mirror of
https://github.com/chartjs/Chart.js.git
synced 2024-10-07 20:59:08 +02:00
559ee6291e
Better linear scale tick formatter + small tick generation
561 lines
19 KiB
JavaScript
561 lines
19 KiB
JavaScript
(function() {
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"use strict";
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var root = this,
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Chart = root.Chart,
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helpers = Chart.helpers;
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Chart.defaults.scale = {
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display: true,
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// grid line settings
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gridLines: {
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show: true,
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color: "rgba(0, 0, 0, 0.1)",
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lineWidth: 1,
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drawOnChartArea: true,
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drawTicks: true,
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zeroLineWidth: 1,
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zeroLineColor: "rgba(0,0,0,0.25)",
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offsetGridLines: false,
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},
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// scale label
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scaleLabel: {
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fontColor: '#666',
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fontFamily: 'Helvetica Neue',
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fontSize: 12,
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fontStyle: 'normal',
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// actual label
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labelString: '',
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// display property
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show: false,
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},
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// label settings
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ticks: {
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beginAtZero: false,
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fontSize: 12,
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fontStyle: "normal",
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fontColor: "#666",
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fontFamily: "Helvetica Neue",
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maxRotation: 90,
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minRotation: 20,
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mirror: false,
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padding: 10,
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reverse: false,
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show: true,
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callback: function(value) {
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return '' + value;
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},
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},
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};
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Chart.Scale = Chart.Element.extend({
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// These methods are ordered by lifecyle. Utilities then follow.
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// Any function defined here is inherited by all scale types.
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// Any function can be extended by the scale type
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beforeUpdate: helpers.noop,
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update: function(maxWidth, maxHeight, margins) {
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// Update Lifecycle - Probably don't want to ever extend or overwrite this function ;)
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this.beforeUpdate();
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// Absorb the master measurements
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this.maxWidth = maxWidth;
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this.maxHeight = maxHeight;
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this.margins = margins;
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// Dimensions
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this.beforeSetDimensions();
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this.setDimensions();
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this.afterSetDimensions();
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// Ticks
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this.beforeBuildTicks();
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this.buildTicks();
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this.afterBuildTicks();
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this.beforeTickToLabelConversion();
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this.convertTicksToLabels();
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this.afterTickToLabelConversion();
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// Tick Rotation
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this.beforeCalculateTickRotation();
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this.calculateTickRotation();
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this.afterCalculateTickRotation();
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// Fit
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this.beforeFit();
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this.fit();
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this.afterFit();
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//
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this.afterUpdate();
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return this.minSize;
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},
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afterUpdate: helpers.noop,
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//
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beforeSetDimensions: helpers.noop,
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setDimensions: function() {
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// Set the unconstrained dimension before label rotation
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if (this.isHorizontal()) {
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// Reset position before calculating rotation
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this.width = this.maxWidth;
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this.left = 0;
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this.right = this.width;
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} else {
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this.height = this.maxHeight;
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// Reset position before calculating rotation
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this.top = 0;
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this.bottom = this.height;
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}
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// Reset padding
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this.paddingLeft = 0;
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this.paddingTop = 0;
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this.paddingRight = 0;
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this.paddingBottom = 0;
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},
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afterSetDimensions: helpers.noop,
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//
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beforeBuildTicks: helpers.noop,
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buildTicks: helpers.noop,
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afterBuildTicks: helpers.noop,
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beforeTickToLabelConversion: helpers.noop,
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convertTicksToLabels: function() {
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// Convert ticks to strings
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this.ticks = this.ticks.map(function(numericalTick, index, ticks) {
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if (this.options.ticks.userCallback) {
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return this.options.ticks.userCallback(numericalTick, index, ticks);
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}
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return this.options.ticks.callback(numericalTick, index, ticks);
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},
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this);
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},
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afterTickToLabelConversion: helpers.noop,
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//
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beforeCalculateTickRotation: helpers.noop,
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calculateTickRotation: function() {
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//Get the width of each grid by calculating the difference
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//between x offsets between 0 and 1.
