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