Given that `ImageData` has been supported for many years in all browsers, see [MDN](https://developer.mozilla.org/en-US/docs/Web/API/ImageData#browser_compatibility), we have a `typeof` check that's only necessary in Node.js environments.
Since the `@napi-rs/canvas` package provides that functionality, we can thus add an `ImageData` polyfill which allows us to ever so slightly simplify the code.
The `@napi-rs/canvas` package has fewer dependencies, which should *hopefully* make installing and using it easier for `pdfjs-dist` end-users. (Over the years we've seen, repeatedly, that `canvas` can be difficult to install successfully.)
Furthermore, this package includes more functionality (such as `Path2D`) which reduces the overall number of dependencies in the PDF.js project.
One point to note is that `@napi-rs/canvas` is a fair bit newer than `canvas`, and has a lot fewer users, however looking at the commit history it does seem to be actively maintained.
Note that I've successfully tested the [Node.js examples](https://github.com/mozilla/pdf.js/tree/master/examples/node), in particular the `pdf2png` one, with this patch applied and things appear to work fine.
Please see:
- https://www.npmjs.com/package/@napi-rs/canvas
- https://github.com/Brooooooklyn/canvas
Fixes https://github.com/mozilla/pdf.js/issues/18957https://github.com/mozilla/pdf.js/pull/18682 introduced a regression that causes the following error:
```
Uncaught TypeError: Failed to construct 'Headers': Invalid name
at PDFNetworkStreamFullRequestReader._onHeadersReceived (pdf.mjs:10214:29)
at NetworkManager.onStateChange (pdf.mjs:10103:22)
```
The mentioned PR replaced a call to `getResponseHeader()` with `getAllResponseHeaders()` without handling cases where it may return null or an empty string. Quote from the [docs](https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/getAllResponseHeaders#return_value):
> Returns:
>
>A string representing all of the response's headers (except those whose field name is Set-Cookie) separated by CRLF, or null if no response has been received. If a network error happened, an empty string is returned.
Run the following code and observe the error in the console. Note that the URL is intentionally set to an invalid value to simulate network error
```js
<script src="//mozilla.github.io/pdf.js/build/pdf.mjs" type="module"></script>
<script type="module">
var url = 'blob:';
pdfjsLib.GlobalWorkerOptions.workerSrc = '//mozilla.github.io/pdf.js/build/pdf.worker.mjs';
var loadingTask = pdfjsLib.getDocument(url);
loadingTask.promise
.then((pdf) => console.log('PDF loaded'))
.catch((reason) => console.error(reason));
</script>
```
The problem with the referenced PDF document has nothing to do with invalid dates, as the issue seems to suggest, but rather with the fact that it has neither an XRef table nor a trailer dictionary.
Given that crucial parts of the internal document structure is missing, you might argue that it's not really a PDF document.
In an attempt to support this kind of corruption, we'll simply iterate through all (previously found) XRef entries and pick one that *might* be a valid /Root dictionary.
There's obviously no guarantee that this works, and it might not be fast in larger PDF documents, but at least it cannot be any worse than *immediately* throwing `InvalidPDFException` as we previously did here.
*Please note:* I'm totally fine with this patch being rejected, since it's somewhat questionable if we should actually attempt to support "PDF documents" with this level of corruption.
- This helper function has only a single call-site, and the function is fairly short.
- It'll only be invoked if range requests are *disabled*, or if the entire PDF manages to load *before* the headers are resolved (which is very unlikely).
Hence, by default, this helper function is not invoked.
- By inlining the code we're able to utilize the existing error-handling at the call-site, rather than having to duplicate it, which further reduces the size of this code.
Finally, while slightly unrelated, this patch also adds optional chaining in one spot in the file (PR 16424 follow-up).
I discovered that doing skip-cache re-reloading of https://opensource.adobe.com/dc-acrobat-sdk-docs/pdfstandards/PDF32000_2008.pdf would *intermittently* cause (some of) the AnnotationLayers to break with errors printed in the console (see below).
In hindsight this bug is really obvious, however it took me quite some time to find it, since the `StructTreePage.prototype.serializable` getter will lookup various data and all of those cases can fail during loading when streaming and/or range requests are being used.
Finally, to prevent any future errors, ensure that the viewer won't break in these sort of situations.
