Palettes
A common use case in the sorts of applications for which VisuallyJs is useful is the requirement to be able to drag and drop new nodes/groups onto the workspace.
Setup
To configure your UI to drag and drop HTML elements onto your canvas, you'll use a PaletteComponent. Here's how to set one up:
import { PaletteComponent, SurfaceComponent, SurfaceProvider } from '@visuallyjs/browser-ui-react';
export default function MyApp() {
return <div>
<SurfaceProvider>
<div className="col-9">
<SurfaceComponent/>
</div>
<div className="col-3">
<PaletteComponent>
<div style={{display:"flex", flexDirection:"column"}}>
<div data-vjs-type="foo" vjs-is-group="true" data-vjs-label="New Foo">FOO</div>
<div data-vjs-type="bar" data-vjs-label="New Bar">BAR</div>
</div>
</PaletteComponent>
</div>
</SurfaceProvider>
</div>
}
The basic contract is that you declare a PaletteComponent in your JSX, and then you write out the children which should be draggable however you like - in this case we use a div with flex column and an div for each draggable type, a pretty common setup. The palette identifies draggable elements by the fact that they have a data-vjs-type attribute set on them. You can override this default behaviour by providing your own dataGenerator - see below.
The PaletteComponent needs to know which surface it is going to be attached to, and it does this by being context aware - in the code above we have a SurfaceProvider wrapping both the surface component and the palette component. When the surface component is instantiated, it populates the surface provider's context, and the palette component is notified of the surface to use.
Providing data for a dragged element
Internally, the palette uses a dataGenerator function to get a suitable piece of backing data for some element that is being dragged. You do not need to provide a dataGenerator: the default behaviour is to retrieve data values from data-vjs-*** attributes on the element a user is dragging. For instance with this element:
<div data-vjs-type="process" data-vjs-label="Process" data-vjs-width="120" data-vjs-height="80">Process</div>
VisuallyJs will prepare this payload for the object representing the drag:
{
"type":"process",
"label":"Process",
"width":"120",
"height":"80"
}
The default mechanism used by VisuallyJs for determining the type of some object is to test the type member. Providing type as we have here (via the data-vjs-type attribute) allows VisuallyJs to determine which template to use to render the node, how it will behave, etc.
You can supply a dataGenerator function if you want to customise the initial dataset for dragged elements:
import { PaletteComponent, SurfaceComponent, SurfaceProvider } from '@visuallyjs/browser-ui-react';
export default function MyApp() {
const dataGenerator = (el) => {
return {
width:120,
height:80,
type:el.getAttribute("data-vjs-type"),
timestamp:new Date().getTime()
}
};
return <div className="row">
<SurfaceProvider>
<div className="col-9">
<SurfaceComponent/>
</div>
<div className="col-3">
<PaletteComponent dataGenerator={dataGenerator}>
<div style={{display:"flex", flexDirection:"column"}}>
<div data-vjs-type="foo" vjs-is-group="true">FOO</div>
<div data-vjs-type="bar">BAR</div>
</div>
</PaletteComponent>
</div>
</SurfaceProvider>
</div>
}
Here, our data generator extracts the data-vjs-type to use for the new node's type, then sets a fixed value for width and height, and adds a timestamp.
Distinguishing between a node and a group
By default, VisuallyJs will look for a data-vjs-is-group attribute on a dragged element. If the value of this attribute is "true", VisuallyJs will assume the element represents a group. You can provide your own groupIdentifier if you wish.
Specifying the size for a new element
By default, the SurfacePalette clones the DOM element on which the user started a drag and then sets the size of the element that is being dragged to match the bounding client rectangle of the element that was cloned.
In some situations, particularly when you have a grid in your surface, you may wish to mandate the size for any new elements that are being dragged on to the surface, which you can do by providing a dragSize object:
<PaletteComponent selector="li" dragSize={{ width:250, h: 100 }}>
</PaletteComponent>
Filtering draggable elements
It is possible, when drag starts, to decide whether or not you want the dragged element to be droppable on the canvas, via the canvasDropFilter prop:
<PaletteComponent selector="li"
canvasDropFilter={(data) => data.type === "someDroppableOnCanvasType"}>
...
</PaletteComponent>
Rotating dragged elements
Since: 1.2.5You can rotate an element that you are dragging from the palette before dropping it, if you have the ResizingToolsPlugin installed on your canvas and you have not explicitly set allowRotation:false on the palette.
