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To achieve this you can extend the line graph to add an option to show/hide tool-tips on a per dataset basses. The annoying thing is there are only a few changes but whole methods have to be overridden to get the changes in there so the below looks like a lot but its basically 3 changes to the following methods
-
Initialize – added option to store showTooltip option in each point
-
getPointsAtEvent – added check to make sure we want to disaply a tool tip when getting points
-
showTooltip – added check again to make sure we want to dispaly a tool tip
to then use it the chart is set up the same but instead you make it a LineTooltip (thats what i have called the extended chart) and pass anextra option in the datasets call showToolip.
datasets: [{
label: "My First dataset",
fillColor: "rgba(220,220,220,0.5)",
strokeColor: "rgba(220,220,220,0.8)",
highlightFill: "rgba(220,220,220,0.75)",
highlightStroke: "rgba(220,220,220,1)",
showTooltip: false, //NEW OPTION DON"T NEED TO INCLUDE IT IF YOU WANT TO DISPLAY BUT WON"T HURT IF YOU DO
data: [15, 10, 10, 10, 10, 10, 10]
}, {
label: "My second dataset",
fillColor: "rgba(220,220,220,0.5)",
strokeColor: "rgba(220,220,220,0.8)",
highlightFill: "rgba(220,220,220,0.75)",
highlightStroke: "rgba(220,220,220,1)",
showTooltip: false, //NEW OPTION DON"T NEED TO INCLUDE IT IF YOU WANT TO DISPLAY BUT WON"T HURT IF YOU DO
data: [100, 100, 100, 100, 100, 100, 100]
}, {
label: "My third dataset",
fillColor: "rgba(151,187,205,0.5)",
strokeColor: "rgba(151,187,205,0.8)",
highlightFill: "rgba(151,187,205,0.75)",
highlightStroke: "rgba(151,187,205,1)",
data: [28, 48, 40, 19, 86, 27, 90]
}]
i have added bigger comment banners in the below code to try and highlight where the changes got made. I have also added this feature to my fork of chartjs as this could be useful to more people https://github.com/leighquince/Chart.js, using this you can just use a normal line chart and add the showTooltip
Below is the example of extending the Line into a custom chart to include this feature, ive called in LineTooltip as but could be called anything you like that.
Chart.types.Line.extend({
name: "LineTooltip",
/*
* we have to add one item in the init so need to rewrite it again here with the one edit
*/
initialize: function(data) {
//have to get the helpers as we are using this outside chart where it was declared
var helpers = Chart.helpers;
//Declare the extension of the default point, to cater for the options passed in to the constructor
this.PointClass = Chart.Point.extend({
strokeWidth: this.options.pointDotStrokeWidth,
radius: this.options.pointDotRadius,
display: this.options.pointDot,
hitDetectionRadius: this.options.pointHitDetectionRadius,
ctx: this.chart.ctx,
inRange: function(mouseX) {
return (Math.pow(mouseX - this.x, 2) < Math.pow(this.radius + this.hitDetectionRadius, 2));
}
});
this.datasets = [];
//Set up tooltip events on the chart
if (this.options.showTooltips) {
helpers.bindEvents(this, this.options.tooltipEvents, function(evt) {
var activePoints = (evt.type !== 'mouseout') ? this.getPointsAtEvent(evt) : [];
this.eachPoints(function(point) {
point.restore(['fillColor', 'strokeColor']);
});
helpers.each(activePoints, function(activePoint) {
activePoint.fillColor = activePoint.highlightFill;
activePoint.strokeColor = activePoint.highlightStroke;
});
this.showTooltip(activePoints);
});
}
//Iterate through each of the datasets, and build this into a property of the chart
helpers.each(data.datasets, function(dataset) {
var datasetObject = {
label: dataset.label || null,
fillColor: dataset.fillColor,
strokeColor: dataset.strokeColor,
pointColor: dataset.pointColor,
pointStrokeColor: dataset.pointStrokeColor,
showTooltip: dataset.showTooltip,
points: []
};
this.datasets.push(datasetObject);
helpers.each(dataset.data, function(dataPoint, index) {
//Add a new point for each piece of data, passing any required data to draw.
