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react-dnd-text-dragpreview

react-dnd-text-dragpreview

react-dnd allows you to use an image for a drag preview. In order to get text as a drag preview, you have to write text to a canvas and export an image. This library wraps up the canvas interaction.

text drag preview in action

Install

npm install react-dnd-text-dragpreview --save-dev

Usage

import { createDragPreview } from 'react-dnd-text-dragpreview'
 
const styles = {
  fontSize: '12px'
}
 
const dragPreviewImage = createDragPreview('Custom Drag Text', styles)

Style Configuration

There are several styling options. These styles look like react inline styles according to naming convention, but only this set are currently available (not all inline styles options).

These are the default styles that you can override via the 2nd argument to createDragPreview:

{
  backgroundColor: '#efefef',
  borderColor: '#1a1a1a',
  color: '#1a1a1a',
  fontSize: 14,
  paddingTop: 5,
  paddingRight: 5,
  paddingBottom: 5,
  paddingLeft: 5
}

React Usage

In React, you're going to be using a dragPreview for react-dnd within a component.

Here's a demo component that uses react-dnd, TableRow, which will show a drag preview of "Moving X rows" when dragging. See comments inline for relevant pieces:

import { DragSource } from 'react-dnd';
import React from 'react'
import { createDragPreview } from 'react-dnd-text-dragpreview'
 
import { ItemTypes } from './constants'
 
const { bool, func, number, object, string } = React.PropTypes
 
// overrides dragPreview style 
var dragPreviewStyle = {
  backgroundColor: 'rgb(68, 67, 67)',
  borderColor: '#F96816',
  color: 'white',
  fontSize: 15,
  paddingTop: 4,
  paddingRight: 7,
  paddingBottom: 6,
  paddingLeft: 7
}
 
const rowSource = {
  beginDrag(props) {
    if (typeof props.onDragRow === 'function')
      props.onDragRow(props.dataId)
 
    return {
      dataId: props.dataId
    }
  }
}
 
function collect(connect, monitor) {
  return {
    connectDragSource: connect.dragSource(),
    connectDragPreview: connect.dragPreview()
  }
}
 
// provides custom message for dragPreview 
function formatDragMessage(numRows) {
  const noun = numRows === 1 ? 'row' : 'rows'
  return `Moving ${num} ${noun}`
}
 
class TableRow extends React.Component {
  componentDidMount() {
    // handles first time dragPreview setup 
    this.dragPreview = createDragPreview(formatDragMessage(this.props.numRows), dragPreviewStyle)
    this.props.connectDragPreview(this.dragPreview)
  }
  componentDidUpdate(prevProps) {
    // handles updates to the dragPreview image as the dynamic numRows value changes 
    this.dragPreview = createDragPreview(formatDragMessage(this.props.numRows), dragPreviewStyle, this.dragPreview)
  }
  render() {
    return this.props.connectDragSource(
      <tr>
        <td className={this.props.css.checkBoxCell}>
          Drag me
        </td>
      </tr>
    )
  }
}
 
TableRow.propTypes = {
  connectDragPreview: func.isRequired,
  connectDragSource: func.isRequired,
  dataId: string.isRequired,
  numRows: number.isRequired,
  onDragRow: func.isRequired
}
 
export default DragSource(ItemTypes.ROW, rowSource, collect)(TableRow)