npm package discovery and stats viewer.

Discover Tips

  • General search

    [free text search, go nuts!]

  • Package details

    pkg:[package-name]

  • User packages

    @[username]

Sponsor

Optimize Toolset

I’ve always been into building performant and accessible sites, but lately I’ve been taking it extremely seriously. So much so that I’ve been building a tool to help me optimize and monitor the sites that I build to make sure that I’m making an attempt to offer the best experience to those who visit them. If you’re into performant, accessible and SEO friendly sites, you might like it too! You can check it out at Optimize Toolset.

About

Hi, 👋, I’m Ryan Hefner  and I built this site for me, and you! The goal of this site was to provide an easy way for me to check the stats on my npm packages, both for prioritizing issues and updates, and to give me a little kick in the pants to keep up on stuff.

As I was building it, I realized that I was actually using the tool to build the tool, and figured I might as well put this out there and hopefully others will find it to be a fast and useful way to search and browse npm packages as I have.

If you’re interested in other things I’m working on, follow me on Twitter or check out the open source projects I’ve been publishing on GitHub.

I am also working on a Twitter bot for this site to tweet the most popular, newest, random packages from npm. Please follow that account now and it will start sending out packages soon–ish.

Open Software & Tools

This site wouldn’t be possible without the immense generosity and tireless efforts from the people who make contributions to the world and share their work via open source initiatives. Thank you 🙏

© 2024 – Pkg Stats / Ryan Hefner

lazy-brush

v2.0.2

Published

Lazy brush - smooth drawing using mouse or finger

Downloads

72,734

Readme

lazy-brush - smooth drawing with a mouse, finger or any pointing device

lazy-brush banner

Demo - NPM - CodePen Examples

The demo app also uses catenary-curve to draw the little "rope" between mouse and brush.

This library provides the math required to implement a "lazy brush". It takes a radius and the {x,y} coordinates of a mouse/pointer and calculates the position of the brush.

The brush will only move when the pointer is outside the "lazy area" of the brush. With this technique it's possible to freely draw smooth lines and curves with just a mouse or finger.

How it works

When the position of the pointer is updated, the distance to the brush is calculated. If this distance is larger than the defined radius, the brush will be moved by distance - radius pixels in the direction where the pointer is.

Usage

lazy-brush is on npm so you can install it with your favorite package manager.

npm install --save lazy-brush

lazy-brush can be easily added in any canvas drawing scenario. It acts like a "proxy" between user input and drawing.

It exports a LazyBrush class. Create a single instance of the class:

const lazy = new LazyBrush({
  radius: 30,
  enabled: true,
  initialPoint: { x: 0, y: 0 }
})

You can now use the update() method whenever the position of the mouse (or touch) changes:

// Move mouse 20 pixels to the right.
lazy.update({ x: 20, y: 0 })
// Brush is not moved, because 20 is less than the radius (30).
console.log(lazy.getBrushCoordinates()) // { x: 0, y: 0 }

// Move mouse 40 pixels to the right.
lazy.update({ x: 40, y: 0 })
// Brush is now moved by 10 pixels because 40 (mouse X) - 30 (radius) = 10.
console.log(lazy.getBrushCoordinates()) // { x: 10, y: 0 }

The function returns a boolean to indicate whether any of the values (brush or pointer) have changed. This can be used to prevent unneccessary canvas redrawing.

If you need to know if the position of the brush was changed, you can get that boolean via LazyBrush.brushHasMoved(). Use this information to decide if you need to redraw the brush on the canvas.

To get the current brush coordinates, use LazyBrush.getBrushCoordinates(). For the pointer coordinates use LazyBrush.getPointerCoordinates(). This will return a Point object with x and y properties.

The functions getBrush() and getPointer() will return a LazyPoint, which has some additional functions like getDistanceTo, getAngleTo or equalsTo.

With Friction

You can also pass a friction value (number between 0 and 1) when calling update():

lazy.update({ x: 40, y: 0 }, { friction: 0.5 })

This will reduce the speed at which the brush moves towards the pointer. A value of 0 means "no friction", which is the same as not passing a value. 1 means "inifinte friction", the brush won't move at all.

You can define a constant value or make it dynamic, for example using a pressur value from a touch event.

Updating both values

You can also update the pointer and the brush coordinates at the same time:

lazy.update({ x: 40, y: 0 }, { both: true })

This can be used when supporting touch events: On touch start you would update both the pointer and the brush so that the pointer can be "moved" away from the brush until the lazy radius is reached. This is how it's implemented in the demo page.

Examples

Check out the basic example for a simple starting point on how to use this library.