11👍
✅
You would need to extend the scale class and override the calculateXLabelRotation method to use a user inputted rotation rather than trying to work it out it’s self. If you do this you would then need to extend the bar or line chart and override the init method to make use of this scale class. (or you could make these changes directly to the scale, bar and line classes and then no need to override).
so first extend scale class and make it use a user defined option
var helpers = Chart.helpers;
Chart.MyScale = Chart.Scale.extend({
calculateXLabelRotation: function() {
//Get the width of each grid by calculating the difference
//between x offsets between 0 and 1.
this.ctx.font = this.font;
var firstWidth = this.ctx.measureText(this.xLabels[0]).width,
lastWidth = this.ctx.measureText(this.xLabels[this.xLabels.length - 1]).width,
firstRotated,
lastRotated;
this.xScalePaddingRight = lastWidth / 2 + 3;
this.xScalePaddingLeft = (firstWidth / 2 > this.yLabelWidth + 10) ? firstWidth / 2 : this.yLabelWidth + 10;
this.xLabelRotation = 0;
if (this.display) {
var originalLabelWidth = helpers.longestText(this.ctx, this.font, this.xLabels),
cosRotation,
firstRotatedWidth;
this.xLabelWidth = originalLabelWidth;
//Allow 3 pixels x2 padding either side for label readability
var xGridWidth = Math.floor(this.calculateX(1) - this.calculateX(0)) - 6;
//check if option is set if so use that
if (this.overrideRotation) {
// do the same as before but manualy set the rotation rather than looping
this.xLabelRotation = this.overrideRotation;
cosRotation = Math.cos(helpers.radians(this.xLabelRotation));
// We're right aligning the text now.
if (firstRotated + this.fontSize / 2 > this.yLabelWidth + 8) {
this.xScalePaddingLeft = firstRotated + this.fontSize / 2;
}
this.xScalePaddingRight = this.fontSize / 2;
this.xLabelWidth = cosRotation * originalLabelWidth;
} else {
//Max label rotate should be 90 - also act as a loop counter
while ((this.xLabelWidth > xGridWidth && this.xLabelRotation === 0) || (this.xLabelWidth > xGridWidth && this.xLabelRotation <= 90 && this.xLabelRotation > 0)) {
cosRotation = Math.cos(helpers.radians(this.xLabelRotation));
firstRotated = cosRotation * firstWidth;
lastRotated = cosRotation * lastWidth;
// We're right aligning the text now.
if (firstRotated + this.fontSize / 2 > this.yLabelWidth + 8) {
this.xScalePaddingLeft = firstRotated + this.fontSize / 2;
}
this.xScalePaddingRight = this.fontSize / 2;
this.xLabelRotation++;
this.xLabelWidth = cosRotation * originalLabelWidth;
}
}
if (this.xLabelRotation > 0) {
this.endPoint -= Math.sin(helpers.radians(this.xLabelRotation)) * originalLabelWidth + 3;
}
} else {
this.xLabelWidth = 0;
this.xScalePaddingRight = this.padding;
this.xScalePaddingLeft = this.padding;
}
},
});
then in the extend the bar class to create a new graph type and override the init method to use the new
Chart.types.Bar.extend({
name: "MyBar",
initialize: function(data) {
//Expose options as a scope variable here so we can access it in the ScaleClass
var options = this.options;
this.ScaleClass = Chart.MyScale.extend({
overrideRotation: options.overrideRotation,
offsetGridLines: true,
calculateBarX: function(datasetCount, datasetIndex, barIndex) {
//Reusable method for calculating the xPosition of a given bar based on datasetIndex & width of the bar
var xWidth = this.calculateBaseWidth(),
xAbsolute = this.calculateX(barIndex) - (xWidth / 2),
barWidth = this.calculateBarWidth(datasetCount);
return xAbsolute + (barWidth * datasetIndex) + (datasetIndex * options.barDatasetSpacing) + barWidth / 2;
},
calculateBaseWidth: function() {
return (this.calculateX(1) - this.calculateX(0)) - (2 * options.barValueSpacing);
},
calculateBarWidth: function(datasetCount) {
