Create and draw image with raw ARGB32 data

[paramaggarwal]

Feature

I want to render image on the canvas from raw RGBA32 data - the same format data that is the output from canvas.toBuffer('raw'). Please guide me on how to expose the relevant variable.

The final else condition here: src/Image.cc#L256-L28 needs to be to set the raw buffer as is - that should enable this usecase.

Please help - thanks.

Steps to Reproduce

var Canvas = require('canvas');
var canvas = Canvas.createCanvas(1, 1);
var ctx = canvas.getContext('2d');

var i = new Image();
i.src = new Buffer('F000', 'hex'); // single red pixel image - raw RGBA32
i.onerror = console.error;

Your Environment

• Version of node-canvas (e.g. 1.4.0): 2.0 alpha
• Environment (e.g. node 4.2.0 on Mac OS X 10.8): Node 9.3.0 on High Sierra

[zbjornson]

Does ctx.putImageData satisfy your use case? That's in RGBA32 order already.

(I could see adding support for ARGB32 since putImageData does a sort of byte-swapping from RGBA to ARGB that isn't especially fast right now.)

https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/putImageData

[paramaggarwal]

Oh, wow - hadn't found this when I was searching. Thanks a lot @zbjornson!

The byte-swapping is fine as it's still better than encoding/decoding PNG. Going to close this issue now - thanks!

[paramaggarwal]

Hello, I have a small follow-up question - what is the difference between the custom canvas.toBuffer('raw') and the standard ctx.getImageData()? Both of them seem to give the raw canvas data.

EDIT: Found my answer here: #306 (comment)