Today I started learning how to work with canvas by doing a basic loading circle animation. Everything works perfect in small res (ca. 100×100 px) but when I tried much larger it all went distorted and blurred and it looks really bad. So this is my question: Can I somehow turn on some anti-aliasing on or somehow make it more sharpen? I already found plenty of sharpening algorithms but for images and I'm not sure if it will work with this.
Circle loading example: (code is not perfect or even finished because I'm still stuck on that blur)
var c = document.getElementById("canvas");
var ctx = c.getContext("2d");
var int_count = 0;
var circ_angle = 1.5;
var count = 10;
var interval = setInterval(function() {
if (int_count == count) {
clearInterval(interval);
}
ctx.clearRect(0, 0, 1000, 1000);
ctx.beginPath();
ctx.arc(100, 70, 50, 1.5 * Math.PI, -1 * Math.PI, true);
ctx.lineWidth = 1;
ctx.strokeStyle = "#717171";
ctx.stroke();
ctx.beginPath();
//1.5 = 0%; 1 = 1/4; 0.5 = 2/4; 0 = 3/4 -1 = full
ctx.font = "40px sarpanch";
ctx.arc(100, 70, 50, 1.5 * Math.PI, circ_angle * Math.PI, true);
//color
if (int_count >= 5 && int_count < 10) {
ctx.strokeStyle = "#ff8000";
}
else if (int_count >= 9) {
ctx.strokeStyle = "#F00";
}
else {
ctx.strokeStyle = "#3a9fbe";
}
ctx.fillText("" + int_count + "", 88, 83);
ctx.lineWidth = 3;
ctx.stroke();
int_count += 1;
circ_angle += (-0.2);
}, 500);
Add the following attributes :
width="759" height="394"
to your <canvas>
instead of specifying them in your css
Never resize your canvas with CSS. Instead, set the canvas size with the width
and height
attributes:
<canvas id="canvas" width="759" height="394"></canvas>
Remove the CSS rules for the canvas.
Next, you'll have to scale every part with JavaScript:
// …
ctx.arc(150, 150, 100, 1.5*Math.PI,-1*Math.PI,true); // instead of 100, 70, 50
// …
ctx.font = "60px sarpanch"; // instead of 40px
ctx.arc(150, 150, 100, 1.5*Math.PI,circ_angle*Math.PI,true); // instead of 100, 70, 50
// …
ctx.fillText(int_count, 130, 170); // instead of 88, 83
// …
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