@xtia/pipe2d-image

pipe2d-image

Summary

Read and write images with the power of Pipe2D

Description

Inspired by graphics shaders, Pipe2D provides a simple unified addressing interface for a transforming pipeline to any 2-dimensional concept.

[interactive demo] [full demo source]

The refraction logic can be summarised as:

import { renderRGBAPipe, createImagePipe } from "@xtia/pipe2d-image";

const refractionStrength = 10;
const refractionImage = await createImagePipe("cursor-refraction-map.png");

// read red and green channels as displacement offsets
const refractionPipe = refractionImage.map(rgba => [
	((rgba.red / 255) - .5) * refractionStrength,
	((rgba.green / 255) - .5) * refractionStrength,
]); // Pipe2D<[x, y]>

function renderCursorBackground(cursorX: number, cursorY: number) {
	// create a pipe to read background from refracted coordinates
	const cursorPipe = backgroundPipe.mapCoordinates((x, y) => {
		const [refractX, refractY] = refractionPipe.get(x, y);
		return [x + refractX, y + refractY];
	}).crop(cursorX, cursorY, cursorCanvas.width, cursorCanvas.height);
	// draw it on a canvas
	renderRGBAPipe(cursorCanvas);
}

API

• createImagePipe(source, options?): Pipe2D<RGBA> creates a pipe that samples an image (HTMLCanvasElement | HTMLImageElement | OffscreenCanvas | ImageData | Pipe2D<RGBA> or 2D rendering context)
• async createImagePipe(url, options?): Pipe2D<RGBA> loads an image from a URL and creates a a pipe that samples it
• renderRGBAPipe(target[, x, y[, dw, dh]]) renders a RGBAPipe to a canvas/canvas context/imageData.
• renderRGBAPipe(): OffscreenCanvas renders a RGBAPipe to and returns a new OffscreenCanvas of the pipe's dimensions.

renderRGBAPipe()'s target may be an HTMLImageElement, in which case the update may not occur synchronously (image elements always load asynchronously), so renderRGBAPipe() will return a Promise, resolved when the image is loaded.