```
Uncaught (in promise)
Object { message: "Missing data [19098296, 19098297)", name: "UnknownErrorException", details: "MissingDataException: Missing data [19098296, 19098297)", stack: "BaseExceptionClosure@resource://pdf.js/build/pdf.mjs:453:29\n@resource://pdf.js/build/pdf.mjs:456:2\n" }
viewer.mjs:8801:55
\#renderAnnotationLayer: "UnknownErrorException: Missing data [17552729, 17552730)". viewer.mjs:8737:15
Uncaught (in promise)
Object { message: "Missing data [17552729, 17552730)", name: "UnknownErrorException", details: "MissingDataException: Missing data [17552729, 17552730)", stack: "BaseExceptionClosure@resource://pdf.js/build/pdf.mjs:453:29\n@resource://pdf.js/build/pdf.mjs:456:2\n" }
viewer.mjs:8801:55
```
- Over time the number and size of these factories have increased, especially the `DOMFilterFactory` class, and this split should thus aid readability/maintainability of the code.
- By introducing a couple of new import maps we can avoid bundling the `DOMCMapReaderFactory`/`DOMStandardFontDataFactory` classes in the Firefox PDF Viewer, since they are dead code there given that worker-thread fetching is always being used.
- This patch has been successfully tested, by running `$ ./mach test toolkit/components/pdfjs/`, in a local Firefox artifact-build.
*Note:* This patch reduces the size of the `gulp mozcentral` output by `1.3` kilo-bytes, which isn't a lot but still cannot hurt.
This way we can directly throw Errors, rather than having to "manually" return rejected Promises, which is ever so slightly shorter.
Also, since `useWorkerFetch` is always true in MOZCENTRAL builds these message-handlers should not be invoked there.
One goal is to make the code for drawing with the Ink tool similar to the one to free highlighting:
it doesn't really make sense to have so different ways to do almost the same thing.
When the zoom level is high, it'll avoid to create a too big canvas covering all the page which consume
more memory, makes the drawing very slow and the overall user xp pretty bad.
A second goal is to be able to easily implement more drawing tools where we would just have to implement
how to draw from the pointer coordinates.
We can convert the handler to an `async` function, which removes the need to create a temporary Promise here.
Given the age of this code it shouldn't hurt to simplify it a little bit.
This allows using the new methods in browsers that support them, e.g. Firefox 133+, while still providing fallbacks where necessary; see https://github.com/tc39/proposal-arraybuffer-base64
*Please note:* These are not actual polyfills, but only implements what we need in the PDF.js code-base. Eventually this patch should be reverted, once support is generally available.
- Add explicit `length` validation of the /ID entries. Given the `EMPTY_FINGERPRINT` constant we're already *implicitly* assuming a particular length.
- Move the constants into the `fingerprints`-getter, since they're not used anywhere else.
- Replace the `hexString` helper function with the standard `Uint8Array.prototype.toHex` method; see https://github.com/tc39/proposal-arraybuffer-base64
This extends PR 13796 to also handle the case where sub-streams contain invalid data, i.e. anything that isn't a Stream, however please note that in these cases there's no guarantee that we'll render the page "correctly".
Note that Adobe Reader, i.e. the PDF reference implementation, cannot render the last page of the referenced PDF document.
Currently we manually localize and update the DOM-elements of the AltText-button, and it seems nicer to utilize Fluent "properly" for that task.
This can be achieved by introducing an explicit `span`-element on the AltText-button (similar to e.g. the regular toolbar-buttons), and adding a few more l10n-strings, since that allows just setting the `data-l10n-id`-attribute on all the relevant DOM-elements.
Finally, note how we no longer need to localize any strings eagerly when initializing the various editors.
Move the `ImageResizer._goodSquareLength` definition into the class itself, since the current position shouldn't be necessary, and also convert it into an actually private field.
It fixes#18956.
In the patch #18029, for performance reasons and because I thought it was useless, I deliberately chose to not fill the mask
with the backdrop color when it's full black: it was a bad idea.
So in this patch we always add the backdrop color to the mask.
After the binary CMap format had been added there were also some ideas about *maybe* providing other formats, see [here](https://github.com/mozilla/pdf.js/pull/8064#issuecomment-279730182), however that was over seven years ago and we still only use binary CMaps.
Hence it now seems reasonable to simplify the relevant code by removing `CMapCompressionType` and instead just use a boolean to indicate the type of the built-in CMaps.
Given that we've not shipped, nor used, anything except binary CMaps for years let's just cache them unconditionally (since that's a tiny bit less code).
The PDF document is clearly corrupt, since it has /FontFile2 entries that are Dictionaries which obviously isn't correct.
While there's obviously no guarantee that things will look perfect this way, actually rendering the text at all should be an improvement in general.
