基本上我希望能够使用画布填充圆圈,但它会以一定的百分比动画.
我只有圆圈填满了80％.
我只有圆圈填满了80％.
我的画布知识并不令人惊讶,这是我在photoshop中制作的图像,用于显示我想要的内容.
我希望圆圈开始为空,然后填充说圆圈的70％.
Canvas有可能,如果是这样吗？任何人都可以了解如何做到这一点？
这是我管理的一个小提琴
- var canvas = document.getElementById('Circle');
- var context = canvas.getContext('2d');
- var centerX = canvas.width / 2;
- var centerY = canvas.height / 2;
- var radius = 80;
- context.beginPath();
- context.arc(centerX,centerY,radius,2 * Math.PI,false);
- context.fillStyle = '#13a8a4';
- context.fill();
- context.lineWidth = 10;
- context.strokeStyle = '#ffffff';
- context.stroke();
任何帮助都将受到大力赞赏
解决方法
剪裁区域使这非常容易.你所要做的就是制作一个圆形剪裁区域,然后填充一个大小的矩形,以获得一个值得填充的“部分圆”.这是一个例子：
- var canvas = document.getElementById('Circle');
- var context = canvas.getContext('2d');
- var centerX = canvas.width / 2;
- var centerY = canvas.height / 2;
- var radius = 80;
- var full = radius*2;
- var amount = 0;
- var amountToIncrease = 10;
- function draw() {
- context.save();
- context.beginPath();
- context.arc(centerX,false);
- context.clip(); // Make a clipping region out of this path
- // instead of filling the arc,we fill a variable-sized rectangle
- // that is clipped to the arc
- context.fillStyle = '#13a8a4';
- // We want the rectangle to get progressively taller starting from the bottom
- // There are two ways to do this:
- // 1. Change the Y value and height every time
- // 2. Using a negative height
- // I'm lazy,so we're going with 2
- context.fillRect(centerX - radius,centerY + radius,radius * 2,-amount);
- context.restore(); // reset clipping region
- context.beginPath();
- context.arc(centerX,false);
- context.lineWidth = 10;
- context.strokeStyle = '#000000';
- context.stroke();
- // Every time,raise amount by some value:
- amount += amountToIncrease;
- if (amount > full) amount = 0; // restart
- }
- draw();
- // Every second we'll fill more;
- setInterval(draw,1000);
