move towards each other in Canvas, when they meet and overlap one should then disappear and the other should fall down. Now I got the animation to do that, but one of the items is flickering.
<!DOCTYPE html>
<html>
<head>
<style>
canvas{border:#666 3px solid;}
</style>
</head>
<body onload="draw(530,15); draw1(1,15);">
<canvas id="canvas" width="600" height="400"></canvas>
<script>
function draw(x,y){
var canvas = document.getElementById('canvas');
var ctx = canvas.getContext('2d');
ctx.save();
ctx.clearRect(x, y, 600, 400);
ctx.fillStyle = "rgba(0,200,0,1)";
ctx.fillRect (x, y, 70, 50);
ctx.restore();
x -= 0.5;
if(x==300)
{
return;
};
var loopTimer = setTimeout('draw('+x+','+y+')',5);
};
function draw1(w,e){
var canvas = document.getElementById('canvas');
var ctx = canvas.getContext('2d');
ctx.save();
ctx.clearRect(w-1,e-2,600,400);
ctx.fillStyle = "rgba(0,200,0,1)";
ctx.fillRect (w, e, 70, 50);
ctx.restore();
w += 1;
if(w==265)
{
w -= 1;
e +=2;
};
var loopTimer = setTimeout('draw1('+w+','+e+')',10);
};
</script>
</body>
</html>
Been trying for two days, but can't seem to fix it properly. Thanks in advance.
You are rendering too many frames per second forcing the browser to present frames. Each time a draw function returns the browser presumes you want to present the frame to the page.
Animations need to be synced to the display refresh rate which for most devices is 60FPS. To do this you have one render loop that handles all the animation. You call this function via requestAnimationFrame (RAF) which ensures that the animation stays in sync with the display hardware and browser rendering.
<!DOCTYPE html>
<html>
<head>
<style>
canvas{border:#666 3px solid;}
</style>
</head>
<!-- dont need this <body onload="draw(530,15); draw1(1,15);">-->
<body>
<canvas id="canvas" width="600" height="400"></canvas>
<script>
var canvas,ctx,x,y,w,e;
var canvas,ctx,x,y,w,e;
function draw() {
ctx.fillStyle = "rgba(0,200,0,1)";
ctx.fillRect(x, y, 70, 50);
};
function draw1(w, e) {
ctx.fillStyle = "rgba(0,200,0,1)";
ctx.fillRect(w, e, 70, 50);
};
function update(time){ // high precision time passed by RAF when it calls this function
ctx.clearRect(0,0,canvas.width,canvas.height); // clear all of the canvas
if(w + 70 >= x){
e += 2;
}else{
x -= 0.75;
w += 1;
};
draw(x,y);
draw1(w,e);
requestAnimationFrame(update)
// at this point the function exits and the browser presents
// the canvas bitmap for display
}
function start(){ // set up
x = 530;
y = 15;
w = 1;
e = 15;
canvas = document.getElementById('canvas');
ctx = canvas.getContext('2d');
requestAnimationFrame(update)
}
window.addEventListener("load",start);
</script>
</body>
</html>
You're method of animation is very outdated (ie, the use of setTimeout). Instead you should be using requestAnimationFrame as demonstrated below. This will give smooth, flicker free animation.
<!DOCTYPE html>
<html>
<head>
<style>
canvas{border:#666 3px solid;}
</style>
</head>
<body onload="requestAnimationFrame(animate);">
<canvas id="canvas" width="600" height="400"></canvas>
<script>
var canvas = document.getElementById('canvas');
var ctx = canvas.getContext('2d');
var x = 530, y = 15;
function animate(){
requestID = requestAnimationFrame(animate);
ctx.clearRect(x, y, 600, 400);
ctx.fillStyle = "rgba(0,200,0,1)";
ctx.fillRect (x, y, 70, 50);
x -= 0.5;
if(x==300)
{
cancelAnimationFrame(requestID)
};
}
</script>
</body>
</html>
the first 2 parameters of ctx.clearReact in both draw functions should be 0:
ctx.clearRect(0, 0, 600, 400);
This means you clear all canvas.
I am working in Jquery.
I have 4 Cordinates , Width, Height, x Position and Y position.
How can i create a Square shape Using This
$('#box').drawRect(20,20,2,30,{color:'red'})
I tried this and Not Working. Looking for a Good Hand
Here is My Demo. http://fiddle.jshell.net/vbm2vhu4/
try using canvas tag in JavaScript..
var c = document.getElementById("myCanvas");
var ctx = c.getContext("2d");
ctx.rect(20, 20, 150, 100);
ctx.stroke();
<canvas id="myCanvas" width="300" height="150" style="border:1px solid #d3d3d3;">
Your browser does not support the HTML5 canvas tag.</canvas>
JSFIDDLE
JAVASCRIPT
Draw a circle
$(document).ready(function(){
var canvas = document.getElementById('myCanvas');
var context = canvas.getContext('2d');
var centerX = canvas.width / 2;
var centerY = canvas.height / 2;
var radius = 70;
context.beginPath();
context.arc(centerX, centerY, radius, 0, 2 * Math.PI, false);
context.fillStyle = 'green';
context.fill();
context.lineWidth = 5;
context.strokeStyle = '#003300';
context.stroke();
});
Drawing a rectangle requires canvas. You really do not need to use jquery for it. It can be well done with Javascript. I am attaching my example here.
<!DOCTYPE html>
<html>
<body>
<canvas id="myCanvas" width="300" height="150">
Browser does not support the HTML5 canvas tag.</canvas>
<script>
var c = document.getElementById("myCanvas");
var ctx = c.getContext("2d");
// Blue rectangle
ctx.beginPath();
ctx.lineWidth = "10";
ctx.strokeStyle = "blue";
ctx.rect(50, 50, 50, 50);
ctx.stroke();
</script>
</body>
</html>
Paste this into a notepad and save as .html and load it in your browser
or jsfiddle http://jsfiddle.net/ssbiswal1987/vsbak0mq/
i have the following code in an html file and when i try to view the code on localhost [MAMP] all i see is a black canvas area with a border around it. i've checked it in chrome and firefox. same results. what am i doing wrong?
<!DOCTYPE html>
<html>
<head>
<title></title>
<meta charset="utf-8">
</head>
<body>
<canvas id="myCanvas" width="500" height="500" style="border:1px solid #000;"></canvas>
<script type="text/javascript" src="http://code.jquery.com/jquery-latest.pack.js"></script>
<script type="text/javascript">
$(function() {
var myCanvas = document.getElementById("myCanvas");
var ctx = canvas.getContext("2d");
ctx.fillRect(50, 50, 100, 100);
//close jquery
});
</script>
</body>
so i figured it out. thanks to Ken and Scott for their help.
var myCanvas = document.getElementById("myCanvas");
var ctx = canvas.getContext("2d");
ctx.fillRect(50, 50, 100, 100);
should have been
var myCanvas = document.getElementById("myCanvas");
var ctx = myCanvas.getContext("2d"); //should have been myCanvas not canvas
ctx.fillRect(50, 50, 100, 100);
The default fill style of the canvas is black, while the canvas itself starts out as transparent. Set it to something else before calling fillRect, and you'll see better results.
ctx.fillStyle = "#F00"
Or, try this to see multiple rectangles:
var myCanvas = document.getElementById("myCanvas");
var ctx = canvas.getContext("2d");
ctx.fillStyle = "green";
ctx.fillRect(0, 0, myCanvas.width, myCanvas.height);
ctx.fillStyle = "red";
ctx.fillRect(50, 50, 100, 100);
FIDDLE