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Components

Components make up the visual parts of a chart and typically include axis, grid-lines and data points encoded in various ways.

Using components in a chart

Each component has a type property which identifies the type of component to create.

To use components, add them in the components array:

picasso.chart({
  settings: {
    components: [{
      type: 'point',
      data: { /* ... */ },
      settings: { /* ... */ }
    }, {
      type: 'axis',
      dock: 'bottom',
      scale: 'x'
    }]
  }
});

Some properties are general and can be used on all components:

  • dock string. Dock setting. Any of top | right | bottom | left
  • show boolean. True if component should be rendered.
  • displayOrder number. The order in which components are rendered (similar to css z-index).
  • prioOrder number. The order in which components are docked from the center area,
  • minimumLayoutMode string.
  • data object. See data section.
  • settings object.
  • created function. Lifecycle hook.
  • beforeMount function. Lifecycle hook.
  • mounted function. Lifecycle hook.
  • beforeRender function. Lifecycle hook.
  • beforeUpdate function. Lifecycle hook.
  • updated function. Lifecycle hook.
  • beforeDestroy function. Lifecycle hook.
  • destroyed function. Lifecycle hook.

settings

Most components use a settings object that is specific to the component itself.

Registering a custom component

A custom component can be registered using the picasso.component registry:

picasso.component(name, definition)

  • name string. Name of the component to register.
  • definition object
    • dock string (optional).
    • displayOrder number (optional).
    • prioOrder number (optional).
    • minimumLayoutMode string (optional).
    • created function (optional). Lifecycle hook.
    • beforeMount function (optional). Lifecycle hook.
    • mounted function (optional). Lifecycle hook.
    • beforeRender function (optional). Lifecycle hook.
    • render function (optional). Lifecycle hook.
    • beforeUpdate function (optional). Lifecycle hook.
    • updated function (optional). Lifecycle hook.
    • beforeDestroy function (optional). Lifecycle hook.
    • destroyed function (optional). Lifecycle hook.

A draw line component

Let's make a component that draws a red line across its entire display area:

picasso.component('drawLine', {
  beforeRender(opts) {
    this.rect = opts.size;
  },
  render() {
    return [{
      type: 'line',
      stroke: 'red',
      strokeWidth: 4,
      x1: this.rect.x,
      y1: this.rect.y,
      x2: this.rect.width,
      y2: this.rect.height
    }];
  }
});

It can then be used like any other component:

picasso.chart({
  element,
  settings: {
    components: [{
      type: 'drawLine'
    }]
  }
});

Visibility of a component

It is possible to get the visibility of a component when it is mounted/unmounted. This can be done in the following example.

Assume a custom component of type foo:


const foo = {
  type: 'foo',
  key: 'myComponent'
};

const chart = picasso.chart({
  element,
  settings: {
    components: [foo]
  }
});

chart.component('myComponent').isVisible(); // returns a boolean determining if the component is visible or not

Component lifecycle hooks

TODO

(Note that the lifecycle hooks in the component definition do not share the same context as hooks used in the component settings of a chart).

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