jake-sl · April 15, 2023 01:45
diff --git a/index.html b/index.html
 <body>
    <input type="file" id="image-input" accept="image/*">
    <input type="range" id="hue-range" min="0" max="360" value="0">
    <input type="color" id="bg-color" value="#ffffff">
    <canvas id="image-canvas"></canvas>
    <script src="main.js"></script>
 </body>
diff --git a/script.js b/script.js
 const imageInput = document.getElementById('image-input');
 const hueRange = document.getElementById('hue-range');
 const bgColor = document.getElementById('bg-color');
 const canvas = document.getElementById('image-canvas');
 const ctx = canvas.getContext('2d');
 let img = new Image();

 imageInput.addEventListener('change', (e) => {
    const reader = new FileReader();
    reader.onload = (event) => {
        img.src = event.target.result;
        img.onload = () => {
            canvas.width = img.width;
            canvas.height = img.height;
            updateImage();
        };
    };
    reader.readAsDataURL(e.target.files[0]);
 });

 hueRange.addEventListener('input', updateImage);
 bgColor.addEventListener('input', updateBackground);

 function createHueRotationMatrix(angle) {
    const cosA = Math.cos(angle);
    const sinA = Math.sin(angle);
    const lumR = 0.213;
    const lumG = 0.715;
    const lumB = 0.072;

    return [
        lumR + cosA * (1 - lumR) + sinA * (-lumR),
        lumG + cosA * (-lumG) + sinA * (-lumG),
        lumB + cosA * (-lumB) + sinA * (1 - lumB),
        0,
        0,
        lumR + cosA * (-lumR) + sinA * (0.143),
        lumG + cosA * (1 - lumG) + sinA * (0.14),
        lumB + cosA * (-lumB) + sinA * (-0.283),
        0,
        0,
        lumR + cosA * (-lumR) + sinA * (-(1 - lumR)),
        lumG + cosA * (-lumG) + sinA * (lumG),
        lumB + cosA * (1 - lumB) + sinA * (lumB),
        0,
        0,
        0,
        0,
        0,
        1,
        0,
    ];
 }

 function updateImage() {
    ctx.clearRect(0, 0, canvas.width, canvas.height);

    // Draw the image in grayscale
    ctx.filter = 'grayscale(100%)';
    ctx.drawImage(img, 0, 0, canvas.width, canvas.height);
    ctx.filter = 'none';

    // Apply the hue rotation color matrix
    const angle = (hueRange.value / 360) * 2 * Math.PI;
    const matrix = createHueRotationMatrix(angle);
    const matrixStr = `matrix(${matrix.join(', ')})`;
    ctx.filter = matrixStr;

    // Draw the colorized image onto the main canvas
    ctx.drawImage(canvas, 0, 0, canvas.width, canvas.height);
    ctx.filter = 'none';
 }

 function hslToRgb(h, s, l) {
    let r, g, b;

    if (s === 0) {
        r = g = b = l; // achromatic
    } else {
        const hue2rgb = (p, q, t) => {
            if (t < 0) t += 1;
            if (t > 1) t -= 1;
            if (t < 1 / 6) return p + (q - p) * 6 * t;
            if (t < 1 / 2) return q;
            if (t < 2 / 3) return p + (q - p) * (2 / 3 - t) * 6;
            return p;
        };

        const q = l < 0.5 ? l * (1 + s) : l + s - l * s;
        const p = 2 * l - q;
        r = hue2rgb(p, q, h + 1 / 3);
        g = hue2rgb(p, q, h);
        b = hue2rgb(p, q, h - 1 / 3);
    }

    return [Math.round(r * 255), Math.round(g * 255), Math.round(b * 255)];
 }


 function rgbToHsl(r, g, b) {
    r /= 255, g /= 255, b /= 255;
    const max = Math.max(r, g, b), min = Math.min(r, g, b);
    let h, s, l = (max + min) / 2;

    if (max === min) {
        h = s = 0; // achromatic
    } else {
        const d = max - min;
        s = l > 0.5 ? d / (2 - max - min) : d / (max + min);
        switch (max) {
            case r: h = (g - b) / d + (g < b ? 6 : 0); break;
            case g: h = (b - r) / d + 2; break;
            case b: h = (r - g) / d + 4; break;
        }
        h /= 6;
    }

