@onesy/utils/canvasFilterFade.js

Utils

"use strict";
var __importDefault = (this && this.__importDefault) || function (mod) {
    return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
const clamp_1 = __importDefault(require("./clamp"));
const canvasFilterFade = (value_, canvas) => {
    const context = canvas.getContext('2d');
    const imageData = context.getImageData(0, 0, canvas.width, canvas.height);
    const { data } = imageData;
    let value = value_;
    if (value > 0)
        value *= -1;
    const factor = (259 * (value + 255)) / (255 * (259 - value));
    for (let i = 0; i < data.length; i += 4) {
        data[i + 0] = (0, clamp_1.default)((factor * (data[i + 0] - 100)) + 100, 0, 255);
        data[i + 1] = (0, clamp_1.default)((factor * (data[i + 1] - 100)) + 100, 0, 255);
        data[i + 2] = (0, clamp_1.default)((factor * (data[i + 2] - 100)) + 100, 0, 255);
    }
    context.putImageData(imageData, 0, 0);
    return canvas;
};
exports.default = canvasFilterFade;