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var labelFont = helpers.fontString(this.options.ticks.fontSize, this.options.ticks.fontStyle, this.options.ticks.fontFamily);
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this.ctx.font = labelFont;
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var firstWidth = this.ctx.measureText(this.ticks[0]).width;
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var lastWidth = this.ctx.measureText(this.ticks[this.ticks.length - 1]).width;
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var firstRotated;
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var lastRotated;
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this.paddingRight = lastWidth / 2 + 3;
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this.paddingLeft = firstWidth / 2 + 3;
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this.labelRotation = 0;
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if (this.options.display && this.isHorizontal()) {
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var originalLabelWidth = helpers.longestText(this.ctx, labelFont, this.ticks);
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var cosRotation;
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var sinRotation;
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var firstRotatedWidth;
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this.labelWidth = originalLabelWidth;
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// Allow 3 pixels x2 padding either side for label readability
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// only the index matters for a dataset scale, but we want a consistent interface between scales
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var tickWidth = this.getPixelForTick(1) - this.getPixelForTick(0) - 6;
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//Max label rotation can be set or default to 90 - also act as a loop counter
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while (this.labelWidth > tickWidth && this.labelRotation <= this.options.ticks.maxRotation) {
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cosRotation = Math.cos(helpers.toRadians(this.labelRotation));
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sinRotation = Math.sin(helpers.toRadians(this.labelRotation));
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firstRotated = cosRotation * firstWidth;
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lastRotated = cosRotation * lastWidth;
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// We're right aligning the text now.
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if (firstRotated + this.options.ticks.fontSize / 2 > this.yLabelWidth) {
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this.paddingLeft = firstRotated + this.options.ticks.fontSize / 2;
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}
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this.paddingRight = this.options.ticks.fontSize / 2;
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if (sinRotation * originalLabelWidth > this.maxHeight) {
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// go back one step
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this.labelRotation--;
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break;
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}
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this.labelRotation++;
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this.labelWidth = cosRotation * originalLabelWidth;
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}
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} else {
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this.labelWidth = 0;
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this.paddingRight = 0;
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this.paddingLeft = 0;
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}
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if (this.margins) {
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this.paddingLeft -= this.margins.left;
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this.paddingRight -= this.margins.right;
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this.paddingLeft = Math.max(this.paddingLeft, 0);
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this.paddingRight = Math.max(this.paddingRight, 0);
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}
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},
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afterCalculateTickRotation: helpers.noop,
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//
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beforeFit: helpers.noop,
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fit: function() {
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this.minSize = {
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width: 0,
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height: 0,
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};
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// Width
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if (this.isHorizontal()) {
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this.minSize.width = this.maxWidth; // fill all the width
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} else {
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this.minSize.width = this.options.gridLines.show && this.options.display ? 10 : 0;
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}
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// height
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if (this.isHorizontal()) {
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this.minSize.height = this.options.gridLines.show && this.options.display ? 10 : 0;
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} else {
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this.minSize.height = this.maxHeight; // fill all the height
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}
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// Are we showing a title for the scale?
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if (this.options.scaleLabel.show) {
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if (this.isHorizontal()) {
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this.minSize.height += (this.options.scaleLabel.fontSize * 1.5);
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} else {
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this.minSize.width += (this.options.scaleLabel.fontSize * 1.5);
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}
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}
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if (this.options.ticks.show && this.options.display) {
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// Don't bother fitting the ticks if we are not showing them
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var labelFont = helpers.fontString(this.options.ticks.fontSize,
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this.options.ticks.fontStyle, this.options.ticks.fontFamily);
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if (this.isHorizontal()) {
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// A horizontal axis is more constrained by the height.
