"use strict";
module.exports = function(Chart) {
var helpers = Chart.helpers;
var globalDefaults = Chart.defaults.global;
var defaultConfig = {
display: true,
//Boolean - Whether to animate scaling the chart from the centre
animate: true,
lineArc: false,
position: "chartArea",
angleLines: {
display: true,
color: "rgba(0, 0, 0, 0.1)",
lineWidth: 1
},
// label settings
ticks: {
//Boolean - Show a backdrop to the scale label
showLabelBackdrop: true,
//String - The colour of the label backdrop
backdropColor: "rgba(255,255,255,0.75)",
//Number - The backdrop padding above & below the label in pixels
backdropPaddingY: 2,
//Number - The backdrop padding to the side of the label in pixels
backdropPaddingX: 2
},
pointLabels: {
//Number - Point label font size in pixels
fontSize: 10,
//Function - Used to convert point labels
callback: function(label) {
return label;
}
}
};
var LinearRadialScale = Chart.Scale.extend({
getValueCount: function() {
return this.chart.data.labels.length;
},
setDimensions: function() {
var options = this.options;
// Set the unconstrained dimension before label rotation
this.width = this.maxWidth;
this.height = this.maxHeight;
this.xCenter = Math.round(this.width / 2);
this.yCenter = Math.round(this.height / 2);
var minSize = helpers.min([this.height, this.width]);
var tickFontSize = helpers.getValueOrDefault(options.ticks.fontSize, globalDefaults.defaultFontSize);
this.drawingArea = (options.display) ? (minSize / 2) - (tickFontSize / 2 + options.ticks.backdropPaddingY) : (minSize / 2);
},
determineDataLimits: function() {
this.min = null;
this.max = null;
helpers.each(this.chart.data.datasets, function(dataset, datasetIndex) {
if (this.chart.isDatasetVisible(datasetIndex)) {
var meta = this.chart.getDatasetMeta(datasetIndex);
helpers.each(dataset.data, function(rawValue, index) {
var value = +this.getRightValue(rawValue);
if (isNaN(value) || meta.data[index].hidden) {
return;
}
if (this.min === null) {
this.min = value;
} else if (value < this.min) {
this.min = value;
}
if (this.max === null) {
this.max = value;
} else if (value > this.max) {
this.max = value;
}
}, this);
}
}, this);
// If we are forcing it to begin at 0, but 0 will already be rendered on the chart,
// do nothing since that would make the chart weird. If the user really wants a weird chart
// axis, they can manually override it
if (this.options.ticks.beginAtZero) {
var minSign = helpers.sign(this.min);
var maxSign = helpers.sign(this.max);
if (minSign < 0 && maxSign < 0) {
// move the top up to 0
this.max = 0;
} else if (minSign > 0 && maxSign > 0) {
// move the botttom down to 0
this.min = 0;
}
}
if (this.options.ticks.min !== undefined) {
this.min = this.options.ticks.min;
} else if (this.options.ticks.suggestedMin !== undefined) {
this.min = Math.min(this.min, this.options.ticks.suggestedMin);
}
if (this.options.ticks.max !== undefined) {
this.max = this.options.ticks.max;
} else if (this.options.ticks.suggestedMax !== undefined) {
this.max = Math.max(this.max, this.options.ticks.suggestedMax);
}
if (this.min === this.max) {
this.min--;
this.max++;
}
},
buildTicks: function() {
this.ticks = [];
// Figure out what the max number of ticks we can support it is based on the size of
// the axis area. For now, we say that the minimum tick spacing in pixels must be 50
// We also limit the maximum number of ticks to 11 which gives a nice 10 squares on
// the graph
var tickFontSize = helpers.getValueOrDefault(this.options.ticks.fontSize, globalDefaults.defaultFontSize);
var maxTicks = Math.min(this.options.ticks.maxTicksLimit ? this.options.ticks.maxTicksLimit : 11, Math.ceil(this.drawingArea / (1.5 * tickFontSize)));
maxTicks = Math.max(2, maxTicks); // Make sure we always have at least 2 ticks
// To get a "nice" value for the tick spacing, we will use the appropriately named
// "nice number" algorithm. See http://stackoverflow.com/questions/8506881/nice-label-algorithm-for-charts-with-minimum-ticks
// for details.
