xray-viewer/xray.js

"use strict";

let overlayLoaded = false;
let baseLoaded = false;

let radius = 200;
let softness = 25;

document.addEventListener("DOMContentLoaded", e => {
    document.querySelector("#load-button").addEventListener("click", e => {
        console.log("Trying to load...");
        const baseInput = document.querySelector("#base-url").value;
        const overlayInput = document.querySelector("#overlay-url").value;
        
        try {
            let baseURL = new URL(baseInput)
            console.log(baseURL);
        } catch {
            document.querySelector("#base-url").value = "";
            document.querySelector("#base-url").placeholder = "Invalid URL...";
        }
        try {
            let overlayURL = new URL(overlayInput)
            console.log(overlayURL);
        } catch {
            document.querySelector("#overlay-url").value = "";
            document.querySelector("#overlay-url").placeholder = "Invalid URL...";
        }

        const overlayImg = document.querySelector("#overlay-img");
        const baseImg = document.querySelector("#base-img");

        overlayImg.src = overlayInput;
        baseImg.src = baseInput;
        
        load();

        try {
            localStorage.setItem("base", baseInput);
            localStorage.setItem("overlay", overlayInput);
        } catch {
            console.error("Couldn't set something in local storage :(")
        }
    });

    let url = new URL(window.location);
    

    const overlay = document.querySelector("#overlay");
    
    overlay.addEventListener("mousemove", e => {
        let x = e.clientX - e.target.getBoundingClientRect().x;
        let y = e.clientY - e.target.getBoundingClientRect().y;
        updateOverlay([[x,y]]);
    });

    overlay.addEventListener("touchmove", e => {
        let offsetX = e.target.getBoundingClientRect().x;
        let offsetY = e.target.getBoundingClientRect().y;

        let touches = [];
        
        for (let i=0; i < e.touches.length; i++) {
            let x = e.touches[i].clientX - offsetX;
            let y = e.touches[i].clientY - offsetY;
            touches.push([x,y]);
        }
        updateOverlay(touches);
    });
    
    document.querySelector("#radius").addEventListener("change", e => {
        try {
            radius = parseInt(e.target.value);
        } catch {
            console.warn("That wasn't a valid radius: " + e.target.value);
        }
    });
    
    document.querySelector("#softness").addEventListener("change", e => {
        try {
            softness = parseInt(e.target.value);
        } catch {
            console.warn("That wasn't a valid softness: " + e.target.value);
        }
    });

    // see if we have params already; if so, use them!

    const overlayImg = document.querySelector("#overlay-img");
    const baseImg = document.querySelector("#base-img");
    const baseInput = document.querySelector("#base-url");
    const overlayInput = document.querySelector("#overlay-url");

    if (url.searchParams.has("base") && url.searchParams.has("overlay")) {
        let baseURL = url.searchParams.get("base");
        let overlayURL = url.searchParams.get("overlay");

        baseImg.src = baseURL;
        overlayImg.src = overlayURL;

        baseInput.value = baseURL;
        overlayInput.value = overlayURL;


        load();
    } else {
    
        try {
            baseInput.value = localStorage.getItem("base");
            overlayInput.value = localStorage.getItem("overlay");
        } catch {
            console.error("Couldn't get something from local storage :(")
        }
    }

    if (url.searchParams.has("radius")) {
        try {
            radius = parseInt(url.searchParams.get("radius"));
            document.querySelector("#radius").value = radius;
        } catch {
            console.warn("That was a bogus radius...");
        }
    }
    if (url.searchParams.has("softness")) {
        try {
            softness = parseInt(url.searchParams.get("softness"));
            document.querySelector("#softness").value = softness;
        } catch {
            console.warn("That was a bogus softness...");
        }
    }
    
    document.querySelector("#share-button").addEventListener("click", e => {
       let shareURL = new URL(window.location);

       // for some reason, the parser gets confused by urlencoded urls...
       // so, to get rid of all parameters, we do this

       let keys = Array.from(shareURL.searchParams.keys());
       do {
           keys = Array.from(shareURL.searchParams.keys());
           keys.forEach(key => {
               shareURL.searchParams.delete(key);
           });
       } while (keys.length > 0)

       shareURL.searchParams.append("base", baseImg.src);
       shareURL.searchParams.append("overlay", overlayImg.src);
       shareURL.searchParams.append("radius", radius);
       shareURL.searchParams.append("softness", softness);

       console.log(shareURL);

       window.location = shareURL;
    });
    
});

function load() {
    document.querySelector("#menu").classList.remove("start");
    const overlayImg = document.querySelector("#overlay-img");
    const baseImg = document.querySelector("#base-img");

    overlayImg.addEventListener("load", function overlayLoad() {
        console.log("The overlay is loaded");
        overlayLoaded = true;

        if (overlayLoaded && baseLoaded) {
            setup();
        }

        overlayImg.removeEventListener("load", overlayLoad);
    })
    baseImg.addEventListener("load", function baseLoad() {
        console.log("The base is loaded");
        baseLoaded = true;

        if (overlayLoaded && baseLoaded) {
            setup();
        }
        
        baseImg.removeEventListener("load", baseLoad);
    })
}

function setup() {
    const overlay = document.querySelector("#overlay");
    const base = document.querySelector("#base");

    overlay.classList.remove("hidden");
    base.classList.remove("hidden");

    const overlayImg = document.querySelector("#overlay-img");
    const baseImg = document.querySelector("#base-img");

    /** @type {CanvasRenderingContext2D} */
    const overlayCtx = overlay.getContext("2d");
    /** @type {CanvasRenderingContext2D} */
    const baseCtx = base.getContext("2d");

    baseCtx.canvas.width = baseImg.width;
    baseCtx.canvas.height = baseImg.height;
    
    baseCtx.drawImage(baseImg, 0, 0);

    overlayCtx.canvas.width = overlayImg.width;
    overlayCtx.canvas.height = overlayImg.height;
    console.log("Done");
}

function updateOverlay(points) {

    /** @type {CanvasRenderingContext2D} */
    const overlayCtx = overlay.getContext("2d");

    const overlayImg = document.querySelector("#overlay-img");

    const w = overlayCtx.canvas.width;
    const h = overlayCtx.canvas.height;


    overlayCtx.save();

    overlayCtx.globalCompositeOperation = "source-over";
    overlayCtx.clearRect(0, 0, w, h);

    points.forEach(point => {
        const [x,y] = point;
        overlayCtx.beginPath();
        overlayCtx.ellipse(x, y, radius, radius, 0, 0, 2 * Math.PI);
    
        const gradient = overlayCtx.createRadialGradient(x, y, 0, x, y, radius);
        gradient.addColorStop((100-softness)/100, '#000000FF');
        gradient.addColorStop(1, '#00000000');
        overlayCtx.fillStyle = gradient;
    
        overlayCtx.fill();
    })
    

    overlayCtx.globalCompositeOperation = "source-in";

    overlayCtx.drawImage(overlayImg, 0, 0);

    overlayCtx.restore();
}