datasetObject.points.push(new this.PointClass({
/*
* set wether to show the tooltip or not, left this as being able to be undfined
* and default to true
*/
showTooltip: dataset.showTooltip === undefined ? true : dataset.showTooltip,
value: dataPoint,
label: data.labels[index],
datasetLabel: dataset.label,
strokeColor: dataset.pointStrokeColor,
fillColor: dataset.pointColor,
highlightFill: dataset.pointHighlightFill || dataset.pointColor,
highlightStroke: dataset.pointHighlightStroke || dataset.pointStrokeColor
}));
}, this);
this.buildScale(data.labels);
this.eachPoints(function(point, index) {
helpers.extend(point, {
x: this.scale.calculateX(index),
y: this.scale.endPoint
});
point.save();
}, this);
}, this);
this.render();
},
/*
* need to edit how points at event works so it only uses points that we want to show the tool tip for
*/
getPointsAtEvent: function(e) {
//have to get the helpers as we are using this outside chart where it was declared
var helpers = Chart.helpers;
var pointsArray = [],
eventPosition = helpers.getRelativePosition(e);
helpers.each(this.datasets, function(dataset) {
helpers.each(dataset.points, function(point) {
if (point.inRange(eventPosition.x, eventPosition.y) && point.showTooltip) pointsArray.push(point);
});
}, this);
return pointsArray;
},
/*
* also need to change how the core showTooltip functions as otherwise, it trys to be helpful
* and grab any points it thinks also need to be displayed
*/
showTooltip: function(ChartElements, forceRedraw) {
//have to get the helpers as we are using this outside chart where it was declared
var helpers = Chart.helpers;
var each = helpers.each;
var indexOf = helpers.indexOf;
var min = helpers.min;
var max = helpers.min;
// Only redraw the chart if we've actually changed what we're hovering on.
if (typeof this.activeElements === 'undefined') this.activeElements = [];
var isChanged = (function(Elements) {
var changed = false;
if (Elements.length !== this.activeElements.length) {
changed = true;
return changed;
}
each(Elements, function(element, index) {
if (element !== this.activeElements[index]) {
changed = true;
}
}, this);
return changed;
}).call(this, ChartElements);
if (!isChanged && !forceRedraw) {
return;
} else {
this.activeElements = ChartElements;
}
this.draw();
if (ChartElements.length > 0) {
// If we have multiple datasets, show a MultiTooltip for all of the data points at that index
if (this.datasets && this.datasets.length > 1) {
var dataArray,
dataIndex;
for (var i = this.datasets.length - 1; i >= 0; i--) {
dataArray = this.datasets[i].points || this.datasets[i].bars || this.datasets[i].segments;
dataIndex = indexOf(dataArray, ChartElements[0]);
if (dataIndex !== -1) {
break;
}
}
var tooltipLabels = [],
tooltipColors = [],
medianPosition = (function(index) {
// Get all the points at that particular index
var Elements = [],
dataCollection,
xPositions = [],
yPositions = [],
xMax,
yMax,
xMin,
yMin;
helpers.each(this.datasets, function(dataset) {
dataCollection = dataset.points || dataset.bars || dataset.segments;
/*
*check to make sure we want to show the point
*/
if (dataCollection[dataIndex] && dataCollection[dataIndex].hasValue() && (dataCollection[dataIndex].showTooltip === undefined || dataCollection[dataIndex].showTooltip)) {
Elements.push(dataCollection[dataIndex]);
}
});
helpers.each(Elements, function(element) {
xPositions.push(element.x);
