Adds info tiddlers for viewport dimensions (#9260)

* feat: added info tiddlers for viewport dimensions

* feat: multi window support for dimensions info tiddlers

* refactor: introduce standalone eventbus and refactor for ES2017

* docs: extended docs for InfoMechanism to cover new additions

core/modules/info/dimensions.js

@@ -0,0 +1,86 @@
+/*\
+title: $:/core/modules/info/windowdimensions.js
+type: application/javascript
+module-type: info
+\*/
+
+exports.getInfoTiddlerFields = function(updateInfoTiddlersCallback) {
+	if(!$tw.browser) {
+		return [];
+	}
+
+	class WindowDimensionsTracker {
+		constructor(updateCallback) {
+			this.updateCallback = updateCallback;
+			this.resizeHandlers = new Map();
+			this.dimensionsInfo = [
+				["outer/width", win => win.outerWidth],
+				["outer/height", win => win.outerHeight],
+				["inner/width", win => win.innerWidth],
+				["inner/height", win => win.innerHeight],
+				["client/width", win => win.document.documentElement.clientWidth],
+				["client/height", win => win.document.documentElement.clientHeight]
+			];
+		}
+
+		buildTiddlers(win,windowId) {
+			const prefix = `$:/info/browser/window/${windowId}/`;
+			return this.dimensionsInfo.map(([suffix, getter]) => ({
+				title: prefix + suffix,
+				text: String(getter(win))
+			}));
+		}
+
+		clearTiddlers(windowId) {
+			const prefix = `$:/info/browser/window/${windowId}/`,
+				deletions = this.dimensionsInfo.map(([suffix]) => prefix + suffix);
+			this.updateCallback([], deletions);
+		}
+
+		getUpdateHandler(win,windowId) {
+			let scheduled = false;
+			return () => {
+				if(!scheduled) {
+					scheduled = true;
+					requestAnimationFrame(() => {
+						this.updateCallback(this.buildTiddlers(win,windowId), []);
+						scheduled = false;
+					});
+				}
+			};
+		}
+
+		trackWindow(win,windowId) {
+			const handler = this.getUpdateHandler(win, windowId);
+			handler(); // initial update
+			win.addEventListener("resize",handler,{passive:true});
+			this.resizeHandlers.set(windowId,{win, handler});
+		}
+
+		untrackWindow(windowId) {
+			const entry = this.resizeHandlers.get(windowId);
+			if(entry) {
+				entry.win.removeEventListener("resize", entry.handler);
+				this.resizeHandlers.delete(windowId);
+			}
+			this.clearTiddlers(windowId);
+		}
+	}
+
+	const tracker = new WindowDimensionsTracker(updateInfoTiddlersCallback);
+
+	// Track main window
+	tracker.trackWindow(window,"system/main");
+
+	// Hook into event bus for user windows
+	if($tw.eventBus) {
+		$tw.eventBus.on("window:opened", ({window: win, windowID}) => {
+			tracker.trackWindow(win, "user/" + windowID);
+		});
+		$tw.eventBus.on("window:closed", ({windowID}) => {
+			tracker.untrackWindow("user/" + windowID);
+		});
+	}
+
+	return [];
+};

core/modules/startup/eventbus.js

@@ -0,0 +1,46 @@
+/*\
+title: $:/core/modules/startup/eventbus.js
+type: application/javascript
+module-type: startup
+
+Event bus for cross module communication
+\*/
+
+exports.name = "eventbus";
+exports.platforms = ["browser"];
+exports.before = ["windows"];
+exports.synchronous = true;
+
+$tw.eventBus = {
+	listenersMap: new Map(),
+
+	on(event,handler) {
+		if(!this.listenersMap.has(event)) {
+			this.listenersMap.set(event,new Set());
+		}
+		const listeners = this.listenersMap.get(event);
+		listeners.add(handler);
+	},
+
+	off(event,handler) {
+		const listeners = this.listenersMap.get(event);
+		if(listeners) {
+			listeners.delete(handler);
+		}
+	},
+
+	once(event,handler) {
+		const wrapper = (...args) => {
+			handler(...args);
+			this.off(event, wrapper);
+		};
+		this.on(event, wrapper);
+	},
+
+	emit(event,data) {
+		const listeners = this.listenersMap.get(event);
+		if(listeners) {
+			listeners.forEach(fn => fn(data));
+		}
+	}
+};

core/modules/startup/info.js

@@ -19,11 +19,17 @@ var TITLE_INFO_PLUGIN = "$:/temp/info-plugin";
 
