firefox-extensions: add default-zoom so that new tabs are readable by default

hosts/common/programs/firefox/addons.nix

@@ -27,6 +27,9 @@ in
       #   package = pkgs.firefox-extensions.ctrl-shift-c-should-copy;
       #   enable = lib.mkDefault false;  # prefer patching firefox source code, so it works in more places
       # };
+      default-zoom = {
+        enable = lib.mkDefault true;
+      };
       # ether-metamask = {
       #   enable = lib.mkDefault false;  # until i can disable the first-run notification
       # };

hosts/common/programs/firefox/default.nix

@@ -248,6 +248,8 @@ in
       // uidensity=2 gives more padding around UI elements.
       // source: <https://codeberg.org/user0/Mobile-Friendly-Firefox>
       defaultPref("browser.uidensity", 2);
+      // layout.css.devPixelsPerPx: acts as a global scale (even for the chrome)
+      // defaultPref("layout.css.devPixelsPerPx", 1.5);
 
       // open external URIs/files via xdg-desktop-portal.
       defaultPref("widget.use-xdg-desktop-portal.mime-handler", 1);

pkgs/by-name/firefox-extensions/default-zoom/background.js

@@ -0,0 +1,24 @@
+// simplified implementation of <https://github.com/jamielinux/default-zoom>
+//
+// XXX(2024-12-01): this implementation works for any tabs loaded with ctrl+t, and ctrl+l.
+// it works for the homepage too, except for a first-run edge case wherein the homepage is loaded
+// before any extensions are loaded
+//
+let defaultZoom = 2.0;
+
+function setZoom(tabId, changeInfo) {
+  if (changeInfo.status) {
+    const gettingZoom = browser.tabs.getZoom(tabId);
+    gettingZoom.then((currentZoom) => {
+      if (defaultZoom !== 1 && currentZoom === 1) {
+        browser.tabs.setZoom(tabId, defaultZoom);
+      }
+    });
+  }
+}
+
+browser.tabs.onCreated.addListener((tab) => {
+  browser.tabs.setZoom(tab.id, defaultZoom);
+});
+
+browser.tabs.onUpdated.addListener(setZoom);

pkgs/by-name/firefox-extensions/default-zoom/default.nix

@@ -0,0 +1,27 @@
+# inlined/simplified version of <https://github.com/jamielinux/default-zoom>
+{
+  stdenvNoCC,
+  zip,
+}:
+stdenvNoCC.mkDerivation {
+  pname = "default-zoom";
+  version = "0.1";
+  src = ./.;
+
+  nativeBuildInputs = [ zip ];
+
+  buildPhase = ''
+    runHook preBuild
+    zip -j firefox.zip \
+      background.html background.js manifest.json
+    runHook postBuild
+  '';
+
+  installPhase = ''
+    runHook preInstall
+    install firefox.zip $out
+    runHook postInstall
+  '';
+
+  passthru.extid = "@default-zoom";
+}

pkgs/by-name/firefox-extensions/default-zoom/manifest.json

@@ -0,0 +1,17 @@
+{
+  "manifest_version": 2,
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "@default-zoom"
+    }
+  },
+  "name": "Default zoom",
+  "description": "statically configure a default zoom value for new tabs",
+  "version": "0.1.0",
+  "background": {
+    "scripts": [
+      "background.js"
+    ]
+  },
+  "permissions": []
+}

pkgs/by-name/firefox-extensions/package.nix

@@ -119,6 +119,7 @@ let
       browserpass-extension = callPackage ./browserpass-extension { };
       bypass-paywalls-clean = callPackage ./bypass-paywalls-clean { };
       ctrl-shift-c-should-copy = callPackage ./ctrl-shift-c-should-copy { };
+      default-zoom = callPackage ./default-zoom { };
       firefox-xdg-open = callPackage ./firefox-xdg-open { };
       i-still-dont-care-about-cookies = callPackage ./i-still-dont-care-about-cookies { };
       # open-in-mpv = callPackage ./open-in-mpv { };