Custom Editor exploration

For #77131

Adds a prototype of custom editors contributed by extensions. This change does the following:

- Introduces a new contribution point for the declarative parts of a custom editor
- Adds API for registering a webview editor provider. This lets VS Code decided when to create a webview editor
- Adds an `openWith` command that lets you select which editor to use to open a resource from the file explorer
- Adds a setting that lets you say that you always want to use a custom editor for a given file extension
- Hooks up auto opening of a custom editor when opening a file from quick open or explorer
- Adds a new extension that contributes a custom image preview for png and jpg files

Still needs a lot of UX work and testing. We are also going to explore a more generic "open handler" based approach for supporting custom editors

Revert

build/lib/i18n.resources.json

@@ -170,6 +170,10 @@
 			"name": "vs/workbench/contrib/webview",
 			"project": "vscode-workbench"
 		},
+		{
+			"name": "vs/workbench/contrib/customEditor",
+			"project": "vscode-workbench"
+		},
 		{
 			"name": "vs/workbench/contrib/welcome",
 			"project": "vscode-workbench"

extensions/image-preview/.vscodeignore

@@ -0,0 +1,10 @@
+test/**
+src/**
+tsconfig.json
+out/test/**
+out/**
+extension.webpack.config.js
+cgmanifest.json
+yarn.lock
+preview-src/**
+webpack.config.js

extensions/image-preview/README.md

@@ -0,0 +1,3 @@
+# Image Preview
+
+**Notice:** This extension is bundled with Visual Studio Code. It can be disabled but not uninstalled.

extensions/image-preview/extension.webpack.config.js

@@ -0,0 +1,20 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+//@ts-check
+
+'use strict';
+
+const withDefaults = require('../shared.webpack.config');
+
+module.exports = withDefaults({
+	context: __dirname,
+	resolve: {
+		mainFields: ['module', 'main']
+	},
+	entry: {
+		extension: './src/extension.ts',
+	}
+});

extensions/image-preview/media/main.css

@@ -0,0 +1,81 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+html, body {
+	height: 100%;
+	max-height: 100%;
+}
+
+body {
+	background: hotpink;
+}
+
+body img {
+	max-width: none;
+	max-height: none;
+}
+
+.container:focus {
+	outline: none !important;
+}
+
+.container {
+	padding: 5px 0 0 10px;
+	box-sizing: border-box;
+	user-select: none;
+}
+
+.container.image {
+	padding: 0;
+	display: flex;
+	box-sizing: border-box;
+}
+
+.container.image img {
+	padding: 0;
+	background-position: 0 0, 8px 8px;
+	background-size: 16px 16px;
+}
+
+.container.image img {
+	background-image:
+		linear-gradient(45deg, rgb(230, 230, 230) 25%, transparent 25%, transparent 75%, rgb(230, 230, 230) 75%, rgb(230, 230, 230)),
+		linear-gradient(45deg, rgb(230, 230, 230) 25%, transparent 25%, transparent 75%, rgb(230, 230, 230) 75%, rgb(230, 230, 230));
+}
+
+.vscode-dark.container.image img {
+	background-image:
+		linear-gradient(45deg, rgb(20, 20, 20) 25%, transparent 25%, transparent 75%, rgb(20, 20, 20) 75%, rgb(20, 20, 20)),
+		linear-gradient(45deg, rgb(20, 20, 20) 25%, transparent 25%, transparent 75%, rgb(20, 20, 20) 75%, rgb(20, 20, 20));
+}
+
+.container img.pixelated {
+	image-rendering: pixelated;
+}
+
+.container img.scale-to-fit {
+	max-width: calc(100% - 20px);
+	max-height: calc(100% - 20px);
+	object-fit: contain;
+}
+
+.container img {
+	margin: auto;
+}
+
+.container.zoom-in {
+	cursor: zoom-in;
+}
+
+.container.zoom-out {
+	cursor: zoom-out;
+}
+
+.container .embedded-link,
+.container .embedded-link:hover {
+	cursor: pointer;
+	text-decoration: underline;
+	margin-left: 5px;
+}