//The padding between datasets is to the right of each bar, providing that there are more than 1 dataset
var baseWidth = this.calculateBaseWidth() - ((datasetCount - 1) * options.barDatasetSpacing);
return (baseWidth / datasetCount);
}
});
this.datasets = [];
//Set up tooltip events on the chart
if (this.options.showTooltips) {
helpers.bindEvents(this, this.options.tooltipEvents, function(evt) {
var activeBars = (evt.type !== 'mouseout') ? this.getBarsAtEvent(evt) : [];
this.eachBars(function(bar) {
bar.restore(['fillColor', 'strokeColor']);
});
helpers.each(activeBars, function(activeBar) {
activeBar.fillColor = activeBar.highlightFill;
activeBar.strokeColor = activeBar.highlightStroke;
});
this.showTooltip(activeBars);
});
}
//Declare the extension of the default point, to cater for the options passed in to the constructor
this.BarClass = Chart.Rectangle.extend({
strokeWidth: this.options.barStrokeWidth,
showStroke: this.options.barShowStroke,
ctx: this.chart.ctx
});
//Iterate through each of the datasets, and build this into a property of the chart
helpers.each(data.datasets, function(dataset, datasetIndex) {
var datasetObject = {
label: dataset.label || null,
fillColor: dataset.fillColor,
strokeColor: dataset.strokeColor,
bars: []
};
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.bars.push(new this.BarClass({
value: dataPoint,
label: data.labels[index],
datasetLabel: dataset.label,
strokeColor: dataset.strokeColor,
fillColor: dataset.fillColor,
highlightFill: dataset.highlightFill || dataset.fillColor,
highlightStroke: dataset.highlightStroke || dataset.strokeColor
}));
}, this);
}, this);
this.buildScale(data.labels);
this.BarClass.prototype.base = this.scale.endPoint;
this.eachBars(function(bar, index, datasetIndex) {
helpers.extend(bar, {
width: this.scale.calculateBarWidth(this.datasets.length),
x: this.scale.calculateBarX(this.datasets.length, datasetIndex, index),
y: this.scale.endPoint
});
bar.save();
}, this);
this.render();
},
});
now you can declare a chart using this chart type and pass in the option overrideRotation
here is a fiddle example http://jsfiddle.net/leighking2/ye3usuhu/
and a snippet
var helpers = Chart.helpers;
Chart.MyScale = Chart.Scale.extend({
calculateXLabelRotation: function() {
//Get the width of each grid by calculating the difference
//between x offsets between 0 and 1.
this.ctx.font = this.font;
var firstWidth = this.ctx.measureText(this.xLabels[0]).width,
lastWidth = this.ctx.measureText(this.xLabels[this.xLabels.length - 1]).width,
firstRotated,
lastRotated;
this.xScalePaddingRight = lastWidth / 2 + 3;
this.xScalePaddingLeft = (firstWidth / 2 > this.yLabelWidth + 10) ? firstWidth / 2 : this.yLabelWidth + 10;
this.xLabelRotation = 0;
if (this.display) {
var originalLabelWidth = helpers.longestText(this.ctx, this.font, this.xLabels),
cosRotation,
firstRotatedWidth;
this.xLabelWidth = originalLabelWidth;
//Allow 3 pixels x2 padding either side for label readability
var xGridWidth = Math.floor(this.calculateX(1) - this.calculateX(0)) - 6;
if (this.overrideRotation) {
this.xLabelRotation = this.overrideRotation;
cosRotation = Math.cos(helpers.radians(this.xLabelRotation));
// We're right aligning the text now.
if (firstRotated + this.fontSize / 2 > this.yLabelWidth + 8) {
this.xScalePaddingLeft = firstRotated + this.fontSize / 2;
}
this.xScalePaddingRight = this.fontSize / 2;
this.xLabelWidth = cosRotation * originalLabelWidth;
} else {
//Max label rotate should be 90 - also act as a loop counter
while ((this.xLabelWidth > xGridWidth && this.xLabelRotation === 0) || (this.xLabelWidth > xGridWidth && this.xLabelRotation <= 90 && this.xLabelRotation > 0)) {
cosRotation = Math.cos(helpers.radians(this.xLabelRotation));
firstRotated = cosRotation * firstWidth;
lastRotated = cosRotation * lastWidth;
// We're right aligning the text now.
