opacity-slider@neatnit: Initial release (#676)

opacity-slider@neatnit/README.md

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+## Opacity Slider
+Right-click on any window's title bar to tweak its opacity! Works great in conjuction with the existing 'Always on top' option.
+
+This even works on some windows that don't have a title bar, such as Firefox's Picture-In-Picture videos.
+
+### Changing window opacity without this extension
+Cinnamon also has a built-in way to change window opacity. You can enable it in System Settings -> Windows -> Titlebar. Under Actions, set Action on title bar with mouse scroll = Adjust opacity. Then you can adjust opacity with the scroll wheel while hovering over the title bar.
+
+This however can be less convenient and much less precise, and it doesn't work for Picture-In-Picture. Opacity Slider works with or without this option enabled.

opacity-slider@neatnit/files/opacity-slider@neatnit/extension.js

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+const PopupMenu = imports.ui.popupMenu;
+const WindowMenu = imports.ui.windowMenu;
+const St = imports.gi.St;
+const gettext = imports.gettext;
+const GLib = imports.gi.GLib;
+
+
+let isEnabled = false, isInstalled = false;
+let base_buildMenu, my_buildMenu;
+let uuid;
+
+// This extension creates a slider for adjusting a window's opacity, and adds it
+// to the context menu when right-clicking a window's title bar.
+// We do this by replacing the funciton that builds the menu, calling the original,
+// and then adding our stuff before returning.
+// Ideally, there would be a cleaner way to add custom actions to this menu, but for
+// now this is the only way.
+
+
+// Some housekeeping
+function init(metadata) {
+    uuid = metadata.uuid;
+    gettext.bindtextdomain(uuid, GLib.get_home_dir() + "/.local/share/locale");
+}
+
+function _(str) {
+	let customTranslation = gettext.dgettext(uuid, str);
+	if(customTranslation !== str) {
+		return customTranslation;
+	}
+	return gettext.gettext(str);
+}
+
+let log = function(text) {
+    global.log("[" + uuid + "]: " + text);
+}
+
+let logW = function(text) {
+    global.logWarning("[" + uuid + "]: " + text);
+}
+
+
+// Conversions between slider value and opacity value
+const opacity_max = 255;
+const opacity_min = 26;
+
+function sliderValueFromOpacity(opacity) {
+    return Math.max(0, Math.min(1, (opacity - opacity_min) / (opacity_max - opacity_min)));
+}
+
+function opacityFromSliderValue(value) {
+    return Math.max(0, Math.min(255, Math.round( (value * (opacity_max-opacity_min) ) + opacity_min )));
+}
+
+
+// add a slider to a menu
+// variant of WindowMenu.prototype.addAction, but that adds a slider instead of a MnemonicLeftOrnamentedMenuItem
+function addSlider(to_menu, value, callback) {
+    let menuItem = new PopupMenu.PopupSliderMenuItem(value);
+    to_menu.addMenuItem(menuItem, to_menu.numMenuItems - 2); // num-2 to add before the Close action
+
+    menuItem.connect('value-changed', callback );
+
+    // this._items is used for mnemonics
+    // before you uncomment the next line you must extend PopupSliderMenuItem and implement stuff
+    // see Cinnamon's windowMenu.js: https://github.com/linuxmint/cinnamon/blob/master/js/ui/windowMenu.js
+
+    //this._items.push(menuItem); 
+
+    return menuItem;
+}
+
+
+
+function install() {
+    // install ourselves by diverting the WindowMenu internal function
+    // hacky as hell!
+
+    base_buildMenu = WindowMenu.WindowMenu.prototype._buildMenu;
+
+    my_buildMenu = function(window, ...args) {
+        // Creating a right-click menu
+
+        // Build the normal menu
+        const retval = base_buildMenu.call(this, window, ...args);
+
+        // If we're enabled, create our extra slider 
+        if (isEnabled) {
+            // Add separator
+            // The position this.numMenuItems-2 adds the item before the last item ("Close")
+            this.addMenuItem(new PopupMenu.PopupSeparatorMenuItem(), this.numMenuItems - 2);
+
+            // Add label
+            const label = new PopupMenu.PopupMenuItem(_("Opacity") + ": ???");
+            this.addMenuItem(label, this.numMenuItems - 2);
+
+            // Function to update the label's text
+            function updateLabel(opacity) {
+                label.setLabel(_("Opacity") + ": " + Math.floor(100*opacity/255).toString() + "%")
+            }
+
+            // Use current opacity to set label text
+            const initial_opacity = window.get_opacity();
+            updateLabel(initial_opacity);
+
+            // Create the slider
+            let slider = addSlider.call(this, this, sliderValueFromOpacity(initial_opacity), (sl, value) => {                
+                // callback: update opacity by slider value
+
+                const opacity = opacityFromSliderValue(value);
+
+                window.set_opacity(opacity);
+
+                updateLabel(opacity);
+            } );
+
+
+            // For both new menu entries, add empty ornament
+            // TODO: add icon too. See MnemonicLeftOrnamentedMenuItem._init in windowMenu.js
+            label.addActor(new St.Bin(), {position: 0});
+            slider.addActor(new St.Bin(), {position: 0});            
+        }
+
+        return retval;
+    }
+
+    log("overriding WindowMenu.prototype._buildMenu");
+    WindowMenu.WindowMenu.prototype._buildMenu = my_buildMenu;
+    isInstalled = true;
+}
+
+function tryUninstall() {
+    // Try to revert the method we overrode to what it was before
+    // We can only do this if no one else overrode it after us
+    // (unless they also cleaned up after themselves like we're doing here)
+    if (WindowMenu.WindowMenu.prototype._buildMenu == my_buildMenu) {
+        // We are clear to undo!
+        log("reverting WindowMenu.prototype._buildMenu to former value")
+        WindowMenu.WindowMenu.prototype._buildMenu = base_buildMenu;
+        isInstalled = false;
+
+        // allow garbage collection
+        base_buildMenu = undefined;
+        my_buildMenu = undefined;
+    } else {
+        logW("cannot revert WindowMenu.prototype._buildMenu: it has been overridden elsewhere")
+    }
+}
+
+function enable() {
+    isEnabled = true;
+
+    if (!isInstalled) {
+        install();
+    }
+}
+
+function disable() {
+    isEnabled = false;
+
+    if (isInstalled) {
+        tryUninstall();
+    }
+}