    return [h, s, l];
 }


 function updateBackground() {
    canvas.style.backgroundColor = bgColor.value;
 }
diff --git a/vyvgyyo.markdown b/vyvgyyo.markdown
	<body>
	<input type="file" id="image-input" accept="image/*">
	<input type="range" id="hue-range" min="0" max="360" value="0">
	<input type="color" id="bg-color" value="#ffffff">
	<canvas id="image-canvas"></canvas>
	<script src="main.js"></script>
	</body>
	const imageInput = document.getElementById('image-input');
	const hueRange = document.getElementById('hue-range');
	const bgColor = document.getElementById('bg-color');
	const canvas = document.getElementById('image-canvas');
	const ctx = canvas.getContext('2d');
	let img = new Image();

	imageInput.addEventListener('change', (e) => {
	const reader = new FileReader();
	reader.onload = (event) => {
	img.src = event.target.result;
	img.onload = () => {
	canvas.width = img.width;
	canvas.height = img.height;
	updateImage();
	};
	};
	reader.readAsDataURL(e.target.files[0]);
	});

	hueRange.addEventListener('input', updateImage);
	bgColor.addEventListener('input', updateBackground);

	function createHueRotationMatrix(angle) {
	const cosA = Math.cos(angle);
	const sinA = Math.sin(angle);
	const lumR = 0.213;
	const lumG = 0.715;
	const lumB = 0.072;

	return [
	lumR + cosA * (1 - lumR) + sinA * (-lumR),
	lumG + cosA * (-lumG) + sinA * (-lumG),
	lumB + cosA * (-lumB) + sinA * (1 - lumB),
	0,
	0,
	lumR + cosA * (-lumR) + sinA * (0.143),
	lumG + cosA * (1 - lumG) + sinA * (0.14),
	lumB + cosA * (-lumB) + sinA * (-0.283),
	0,
	0,
	lumR + cosA * (-lumR) + sinA * (-(1 - lumR)),
	lumG + cosA * (-lumG) + sinA * (lumG),
	lumB + cosA * (1 - lumB) + sinA * (lumB),
	0,
	0,
	0,
	0,
	0,
	1,
	0,
	];
	}

	function updateImage() {
	ctx.clearRect(0, 0, canvas.width, canvas.height);

	// Draw the image in grayscale
	ctx.filter = 'grayscale(100%)';
	ctx.drawImage(img, 0, 0, canvas.width, canvas.height);
	ctx.filter = 'none';

	// Apply the hue rotation color matrix
	const angle = (hueRange.value / 360) * 2 * Math.PI;
	const matrix = createHueRotationMatrix(angle);
	const matrixStr = `matrix(${matrix.join(', ')})`;
	ctx.filter = matrixStr;

	// Draw the colorized image onto the main canvas
	ctx.drawImage(canvas, 0, 0, canvas.width, canvas.height);
	ctx.filter = 'none';
	}

	function hslToRgb(h, s, l) {
	let r, g, b;

	if (s === 0) {
	r = g = b = l; // achromatic
	} else {
	const hue2rgb = (p, q, t) => {
	if (t < 0) t += 1;
	if (t > 1) t -= 1;
	if (t < 1 / 6) return p + (q - p) * 6 * t;
	if (t < 1 / 2) return q;
	if (t < 2 / 3) return p + (q - p) * (2 / 3 - t) * 6;
	return p;
	};

	const q = l < 0.5 ? l * (1 + s) : l + s - l * s;
	const p = 2 * l - q;
	r = hue2rgb(p, q, h + 1 / 3);
	g = hue2rgb(p, q, h);
	b = hue2rgb(p, q, h - 1 / 3);
	}

	return [Math.round(r * 255), Math.round(g * 255), Math.round(b * 255)];
	}


	function rgbToHsl(r, g, b) {
	r /= 255, g /= 255, b /= 255;
	const max = Math.max(r, g, b), min = Math.min(r, g, b);
	let h, s, l = (max + min) / 2;

	if (max === min) {
	h = s = 0; // achromatic
	} else {
	const d = max - min;
	s = l > 0.5 ? d / (2 - max - min) : d / (max + min);
	switch (max) {
	case r: h = (g - b) / d + (g < b ? 6 : 0); break;
	case g: h = (b - r) / d + 2; break;
	case b: h = (r - g) / d + 4; break;
	}
	h /= 6;
	}

	return [h, s, l];
	}


	function updateBackground() {
	canvas.style.backgroundColor = bgColor.value;
	}