 exports.startup = function() {
 	// Function to bake the info plugin with new tiddlers
-	var updateInfoPlugin = function(tiddlerFieldsArray) {
+	// additions: array of tiddler field objects
+	// removals: array of titles to remove
+	var updateInfoPlugin = function(additions = [], removals = []) {
 		// Get the existing tiddlers
 		var json = $tw.wiki.getTiddlerData(TITLE_INFO_PLUGIN,{tiddlers: {}});
-		// Add the new ones
-		$tw.utils.each(tiddlerFieldsArray,function(fields) {
+		$tw.utils.each(removals,function(title) {
+			if(json.tiddlers[title]) {
+				delete json.tiddlers[title];
+			}
+		});
+		$tw.utils.each(additions,function(fields) {
 			if(fields && fields.title) {
 				json.tiddlers[fields.title] = fields;
 			}
@@ -47,7 +53,7 @@ exports.startup = function() {
 		}
 	});
 	updateInfoPlugin(tiddlerFieldsArray);
-	var changes = $tw.wiki.readPluginInfo([TITLE_INFO_PLUGIN]);
+	$tw.wiki.readPluginInfo([TITLE_INFO_PLUGIN]);
 	$tw.wiki.registerPluginTiddlers("info",[TITLE_INFO_PLUGIN]);
 	$tw.wiki.unpackPluginTiddlers();
 };

core/modules/startup/windows.js

@@ -56,9 +56,11 @@ exports.startup = function() {
 		srcDocument.write("<!DOCTYPE html><head></head><body class='tc-body tc-single-tiddler-window'></body></html>");
 		srcDocument.close();
 		srcDocument.title = windowTitle;
+		$tw.eventBus.emit("window:opened",{windowID, window: srcWindow});
 		srcWindow.addEventListener("beforeunload",function(event) {
 			delete $tw.windows[windowID];
 			$tw.wiki.removeEventListener("change",refreshHandler);
+			$tw.eventBus.emit("window:closed",{windowID});
 		},false);
 		// Set up the styles
 		var styleWidgetNode = $tw.wiki.makeTranscludeWidget("$:/core/ui/PageStylesheet",{

editions/tw5.com/tiddlers/mechanisms/InfoMechanism.tid

@@ -1,5 +1,5 @@
 created: 20140720164948099
-modified: 20201124185829706
+modified: 20250819181815032
 tags: Mechanisms
 title: InfoMechanism
 type: text/vnd.tiddlywiki
@@ -19,6 +19,7 @@ System tiddlers in the namespace `$:/info/` are used to expose information about
 |[[$:/info/browser/language]] |<<.from-version "5.1.20">> Language as reported by browser (note that some browsers report two character codes such as `en` while others report full codes such as `en-GB`) |
 |[[$:/info/browser/screen/width]] |Screen width in pixels |
 |[[$:/info/browser/screen/height]] |Screen height in pixels |
+|`$:/info/browser/window/*` |<<.from-version "5.4.0">> Tiddlers reporting window dimensions, updated when the windows are resized |
 |[[$:/info/node]] |Running under [[Node.js]]? ("yes" or "no") |
 |[[$:/info/url/full]] |<<.from-version "5.1.14">> Full URL of wiki (eg, ''<<example full>>'') |
 |[[$:/info/url/host]] |<<.from-version "5.1.14">> Host portion of URL of wiki (eg, ''<<example host>>'') |
@@ -29,3 +30,27 @@ System tiddlers in the namespace `$:/info/` are used to expose information about
 |[[$:/info/url/protocol]] |<<.from-version "5.1.14">> Protocol portion of URL of wiki (eg, ''<<example protocol>>'') |
 |[[$:/info/url/search]] |<<.from-version "5.1.14">> Search portion of URL of wiki (eg, ''<<example search>>'') |
 |[[$:/info/darkmode]] |<<.from-version "5.1.23">> Is dark mode enabled? ("yes" or "no") |
+
+! Main Window Dimension Tiddlers
+
+<<.from-version "5.4.0">> These tiddlers reports the dimensions of the main ~TiddlyWiki window and are updated automatically whenever the main window is resized.
+
+|!Title |!Description |
+|[[$:/info/browser/window/system/main/outer/width]] |Full browser window including chrome, tabs, toolbars |
+|[[$:/info/browser/window/system/main/outer/height]] |Full browser window including chrome, tabs, toolbars |
+|[[$:/info/browser/window/system/main/inner/width]] |Viewport width including scrollbars |
+|[[$:/info/browser/window/system/main/inner/height]] |Viewport height including scrollbars |
+|[[$:/info/browser/window/system/main/client/width]] |Content width excluding scrollbars |
+|[[$:/info/browser/window/system/main/client/height]] |Content height excluding scrollbars |
+
+! User-Created Window Dimension Tiddlers
+
+<<.from-version "5.4.0">> These tiddler reports the dimensions of additional windows opened via [[tm-open-window|WidgetMessage: tm-open-window]]. The windowID used when opening the window is used to identify the corresponding info tiddlers. These tiddlers are updated automatically whenever the main window is resized.
+
+|!Title |!Description |
+|`$:/info/browser/window/user/<windowID>/outer/width` | Full browser window including chrome, tabs, toolbars |
+|`$:/info/browser/window/user/<windowID>/outer/height` | Full browser window including chrome, tabs, toolbars |
+|`$:/info/browser/window/user/<windowID>/inner/width` |Viewport width including scrollbars |
+|`$:/info/browser/window/user/<windowID>/inner/height` |Viewport height including scrollbars |
+|`$:/info/browser/window/user/<windowID>/client/width` |Content width excluding scrollbars |
+|`$:/info/browser/window/user/<windowID>/client/height` |Content height excluding scrollbars |