我只是学习有关HTML5画布的一些细节,并在进步,我想建立由楔子简单色轮(建在一个时间上的1度的楔形,并添加它到360度)。但是,我得到的梯度一些奇怪的标记图如下图所示:
.
下面是所产生的色轮的小提琴:qazxsw POI
特别是,这是JS代码:
http://jsfiddle.net/53JBM/
如果任何人都可以指出什么我做错了,或者有更好的方法来完成,我试图做到这一点,将不胜感激:)
这是否足以给你,请检查
var canvas = document.getElementById("picker");
var context = canvas.getContext("2d");
var x = canvas.width / 2;
var y = canvas.height / 2;
var radius = 100;
var counterClockwise = false;
for(var angle=0; angle<=360; angle+=1){
var startAngle = (angle-1)*Math.PI/180;
var endAngle = angle * Math.PI/180;
context.beginPath();
context.moveTo(x, y);
context.arc(x, y, radius, startAngle, endAngle, counterClockwise);
context.closePath();
context.fillStyle = 'hsl('+angle+', 100%, 50%)';
context.fill();
}
试试这个它看起来很棒。顺便感谢,这正是我试图让。
var startAngle = (angle-2)*Math.PI/180;
var canvas = document.getElementById("picker");
var context = canvas.getContext("2d");
var x = canvas.width / 2;
var y = canvas.height / 2;
var radius = 100;
var counterClockwise = false;
for(var angle=0; angle<=360; angle+=1){
var startAngle = (angle-2)*Math.PI/180;
var endAngle = angle * Math.PI/180;
context.beginPath();
context.moveTo(x, y);
context.arc(x, y, radius, startAngle, endAngle, counterClockwise);
context.closePath();
var gradient = context.createRadialGradient(x, y, 0, x, y, radius);
gradient.addColorStop(0,'hsl('+angle+', 10%, 100%)');
gradient.addColorStop(1,'hsl('+angle+', 100%, 50%)');
context.fillStyle = gradient;
context.fill();
}
类似的方法,只是颜色
<body>
<canvas id="picker"></canvas>
</body>
var canvas = document.getElementById("picker");
var context = canvas.getContext("2d");
var x = canvas.width / 2;
var y = canvas.height / 2;
var radius = 50;
var thickness = 0.6;
for(var angle=0; angle<=360; angle+=1){
var startAngle = (angle-2)*Math.PI/180;
var endAngle = angle * Math.PI/180;
context.beginPath();
context.arc(x, y, (1-thickness/2)*radius, startAngle, endAngle, false);
context.lineWidth = thickness*radius;
context.strokeStyle = 'hsl('+angle+', 100%, 50%)';
context.stroke();
}
编辑:在这里完整的项目:<body>
<canvas id="picker"></canvas>
</body>