ChartJS - 在工具提示中显示单行数据
我正在使用chartJS库，并尝试弄清楚我需要做些什么才能在工具提示中显示单行数据。
例如，
我在这里的蓝线上空盘旋，看到那个标记处的每个数据点。我想做的是仅查看蓝线的所有三个数据点。
我从chart js tooltip how to control the data that show
取得了一些进展 getPointsAtEvent: function(e) {
var pointsArray = [], eventPosition = helpers.getRelativePosition(e);
var breakLoop = 0;
helpers.each(this.datasets, function(dataset) {
helpers.each(dataset.points, function(point) {
if (point.inRange(eventPosition.x, eventPosition.y) && point.showTooltip && !point.ignore) {
if(eventPosition.y + 2 >= point.y && eventPosition.y - 2 <= point.y) {
pointsArray.push(point);
breakLoop = 1;
return false;
}
}
});
if(breakLoop) {
return false;
}
}, this);
//console.log(pointsArray);
return pointsArray;
},
我的图表修改是否会在图表上返回1个数据点。我假设下一步是覆盖showToolTip方法。
2 个答案:
答案 0 :(得分：0)
如果您扩展折线图，请使用我上面的代码，并且下面粘贴的代码可以在某种程度上获得所需的效果。
showTooltip: function(ChartElements, forceRedraw) { //custom edit
//we will get value from ChartElements (which should be only 1 element long in this case) and use it to match the line row we want to see.
try {
var numMatch = ChartElements[0].value;
}
catch(err) {
var isChanged = (function(Elements) {
var changed = true;
return changed;
}).call(this, ChartElements);
}
// 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;
}
helpers.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 (this.options.customTooltips) {
this.options.customTooltips(false);
}
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 = helpers.indexOf(dataArray, ChartElements[0]);
if (dataIndex !== -1) {
break;
}
}
var eleLast = "";
var eleFirst = "";
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;
//console.log(dataset);
for(i = 0; i < dataset.points.length; i++) {
if(dataset.points[i].value === numMatch) {
for(var k = 0; k < dataset.points.length; k++) {
Elements.push(dataset.points[k]);
}
}
}
});
//save elements last label string
eleLast = Elements[Elements.length-1].label;
eleFirst = Elements[0].label;
//console.log(Elements);
helpers.each(Elements, function(element) {
if(element.value === numMatch) {
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 = helpers.min(yPositions);
yMax = helpers.max(yPositions);
xMin = helpers.min(xPositions);
xMax = helpers.max(xPositions);
return {
x: (xMin > this.chart.width / 2) ? xMin : xMax,
y: (yMin + yMax) / 2
};
}).call(this, dataIndex);
var newLabel = eleFirst + " to " + eleLast;
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: newLabel,
chart: this.chart,
ctx: this.chart.ctx,
custom: this.options.customTooltips
}).draw();
} else {
helpers.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: helpers.template(this.options.tooltipTemplate, Element),
chart: this.chart,
custom: this.options.customTooltips
}).draw();
}, this);
}
}
return this;
},
显然，这只是一个快速而肮脏的修复，如果我有更多时间来处理它，我希望每个数据点都显示其相应的值。
答案 1 :(得分：0)
如果这是您拥有的唯一图表（即因为以下代码更改了某些全局chart.js元素），您可以使用以下代码
var originalMultiTooltip = Chart.MultiTooltip;
Chart.MultiTooltip = function () {
var argument = arguments[0];
// locate the series using the active point
var activeDatasetLabel = myChart.activeElements[0].datasetLabel;
myChart.datasets.forEach(function (dataset) {
if (dataset.label === activeDatasetLabel) {
// swap out the labels and colors in arguments
argument.labels = dataset.points.map(function (point) { return point.value; });
argument.legendColors = dataset.points.map(function (point) {
return {
fill: point._saved.fillColor || point.fillColor,
stroke: point._saved.strokeColor || point.strokeColor
};
});
argument.title = activeDatasetLabel;
// position it near the active point
argument.y = myChart.activeElements[0].y;
}
})
return new originalMultiTooltip(arguments[0]);
}
// this distance function returns the square of the distance if within detection range, otherwise it returns Infinity
var distance = function (chartX, chartY) {
var hitDetectionRange = this.hitDetectionRadius + this.radius;
var distance = Math.pow(chartX - this.x, 2) + Math.pow(chartY - this.y, 2);
return (distance < Math.pow(hitDetectionRange, 2)) ? distance : Infinity;
}
myChart.getPointsAtEvent = function (e) {
var pointsArray = [],
eventPosition = Chart.helpers.getRelativePosition(e);
var leastDistance = Infinity;
Chart.helpers.each(myChart.datasets, function (dataset) {
Chart.helpers.each(dataset.points, function (point) {
// our active point is the one closest to the hover event
var pointDistance = distance.call(point, eventPosition.x, eventPosition.y)
if (isFinite(pointDistance) && pointDistance < leastDistance) {
leastDistance = pointDistance;
pointsArray = [ point ];
}
});
}, myChart);
return pointsArray;
}
它做了两件事
- 取代
getPointsAtEvent只选择一个点 - 包装
MultiTooltip构造函数以换出与活动点系列中的所有值一起传递的值列表。
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