To configure the palette to allow rotation, set allowRotation to be true on the palette props:
import { PaletteComponent, SurfaceComponent, SurfaceProvider } from '@visuallyjs/browser-ui-react';
export default function MyApp() {
const renderOptions = {
plugins:[
{
type:`%ResizingToolsPlugin.type`,
options:{
rotatable:true
}
}
]
}
return <div>
<SurfaceProvider>
<div className="col-9">
<SurfaceComponent renderOptions={{renderOptions}}/>
</div>
<div className="col-3">
<PaletteComponent>
<div style={{display:"flex", flexDirection:"column"}}>
<div data-vjs-type="foo" vjs-is-group="true" data-vjs-label="New Foo">FOO</div>
<div data-vjs-type="bar" data-vjs-label="New Bar">BAR</div>
</div>
</PaletteComponent>
</div>
</SurfaceProvider>
</div>
}
Hold down the meta key (CMD on mac) to rotate an element as you are dragging it from the palette in this canvas:
Rotation stops
If you specify rotationStops in your resizing tools options, the palette will honour them:
import { PaletteComponent, SurfaceComponent, SurfaceProvider } from '@visuallyjs/browser-ui-react';
export default function MyApp() {
const renderOptions = {
plugins:[
{
type:`%ResizingToolsPlugin.type`,
options:{
rotatable:true,
rotationStops:4
}
}
]
}
return <div>
<SurfaceProvider>
<div className="col-9">
<SurfaceComponent renderOptions={{renderOptions}}/>
</div>
<div className="col-3">
<PaletteComponent>
<div style={{display:"flex", flexDirection:"column"}}>
<div data-vjs-type="foo" vjs-is-group="true" data-vjs-label="New Foo">FOO</div>
<div data-vjs-type="bar" data-vjs-label="New Bar">BAR</div>
</div>
</PaletteComponent>
</div>
</SurfaceProvider>
</div>
}
Tap the meta key (CMD on mac) to rotate an element by steps as you are dragging it from the palette in this canvas:
Rotation speed
With free rotation (no rotationStops specified), elements will take 2000ms to perform an entire 360 degree rotation. This can be changed via the rotationSpeed setting on the resizing tools plugin:
{
type:ResizingToolsPlugin.type,
options:{
rotatable:true,
rotationStops:4
}
}
Drop on edge
To configure the palette to allow dropping a new vertex onto an existing edge, which will then be split, set allowDropOnEdge to be true on the palette props:
import { PaletteComponent, SurfaceComponent, SurfaceProvider } from '@visuallyjs/browser-ui-react';
export default function MyApp() {
return <div>
<SurfaceProvider>
<div className="col-9">
<SurfaceComponent/>
</div>
<div className="col-3">
<PaletteComponent allowDropOnEdge={true}>
<div style={{display:"flex", flexDirection:"column"}}>
<div data-vjs-type="foo" vjs-is-group="true" data-vjs-label="New Foo">FOO</div>
<div data-vjs-type="bar" data-vjs-label="New Bar">BAR</div>
</div>
</PaletteComponent>
</div>
</SurfaceProvider>
</div>
}
This is the simplest configuration, in which we instruct the palette to allow any vertex to be dropped on an edge. If you want more fine-grained control, you can supply a function instead, of this type:
export type CanDropOnEdgeFilter = (d: ObjectData) => boolean;
The function is invoked with the payload for the item that is currently being dragged.
Getting notification of a new vertex
You can create a PaletteComponent with an onVertexAdded callback, which will be invoked whenever a new vertex has been dropped onto the canvas:
<PaletteComponent selector="li"
onVertexAdded={(vertex, dropTarget) => { } }>
...
</PaletteComponent>
vertex is the new vertex that was added. In the event that the new vertex was dropped on top of some existing node, dropTarget will be provided, containing information about the node onto which the new vertex was dropped, as well as its position and size.
Working with decorators
If you have any Decorators in your UI, you may wish to inform the drop manager about the elements they have created, because without doing this the drop manager will not be able to recognise them as background. To do this, you use the canvasSelector prop:
<PaletteComponent selector="li" canvasSelector=".someElementMyDecoratorCreated">
</PaletteComponent>
canvasSelector takes any valid CSS3 selector. This identifies the elements that your decorator has created that the drop manager should treat as background.
