@tsparticles/plugin-canvas-mask/esm/utils.js

tsParticles canvas mask plugin

import { getRandom, half, percentDenominator, } from "@tsparticles/engine";
export function addParticlesFromCanvasPixels(container, data, position, scale, override, filter) {
    const { height, width } = data, numPixels = height * width, indexArray = shuffle(range(numPixels)), maxParticles = Math.min(numPixels, container.actualOptions.particles.number.value), canvasSize = container.canvas.size;
    let selectedPixels = 0;
    const positionOffset = {
        x: (canvasSize.width * position.x) / percentDenominator - width * scale * half,
        y: (canvasSize.height * position.y) / percentDenominator - height * scale * half,
    };
    while (selectedPixels < maxParticles && indexArray.length) {
        const defaultIndex = 0, nextIndex = indexArray.pop() ?? defaultIndex, pixelPos = {
            x: nextIndex % width,
            y: Math.floor(nextIndex / width),
        }, row = data.pixels[pixelPos.y];
        if (!row) {
            continue;
        }
        const pixel = row[pixelPos.x];
        if (!pixel) {
            continue;
        }
        const shouldCreateParticle = filter(pixel);
        if (!shouldCreateParticle) {
            continue;
        }
        const pos = {
            x: pixelPos.x * scale + positionOffset.x,
            y: pixelPos.y * scale + positionOffset.y,
        }, pOptions = {};
        if (override.color) {
            pOptions.paint = {
                fill: {
                    color: {
                        value: pixel,
                    },
                    enable: true,
                },
            };
        }
        if (override.opacity) {
            pOptions["opacity"] = {
                value: pixel.a,
            };
        }
        container.particles.addParticle(pos, pOptions);
        selectedPixels++;
    }
}
function shuffle(array) {
    const lengthOffset = 1, minIndex = 0;
    for (let currentIndex = array.length - lengthOffset; currentIndex >= minIndex; currentIndex--) {
        const randomIndex = Math.floor(getRandom() * currentIndex), currentItem = array[currentIndex], randomItem = array[randomIndex];
        if (randomItem === currentItem) {
            continue;
        }
        if (randomItem === undefined || currentItem === undefined) {
            continue;
        }
        array[currentIndex] = randomItem;
        array[randomIndex] = currentItem;
    }
    return array;
}
const range = (n) => [...Array(n).keys()];