Mon 21 Jul 22:43:21 CEST 2025

js/ui/chart/docs/general/colors.md

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+# Colors
+
+When supplying colors to Chart options, you can use a number of formats. You can specify the color as a string in hexadecimal, RGB, or HSL notations. If a color is needed, but not specified, Chart.js will use the global default color. This color is stored at `Chart.defaults.global.defaultColor`. It is initially set to `'rgba(0, 0, 0, 0.1)'`.
+
+You can also pass a [CanvasGradient](https://developer.mozilla.org/en-US/docs/Web/API/CanvasGradient) object. You will need to create this before passing to the chart, but using it you can achieve some interesting effects.
+
+## Patterns and Gradients
+
+An alternative option is to pass a [CanvasPattern](https://developer.mozilla.org/en-US/docs/Web/API/CanvasPattern) or [CanvasGradient](https://developer.mozilla.org/en/docs/Web/API/CanvasGradient) object instead of a string colour.
+
+For example, if you wanted to fill a dataset with a pattern from an image you could do the following.
+
+```javascript
+var img = new Image();
+img.src = 'https://example.com/my_image.png';
+img.onload = function() {
+    var ctx = document.getElementById('canvas').getContext('2d');
+    var fillPattern = ctx.createPattern(img, 'repeat');
+
+    var chart = new Chart(ctx, {
+        data: {
+            labels: ['Item 1', 'Item 2', 'Item 3'],
+            datasets: [{
+                data: [10, 20, 30],
+                backgroundColor: fillPattern
+            }]
+        }
+    });
+};
+```
+
+Using pattern fills for data graphics can help viewers with vision deficiencies (e.g. color-blindness or partial sight) to [more easily understand your data](http://betweentwobrackets.com/data-graphics-and-colour-vision/).
+
+Using the [Patternomaly](https://github.com/ashiguruma/patternomaly) library you can generate patterns to fill datasets.
+
+```javascript
+var chartData = {
+    datasets: [{
+        data: [45, 25, 20, 10],
+        backgroundColor: [
+            pattern.draw('square', '#ff6384'),
+            pattern.draw('circle', '#36a2eb'),
+            pattern.draw('diamond', '#cc65fe'),
+            pattern.draw('triangle', '#ffce56')
+        ]
+    }],
+    labels: ['Red', 'Blue', 'Purple', 'Yellow']
+};
+```