extensions/image-preview/media/main.js

@@ -0,0 +1,260 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+// @ts-check
+"use strict";
+
+(function () {
+	/**
+	 * @param {number} value
+	 * @param {number} min
+	 * @param {number} max
+	 * @return {number}
+	 */
+	function clamp(value, min, max) {
+		return Math.min(Math.max(value, min), max);
+	}
+
+	function getSettings() {
+		const element = document.getElementById('image-preview-settings');
+		if (element) {
+			const data = element.getAttribute('data-settings');
+			if (data) {
+				return JSON.parse(data);
+			}
+		}
+
+		throw new Error(`Could not load settings`);
+	}
+
+	/**
+	 * Enable image-rendering: pixelated for images scaled by more than this.
+	 */
+	const PIXELATION_THRESHOLD = 3;
+
+	const SCALE_PINCH_FACTOR = 0.075;
+	const MAX_SCALE = 20;
+	const MIN_SCALE = 0.1;
+
+	const zoomLevels = [
+		0.1,
+		0.2,
+		0.3,
+		0.4,
+		0.5,
+		0.6,
+		0.7,
+		0.8,
+		0.9,
+		1,
+		1.5,
+		2,
+		3,
+		5,
+		7,
+		10,
+		15,
+		20
+	];
+
+	const isMac = getSettings().isMac;
+
+	const vscode = acquireVsCodeApi();
+
+	const initialState = vscode.getState() || { scale: 'fit', offsetX: 0, offsetY: 0 };
+
+	// State
+	let scale = initialState.scale;
+	let ctrlPressed = false;
+	let altPressed = false;
+
+	// Elements
+	const container =  /** @type {HTMLElement} */(document.querySelector('body'));
+	const image = document.querySelector('img');
+
+	function updateScale(newScale) {
+		if (!image || !image.parentElement) {
+			return;
+		}
+
+		if (newScale === 'fit') {
+			scale = 'fit';
+			image.classList.add('scale-to-fit');
+			image.classList.remove('pixelated');
+			image.style.minWidth = 'auto';
+			image.style.width = 'auto';
+			vscode.setState(undefined);
+			// InlineImageView.imageStateCache.delete(cacheKey);
+		} else {
+			const oldWidth = image.width;
+			const oldHeight = image.height;
+
+			scale = clamp(newScale, MIN_SCALE, MAX_SCALE);
+			if (scale >= PIXELATION_THRESHOLD) {
+				image.classList.add('pixelated');
+			} else {
+				image.classList.remove('pixelated');
+			}
+
+			const { scrollTop, scrollLeft } = image.parentElement;
+			const dx = (scrollLeft + image.parentElement.clientWidth / 2) / image.parentElement.scrollWidth;
+			const dy = (scrollTop + image.parentElement.clientHeight / 2) / image.parentElement.scrollHeight;
+
+			image.classList.remove('scale-to-fit');
+			image.style.minWidth = `${(image.naturalWidth * scale)}px`;
+			image.style.width = `${(image.naturalWidth * scale)}px`;
+
+			const newWidth = image.width;
+			const scaleFactor = (newWidth - oldWidth) / oldWidth;
+
+			const newScrollLeft = ((oldWidth * scaleFactor * dx) + scrollLeft);
+			const newScrollTop = ((oldHeight * scaleFactor * dy) + scrollTop);
+			// scrollbar.setScrollPosition({
+			// 	scrollLeft: newScrollLeft,
+			// 	scrollTop: newScrollTop,
+			// });
+
+			vscode.setState({ scale: scale, offsetX: newScrollLeft, offsetY: newScrollTop });
+			// InlineImageView.imageStateCache.set(cacheKey, { scale: scale, offsetX: newScrollLeft, offsetY: newScrollTop });
+		}
+
+		vscode.postMessage({
+			type: 'zoom',
+			value: scale
+		});
+	}
+
+	function firstZoom() {
+		if (!image) {
+			return;
+		}
+
+		scale = image.clientWidth / image.naturalWidth;
+		updateScale(scale);
+	}
+
+	window.addEventListener('keydown', (/** @type {KeyboardEvent} */ e) => {
+		if (!image) {
+			return;
+		}
+		ctrlPressed = e.ctrlKey;
+		altPressed = e.altKey;
+
+		if (isMac ? altPressed : ctrlPressed) {
+			container.classList.remove('zoom-in');
+			container.classList.add('zoom-out');
+		}
+	});
+
+	window.addEventListener('keyup', (/** @type {KeyboardEvent} */ e) => {
+		if (!image) {
+			return;
+		}
+
+		ctrlPressed = e.ctrlKey;
+		altPressed = e.altKey;
+
+		if (!(isMac ? altPressed : ctrlPressed)) {
+			container.classList.remove('zoom-out');
+			container.classList.add('zoom-in');
+		}
+	});
+
+	container.addEventListener('click', (/** @type {MouseEvent} */ e) => {
+		if (!image) {
+			return;
+		}
+
+		if (e.button !== 0) {
+			return;
+		}
+
+		// left click
+		if (scale === 'fit') {
+			firstZoom();
+		}
+
+		if (!(isMac ? altPressed : ctrlPressed)) { // zoom in
+			let i = 0;
+			for (; i < zoomLevels.length; ++i) {
+				if (zoomLevels[i] > scale) {
+					break;
+				}
+			}
+			updateScale(zoomLevels[i] || MAX_SCALE);
+		} else {
+			let i = zoomLevels.length - 1;
+			for (; i >= 0; --i) {
+				if (zoomLevels[i] < scale) {
+					break;
+				}
+			}
+			updateScale(zoomLevels[i] || MIN_SCALE);
+		}
+	});
+
+	container.addEventListener('wheel', (/** @type {WheelEvent} */ e) => {
+		if (!image) {
+			return;
+		}
+
+		const isScrollWheelKeyPressed = isMac ? altPressed : ctrlPressed;
+		if (!isScrollWheelKeyPressed && !e.ctrlKey) { // pinching is reported as scroll wheel + ctrl
+			return;
+		}
+
+		e.preventDefault();
+		e.stopPropagation();
+
+		if (scale === 'fit') {
+			firstZoom();
+		}
+
+		let delta = e.deltaY > 0 ? 1 : -1;
+		updateScale(scale * (1 - delta * SCALE_PINCH_FACTOR));
+	});
+
+	window.addEventListener('scroll', () => {
+		if (!image || !image.parentElement || scale === 'fit') {
+			return;
+		}
+
+		const entry = vscode.getState();
+		if (entry) {
+			vscode.setState({ scale: entry.scale, offsetX: window.scrollX, offsetY: window.scrollY });
+		}
+	});
+
+	container.classList.add('image');
+	container.classList.add('zoom-in');
+
+	image.classList.add('scale-to-fit');
+	image.style.visibility = 'hidden';
+
+	image.addEventListener('load', () => {
+		if (!image) {
+			return;
+		}
+
+		vscode.postMessage({
+			type: 'size',
+			value: `${image.naturalWidth}x${image.naturalHeight}`,
+		});
+
+		image.style.visibility = 'visible';
+		updateScale(scale);
+
+		if (initialState.scale !== 'fit') {
+			window.scrollTo(initialState.offsetX, initialState.offsetY);
+		}
+	});
+
+	window.addEventListener('message', e => {
+		switch (e.data.type) {
+			case 'setScale':
+				updateScale(e.data.scale);
+				break;
+		}
+	});
+}());