var niceRange = helpers.niceNum(this.max - this.min, false);
var spacing = helpers.niceNum(niceRange / (maxTicks - 1), true);
var niceMin = Math.floor(this.min / spacing) * spacing;
var niceMax = Math.ceil(this.max / spacing) * spacing;
var numSpaces = Math.ceil((niceMax - niceMin) / spacing);
// Put the values into the ticks array
this.ticks.push(this.options.ticks.min !== undefined ? this.options.ticks.min : niceMin);
for (var j = 1; j < numSpaces; ++j) {
this.ticks.push(niceMin + (j * spacing));
}
this.ticks.push(this.options.ticks.max !== undefined ? this.options.ticks.max : niceMax);
// At this point, we need to update our max and min given the tick values since we have expanded the
// range of the scale
this.max = helpers.max(this.ticks);
this.min = helpers.min(this.ticks);
if (this.options.ticks.reverse) {
this.ticks.reverse();
this.start = this.max;
this.end = this.min;
} else {
this.start = this.min;
this.end = this.max;
}
this.zeroLineIndex = this.ticks.indexOf(0);
},
convertTicksToLabels: function() {
Chart.Scale.prototype.convertTicksToLabels.call(this);
// Point labels
this.pointLabels = this.chart.data.labels.map(this.options.pointLabels.callback, this);
},
getLabelForIndex: function(index, datasetIndex) {
return +this.getRightValue(this.chart.data.datasets[datasetIndex].data[index]);
},
fit: function() {
/*
* Right, this is really confusing and there is a lot of maths going on here
* The gist of the problem is here: https://gist.github.com/nnnick/696cc9c55f4b0beb8fe9
*
* Reaction: https://dl.dropboxusercontent.com/u/34601363/toomuchscience.gif
*
* Solution:
*
* We assume the radius of the polygon is half the size of the canvas at first
* at each index we check if the text overlaps.
*
* Where it does, we store that angle and that index.
*
* After finding the largest index and angle we calculate how much we need to remove
* from the shape radius to move the point inwards by that x.
*
* We average the left and right distances to get the maximum shape radius that can fit in the box
* along with labels.
*
* Once we have that, we can find the centre point for the chart, by taking the x text protrusion
* on each side, removing that from the size, halving it and adding the left x protrusion width.
*
* This will mean we have a shape fitted to the canvas, as large as it can be with the labels
* and position it in the most space efficient manner
*
* https://dl.dropboxusercontent.com/u/34601363/yeahscience.gif
*/
var pointLabels = this.options.pointLabels;
var pointLabelFontSize = helpers.getValueOrDefault(pointLabels.fontSize, globalDefaults.defaultFontSize);
var pointLabeFontStyle = helpers.getValueOrDefault(pointLabels.fontStyle, globalDefaults.defaultFontStyle);
var pointLabeFontFamily = helpers.getValueOrDefault(pointLabels.fontFamily, globalDefaults.defaultFontFamily);
var pointLabeFont = helpers.fontString(pointLabelFontSize, pointLabeFontStyle, pointLabeFontFamily);
// Get maximum radius of the polygon. Either half the height (minus the text width) or half the width.
// Use this to calculate the offset + change. - Make sure L/R protrusion is at least 0 to stop issues with centre points
var largestPossibleRadius = helpers.min([(this.height / 2 - pointLabelFontSize - 5), this.width / 2]),
pointPosition,
i,
textWidth,
halfTextWidth,
furthestRight = this.width,
furthestRightIndex,
furthestRightAngle,
furthestLeft = 0,
furthestLeftIndex,
furthestLeftAngle,
xProtrusionLeft,
xProtrusionRight,
radiusReductionRight,
radiusReductionLeft,
maxWidthRadius;
this.ctx.font = pointLabeFont;
for (i = 0; i < this.getValueCount(); i++) {
// 5px to space the text slightly out - similar to what we do in the draw function.