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var maxLabelHeight = this.maxHeight - this.minSize.height;
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var longestLabelWidth = helpers.longestText(this.ctx, labelFont, this.ticks);
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var labelHeight = (Math.sin(helpers.toRadians(this.labelRotation)) * longestLabelWidth) + 1.5 * this.options.ticks.fontSize;
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this.minSize.height = Math.min(this.maxHeight, this.minSize.height + labelHeight);
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labelFont = helpers.fontString(this.options.ticks.fontSize, this.options.ticks.fontStyle, this.options.ticks.fontFamily);
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this.ctx.font = labelFont;
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var firstLabelWidth = this.ctx.measureText(this.ticks[0]).width;
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var lastLabelWidth = this.ctx.measureText(this.ticks[this.ticks.length - 1]).width;
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// Ensure that our ticks are always inside the canvas. When rotated, ticks are right aligned which means that the right padding is dominated
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// by the font height
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var cosRotation = Math.cos(helpers.toRadians(this.labelRotation));
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var sinRotation = Math.sin(helpers.toRadians(this.labelRotation));
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this.paddingLeft = this.labelRotation !== 0 ? (cosRotation * firstLabelWidth) + 3 : firstLabelWidth / 2 + 3; // add 3 px to move away from canvas edges
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this.paddingRight = this.labelRotation !== 0 ? (sinRotation * (this.options.ticks.fontSize / 2)) + 3 : lastLabelWidth / 2 + 3; // when rotated
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} else {
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// A vertical axis is more constrained by the width. Labels are the dominant factor here, so get that length first
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var maxLabelWidth = this.maxWidth - this.minSize.width;
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var largestTextWidth = helpers.longestText(this.ctx, labelFont, this.ticks);
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if (largestTextWidth < maxLabelWidth) {
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// We don't need all the room
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this.minSize.width += largestTextWidth;
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} else {
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// Expand to max size
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this.minSize.width = this.maxWidth;
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}
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this.paddingTop = this.options.ticks.fontSize / 2;
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this.paddingBottom = this.options.ticks.fontSize / 2;
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}
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}
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if (this.margins) {
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this.paddingLeft -= this.margins.left;
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this.paddingTop -= this.margins.top;
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this.paddingRight -= this.margins.right;
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this.paddingBottom -= this.margins.bottom;
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this.paddingLeft = Math.max(this.paddingLeft, 0);
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this.paddingTop = Math.max(this.paddingTop, 0);
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this.paddingRight = Math.max(this.paddingRight, 0);
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this.paddingBottom = Math.max(this.paddingBottom, 0);
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}
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this.width = this.minSize.width;
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this.height = this.minSize.height;
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},
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afterFit: helpers.noop,
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// Shared Methods
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isHorizontal: function() {
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return this.options.position == "top" || this.options.position == "bottom";
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},
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// Get the correct value. NaN bad inputs, If the value type is object get the x or y based on whether we are horizontal or not
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getRightValue: function getRightValue(rawValue) {
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// Null and undefined values first
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if (rawValue === null || typeof(rawValue) === 'undefined') {
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return NaN;
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}
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// isNaN(object) returns true, so make sure NaN is checking for a number
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if (typeof(rawValue) === 'number' && isNaN(rawValue)) {
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return NaN;
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}
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// If it is in fact an object, dive in one more level
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if (typeof(rawValue) === "object") {
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return getRightValue(this.isHorizontal() ? rawValue.x : rawValue.y);
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}
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// Value is good, return it
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return rawValue;
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},
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// Used to get the value to display in the tooltip for the data at the given index
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// function getLabelForIndex(index, datasetIndex)
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getLabelForIndex: helpers.noop,
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// Used to get data value locations. Value can either be an index or a numerical value
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getPixelForValue: helpers.noop,
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// Used for tick location, should
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getPixelForTick: function(index, includeOffset) {
