forked from chartjs/Chart.js
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element.arc.js
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element.arc.js
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'use strict';
var defaults = require('../core/core.defaults');
var Element = require('../core/core.element');
var helpers = require('../helpers/index');
defaults._set('global', {
elements: {
arc: {
backgroundColor: defaults.global.defaultColor,
borderColor: '#fff',
borderWidth: 2,
borderAlign: 'center'
}
}
});
module.exports = Element.extend({
inLabelRange: function(mouseX) {
var vm = this._view;
if (vm) {
return (Math.pow(mouseX - vm.x, 2) < Math.pow(vm.radius + vm.hoverRadius, 2));
}
return false;
},
inRange: function(chartX, chartY) {
var vm = this._view;
if (vm) {
var pointRelativePosition = helpers.getAngleFromPoint(vm, {x: chartX, y: chartY});
var angle = pointRelativePosition.angle;
var distance = pointRelativePosition.distance;
// Sanitise angle range
var startAngle = vm.startAngle;
var endAngle = vm.endAngle;
while (endAngle < startAngle) {
endAngle += 2.0 * Math.PI;
}
while (angle > endAngle) {
angle -= 2.0 * Math.PI;
}
while (angle < startAngle) {
angle += 2.0 * Math.PI;
}
// Check if within the range of the open/close angle
var betweenAngles = (angle >= startAngle && angle <= endAngle);
var withinRadius = (distance >= vm.innerRadius && distance <= vm.outerRadius);
return (betweenAngles && withinRadius);
}
return false;
},
getCenterPoint: function() {
var vm = this._view;
var halfAngle = (vm.startAngle + vm.endAngle) / 2;
var halfRadius = (vm.innerRadius + vm.outerRadius) / 2;
return {
x: vm.x + Math.cos(halfAngle) * halfRadius,
y: vm.y + Math.sin(halfAngle) * halfRadius
};
},
getArea: function() {
var vm = this._view;
return Math.PI * ((vm.endAngle - vm.startAngle) / (2 * Math.PI)) * (Math.pow(vm.outerRadius, 2) - Math.pow(vm.innerRadius, 2));
},
tooltipPosition: function() {
var vm = this._view;
var centreAngle = vm.startAngle + ((vm.endAngle - vm.startAngle) / 2);
var rangeFromCentre = (vm.outerRadius - vm.innerRadius) / 2 + vm.innerRadius;
return {
x: vm.x + (Math.cos(centreAngle) * rangeFromCentre),
y: vm.y + (Math.sin(centreAngle) * rangeFromCentre)
};
},
draw: function() {
var ctx = this._chart.ctx;
var vm = this._view;
var sA = vm.startAngle;
var eA = vm.endAngle;
var pixelMargin = (vm.borderAlign === 'inner') ? 0.33 : 0;
var angleMargin;
if (vm.circumference > Math.PI * 2) {
sA += (eA - sA) % (Math.PI * 2);
}
ctx.save();
ctx.beginPath();
ctx.arc(vm.x, vm.y, Math.max(vm.outerRadius - pixelMargin, 0), sA, eA);
ctx.arc(vm.x, vm.y, vm.innerRadius, eA, sA, true);
ctx.closePath();
ctx.fillStyle = vm.backgroundColor;
ctx.fill();
if (vm.borderWidth) {
if (vm.borderAlign === 'inner') {
// Draw an inner border by cliping the arc and drawing a double-width border
// Enlarge the clipping arc by 0.33 pixels to eliminate glitches between borders
ctx.beginPath();
angleMargin = pixelMargin / vm.outerRadius;
ctx.arc(vm.x, vm.y, vm.outerRadius, sA - angleMargin, eA + angleMargin);
if (vm.innerRadius > pixelMargin) {
angleMargin = pixelMargin / vm.innerRadius;
ctx.arc(vm.x, vm.y, vm.innerRadius - pixelMargin, eA + angleMargin, sA - angleMargin, true);
} else {
ctx.arc(vm.x, vm.y, pixelMargin, eA + Math.PI / 2, sA - Math.PI / 2);
}
ctx.closePath();
ctx.clip();
ctx.beginPath();
ctx.arc(vm.x, vm.y, vm.outerRadius, sA, eA);
ctx.arc(vm.x, vm.y, vm.innerRadius, eA, sA, true);
ctx.closePath();
ctx.lineWidth = vm.borderWidth * 2;
ctx.lineJoin = 'round';
} else {
ctx.lineWidth = vm.borderWidth;
ctx.lineJoin = 'bevel';
}
ctx.strokeStyle = vm.borderColor;
ctx.stroke();
}
ctx.restore();
}
});