Animate A Fill Circle Like Pie Chart Using Canvas
Basically I want to be able to Fill a Circle using canvas, but it animate like pie chart and mask to show new image in circle. My canvas knowledge isn't amazing, Here is an image t
Solution 1:
This is one way:
- Draw your gray background.
- Fill your percent-arc with a starting angle at -Math.PI*2 (=="12 on a clock") and an ending angle of -Math.PI*2 + Math.PI*2*percent (==a full circle of 2PI times your desired percent).
- Draw your logo.
To animate, just use a requestAnimationFrame
loop that incrementally draws the percent-arc starting at 0 percent and ending at your target percent.
Example code and a Demo:
var canvas=document.getElementById("canvas");
var ctx=canvas.getContext("2d");
var cw=canvas.width;
var ch=canvas.height;
var nextTime=0;
var duration=1000;
var endingPct=75;
var pct=0;
var increment=duration/pct;
requestAnimationFrame(animate);
functionanimate(time){
draw(pct);
pct++;
if(pct<=endingPct){requestAnimationFrame(animate);}
}
functiondraw(pct){
var endRadians=-Math.PI/2+Math.PI*2*pct/100;
ctx.fillStyle='lightgray';
ctx.fillRect(0,0,cw,ch);
ctx.beginPath();
ctx.arc(150,125,100,-Math.PI/2,endRadians);
ctx.lineTo(150,125);
ctx.fillStyle='white';
ctx.fill();
ctx.beginPath();
ctx.moveTo(150,100);
ctx.lineTo(175,150);
ctx.quadraticCurveTo(150,125,125,150);
ctx.closePath();
ctx.strokeStyle='#13a8a4';
ctx.lineJoin='bevel';
ctx.lineWidth=10;
ctx.stroke();
ctx.fillStyle='black';
ctx.textAlign='center';
ctx.textBaseline='middle'
ctx.font='18px arial';
ctx.fillText('ADUR',150,175);
}
body{ background-color: ivory; }
#canvas{border:1px solid red; margin:0 auto; }
<canvasid="canvas"width=300height=300></canvas>
[Update: We needed an image clipped inside the animated wedge]
var canvas=document.getElementById("canvas");
var ctx=canvas.getContext("2d");
var cw=canvas.width;
var ch=canvas.height;
var nextTime=0;
var duration=1000;
var endingPct=75;
var pct=0;
var increment=duration/pct;
var cx=cw/2;
var cy=ch/2;
var img=newImage();
img.onload=start;
img.src="https://dl.dropboxusercontent.com/u/139992952/multple/mm.jpg";
functionstart(){
requestAnimationFrame(animate);
}
functionanimate(time){
draw(pct);
pct++;
if(pct<=endingPct){requestAnimationFrame(animate);}
}
functiondraw(pct){
//var endRadians=-Math.PI/2+Math.PI*2*pct/100;
//
ctx.fillStyle='lightgray';
ctx.fillRect(0,0,cw,ch);
//
ctx.beginPath();
ctx.arc(cx,cy,100,-Math.PI/2,endRadians);
ctx.lineTo(cx,cy);
ctx.save();
ctx.clip();
ctx.drawImage(img,cx-img.width/2,cx-img.height/2);
ctx.restore();
}
body{ background-color: ivory; }
#canvas{border:1px solid red; margin:0 auto; }
<canvasid="canvas"width=300height=300></canvas>
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