pointPosition = this.getPointPosition(i, largestPossibleRadius);
textWidth = this.ctx.measureText(this.pointLabels[i] ? this.pointLabels[i] : '').width + 5;
if (i === 0 || i === this.getValueCount() / 2) {
// If we're at index zero, or exactly the middle, we're at exactly the top/bottom
// of the radar chart, so text will be aligned centrally, so we'll half it and compare
// w/left and right text sizes
halfTextWidth = textWidth / 2;
if (pointPosition.x + halfTextWidth > furthestRight) {
furthestRight = pointPosition.x + halfTextWidth;
furthestRightIndex = i;
}
if (pointPosition.x - halfTextWidth < furthestLeft) {
furthestLeft = pointPosition.x - halfTextWidth;
furthestLeftIndex = i;
}
} else if (i < this.getValueCount() / 2) {
// Less than half the values means we'll left align the text
if (pointPosition.x + textWidth > furthestRight) {
furthestRight = pointPosition.x + textWidth;
furthestRightIndex = i;
}
} else if (i > this.getValueCount() / 2) {
// More than half the values means we'll right align the text
if (pointPosition.x - textWidth < furthestLeft) {
furthestLeft = pointPosition.x - textWidth;
furthestLeftIndex = i;
}
}
}
xProtrusionLeft = furthestLeft;
xProtrusionRight = Math.ceil(furthestRight - this.width);
furthestRightAngle = this.getIndexAngle(furthestRightIndex);
furthestLeftAngle = this.getIndexAngle(furthestLeftIndex);
radiusReductionRight = xProtrusionRight / Math.sin(furthestRightAngle + Math.PI / 2);
radiusReductionLeft = xProtrusionLeft / Math.sin(furthestLeftAngle + Math.PI / 2);
// Ensure we actually need to reduce the size of the chart
radiusReductionRight = (helpers.isNumber(radiusReductionRight)) ? radiusReductionRight : 0;
radiusReductionLeft = (helpers.isNumber(radiusReductionLeft)) ? radiusReductionLeft : 0;
this.drawingArea = Math.round(largestPossibleRadius - (radiusReductionLeft + radiusReductionRight) / 2);
this.setCenterPoint(radiusReductionLeft, radiusReductionRight);
},
setCenterPoint: function(leftMovement, rightMovement) {
var maxRight = this.width - rightMovement - this.drawingArea,
maxLeft = leftMovement + this.drawingArea;
this.xCenter = Math.round(((maxLeft + maxRight) / 2) + this.left);
// Always vertically in the centre as the text height doesn't change
this.yCenter = Math.round((this.height / 2) + this.top);
},
getIndexAngle: function(index) {
var angleMultiplier = (Math.PI * 2) / this.getValueCount();
// Start from the top instead of right, so remove a quarter of the circle
return index * angleMultiplier - (Math.PI / 2);
},
getDistanceFromCenterForValue: function(value) {
if (value === null) {
return 0; // null always in center
}
// Take into account half font size + the yPadding of the top value
var scalingFactor = this.drawingArea / (this.max - this.min);
if (this.options.reverse) {
return (this.max - value) * scalingFactor;
} else {
return (value - this.min) * scalingFactor;
}
},
getPointPosition: function(index, distanceFromCenter) {
var thisAngle = this.getIndexAngle(index);
return {
x: Math.round(Math.cos(thisAngle) * distanceFromCenter) + this.xCenter,
y: Math.round(Math.sin(thisAngle) * distanceFromCenter) + this.yCenter
};
},
getPointPositionForValue: function(index, value) {
return this.getPointPosition(index, this.getDistanceFromCenterForValue(value));
},
getBasePosition: function() {
var me = this;
var min = me.min;
var max = me.max;
return me.getPointPositionForValue(0,
me.beginAtZero? 0:
min < 0 && max < 0? max :
min > 0 && max > 0? min :
0);
},
draw: function() {
if (this.options.display) {
var ctx = this.ctx;
helpers.each(this.ticks, function(label, index) {
// Don't draw a centre value (if it is minimum)
if (index > 0 || this.options.reverse) {
var yCenterOffset = this.getDistanceFromCenterForValue(this.ticks[index]);
var yHeight = this.yCenter - yCenterOffset;
// Draw circular lines around the scale
if (this.options.gridLines.display) {
ctx.strokeStyle = this.options.gridLines.color;
ctx.lineWidth = this.options.gridLines.lineWidth;