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if (this.isHorizontal()) {
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var innerWidth = this.width - (this.paddingLeft + this.paddingRight);
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var tickWidth = innerWidth / Math.max((this.ticks.length - ((this.options.gridLines.offsetGridLines) ? 0 : 1)), 1);
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var pixel = (tickWidth * index) + this.paddingLeft;
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if (includeOffset) {
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pixel += tickWidth / 2;
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}
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return this.left + Math.round(pixel);
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} else {
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var innerHeight = this.height - (this.paddingTop + this.paddingBottom);
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return this.top + (index * (innerHeight / (this.ticks.length - 1)));
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}
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},
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// Utility for getting the pixel location of a percentage of scale
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getPixelForDecimal: function(decimal, includeOffset) {
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if (this.isHorizontal()) {
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var innerWidth = this.width - (this.paddingLeft + this.paddingRight);
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var valueOffset = (innerWidth * decimal) + this.paddingLeft;
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return this.left + Math.round(valueOffset);
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} else {
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return this.top + (decimal * this.height);
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}
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},
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// Actualy draw the scale on the canvas
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// @param {rectangle} chartArea : the area of the chart to draw full grid lines on
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draw: function(chartArea) {
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if (this.options.display) {
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var setContextLineSettings;
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var isRotated = this.labelRotation !== 0;
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var skipRatio;
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var scaleLabelX;
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var scaleLabelY;
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// Make sure we draw text in the correct color and font
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this.ctx.fillStyle = this.options.ticks.fontColor;
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var labelFont = helpers.fontString(this.options.ticks.fontSize, this.options.ticks.fontStyle, this.options.ticks.fontFamily);
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if (this.isHorizontal()) {
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setContextLineSettings = true;
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var yTickStart = this.options.position == "bottom" ? this.top : this.bottom - 10;
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var yTickEnd = this.options.position == "bottom" ? this.top + 10 : this.bottom;
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skipRatio = false;
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if ((this.options.ticks.fontSize + 4) * this.ticks.length > (this.width - (this.paddingLeft + this.paddingRight))) {
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skipRatio = 1 + Math.floor(((this.options.ticks.fontSize + 4) * this.ticks.length) / (this.width - (this.paddingLeft + this.paddingRight)));
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}
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helpers.each(this.ticks, function(label, index) {
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// Blank ticks
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if ((skipRatio > 1 && index % skipRatio > 0) || (label === undefined || label === null)) {
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return;
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}
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var xLineValue = this.getPixelForTick(index); // xvalues for grid lines
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var xLabelValue = this.getPixelForTick(index, this.options.gridLines.offsetGridLines); // x values for ticks (need to consider offsetLabel option)
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if (this.options.gridLines.show) {
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if (index === (typeof this.zeroLineIndex !== 'undefined' ? this.zeroLineIndex : 0)) {
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// Draw the first index specially
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this.ctx.lineWidth = this.options.gridLines.zeroLineWidth;
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this.ctx.strokeStyle = this.options.gridLines.zeroLineColor;
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setContextLineSettings = true; // reset next time
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} else if (setContextLineSettings) {
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this.ctx.lineWidth = this.options.gridLines.lineWidth;
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this.ctx.strokeStyle = this.options.gridLines.color;
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setContextLineSettings = false;
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}
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xLineValue += helpers.aliasPixel(this.ctx.lineWidth);
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// Draw the label area
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this.ctx.beginPath();
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if (this.options.gridLines.drawTicks) {
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this.ctx.moveTo(xLineValue, yTickStart);
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this.ctx.lineTo(xLineValue, yTickEnd);
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}
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// Draw the chart area
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if (this.options.gridLines.drawOnChartArea) {
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this.ctx.moveTo(xLineValue, chartArea.top);
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this.ctx.lineTo(xLineValue, chartArea.bottom);
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}
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// Need to stroke in the loop because we are potentially changing line widths & colours
