Add img2brush tool to website

Pending insertion of a link into the reference docs

.docs/.eleventy.js

@@ -75,7 +75,7 @@ async function fetch(url) {
 }
 
 module.exports = function(eleventyConfig) {
-	
+	eleventyConfig.addPassthroughCopy("img2brush/img2brush.js");
 	eleventyConfig.addAsyncShortcode("fetch", fetch);
 	
 	// eleventyConfig.addPassthroughCopy("images");

.docs/css/theme.css

@@ -411,3 +411,30 @@ footer {
 	flex-direction: column;
 	align-items: center;
 }
+
+@keyframes move-diagonal {
+	from {
+		background-position: -2px -2px, -2px -2px, -1px -1px, -1px -1px;
+	}
+	to {
+		background-position: -52px -52px, -52px -52px, -51px -51px, -51px -51px;
+	}
+}
+
+
+#dropzone {
+	border: 0.3em dashed #aaaaaa;
+	transition: border 0.2s;
+	justify-content: flex-start;
+}
+#dropzone.dropzone-active {
+	border: 0.3em dashed hsl(203, 79%, 55%);
+	
+	/* Ref https://www.magicpattern.design/tools/css-backgrounds */
+	background-image:  linear-gradient(var(--bg-bright) 2px, transparent 2px), linear-gradient(90deg, var(--bg-bright) 2px, transparent 2px), linear-gradient(var(--bg-bright) 1px, transparent 1px), linear-gradient(90deg, var(--bg-bright) 1px, var(--bg-transcluscent) 1px);
+	background-size: 50px 50px, 50px 50px, 10px 10px, 10px 10px;
+	background-position: -2px -2px, -2px -2px, -1px -1px, -1px -1px;
+	
+	animation: move-diagonal 5s linear infinite;
+}
+#brushimg-preview { flex: 1; }

.docs/img2brush/img2brush.js

@@ -0,0 +1,97 @@
+window.addEventListener("load", () => {
+	let dropzone = document.querySelector("#dropzone");
+	dropzone.addEventListener("dragenter", handle_drag_enter);
+	dropzone.addEventListener("dragleave", handle_drag_leave);
+	dropzone.addEventListener("dragover", handle_drag_over);
+	dropzone.addEventListener("drop", handle_drop);
+	
+	document.querySelector("#brushimg-tsv").addEventListener("click", select_output);
+	let button_copy = document.querySelector("#brushimg-copy")
+	button_copy.addEventListener("click", () => {
+		select_output();
+		button_copy.innerHTML = document.execCommand("copy") ? "Copied!" : "Failed to copy :-(";
+	})
+});
+
+function select_output() {
+	let output = document.querySelector("#brushimg-tsv");
+	
+	let selection = window.getSelection();
+	
+	if (selection.rangeCount > 0)
+		selection.removeAllRanges();
+
+	let range = document.createRange();
+	range.selectNode(output);
+	selection.addRange(range);
+}
+
+
+function handle_drag_enter(event) {
+	event.target.classList.add("dropzone-active");
+}
+function handle_drag_leave(event) {
+	event.target.classList.remove("dropzone-active");
+}
+
+function handle_drag_over(event) {
+	event.preventDefault();
+}
+
+function handle_drop(event) {
+	event.stopPropagation();
+	event.preventDefault();
+	event.target.classList.remove("dropzone-active");
+	
+	let image_file = null;
+	
+	image_file = event.dataTransfer.files[0];
+	
+	let reader = new FileReader();
+	reader.addEventListener("load", function(_event) {
+		let image = new Image();
+		image.src = reader.result;
+		image.addEventListener("load", () => handle_new_image(image));
+		
+		
+		document.querySelector("#brushimg-preview").src = image.src;
+	});
+	reader.readAsDataURL(image_file);
+	
+	return false;
+}
+
+function image2pixels(image) {
+	let canvas = document.createElement("canvas"),
+		ctx = canvas.getContext("2d");
+	
+	canvas.width = image.width;
+	canvas.height = image.height;
+	
+	ctx.drawImage(image, 0, 0);
+	
+	return ctx.getImageData(0, 0, image.width, image.height);
+}
+
+function handle_new_image(image) {
+	let tsv = pixels2tsv(image2pixels(image));
+	document.querySelector("#brushimg-stats").value = `${image.width} x ${image.height} | ${image.width * image.height} pixels`;
+	document.querySelector("#brushimg-tsv").value = tsv;
+}
+
+function round(number, decimal_places = 0) {
+	let multiplier = Math.pow(10, decimal_places);
+	return Math.round(number * multiplier) / multiplier;
+}
+
+function pixels2tsv(pixels) {
+	let result = "";
+	for(let y = 0; y < pixels.height; y++) {
+		let row = [];
+		for(let x = 0; x < pixels.width; x++) {
+			row.push(round(pixels.data[((y*pixels.width + x) * 4) + 3], 3));
+		}
+		result += row.join(`\t`) + `\n`;
+	}
+	return result;
+}

.docs/img2brush/index.html

@@ -0,0 +1,34 @@
+---
+layout: theme.njk
+title: Image to brush converter
+---
+
+<section class="panel-generic">
+	<h1>Image to sculpting brush converter</h1>
+	
+	<p>Convert any image to a sculpting brush here! The <strong>alpha (opacity) channel</strong> is used to determine the weight of the brush - <strong>all colour is ignored</strong>.</p>
+</section>
+
+<section id="dropzone" class="bigbox panel-generic">
+	<h2>Input</h2>
+	<p>Drop your image here.</p>
+	
+	<img id="brushimg-preview" alt="" />
+	
+	<output id="brushimg-stats"></output>
+</section>
+
+
+<section class="panel-generic">
+	<h2>Output</h2>
+	
+	<p>Paste the output below into a text file in <code>worldeditadditions/lib/sculpt/brushes</code> with the file extension <code>.txt</code> and restart your Minetest server for the brush to be recognised.</p>
+	
+	<p class="text-centre">
+		<button id="brushimg-copy" class="bigbutton">Copy</button>
+	</p>
+	
+	<pre><output id="brushimg-tsv"><em>(your output will appear here as soon as you drop an image above)</em></output></pre>
+</section>
+
+<script src="./img2brush.js"></script>