yPositions.push(element.y);
//Include any colour information about the element
tooltipLabels.push(helpers.template(this.options.multiTooltipTemplate, element));
tooltipColors.push({
fill: element._saved.fillColor || element.fillColor,
stroke: element._saved.strokeColor || element.strokeColor
});
}, this);
yMin = min(yPositions);
yMax = max(yPositions);
xMin = min(xPositions);
xMax = max(xPositions);
return {
x: (xMin > this.chart.width / 2) ? xMin : xMax,
y: (yMin + yMax) / 2
};
}).call(this, dataIndex);
new Chart.MultiTooltip({
x: medianPosition.x,
y: medianPosition.y,
xPadding: this.options.tooltipXPadding,
yPadding: this.options.tooltipYPadding,
xOffset: this.options.tooltipXOffset,
fillColor: this.options.tooltipFillColor,
textColor: this.options.tooltipFontColor,
fontFamily: this.options.tooltipFontFamily,
fontStyle: this.options.tooltipFontStyle,
fontSize: this.options.tooltipFontSize,
titleTextColor: this.options.tooltipTitleFontColor,
titleFontFamily: this.options.tooltipTitleFontFamily,
titleFontStyle: this.options.tooltipTitleFontStyle,
titleFontSize: this.options.tooltipTitleFontSize,
cornerRadius: this.options.tooltipCornerRadius,
labels: tooltipLabels,
legendColors: tooltipColors,
legendColorBackground: this.options.multiTooltipKeyBackground,
title: ChartElements[0].label,
chart: this.chart,
ctx: this.chart.ctx
}).draw();
} else {
each(ChartElements, function(Element) {
var tooltipPosition = Element.tooltipPosition();
new Chart.Tooltip({
x: Math.round(tooltipPosition.x),
y: Math.round(tooltipPosition.y),
xPadding: this.options.tooltipXPadding,
yPadding: this.options.tooltipYPadding,
fillColor: this.options.tooltipFillColor,
textColor: this.options.tooltipFontColor,
fontFamily: this.options.tooltipFontFamily,
fontStyle: this.options.tooltipFontStyle,
fontSize: this.options.tooltipFontSize,
caretHeight: this.options.tooltipCaretSize,
cornerRadius: this.options.tooltipCornerRadius,
text: template(this.options.tooltipTemplate, Element),
chart: this.chart
}).draw();
}, this);
}
}
return this;
},
});
var ctx = document.getElementById("chart").getContext("2d");
var data = {
labels: ["January", "February", "March", "April", "May", "June", "July"],
datasets: [{
label: "My First dataset",
fillColor: "rgba(220,220,220,0.5)",
strokeColor: "rgba(220,220,220,0.8)",
highlightFill: "rgba(220,220,220,0.75)",
highlightStroke: "rgba(220,220,220,1)",
showTooltip: false, //TO USE JUST ADD THIS NEW OPTION ONLY REALLY NEEDS TO PRESENT IF SETTING TO FALSE
data: [15, 10, 10, 10, 10, 10, 10]
}, {
label: "My second dataset",
fillColor: "rgba(220,220,220,0.5)",
strokeColor: "rgba(220,220,220,0.8)",
highlightFill: "rgba(220,220,220,0.75)",
highlightStroke: "rgba(220,220,220,1)",
showTooltip: false, //TO USE JUST ADD THIS NEW OPTION ONLY REALLY NEEDS TO PRESENT IF SETTING TO FALSE
data: [100, 100, 100, 100, 100, 100, 100]
}, {
label: "My third dataset",
fillColor: "rgba(151,187,205,0.5)",
strokeColor: "rgba(151,187,205,0.8)",
highlightFill: "rgba(151,187,205,0.75)",
highlightStroke: "rgba(151,187,205,1)",
data: [28, 48, 40, 19, 86, 27, 90]
}]
};
var myBarChart = new Chart(ctx).LineTooltip(data);<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/1.0.2/Chart.min.js"></script>
<canvas id="chart" width="600px"></canvas>and a fiddle if you find that easy to view http://jsfiddle.net/leighking2/1Lammwpt/
Source:stackexchange.com