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119 lines
2.8 KiB
Markdown
119 lines
2.8 KiB
Markdown
# Linear Gradient
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```js chart-editor
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// <block:actions:3>
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const actions = [
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{
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name: 'Randomize',
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handler(chart) {
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chart.data.datasets.forEach(dataset => {
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dataset.data = Utils.numbers({count: chart.data.labels.length, min: -100, max: 100});
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});
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chart.update();
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}
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},
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{
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name: 'Add Data',
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handler(chart) {
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const data = chart.data;
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if (data.datasets.length > 0) {
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data.labels = Utils.months({count: data.labels.length + 1});
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for (let index = 0; index < data.datasets.length; ++index) {
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data.datasets[index].data.push(Utils.rand(-100, 100));
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}
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chart.update();
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}
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}
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},
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{
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name: 'Remove Data',
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handler(chart) {
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chart.data.labels.splice(-1, 1); // remove the label first
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chart.data.datasets.forEach(dataset => {
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dataset.data.pop();
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});
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chart.update();
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}
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}
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];
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// </block:actions>
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// <block:getGradient:0>
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let width, height, gradient;
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function getGradient(ctx, chartArea) {
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const chartWidth = chartArea.right - chartArea.left;
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const chartHeight = chartArea.bottom - chartArea.top;
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if (!gradient || width !== chartWidth || height !== chartHeight) {
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// Create the gradient because this is either the first render
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// or the size of the chart has changed
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width = chartWidth;
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height = chartHeight;
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gradient = ctx.createLinearGradient(0, chartArea.bottom, 0, chartArea.top);
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gradient.addColorStop(0, Utils.CHART_COLORS.blue);
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gradient.addColorStop(0.5, Utils.CHART_COLORS.yellow);
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gradient.addColorStop(1, Utils.CHART_COLORS.red);
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}
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return gradient;
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}
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// </block:getGradient>
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// <block:setup:2>
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const DATA_COUNT = 7;
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const NUMBER_CFG = {count: DATA_COUNT, min: -100, max: 100};
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const labels = Utils.months({count: 7});
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const data = {
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labels: labels,
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datasets: [
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{
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label: 'Dataset 1',
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data: Utils.numbers(NUMBER_CFG),
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borderColor: function(context) {
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const chart = context.chart;
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const {ctx, chartArea} = chart;
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if (!chartArea) {
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// This case happens on initial chart load
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return;
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}
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return getGradient(ctx, chartArea);
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},
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},
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]
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};
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// </block:setup>
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// <block:config:1>
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const config = {
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type: 'line',
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data: data,
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options: {
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responsive: true,
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plugins: {
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legend: {
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position: 'top',
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},
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}
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},
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};
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// </block:config>
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module.exports = {
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actions: actions,
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config: config,
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};
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```
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## Docs
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* [Colors](../../general/colors.md)
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* [Patterns and Gradients](../../general/colors.md#patterns-and-gradients)
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* [Data structures (`labels`)](../../general/data-structures.md)
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* [Options](../../general/options.md)
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* [Scriptable Options](../../general/options.md#scriptable-options)
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* [Line](../../charts/line.md)
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