In Gulp 4, which we use for years now, the `gulp.src()` function
supports the `removeBOM` option to disable the default BOM stripping,
so this commit uses that to get rid of our `vinyl-fs` dependency.
Note that this actually makes disabling BOM stripping work again. It's
currently broken because in `vinyl-fs` 3, that we already use since 2018
in commit 95de23e, the `stripBOM` option was renamed to `removeBOM`, so
the current code doesn't actually disable BOM stripping which we now
confirmed and sadly broke for years without anyone noticing. Most likely
this is because the BOM is not required for UTF-8 documents, but while
not necessary it also can't hurt to have it for tools that use it to
determine if a document is UTF-8.
*Please note:* This only removes the preference itself, however both the viewer-option and the actual implementation is still available.
The `useOnlyCssZoom` functionality was only ever used, by default, in the PDF Viewer for the B2G/FirefoxOS project (which was abandoned years ago). Given that CSS-only zooming can easily make the document look blurry even at low zoom levels, this functionality was only intended for low-powered mobile devices.
Hence it seems reasonable to remove the `useOnlyCssZoom` preference now, since neither the default viewer nor the GeckoView-specific viewer uses this functionality.
Trying to update Stylelint to version `15.10.1`, and beyond, broke linting. Looking at the changes the issue appears to be that the `bin/stylelint.js` file was replaced with `bin/stylelint.mjs` instead, which our `gulp lint` runner wasn't able to automatically find; see https://github.com/stylelint/stylelint/compare/15.10.0...15.10.1
When the flag is set, the appearance has to be generated from the value so it's
useless/meaningless to extract the content from the existing appearance.
When a pdf has /NeedAppearances set to true, the annotation appearance must be
generated from its value and we must take into account the hasOwnCanvas property.
*Please note:* I'm not aware of any bugs caused by this, however that might be more luck than anything else.
In PR 16392 the `incrementalUpdate` function, and all of its various helpers, were made asynchronous. However the call-site in `src/core/worker.js` wasn't updated, which means that we currently reset temporary XRef-entries while saving is ongoing.
By leveraging import maps we can get rid of *most* of the remaining `require`-calls in the `src/display/`-folder, since we should strive to use modern `import`-statements wherever possible.
The only remaining cases are Node.js-specific dependencies, since those seem very difficult to convert unless we start producing a bundle *specifically* for Node.js environments.
With the changes in the previous patch the `isNodeJS`-helper no longer needs to live in its own file, which helps get rid of a closure in the *built* files.
In the last couple of years we've been quicker to remove support for older browsers/environments, which means that at this point in time we don't bundle that many polyfills. (The polyfills are also generally simpler nowadays, ever since we removed support for e.g. Internet Explorer.)
Rather than having to *manually* handle the polyfills, we can actually let Babel take care of bundling the necessary polyfills for us; please refer to https://babeljs.io/docs/babel-preset-env
The only exception here is the Node.js-specific compatibility-code, which is moved into the `src/display/node_utils.js` file. This ought to be fine since workers are not available/used in Node.js-environments.
*Please note:* For the `legacy`-builds this will increase the size of the *built* files, however that seems like a very small price to pay in order to simplify maintenance of the general PDF.js library.