CSS
| Class | Description |
|---|---|
vjs-palette-auto-edge-connect-active | Assigned to the UI's canvas when a drag has started and auto edge connect is active. |
vjs-palette-current-shape-type | Assigned to a shape in a ShapePalette that matches the type of the model's currently selected shape. |
vjs-palette-drag-active | Assigned to possible drop targets when an element is being dragged from the Palette |
vjs-palette-drag-hover | Assigned to a drop target when an element that is being dragged from the Palette is hovering over it. |
vjs-palette-drag-hover-cannot-drop | Assigned to a vertex or the canvas when an element that is being dragged from the palette is hovering over it but drop is not allowed. |
vjs-palette-current | Assigned to an element when it is being dragged from a palette |
vjs-palette-selected-element | Assigned to the currently selected element in a palette when in tap/draw mode. |
vjs-palette-tap-mode-active | Assigned to the surface canvas when a user has tapped an element in a palette in tap mode. this class can be used to show the user that a vertex can be dropped via click or drawn on the canvas |
In order to use these classes for visual cues in the UI, you'll probably want to define slightly different selectors for each target type. Let's suppose when a drag starts we want to outline our canvas and any nodes/groups with a purple line, and we want to draw any possible target edges with a purple line too:
.vjs-surface.vjs-palette-active, .vjs-node.vjs-palette-active, .vjs-group.vjs-palette-active {
outline:4px solid purple;
}
svg.vjs-palette-active path {
stroke:purple;
}
Now when something is the current drop target, we'll either outline it green or make its path green:
.vjs-surface.vjs-palette-hover, .vjs-node.vjs-palette-hover, .vjs-group.vjs-palette-hover {
outline:4px solid green;
}
svg.vjs-palette-hover path {
stroke:green;
}
This is just an example of course. You can do anything with the CSS that you like.
Options
PaletteComponent| Name | Type | Description |
|---|---|---|
| allowClickToAdd? | boolean | When in draw mode, allow addition of new vertices simply by clicking, instead of requiring a shape be drawn. (When this is true, the drag to draw functionality also still works) |
| allowDropOnCanvas? | boolean | Whether or not to allow drop on whitespace in the canvas. Defaults to true. |
| allowDropOnEdge? | boolean | CanDropOnEdgeFilter | Whether or not to allow drop on edge. Defaults to false. |
| allowDropOnGroup? | boolean | Whether or not to allow drop on existing vertices. Defaults to true. |
| allowDropOnNode? | boolean | Defaults to false. Allows items to be dropped onto nodes in the canvas. If this is true and an element is dropped onto a node, the result is the same as if the element has been dropped onto whitespace. Note that when this is false and the user has dragged something over a node, the drag item is still not considered to be over the canvas, and releasing the mouse button at that time will not cause a new node to be added. Use |
| allowRotation? | boolean | Whether or not to allow rotation of elements being dragged. Defaults to true. |
| autoEdgeConnect? | boolean | AutoEdgeConnectOptions | Controls whether the palette will automatically connect a new vertex being dragged onto the canvas to existing vertices, if the shape definitions for the new vertex and/or the existing vertices have source/target elements. You can set this to simply 'true', and use defaults, or you can provide values for various options. |
| canvasDropFilter? | CanvasDropFilter | Optional filter to test if objects may be dropped on the canvas. |
| className? | string | Optional extra css classes to set on the element |
| clickToAddOnly? | boolean | This flag relates to "draw" mode, and defaults to false. When true, the palette only supports click to draw new vertices, not drag. This flag is forced to true if the associated UI does not have |
| dataGenerator? | DataGeneratorFunction | Function to use to get a dataset for an item that is being dragged or has been tapped. If omitted, Visually JS will use a default data generator that extracts data values from any |
| dragSize? | Size | Optional size to use for elements dragged from the palette, when in "drag" mode |
| groupIdentifier? | GroupIdentifierFunction | Function to use to determine whether an item that is being dragged or has been tapped represents a group. |
| ignoreDropOnNode? | boolean | Defaults to false. When true, the palette treats nodes as if they are part of the canvas - a user can drag new items on top of existing nodes and the new item will be added to the canvas. If you want to force your users to drop on canvas whitespace, don't set this. Note that this flag will force |
| mode? | PaletteMode | Mode to operate in - 'drag', 'tap' or 'draw'. Defaults to 'drag'. |
| onVertexAdded? | OnVertexAddedCallback | Optional callback that will be invoked after a new vertex has been dropped and added to the dataset. |
| rotationSpeed? | number | The number of milliseconds required to complete a full rotation of an element when the trigger key is held down. Defaults to 2000. |
| selectAfterAdd? | boolean | Defaults to false. When true, a newly added vertex is set as the model's current selection. |
| selector? | string | CSS 3 selector identifying what child elements of |
| showGroups? | boolean | Whether or not to show groups in the palette. Defaults to true. |
| surface? | Surface | The surface to attach to. Optional: this component can derive a surface from a SurfaceProvider or SurfaceComponent. You'll only need this in certain advanced scenarios. |
| typeGenerator? | TypeGeneratorFunction | Function to use to get the type of an item that is being dragged or has been tapped. |