I have a canvas that dynamically changes size on user input ie whenever he types in input text box. It works fine if the user inputs a new size greater than the current one but if i try to shrink it the canvas size the previous value persists... how can i do this without refreshing the page? Here's the code:
<p style="line-height: 18px; font-size:18px; font-family: times;">
<br>
<div id = "div1">
<canvas id="canvas"></canvas>
<button onclick="myFunction()">Clickme</button>
<input type= "number" id ="tx1">
<input type= "number" id ="tx2">
<script>
function myFunction(){
var node = document.getElementById("div1");
var kid1 = document.createElement("p");
var kid2 = document.createTextNode("hey");
var kid3 = document.createElement("span");
node.appendChild(kid1);
node.appendChild(kid2);
node.appendChild(kid3);
}
window.onkeyup = function (e) {
var code = e.keyCode ? e.keyCode : e.which;
var t1=document.getElementById('tx1').value;
var t2=document.getElementById('tx2').value;
console.log(t1);
var canvas = document.getElementById("canvas");
var ctx = canvas.getContext('2d');
ctx.fillStyle = 'green';
ctx.fillRect(10, 10, t1, t2);
};
</script>
Try adding a clearRect() in your code
window.onkeyup = function (e) {
var code = e.keyCode ? e.keyCode : e.which;
var t1=document.getElementById('tx1').value;
var t2=document.getElementById('tx2').value;
var canvas = document.getElementById("canvas");
var ctx = canvas.getContext('2d');
ctx.clearRect(10,10,canvas.width,canvas.height);
ctx.fillStyle = 'green';
ctx.fillRect(10, 10, t1, t2);
};
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