opacity-slider@neatnit/files/opacity-slider@neatnit/metadata.json

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+{
+    "uuid": "opacity-slider@neatnit",
+    "name": "Opacity Slider",
+    "version": "1.0.0",
+    "description": "Change a window's opacity from the title bar right-click menu.",
+    "url": "https://codeberg.org/NeatNit/cinnamon-opacity-slider",
+    "author": "NeatNit",
+    "cinnamon-version": ["5.6", "6.0"]
+}

opacity-slider@neatnit/files/opacity-slider@neatnit/po/opacity-slider@neatnit.pot

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+# SOME DESCRIPTIVE TITLE.
+# This file is put in the public domain.
+# FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
+#
+#, fuzzy
+msgid ""
+msgstr ""
+"Project-Id-Version: opacity-slider@neatnit 1.0.0\n"
+"Report-Msgid-Bugs-To: https://github.com/linuxmint/cinnamon-spices-"
+"extensions/issues\n"
+"POT-Creation-Date: 2024-07-21 03:08+0300\n"
+"PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
+"Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
+"Language-Team: LANGUAGE <[email protected]>\n"
+"Language: \n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+
+#: extension.js:94 extension.js:99
+msgid "Opacity"
+msgstr ""
+
+#. metadata.json->name
+msgid "Opacity Slider"
+msgstr ""
+
+#. metadata.json->description
+msgid "Change a window's opacity from the title bar right-click menu."
+msgstr ""

opacity-slider@neatnit/info.json

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+{
+    "author": "NeatNit",
+    "license": "GPL-3.0+"
+}