我需要使用raphael.js绘制不同大小的同心圆弧。我试图理解类似于我所需内容的http://raphaeljs.com/polar-clock.html 的代码,但是没有注释,很难理解。最好的情况下,我需要一个函数来创建一个路径,该路径距离某个中心点一定的距离,在某个角度开始,并在某个其他角度结束。
那个答案可以,但无法进行动画。我从极坐标时钟中提取了关键的部分给你。这是一个会逐渐增长的红色弧线动画。享受吧。
// Custom Arc Attribute, position x&y, value portion of total, total value, Radius
var archtype = Raphael("canvas", 200, 100);
archtype.customAttributes.arc = function (xloc, yloc, value, total, R) {
var alpha = 360 / total * value,
a = (90 - alpha) * Math.PI / 180,
x = xloc + R * Math.cos(a),
y = yloc - R * Math.sin(a),
path;
if (total == value) {
path = [
["M", xloc, yloc - R],
["A", R, R, 0, 1, 1, xloc - 0.01, yloc - R]
];
} else {
path = [
["M", xloc, yloc - R],
["A", R, R, 0, +(alpha > 180), 1, x, y]
];
}
return {
path: path
};
};
//make an arc at 50,50 with a radius of 30 that grows from 0 to 40 of 100 with a bounce
var my_arc = archtype.path().attr({
"stroke": "#f00",
"stroke-width": 14,
arc: [50, 50, 0, 100, 30]
});
my_arc.animate({
arc: [50, 50, 40, 100, 30]
}, 1500, "bounce");
var paper = Raphael("raphael_paper", 800, 800);
我们向这个 Raphael 对象添加一个自定义的 arc
属性,该属性是一个函数,接受圆心坐标(x 和 y 坐标)、起始角度、终止角度、内半径和外半径:
paper.customAttributes.arc = function (centerX, centerY, startAngle, endAngle, innerR, outerR) {
var radians = Math.PI / 180,
largeArc = +(endAngle - startAngle > 180);
// calculate the start and end points for both inner and outer edges of the arc segment
// the -90s are about starting the angle measurement from the top get rid of these if this doesn't suit your needs
outerX1 = centerX + outerR * Math.cos((startAngle-90) * radians),
outerY1 = centerY + outerR * Math.sin((startAngle-90) * radians),
outerX2 = centerX + outerR * Math.cos((endAngle-90) * radians),
outerY2 = centerY + outerR * Math.sin((endAngle-90) * radians),
innerX1 = centerX + innerR * Math.cos((endAngle-90) * radians),
innerY1 = centerY + innerR * Math.sin((endAngle-90) * radians),
innerX2 = centerX + innerR * Math.cos((startAngle-90) * radians),
innerY2 = centerY + innerR * Math.sin((startAngle-90) * radians);
// build the path array
var path = [
["M", outerX1, outerY1], //move to the start point
["A", outerR, outerR, 0, largeArc, 1, outerX2, outerY2], //draw the outer edge of the arc
["L", innerX1, innerY1], //draw a line inwards to the start of the inner edge of the arc
["A", innerR, innerR, 0, largeArc, 0, innerX2, innerY2], //draw the inner arc
["z"] //close the path
];
return {path: path};
};
var redParams = {stroke: "#f00", "stroke-width": 1, fill:"#eee"},
greenParams = {stroke: "#0f0", "stroke-width": 1, fill:"#eee"},
blueParams = {stroke: "#00f", "stroke-width": 1, fill:"#eee"},
cx = 300, cy = 300, innerRadius = 100, outerRadius = 250,
var red = paper.path().attr(redParams).attr({arc: [cx, cy, 0, 90, innerRadius, outerRadius]});
var green = paper.path().attr(greenParams).attr({arc: [cx, cy, 270, 320, innerRadius, outerRadius]});
var blue = paper.path().attr(blueParams).attr({arc: [cx, cy, 95, 220, innerRadius, outerRadius]});
实际上我自己找到了答案。一开始我想到了一些复杂的贝塞尔曲线,但这个方法很简单。
-> 使用SVG路径语法创建路径,在raphael中可以直接使用。
function arc(center, radius, startAngle, endAngle) {
angle = startAngle;
coords = toCoords(center, radius, angle);
path = "M " + coords[0] + " " + coords[1];
while(angle<=endAngle) {
coords = toCoords(center, radius, angle);
path += " L " + coords[0] + " " + coords[1];
angle += 1;
}
return path;
}
function toCoords(center, radius, angle) {
var radians = (angle/180) * Math.PI;
var x = center[0] + Math.cos(radians) * radius;
