canvas-webp v1.0.0

This module enables WebP encoding of canvases:

const Canvas = require("canvas");
require("canvas-webp");

const canvas = Canvas.createCanvas(w, h);
// Do stuff with your canvas...

// Encode using default settings (lossless: true)
const buff = canavs.toBuffer("image/webp");
// Encode using custom settings:
const buff = canvas.toBuffer("image/webp", {lossless: true}); // quality does not apply
const buff = canvas.toBuffer("image/webp", {lossless: false, quality: zeroToOne});

Compatible with node-canvas 1.x and 2.x.

It's relatively straightforward to add canvas.createWEBPStream(), but I haven't implemented it yet.

:warning: libwebp compatibility
I'm still figuring out the best way to distribute this so users don't have to build and install libwebp.

• I built the win32 and win64 libraries because the ones Google distributes appear to be built with mingw instead of MSVC.

• I built the linux library because the one Google distributes appears to be built with -fno-pic (or otherwise had a PIC-related issue). I built it on Ubuntu 16.06 with GCC 5.4. I think that means it's incompatible with any distro that uses ld older than 2.26.1 (including Ubuntu 14), but forward-compatible (e.g. Ubuntu 18 should work). I've momentarily given up on getting travis to use a newer GCC or building it with an older GCC (https://travis-ci.org/zbjornson/node-canvas-webp).

• I have not built or tested the mac version. It probably needs to be built.

• More info: https://developers.google.com/speed/webp/docs/compiling.