svelte-coordinate-conversion

converts coordinates between viewport, document and element coordinate systems (not only in Svelte)

NPM users: please consider the Github README for the latest description of this package (as updating the docs would otherwise always require a new NPM package version)

Just a small note: if you like this module and plan to use it, consider "starring" this repository (you will find the "Star" button on the top right of this page), so that I know which of my repositories to take most care of.

Installation

svelte-coordinate-conversion may be used as an ECMAScript module (ESM), a CommonJS or AMD module or from a global variable.

You may either install the package into your build environment using NPM with the command

npm install svelte-coordinate-conversion

or load the plain script file directly

<script src="https://unpkg.com/svelte-coordinate-conversion"></script>

Access

How to access the package depends on the type of module you prefer

• ESM (or Svelte): import Conversion from 'svelte-coordinate-conversion'
• CommonJS: const Conversion = require('svelte-coordinate-conversion')
• AMD: require(['svelte-coordinate-conversion'], (Conversion) => {...})

Alternatively, you may access the global variable Conversion directly.

Note for ECMAScript module users: all module functions and values are exported individually, thus allowing your bundler to perform some "tree-shaking" in order to include actually used functions or values (together with their dependencies) only.

Usage within Svelte

For Svelte it is recommended to import the package within a module context:

<script context="module">
  import { fromLocalTo,fromViewportTo,fromDocumentTo } from 'svelte-coordinate-conversion'
  import { onMount } from 'svelte'
</script>

<script>
  let TargetElement // element, whose local position is to be read or set
  let localPosition, ViewportPosition, DocumentPosition
  
  onMount(() => {
    localPosition    = { left:0, top:0 } // local position to be converted
    ViewportPosition = fromLocalTo('viewport',localPosition,TargetElement)
    DocumentPosition = fromLocalTo('document',localPosition,TargetElement)

    ViewportPosition = { left:0, top:0 } // viewport position to be converted
    localPosition    = fromViewportTo('local',   ViewportPosition,TargetElement)
    DocumentPosition = fromViewportTo('document',ViewportPosition)

    DocumentPosition = { left:0, top:0 } // document position to be converted
    localPosition    = fromDocumentTo('local',   DocumentPosition,TargetElement)
    ViewportPosition = fromDocumentTo('viewport',DocumentPosition)
  })
</script>

<div bind:this={TargetElement}></div>

Usage as ECMAscript Module

Using svelte-coordinate-conversion as an ECMAscript module looks very similar to the Svelte use case:

import { fromLocalTo,fromViewportTo,fromDocumentTo } from 'svelte-coordinate-conversion'

let TargetElement // element, whose local position is to be read or set
let localPosition, ViewportPosition, DocumentPosition
  
localPosition    = { left:0, top:0 } // local position to be converted
ViewportPosition = fromLocalTo('viewport',localPosition,TargetElement)
DocumentPosition = fromLocalTo('document',localPosition,TargetElement)

ViewportPosition = { left:0, top:0 } // viewport position to be converted
localPosition    = fromViewportTo('local',   ViewportPosition,TargetElement)
DocumentPosition = fromViewportTo('document',ViewportPosition)

DocumentPosition = { left:0, top:0 } // document position to be converted
localPosition    = fromDocumentTo('local',   DocumentPosition,TargetElement)
ViewportPosition = fromDocumentTo('viewport',DocumentPosition)

Usage as CommonJS or AMD Module (or as a global Variable)

Let's assume that you already "required" or "imported" (or simply loaded) the module according to your local environment. In that case, you may use it as follows:

let TargetElement // element, whose local position is to be read or set
let localPosition, ViewportPosition, DocumentPosition
  
localPosition    = { left:0, top:0 } // local position to be converted
ViewportPosition = Conversion.fromLocalTo('viewport',localPosition,TargetElement)
DocumentPosition = Conversion.fromLocalTo('document',localPosition,TargetElement)

ViewportPosition = { left:0, top:0 } // viewport position to be converted
localPosition    = Conversion.fromViewportTo('local',   ViewportPosition,TargetElement)
DocumentPosition = Conversion.fromViewportTo('document',ViewportPosition)

DocumentPosition = { left:0, top:0 } // document position to be converted
localPosition    = Conversion.fromDocumentTo('local',   DocumentPosition,TargetElement)
ViewportPosition = Conversion.fromDocumentTo('viewport',DocumentPosition)

Example

An example is available on the Svelte REPL - feel free to play with it!

• svelte-coordinate-conversion

Background Information

From time to time it becomes necessary to covert browser coordinates between various coordinate systems, e.g., from relative to an element to relative to the current viewport or the whole document. This package simplifies such conversions.

JavaScript API

The package offers a JavaScript default export, which may be imported as follows

import Conversion from 'svelte-coordinate-conversion'

With such an import, the JavaScript API can be used as follows:

• Conversion.fromLocalTo('viewport',localPosition,TargetElement)converts localPosition (which is relative to the TargetElement) into a position relative to the current viewport
• Conversion.fromLocalTo('document',localPosition,TargetElement)converts localPosition (which is relative to the TargetElement) into a position relative to the document
• Conversion.fromViewportTo('local',ViewportPosition,TargetElement)converts ViewportPosition (which is relative to the current viewport) into a position relative to element TargetElement
• Conversion.fromViewportTo('document',ViewportPosition)converts ViewportPosition (which is relative to the current viewport) into a position relative to the document
• Conversion.fromDocumentTo('local',DocumentPosition,TargetElement)converts DocumentPosition (which is relative to the document) into a position relative to element TargetElement
• Conversion.fromDocumentTo('viewport',DocumentPosition)converts DocumentPosition (which is relative to the document) into a position relative to the current viewport

Build Instructions

You may easily build this package yourself.

Just install NPM according to the instructions for your platform and follow these steps:

1. either clone this repository using git or download a ZIP archive with its contents to your disk and unpack it there
2. open a shell and navigate to the root directory of this repository
3. run npm install in order to install the complete build environment
4. execute npm run build to create a new build

You may also look into the author's build-configuration-study for a general description of his build environment.

License

MIT License