if (firstRotated + this.fontSize / 2 > this.yLabelWidth + 8) {
this.xScalePaddingLeft = firstRotated + this.fontSize / 2;
}
this.xScalePaddingRight = this.fontSize / 2;
this.xLabelRotation++;
this.xLabelWidth = cosRotation * originalLabelWidth;
}
}
if (this.xLabelRotation > 0) {
this.endPoint -= Math.sin(helpers.radians(this.xLabelRotation)) * originalLabelWidth + 3;
}
} else {
this.xLabelWidth = 0;
this.xScalePaddingRight = this.padding;
this.xScalePaddingLeft = this.padding;
}
},
});
Chart.types.Bar.extend({
name: "MyBar",
initialize: function(data) {
//Expose options as a scope variable here so we can access it in the ScaleClass
var options = this.options;
this.ScaleClass = Chart.MyScale.extend({
overrideRotation: options.overrideRotation,
offsetGridLines: true,
calculateBarX: function(datasetCount, datasetIndex, barIndex) {
//Reusable method for calculating the xPosition of a given bar based on datasetIndex & width of the bar
var xWidth = this.calculateBaseWidth(),
xAbsolute = this.calculateX(barIndex) - (xWidth / 2),
barWidth = this.calculateBarWidth(datasetCount);
return xAbsolute + (barWidth * datasetIndex) + (datasetIndex * options.barDatasetSpacing) + barWidth / 2;
},
calculateBaseWidth: function() {
return (this.calculateX(1) - this.calculateX(0)) - (2 * options.barValueSpacing);
},
calculateBarWidth: function(datasetCount) {
//The padding between datasets is to the right of each bar, providing that there are more than 1 dataset
var baseWidth = this.calculateBaseWidth() - ((datasetCount - 1) * options.barDatasetSpacing);
return (baseWidth / datasetCount);
}
});
this.datasets = [];
//Set up tooltip events on the chart
if (this.options.showTooltips) {
helpers.bindEvents(this, this.options.tooltipEvents, function(evt) {
var activeBars = (evt.type !== 'mouseout') ? this.getBarsAtEvent(evt) : [];
this.eachBars(function(bar) {
bar.restore(['fillColor', 'strokeColor']);
});
helpers.each(activeBars, function(activeBar) {
activeBar.fillColor = activeBar.highlightFill;
activeBar.strokeColor = activeBar.highlightStroke;
});
this.showTooltip(activeBars);
});
}
//Declare the extension of the default point, to cater for the options passed in to the constructor
this.BarClass = Chart.Rectangle.extend({
strokeWidth: this.options.barStrokeWidth,
showStroke: this.options.barShowStroke,
ctx: this.chart.ctx
});
//Iterate through each of the datasets, and build this into a property of the chart
helpers.each(data.datasets, function(dataset, datasetIndex) {
var datasetObject = {
label: dataset.label || null,
fillColor: dataset.fillColor,
strokeColor: dataset.strokeColor,
bars: []
};
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.bars.push(new this.BarClass({
value: dataPoint,
label: data.labels[index],
datasetLabel: dataset.label,
strokeColor: dataset.strokeColor,
fillColor: dataset.fillColor,
highlightFill: dataset.highlightFill || dataset.fillColor,
highlightStroke: dataset.highlightStroke || dataset.strokeColor
}));
}, this);
}, this);
this.buildScale(data.labels);
this.BarClass.prototype.base = this.scale.endPoint;
this.eachBars(function(bar, index, datasetIndex) {
helpers.extend(bar, {
width: this.scale.calculateBarWidth(this.datasets.length),
x: this.scale.calculateBarX(this.datasets.length, datasetIndex, index),
y: this.scale.endPoint
});
bar.save();
}, this);
this.render();
},
});
var randomScalingFactor = function() {
return Math.round(Math.random() * 100)
};
var barChartData = {
labels: ["January", "February", "March", "April", "May", "June", "July"],
datasets: [{
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)",
data: [randomScalingFactor(), randomScalingFactor(), randomScalingFactor(), randomScalingFactor(), randomScalingFactor(), randomScalingFactor(), randomScalingFactor()]
}, {
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: [randomScalingFactor(), randomScalingFactor(), randomScalingFactor(), randomScalingFactor(), randomScalingFactor(), randomScalingFactor(), randomScalingFactor()]
}, {
fillColor: "rgba(15,18,20,0.5)",
strokeColor: "rgba(15,18,20,0.8)",
highlightFill: "rgba(15,18,20,0.75)",
highlightStroke: "rgba(15,18,20,1)",
data: [randomScalingFactor(), randomScalingFactor(), randomScalingFactor(), randomScalingFactor(), randomScalingFactor(), randomScalingFactor(), randomScalingFactor()]
}]
}
window.onload = function() {
var ctx = document.getElementById("canvas").getContext("2d");
window.myBar = new Chart(ctx).MyBar(barChartData, {
overrideRotation: 30
});
}<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/1.0.1/Chart.js"></script>
<canvas id="canvas" height="150" width="300"></canvas>25👍
If you are using chart.js 2.x, just set maxRotation: 90 and minRotation: 90 in ticks options. It works for me!
And if you want to all x-labels, you may want to set autoSkip: false.
The following is an example.
var myChart = new Chart(ctx, {
type: 'bar',
data: chartData,
options: {
scales: {
xAxes: [{
ticks: {
autoSkip: false,
maxRotation: 90,
minRotation: 90
}
}]
}
}
});
0👍
Note that for chart.js 3.x the way of specifying the axis scale options has changed: see https://www.chartjs.org/docs/master/getting-started/v3-migration.html#scales
Consequently in the above answer for 2.x you need to remove the square brackets like this:
var myChart = new Chart(ctx, {
type: 'bar',
data: chartData,
options: {
scales: {
xAxes: {
ticks: {
autoSkip: false,
maxRotation: 90,
minRotation: 90
}
}
}
}
});
Source:stackexchange.com