if (this.options.lineArc) {
// Draw circular arcs between the points
ctx.beginPath();
ctx.arc(this.xCenter, this.yCenter, yCenterOffset, 0, Math.PI * 2);
ctx.closePath();
ctx.stroke();
} else {
// Draw straight lines connecting each index
ctx.beginPath();
for (var i = 0; i < this.getValueCount(); i++) {
var pointPosition = this.getPointPosition(i, this.getDistanceFromCenterForValue(this.ticks[index]));
if (i === 0) {
ctx.moveTo(pointPosition.x, pointPosition.y);
} else {
ctx.lineTo(pointPosition.x, pointPosition.y);
}
}
ctx.closePath();
ctx.stroke();
}
}
if (this.options.ticks.display) {
var tickFontColor = helpers.getValueOrDefault(this.options.ticks.fontColor, globalDefaults.defaultFontColor);
var tickFontSize = helpers.getValueOrDefault(this.options.ticks.fontSize, globalDefaults.defaultFontSize);
var tickFontStyle = helpers.getValueOrDefault(this.options.ticks.fontStyle, globalDefaults.defaultFontStyle);
var tickFontFamily = helpers.getValueOrDefault(this.options.ticks.fontFamily, globalDefaults.defaultFontFamily);
var tickLabelFont = helpers.fontString(tickFontSize, tickFontStyle, tickFontFamily);
ctx.font = tickLabelFont;
if (this.options.ticks.showLabelBackdrop) {
var labelWidth = ctx.measureText(label).width;
ctx.fillStyle = this.options.ticks.backdropColor;
ctx.fillRect(
this.xCenter - labelWidth / 2 - this.options.ticks.backdropPaddingX,
yHeight - tickFontSize / 2 - this.options.ticks.backdropPaddingY,
labelWidth + this.options.ticks.backdropPaddingX * 2,
tickFontSize + this.options.ticks.backdropPaddingY * 2
);
}
ctx.textAlign = 'center';
ctx.textBaseline = "middle";
ctx.fillStyle = tickFontColor;
ctx.fillText(label, this.xCenter, yHeight);
}
}
}, this);
if (!this.options.lineArc) {
ctx.lineWidth = this.options.angleLines.lineWidth;
ctx.strokeStyle = this.options.angleLines.color;
for (var i = this.getValueCount() - 1; i >= 0; i--) {
if (this.options.angleLines.display) {
var outerPosition = this.getPointPosition(i, this.getDistanceFromCenterForValue(this.options.reverse ? this.min : this.max));
ctx.beginPath();
ctx.moveTo(this.xCenter, this.yCenter);
ctx.lineTo(outerPosition.x, outerPosition.y);
ctx.stroke();
ctx.closePath();
}
// Extra 3px out for some label spacing
var pointLabelPosition = this.getPointPosition(i, this.getDistanceFromCenterForValue(this.options.reverse ? this.min : this.max) + 5);
var pointLabelFontColor = helpers.getValueOrDefault(this.options.pointLabels.fontColor, globalDefaults.defaultFontColor);
var pointLabelFontSize = helpers.getValueOrDefault(this.options.pointLabels.fontSize, globalDefaults.defaultFontSize);
var pointLabeFontStyle = helpers.getValueOrDefault(this.options.pointLabels.fontStyle, globalDefaults.defaultFontStyle);
var pointLabeFontFamily = helpers.getValueOrDefault(this.options.pointLabels.fontFamily, globalDefaults.defaultFontFamily);
var pointLabeFont = helpers.fontString(pointLabelFontSize, pointLabeFontStyle, pointLabeFontFamily);
ctx.font = pointLabeFont;
ctx.fillStyle = pointLabelFontColor;
var labelsCount = this.pointLabels.length,
halfLabelsCount = this.pointLabels.length / 2,
quarterLabelsCount = halfLabelsCount / 2,
upperHalf = (i < quarterLabelsCount || i > labelsCount - quarterLabelsCount),
exactQuarter = (i === quarterLabelsCount || i === labelsCount - quarterLabelsCount);
if (i === 0) {
ctx.textAlign = 'center';
} else if (i === halfLabelsCount) {
ctx.textAlign = 'center';
} else if (i < halfLabelsCount) {
ctx.textAlign = 'left';
} else {
ctx.textAlign = 'right';
}
// Set the correct text baseline based on outer positioning
if (exactQuarter) {
ctx.textBaseline = 'middle';
} else if (upperHalf) {
ctx.textBaseline = 'bottom';
} else {
ctx.textBaseline = 'top';
}
ctx.fillText(this.pointLabels[i] ? this.pointLabels[i] : '', pointLabelPosition.x, pointLabelPosition.y);
}
}
}
}
});
Chart.scaleService.registerScaleType("radialLinear", LinearRadialScale, defaultConfig);
};
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