var y = center[1] + Math.sin(radians) * radius;
return [x, y];
}
为了消除用户592699的回答中的猜测,这是完整可用的代码:
<script src="raphael.js"></script>
<script>
var paper = Raphael(20, 20, 320, 320);
function arc(center, radius, startAngle, endAngle) {
angle = startAngle;
coords = toCoords(center, radius, angle);
path = "M " + coords[0] + " " + coords[1];
while(angle<=endAngle) {
coords = toCoords(center, radius, angle);
path += " L " + coords[0] + " " + coords[1];
angle += 1;
}
return path;
}
function toCoords(center, radius, angle) {
var radians = (angle/180) * Math.PI;
var x = center[0] + Math.cos(radians) * radius;
var y = center[1] + Math.sin(radians) * radius;
return [x, y];
}
paper.path(arc([100, 100], 80, 0, 270)); // draw an arc
// centered at (100, 100),
// radius 80, starting at degree 0,
// beginning at coordinate (80, 0)
// which is relative to the center
// of the circle,
// going clockwise, until 270 degree
</script>
对于那些希望弧线是闭合路径而不是描边的人,我扩展了genkilabs的答案以提供解决方案。在需要给弧线外部描边的情况下,这可能有所帮助。
// Custom Arc Attribute, position x&y, value portion of total, total value, Radius, width
var archtype = Raphael("canvas", 200, 100);
archtype.customAttributes.arc = function (xloc, yloc, value, total, R, width) {
if(!width) width = R * 0.4;
var alpha = 360 / total * value,
a = (90 - alpha) * Math.PI / 180,
w = width / 2,
r1 = R + w,
r2 = R - w,
x1 = xloc + r1 * Math.cos(a),
y1 = yloc - r1 * Math.sin(a),
x2 = xloc + r2 * Math.cos(a),
y2 = yloc - r2 * Math.sin(a),
path;
if (total == value) {
path = [
["M", xloc, yloc - r1],
["A", r1, r1, 0, 1, 1, xloc - 0.01, yloc - r1],
["Z"],
["M", xloc - 0.01, yloc - r2],
["A", r2, r2, 0, 1, 0, xloc, yloc - r2],
["Z"]
];
} else {
path = [
["M", xloc, yloc - r1],
["A", r1, r1, 0, +(alpha > 180), 1, x1, y1],
["L", x2, y2],
["A", r2, r2, 0, +(alpha > 180), 0, xloc, yloc - r2],
["L", xloc, yloc - r1],
["Z"]
];
}
return {
path: path
};
};
//make an arc at 50,50 with a radius of 30 that grows from 0 to 40 of 100 with a bounce
var my_arc = archtype.path().attr({
"fill": "#00f",
"stroke": "#f00",
"stroke-width": 5,
arc: [50, 50, 0, 100, 30]
});
my_arc.animate({
arc: [50, 50, 40, 100, 30]
}, 1500, "bounce");
您也可以不使用循环来实现此操作。以下方法可以实现此操作,并且适用于负角度。
将 Raphael 对象作为 r 传入。角度从0度开始,这是圆的顶部,而不是右侧,这与其他解决方案中列出的方式不同。
function drawArc(r, centerX, centerY, radius, startAngle, endAngle) {
var startX = centerX+radius*Math.cos((90-startAngle)*Math.PI/180);
var startY = centerY-radius*Math.sin((90-startAngle)*Math.PI/180);
var endX = centerX+radius*Math.cos((90-endAngle)*Math.PI/180);
var endY = centerY-radius*Math.sin((90-endAngle)*Math.PI/180);
var flg1 = 0;
if (startAngle>endAngle)
flg1 = 1;
else if (startAngle<180 && endAngle<180)
flg1 = 0;
else if (startAngle>180 && endAngle>180)
flg1 = 0;
else if (startAngle<180 && endAngle>180)
flg1 = 0; // edited for bugfix here, previously this was 1
else if (startAngle>180 && endAngle<180)
flg1 = 1;
return r.path([['M',startX, startY],['A',radius,radius,0,flg1,1,endX,endY]]);
};
paper.customAttributes.arc = function (xloc, yloc, percent, rad, rot, invert) {
var alpha = 3.6 * percent,
a = (90 - alpha) * Math.PI / 180,
x = xloc + rad * Math.cos(a),
y = yloc - rad * Math.sin(a),
path;
if (invert) {
x = xloc - rad * Math.cos(a);
}
if (percent >= 100) {
path = [
["M", xloc, yloc - rad],
["A", rad, rad, 0, 1, 1, xloc - 0.01, yloc - rad]
];
} else {
path = [
["M", xloc, yloc - rad],
["A", rad, rad, 0, +(alpha > 180), +(!invert), x, y]
];
}
return {
path: path,
transform: "r"+rot+","+xloc+","+yloc,
};
};