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this.ctx.stroke();
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}
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if (this.options.ticks.show) {
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this.ctx.save();
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this.ctx.translate(xLabelValue, (isRotated) ? this.top + 12 : this.options.position === "top" ? this.bottom - 10 : this.top + 10);
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this.ctx.rotate(helpers.toRadians(this.labelRotation) * -1);
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this.ctx.font = labelFont;
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this.ctx.textAlign = (isRotated) ? "right" : "center";
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this.ctx.textBaseline = (isRotated) ? "middle" : this.options.position === "top" ? "bottom" : "top";
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this.ctx.fillText(label, 0, 0);
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this.ctx.restore();
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}
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}, this);
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if (this.options.scaleLabel.show) {
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// Draw the scale label
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this.ctx.textAlign = "center";
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this.ctx.textBaseline = 'middle';
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this.ctx.fillStyle = this.options.scaleLabel.fontColor; // render in correct colour
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this.ctx.font = helpers.fontString(this.options.scaleLabel.fontSize, this.options.scaleLabel.fontStyle, this.options.scaleLabel.fontFamily);
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scaleLabelX = this.left + ((this.right - this.left) / 2); // midpoint of the width
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scaleLabelY = this.options.position == 'bottom' ? this.bottom - (this.options.scaleLabel.fontSize / 2) : this.top + (this.options.scaleLabel.fontSize / 2);
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this.ctx.fillText(this.options.scaleLabel.labelString, scaleLabelX, scaleLabelY);
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}
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} else {
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setContextLineSettings = true;
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var xTickStart = this.options.position == "right" ? this.left : this.right - 5;
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var xTickEnd = this.options.position == "right" ? this.left + 5 : this.right;
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helpers.each(this.ticks, function(label, index) {
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var yLineValue = this.getPixelForTick(index); // xvalues for grid lines
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if (this.options.gridLines.show) {
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if (index === (typeof this.zeroLineIndex !== 'undefined' ? this.zeroLineIndex : 0)) {
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// Draw the first index specially
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this.ctx.lineWidth = this.options.gridLines.zeroLineWidth;
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this.ctx.strokeStyle = this.options.gridLines.zeroLineColor;
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setContextLineSettings = true; // reset next time
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} else if (setContextLineSettings) {
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this.ctx.lineWidth = this.options.gridLines.lineWidth;
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this.ctx.strokeStyle = this.options.gridLines.color;
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setContextLineSettings = false;
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}
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yLineValue += helpers.aliasPixel(this.ctx.lineWidth);
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// Draw the label area
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this.ctx.beginPath();
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if (this.options.gridLines.drawTicks) {
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this.ctx.moveTo(xTickStart, yLineValue);
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this.ctx.lineTo(xTickEnd, yLineValue);
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}
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// Draw the chart area
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if (this.options.gridLines.drawOnChartArea) {
|
|
this.ctx.moveTo(chartArea.left, yLineValue);
|
|
this.ctx.lineTo(chartArea.right, yLineValue);
|
|
}
|
|
|
|
// Need to stroke in the loop because we are potentially changing line widths & colours
|
|
this.ctx.stroke();
|
|
}
|
|
|
|
if (this.options.ticks.show) {
|
|
var xLabelValue;
|
|
var yLabelValue = this.getPixelForTick(index, this.options.gridLines.offsetGridLines); // x values for ticks (need to consider offsetLabel option)
|
|
|
|
this.ctx.save();
|
|
|
|
if (this.options.position == "left") {
|
|
if (this.options.ticks.mirror) {
|
|
xLabelValue = this.right + this.options.ticks.padding;
|
|
this.ctx.textAlign = "left";
|
|
} else {
|
|
xLabelValue = this.right - this.options.ticks.padding;
|
|
this.ctx.textAlign = "right";
|
|
}
|
|
} else {
|
|
// right side
|
|
if (this.options.ticks.mirror) {
|
|
xLabelValue = this.left - this.options.ticks.padding;
|
|
this.ctx.textAlign = "right";
|
|
} else {
|
|
xLabelValue = this.left + this.options.ticks.padding;
|
|
this.ctx.textAlign = "left";
|
|
}
|
|
}
|
|
|
|
|
|
this.ctx.translate(xLabelValue, yLabelValue);
|
|
this.ctx.rotate(helpers.toRadians(this.labelRotation) * -1);
|
|
this.ctx.font = labelFont;
|
|
this.ctx.textBaseline = "middle";
|
|
this.ctx.fillText(label, 0, 0);
|
|
this.ctx.restore();
|
|
}
|
|
}, this);
|
|
|
|
if (this.options.scaleLabel.show) {
|
|
// Draw the scale label
|
|
scaleLabelX = this.options.position == 'left' ? this.left + (this.options.scaleLabel.fontSize / 2) : this.right - (this.options.scaleLabel.fontSize / 2);
|
|
scaleLabelY = this.top + ((this.bottom - this.top) / 2);
|
|
var rotation = this.options.position == 'left' ? -0.5 * Math.PI : 0.5 * Math.PI;
|
|
|
|
this.ctx.save();
|
|
this.ctx.translate(scaleLabelX, scaleLabelY);
|
|
this.ctx.rotate(rotation);
|
|
this.ctx.textAlign = "center";
|
|
this.ctx.fillStyle = this.options.scaleLabel.fontColor; // render in correct colour
|
|
this.ctx.font = helpers.fontString(this.options.scaleLabel.fontSize, this.options.scaleLabel.fontStyle, this.options.scaleLabel.fontFamily);
|
|
this.ctx.textBaseline = 'middle';
|
|
this.ctx.fillText(this.options.scaleLabel.labelString, 0, 0);
|
|
this.ctx.restore();
|
|
}
|
|
}
|
|
}
|
|
}
|
|
});
|
|
|
|
}).call(this);
|