javascript - 如何在条形图中添加自定义文本以及如何减小图表js中y轴的步长(条形图)

Question

我正在尝试在栏中插入自定义文本，我搜索了很多线程，但仍然没有得到任何解决方案。然后我想减小 y 轴的步长。我已附上我的代码。

jQuery( document ).ready(function() {
    var ctx = document.getElementById('myChart');
    if(ctx){
        var ctxn = ctx.getContext('2d');
        var myChart = new Chart(ctxn, {
            type: 'bar',
            data: {
                labels: ['Sale Estimate'],
                datasets: [{
                    label: 'Original Sale Estimate',
                    data: [4200000],
                    backgroundColor: '#bcbec0'
                }, {
                    label: 'Final Sale Price',
                    data: [5000000],
                    backgroundColor: '#5a00fe'
                }]
            },
            options: {
                scales: {
                    yAxes: [{
                        ticks: {
                            beginAtZero: true,
                            stacked: true,
                            // Abbreviate the millions
                            callback: function(value, index, values) {
                                return '$' +value / 1e6 + 'M';
                            }
                        }
                    }],
                    xAxes: [{
                        // Change here
                        gridLines : {
                                display : false
                        },
                        barPercentage: 0.8,
                        barThickness: 84,
                        stacked: true
                    }]
                }, legend: {
                    display: false
                },
                tooltips: {
                    callbacks: {
                        label: function(tooltipItems, data) { 
                            var roundoffLabel = Math.round(tooltipItems.yLabel);
                            var millionAft = convertNum(roundoffLabel);
                            return data.datasets[tooltipItems.datasetIndex].label +': ' + '$' + millionAft;
                        },labelTextColor: function(tooltipItem, chart) {
                            return '#000';
                        }
                     },
                     titleSpacing: 5,
                     backgroundColor: '#ffffff',
                     titleFontColor : '#000000',
                     cornerRadius : 0,
                     xPadding : 10,
                     yPadding : 10,
                     mode: 'index'
                }
            }
        });
    }
});

我当前的代码给出了这个输出。我需要上面附有精确的设计。我尝试减小 y 轴的步长，但找不到正确的解决方案。

请任何人帮我解决这个问题。

Answer 1

您可以使用添加标签

afterDatasetsDraw

并使用

更改步骤

stepSize

jQuery( document ).ready(function() {
    var maxValue = 5200000;
    var ctx = document.getElementById('myChart');
    if(ctx){
        var ctxn = ctx.getContext('2d');
        var myChart = new Chart(ctxn, {
            type: 'bar',
            data: {
                labels: ['Sale Estimate'],
                datasets: [{
                    label: 'Original Sale Estimate',
                    data: [3950000],
                    backgroundColor: '#bcbec0'
                }, {
                    label: 'Final Sale Price',
                    data: [maxValue],
                    backgroundColor: '#5a00fe'
                }]
            },
            options: {
                scales: {
                    yAxes: [{
                        ticks: {
                            beginAtZero: true,
                            stacked: true,
                            // Abbreviate the millions
                            callback: function(value, index, values) {
                                return '$ ' + value / 1e6 + 'M';
                            },
                            stepSize: 1000000, // <----- This prop sets the stepSize,
                            max: 6000000
                        }
                    }],
                    xAxes: [{
                        // Change here
                        gridLines : {
                                display : false
                        },
                        barPercentage: 0.8,
                        barThickness: 84,
                        stacked: true
                    }]
                }, legend: {
                    display: false
                },
                tooltips: {
                    callbacks: {
                        label: function(tooltipItems, data) { 
                            var roundoffLabel = Math.round(tooltipItems.yLabel);
                            var millionAft = parseFloat(roundoffLabel);
                            return data.datasets[tooltipItems.datasetIndex].label +': ' + '$' + millionAft;
                        },labelTextColor: function(tooltipItem, chart) {
                            return '#000';
                        }
                     },
                     titleSpacing: 5,
                     backgroundColor: '#ffffff',
                     titleFontColor : '#000000',
                     cornerRadius : 0,
                     xPadding : 10,
                     yPadding : 10,
                     mode: 'index'
                }
            }
        });
        Chart.plugins.register({
            afterDatasetsDraw: function(chart, easing) {
                // To only draw at the end of animation, check for easing === 1
                var ctx = chart.ctx;
                chart.data.datasets.forEach(function (dataset, i) {
                    var meta = chart.getDatasetMeta(i);
                    if (!meta.hidden) {
                        meta.data.forEach(function(element, index) {
                            if (dataset.data[index] == 5000000) return;
                            // Draw the text in white, with the specified font
                            ctx.fillStyle = 'rgb(255, 255, 255)';
                            var fontSize = 16;
                            var fontStyle = 'bold';
                            var fontFamily = 'Arial';
                            ctx.font = Chart.helpers.fontString(fontSize, fontStyle, fontFamily);
                            // Just naively convert to string for now
                            var dataString = dataset.data[index].toString();
                            // Make sure alignment settings are correct
                            ctx.textAlign = 'center';
                            ctx.textBaseline = 'text-top';
                            var padding = 30;
                            var position = element.tooltipPosition();
                            ctx.fillText((maxValue - dataset.data[index])/1000000, position.x, position.y - (fontSize / 2) - padding);
                            //ctx.fillText(dataset.data[index], position.x, position.y - (fontSize / 2) - padding);
                            padding = 12;
                            fontStyle = 'normal';
                            ctx.font = Chart.helpers.fontString(fontSize, fontStyle, fontFamily);
                            ctx.fillText("million", position.x, position.y - (fontSize / 2) - padding);
                        });
                    }
                });
            }
        });
    }
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.8.0/Chart.min.js" type="text/javascript"></script>
<canvas id="myChart"></canvas>